POOLING AND SERVICING AGREEMENT

CREDIT SUISSE FIRST BOSTON MORTGAGE SECURITIES CORP.,

Depositor,

DLJ MORTGAGE CAPITAL, INC.,

Seller,

WELLS FARGO BANK N.A.,

Servicer, Master Servicer and Trust Administrator,

SELECT PORTFOLIO SERVICING, INC.,

Servicer and Modification Oversight Agent,

and

U.S. BANK NATIONAL ASSOCIATION,

Trustee

POOLING AND SERVICING AGREEMENT

Dated as of November 1, 2006

relating to

CSAB MORTGAGE-BACKED PASS-THROUGH CERTIFICATES, SERIES 2006-4

TABLE OF CONTENTS

ARTICLE I

DEFINITIONS

8

ARTICLE II

CONVEYANCE OF MORTGAGE LOANS; REPRESENTATIONS AND WARRANTIES

53

SECTION 2.01

Conveyance of Trust Fund.

53

SECTION 2.02

Acceptance by the Trustee.

57

SECTION 2.03

Representations and Warranties of the Seller, Master Servicer and Servicers.

60

SECTION 2.04

Representations and Warranties of the Depositor as to the Mortgage Loans.

62

SECTION 2.05

Delivery of Opinion of Counsel in Connection with Substitutions.

62

SECTION 2.06

Issuance of Certificates.

63

SECTION 2.07

REMIC Provisions.

63

SECTION 2.08

Covenants of the Master Servicer and each Servicer.

68

ARTICLE III

ADMINISTRATION AND SERVICING OF MORTGAGE LOANS

70

SECTION 3.01

Master Servicing and Servicing of Mortgage Loans.

70

SECTION 3.02

Sub-servicing; Enforcement of the Obligations of Sub-Servicers.

72

SECTION 3.03

Master Servicing by Master Servicer

74

SECTION 3.04

Trustee to Act as Master Servicer or Servicer.

75

SECTION 3.05

Collection of Mortgage Loans; Collection Accounts; Certificate Account.

75

SECTION 3.06

Establishment of and Deposits to Escrow Accounts; Permitted Withdrawals from

Escrow Accounts; Payments of Taxes, Insurance and Other Charges.

80

SECTION 3.07

Access to Certain Documentation and Information Regarding the Non-Designated

Mortgage Loans; Inspections.

81

SECTION 3.08

Permitted Withdrawals from the Collection Accounts and Certificate Account.

82

SECTION 3.09

Maintenance of Hazard Insurance; Mortgage Impairment Insurance and Mortgage

Guaranty Insurance Policy; Claims; Restoration of Mortgaged Property.

84

SECTION 3.10

Enforcement of Due-on-Sale Clauses; Assumption Agreements.

88

SECTION 3.11

Realization Upon Defaulted Mortgage Loans; Repurchase of Certain Mortgage

Loans.

89

SECTION 3.12

Trustee and Trust Administrator to Cooperate; Release of Mortgage Files.

93

SECTION 3.13

Documents, Records and Funds in Possession a Servicer to be Held for the Trust.

94

SECTION 3.14

Servicing Compensation and Master Servicing Compensation.

94

SECTION 3.15

Access to Certain Documentation.

95

SECTION 3.16

[Reserved].

95

SECTION 3.17

[Reserved].

95

SECTION 3.18

Maintenance of Fidelity Bond and Errors and Omissions Insurance.

95

SECTION 3.19

Special Serviced Mortgage Loans.

96

SECTION 3.20

Designated Mortgage Loans.

98

SECTION 3.21

Indemnification of Servicers and Master Servicer

99

SECTION 3.22

Assigned Prepayment Premiums.

99

ARTICLE IV

PAYMENTS AND STATEMENTS TO CERTIFICATEHOLDERS

101

SECTION 4.01

Priorities of Distribution.

101

SECTION 4.02

Allocation of Losses.

107

SECTION 4.03

Recoveries.

108

SECTION 4.04

Monthly Statements to Certificateholders.

108

SECTION 4.05

Servicers and Master Servicer to Cooperate.

109

SECTION 4.06

[Reserved].

110

SECTION 4.07

Basis Risk Reserve Fund.

110

SECTION 4.08

The Interest Rate Cap Agreements.

111

ARTICLE V

ADVANCES BY THE MASTER SERVICER AND SERVICERS

114

SECTION 5.01

Advances by the Master Servicer and Servicers.

114

ARTICLE VI

THE CERTIFICATES

116

SECTION 6.01

The Certificates.

116

SECTION 6.02

Registration of Transfer and Exchange of Certificates.

117

SECTION 6.03

Mutilated, Destroyed, Lost or Stolen Certificates.

122

SECTION 6.04

Persons Deemed Owners.

122

SECTION 6.05

Access to List of Certificateholders’ Names and Addresses.

123

SECTION 6.06

Maintenance of Office or Agency.

123

SECTION 6.07

Book-Entry Certificates.

123

SECTION 6.08

Notices to Clearing Agency.

124

SECTION 6.09

Definitive Certificates.

124

ARTICLE VII

THE DEPOSITOR, THE SELLER, THE MASTER SERVICER,  THE SERVICERS

AND ANY SPECIAL SERVICER

126

SECTION 7.01

Liabilities of the Seller, the Depositor, the Master Servicer, the Servicers and any

Special Servicer.

126

SECTION 7.02

Merger or Consolidation of the Seller, the Depositor, the Master Servicer, the

Servicers or any Special Servicer.

126

SECTION 7.03

Limitation on Liability of the Seller, the Depositor, the Master Servicer, the

Servicers, any Special Servicer and Others.

127

SECTION 7.04

Master Servicer and Servicer Not to Resign; Transfer of Servicing.

128

SECTION 7.05

Master Servicer, Seller, Special Servicer and Servicers May Own Certificates.

129

ARTICLE VIII

DEFAULT

130

SECTION 8.01

Events of Default.

130

SECTION 8.02

Master Servicer or Trust Administrator to Act; Appointment of Successor.

133

SECTION 8.03

Notification to Certificateholders.

135

SECTION 8.04

Waiver of Events of Default.

135

ARTICLE IX

CONCERNING THE TRUSTEE

136

SECTION 9.01

Duties of Trustee.

136

SECTION 9.02

Certain Matters Affecting the Trustee.

138

SECTION 9.03

Trustee Not Liable for Certificates or Mortgage Loans.

139

SECTION 9.04

Trustee May Own Certificates.

139

SECTION 9.05

Trustee’s Fees and Expenses.

140

SECTION 9.06

Eligibility Requirements for Trustee.

140

SECTION 9.07

Resignation and Removal of Trustee.

141

SECTION 9.08

Successor Trustee.

141

SECTION 9.09

Merger or Consolidation of Trustee.

142

SECTION 9.10

Appointment of Co-Trustee or Separate Trustee.

142

SECTION 9.11

Office of the Trustee.

143

ARTICLE X

CONCERNING THE TRUST ADMINISTRATOR

144

SECTION 10.01

Duties of Trust Administrator.

144

SECTION 10.02

Certain Matters Affecting the Trust Administrator.

146

SECTION 10.03

Trust Administrator Not Liable for Certificates or Mortgage Loans.

147

SECTION 10.04

Trust Administrator May Own Certificates.

148

SECTION 10.05

Trust Administrator’s Fees and Expenses.

148

SECTION 10.06

Eligibility Requirements for Trust Administrator.

149

SECTION 10.07

Resignation and Removal of Trust Administrator.

149

SECTION 10.08

Successor Trust Administrator.

150

SECTION 10.09

Merger or Consolidation of Trust Administrator.

151

SECTION 10.10

Appointment of Co-Trust Administrator or Separate Trust Administrator.

151

SECTION 10.11

Office of the Trust Administrator.

153

SECTION 10.12

Tax Return.

153

SECTION 10.13

[Reserved].

153

SECTION 10.14

Determination of Certificate Index.

153

ARTICLE XI

TERMINATION

154

SECTION 11.01

Termination upon Liquidation or Purchase of all Mortgage Loans.

154

SECTION 11.02

Determination of the Terminating Entity

155

SECTION 11.03

Procedure Upon Optional Termination or Auction Sale.

156

SECTION 11.04

Additional Termination Requirements.

158

ARTICLE XII

MISCELLANEOUS PROVISIONS

160

SECTION 12.01

Amendment.

160

SECTION 12.02

Recordation of Agreement; Counterparts.

162

SECTION 12.03

Governing Law.

163

SECTION 12.04

Intention of Parties.

163

SECTION 12.05

Notices.

164

SECTION 12.06

Severability of Provisions.

165

SECTION 12.07

Limitation on Rights of Certificateholders.

165

SECTION 12.08

Certificates Nonassessable and Fully Paid.

166

SECTION 12.09

Protection of Assets.

166

SECTION 12.10

Non-Solicitation.

166

ARTICLE XIII

CERTAIN MATTERS REGARDING THE CERTIFICATE INSURER

168

SECTION 13.01

Exercise of Rights of Holder of the Insured Certificates.

168

SECTION 13.02

Trustee and Trust Administrator to Act Solely with Consent of Certificate Insurer.

168

SECTION 13.03

Trust Fund and Accounts Held for Benefit of Certificate Insurer.

168

SECTION 13.04

Claims Upon the Policy; Policy Payments Account.

169

SECTION 13.05

Effect of Payments by Certificate Insurer; Subrogation.

172

SECTION 13.06

Notices to Certificate Insurer.

173

SECTION 13.07

Third Party Beneficiary.

173

SECTION 13.08

Trust Administrator to Hold the Policy.

173

SECTION 13.09

Termination of Certain of Certificate Insurer’s Rights.

174

SECTION 13.10

Survival of Indemnification.

174

ARTICLE XIV

EXCHANGE ACT REPORTING

174

SECTION 14.01

Commission Reporting.

174

SECTION 14.02

Form 10-D Reporting

175

SECTION 14.03

Form 10-K Reporting

176

SECTION 14.04

Form 8-K Reporting

177

SECTION 14.05

Delisting; Amendment; Late Filing of Reports

178

SECTION 14.06

Annual Statements of Compliance

179

SECTION 14.07

Annual Assessments of Compliance

180

SECTION 14.08

Accountant’s Attestation

181

SECTION 14.09

Sarbanes-Oxley Certification

182

SECTION 14.10

Indemnification

183

EXHIBITS

Exhibit A:

Form of Class A Certificate

A-1

Exhibit B:

[Reserved]

B-1

Exhibit C:

Form of Class AR Certificate

C-1

Exhibit D:

Form of Class X Certificates

D-1

Exhibit E:

Form of Class P Certificate

E-1

Exhibit F:

Form of Class M Certificate

F-1

Exhibit G:

[Reserved]

G-1

Exhibit H:

Form of Reverse of Certificates

H-1

Exhibit I:

Form of Servicer Information

I-1

Exhibit I-A:

SPS Reporting – Base Liquidation Report

I-A-1

Exhibit J:

Form of Initial Certification of Trustee

J-1

Exhibit K:

Form of Final Certification of Trustee

K-1

Exhibit L:

Form of Request for Release

L-1

Exhibit M:

Form of Transferor Certificate

M-1

Exhibit N-1

Form of Investment Letter

N-1-1

Exhibit N-2:

Form of Rule 144A Letter

N-2-1

Exhibit N-3:

Form of Regulation S Letter

N-3-1

Exhibit O:

Form of Investor Transfer Affidavit and Agreement

O-1

Exhibit P:

Form of Transfer Certificate

P-1

Exhibit Q:

Relevant Servicing Criteria

Q-1

Exhibit R:

Additional Form 10-D Disclosure

R-1

Exhibit S:

Form of Monthly Statement to Certificateholders

S-1

Exhibit T:

Form 8-K Disclosure Information

T-1

Exhibit U:

Form of Annual Certification

U-1

Exhibit V:

Additional Disclosure Notification

V-1

Exhibit W:

Additional Form 10-K Disclosure

W-1

Exhibit X:  

[Reserved]

X-1

Exhibit Y:  

Form of Officer’s Certificate

Y-1

SCHEDULES

Schedule I:

Mortgage Loan Schedule

I-1

Schedule IIA:

Representations and Warranties of DLJMC

IIA-1

Schedule IIB:

Representations and Warranties of Wells Fargo

IIB-1

Schedule IIC:

Representations and Warranties of SPS

IIC-1

Schedule IID:

Representations and Warranties of Wells Fargo

IID-1

Schedule III:

Representations and Warranties of DLJMC as to the Mortgage Loans

IIIA-1

THIS POOLING AND SERVICING AGREEMENT, dated as of November 1, 2006, is hereby executed by and among CREDIT SUISSE FIRST BOSTON MORTGAGE SECURITIES  CORP., a Delaware corporation, as depositor (the "Depositor"), DLJ MORTGAGE CAPITAL, INC. ("DLJMC"), a Delaware corporation, as seller (the "Seller"), WELLS FARGO BANK, N.A. ("Wells Fargo"), a national banking association, in its capacity as a servicer (a "Servicer"), as master servicer (the "Master Servicer") and as trust administrator (the "Trust Administrator"), SELECT PORTFOLIO SERVICING, INC. ("SPS"), a Utah corporation, in its capacity as a servicer (a "Servicer") and as modification oversight agent (the "Modification Oversight Agent") and U.S. BANK NATIONAL ASSOCIATION, a national banking association, as trustee (the "Trustee").  Capitalized terms used in this Agreement and not otherwise defined will have the meanings assigned to them in Article I below.

PRELIMINARY STATEMENT

As provided herein, the Trust Administrator shall elect that the Trust Fund (exclusive of the Supplemental Interest Trust, the Interest Rate Cap Accounts, the Interest Rate Cap Agreements and the Basis Risk Reserve Fund) be treated for federal income tax purposes as comprising two real estate mortgage investment conduits (each a "REMIC" or, in the alternative, "Subsidiary REMIC 1" and "Master REMIC").  Each Class of Certificates, other than the Class AR Certificates and exclusive of the right to receive amounts from the Basis Risk Reserve Fund or Supplemental Interest Trust in the case of each Certificate other than the Class X, Class P or Class AR Certificates, represents ownership of a regular interest in the Master REMIC for purposes of the REMIC Provisions.  The Class AR Certificates represent ownership of the sole class of residual interest in each REMIC for purposes of the REMIC Provisions.  The Master REMIC shall hold as its assets the Class P Reserve Fund and several classes of uncertificated Lower Tier Interests in Subsidiary REMIC 1, other than the Class LT1-R Interest, and each such Lower Tier Interest is hereby designated as a regular interest in Subsidiary REMIC 1.  Subsidiary REMIC 1 shall hold as its assets the Mortgage Loans and all collections and accounts related thereto.  The startup day for each REMIC created hereby for purposes of the REMIC Provisions is the Closing Date.  In addition, for purposes of the REMIC Provisions, the latest possible maturity date for each regular interest in each REMIC created hereby is the Distribution Date following the third anniversary of the scheduled maturity date of the Mortgage Loan having the latest scheduled maturity date as of the Cut-off Date.

Subsidiary REMIC 1

The following table sets forth (or describes) the class designation, interest rate, and initial principal amount for each uncertificated REMIC interest in Subsidiary REMIC 1:

________________

(1)

This interest has an initial principal balance equal to one-half of the initial Class Principal Balance of its Corresponding Class of Master REMIC Certificates.

(2)

This interest has an initial principal balance equal to the excess of (i) the aggregate of the Stated Principal Balances, as of the Cut-Off Date, of the Mortgage Loans less (ii) the sum of the initial principal balances of each other interest in Subsidiary REMIC 1.  

(3)

This interest shall bear interest at a per annum rate equal to the weighted average of the Net Mortgage Rates of the Mortgage Loans, adjusted to reflect any amounts paid in respect of Certificate Insurer Premiums.

(4)

The Class LT1-R Interest is the sole class of residual interest in Subsidiary REMIC 1.  It does not have an interest rate or a principal balance.  The Class AR Certificate represents beneficial ownership interest of the Class LT1-R Interest.

On each Distribution Date, the Trust Administrator shall allocate interest (in an amount equal to the aggregate amount of interest distributable on such Distribution Date with respect to the Mortgage Loans to the Interests in Subsidiary REMIC 1 at the rates shown above, pro rata, based on the amount of interest accrued on each such Interest for the related Interest Accrual Period, provided, however, that interest that accrues on the Class LT1-Q Interest shall be deferred in an amount equal to one-half of the increase, if any, in the Overcollateralization Amount for such Distribution Date.  Any interest so deferred shall itself bear interest at the interest rate for the Class LT1-Q Interest.  An amount equal to the interest so deferred shall be distributed as additional principal on the other Subsidiary REMIC 1 Interests having a principal balance in the manner described below.

On each Distribution Date, principal collections and realized losses with respect to the Mortgage Loans shall be allocated in the following order of priority:

(i)

  First, concurrently, to each Subsidiary REMIC 1 Interest with a Corresponding Class of Master REMIC Certificates until the principal balance of each such Subsidiary REMIC 1 Interest equals one-half of the Class Principal Amount of its Corresponding Class of Certificates immediately after such Distribution Date; and

(ii)  Second, to the Class LT1-Q Interests, any remaining amounts.

On each Distribution Date, Assigned Prepayment Premiums collected in connection with the Principal Prepayment of any Prepayment Premium Loan shall be distributed to the Class LT1-Q Interest.

Master REMIC

(1)

These Certificates are subject to a limitation on its Pass-Through Rate equal to the Net Funds Cap.  After the first possible Optional Termination Date for the Mortgage Loans, the per annum Pass-Through Rate on these Certificates, other than the Class A-1-A and Class A-2A Certificates, will increase by 0.50%, per annum, subject to the Net Funds Cap.

(2)

The initial Pass-Through Rate on the Class A-1-B Certificates is 5.4100% per annum.  On each Distribution Date after the first Distribution Date, the per annum Pass-Through Rate on these Certificates will be equal to the lesser of (i) the Certificate Index plus 0.090% and (ii) the Net Funds Cap.

(3)

The initial Pass-Through Rate on the Class A-1-C Certificates is 5.4600% per annum.  On each Distribution Date after the first Distribution Date, the per annum Pass-Through Rate on these Certificates will be equal to the lesser of (i) the Certificate Index plus 0.140% and (ii) the Net Funds Cap.

(4)

The initial Pass-Through Rate on the Class A-1-D Certificates is 5.3900% per annum.  On each Distribution Date after the first Distribution Date, the per annum Pass-Through Rate on these Certificates will be equal to the lesser of (i) the Certificate Index plus 0.070% and (ii) the Net Funds Cap.

(5)

The initial Pass-Through Rate on the Class A-2-B Certificates is 5.4800% per annum.  On each Distribution Date after the first Distribution Date and on or prior to the first possible Optional Termination Date, the per annum Pass-Through Rate on these Certificates will be equal to the least of (i) the Certificate Index plus 0.160%, (ii) the Net Funds Cap and (iii) 11.00% per annum.  

(6)

The initial Pass-Through Rate on the Class A-3 Certificates is 5.5400% per annum.  On each Distribution Date after the first Distribution Date and on or prior to the first possible Optional Termination Date, the per annum Pass-Through Rate on these Certificates will be equal to the least of (i) the Certificate Index plus 0.220%, (ii) the Net Funds Cap and (iii) 11.00% per annum.  

(7)

The initial Pass-Through Rate on the Class M-1-B Certificates is 5.6600% per annum.  On each Distribution Date after the first Distribution Date and on or prior to the first possible Optional Termination Date, the per annum Pass-Through Rate on these Certificates will be equal to the least of (i) the Certificate Index plus 0.340%, (ii) the Net Funds Cap and (iii) 11.00% per annum.  After the first possible Optional Termination Date, the per annum Pass-Through Rate on these Certificates will equal the least of (i) the Certificate Index plus 0.510%, (ii) the Net Funds Cap and (iii) 11.00% per annum.

(8)

The initial Pass-Through Rate on the Class M-2 Certificates is 5.7300% per annum.  On each Distribution Date after the first Distribution Date and on or prior to the first possible Optional Termination Date, the per annum Pass-Through Rate on these Certificates will be equal to the least of (i) the Certificate Index plus 0.410%, (ii) the Net Funds Cap and (iii) 11.00% per annum.  After the first possible Optional Termination Date, the per annum Pass-Through Rate on these Certificates will equal the least of (i) the Certificate Index plus 0.615%, (ii) the Net Funds Cap and (iii) 11.00% per annum.

(9)

The initial Pass-Through Rate on the Class M-3 Certificates is 5.7700% per annum.  On each Distribution Date after the first Distribution Date and on or prior to the first possible Optional Termination Date, the per annum Pass-Through Rate on these Certificates will be equal to the least of (i) the Certificate Index plus 0.450%, (ii) the Net Funds Cap and (iii) 11.00% per annum.  After the first possible Optional Termination Date, the per annum Pass-Through Rate on these Certificates will equal the least of (i) the Certificate Index plus 0.675%, (ii) the Net Funds Cap and (iii) 11.00% per annum.

(10)

The initial Pass-Through Rate on the Class M-5 Certificates is 6.2900% per annum.  On each Distribution Date after the first Distribution Date and on or prior to the first possible Optional Termination Date, the per annum Pass-Through Rate on these Certificates will be equal to the least of (i) the Certificate Index plus 0.970%, (ii) the Net Funds Cap and (iii) 11.00% per annum.  After the first possible Optional Termination Date, the per annum Pass-Through Rate on these Certificates will equal the least of (i) the Certificate Index plus 1.455%, (ii) the Net Funds Cap and (iii) 11.00% per annum.

(11)

The initial Pass-Through Rate on the Class M-6 Certificates is 2.600% per annum.  On each Distribution Date after the first Distribution Date and on or prior to the first possible Optional Termination Date, the per annum Pass-Through Rate on these Certificates will be equal to the least of (i) the Certificate Index plus 1.250%, (ii) the Net Funds Cap and (iii) 11.00% per annum.  After the first possible Optional Termination Date, the per annum Pass-Through Rate on these Certificates will equal the least of (i) the Certificate Index plus 1.750%, (ii) the Net Funds Cap and (iii) 11.00% per annum.

(12)

The initial Pass-Through Rate on the Class M-7 Certificates is 6.8200% per annum.  On each Distribution Date after the first Distribution Date and on or prior to the first possible Optional Termination Date, the per annum Pass-Through Rate on these Certificates will be equal to the least of (i) the Certificate Index plus 1.500%, (ii) the Net Funds Cap and (iii) 11.00% per annum.  After the first possible Optional Termination Date, the per annum Pass-Through Rate on these Certificates will equal the least of (i) the Certificate Index plus 2.000%, (ii) the Net Funds Cap and (iii) 11.00% per annum.

(13)

The initial Pass-Through Rate on the Class M-8 Certificates is 7.0700% per annum.  On each Distribution Date after the first Distribution Date and on or prior to the first possible Optional Termination Date, the per annum Pass-Through Rate on these Certificates will be equal to the least of (i) the Certificate Index plus 1.750%, (ii) the Net Funds Cap and (iii) 11.00% per annum.  After the first possible Optional Termination Date, the per annum Pass-Through Rate on these Certificates will equal the least of (i) the Certificate Index plus 2.250%, (ii) the Net Funds Cap and (iii) 11.00% per annum.

(14)

The Class AR Certificates shall represent beneficial ownership of the LT1-R Interest and of the residual interest in the Master REMIC.

(15)

The Class P Certificates will be entitled to all Assigned Prepayment Premiums.  For purposes of  compliance with REMIC Provisions, the Class P Certificates shall have a principal balance of $200.

(16)

The Class X Certificates shall represent ownership of a regular interest in the Master REMIC (the "Class X Interest").  The Class X Interest shall have an initial principal balance equal to $260.51 and the right to receive distributions in respect of such amount.  The Class X Interest shall also comprise a notional component, which has a notional balance that will at all times equal the aggregate of the class principal balances of the Subsidiary REMIC Interests in Subsidiary REMIC 1.  For each Distribution Date (and the related Accrual Period) this notional component shall bear interest at a per annum rate equal to the excess, if any, of (i) the weighted average of the interest rates on the Subsidiary REMIC Interests in Subsidiary REMIC 1, over (ii) the Adjusted Subsidiary REMIC 1 WAC.  In addition, for federal income tax purposes, the Class X Certificates shall represent ownership of the Basis Risk Reserve Fund and the Supplemental Interest Trust.  The initial Class X notional amount will be $748,985,360.51.

The foregoing REMIC structure is intended to cause all of the cash from the Mortgage Loans to flow through to the Master REMIC as cash flow on a REMIC regular interest, without creating any shortfall—actual or potential (other than for credit losses) to any REMIC regular interest.  To the extent that the structure is believed to diverge from such intention the Trust Administrator shall resolve ambiguities to accomplish such result and shall to the extent necessary rectify any drafting errors or seek clarification to the structure without Certificateholder approval (but with guidance of counsel) to accomplish such intention.

Set forth below are designations of Classes of Certificates to the categories used herein:

Book-Entry Certificates

All Classes of Certificates other than the Physical Certificates.

Class A Certificates

The Class A-1-A, Class A-1-B, Class A-1-C, Class A-1-D, Class A-2-A, Class A-2-B, Class A-3, Class A-4, Class A-5, Class A-6-A, Class A-6-B and Class AR Certificates.

ERISA-Restricted Certificates

Residual Certificates, Private Certificates and any Certificates that do not satisfy the applicable ratings requirement under the Underwriter’s Exemption.

Floating Rate Certificates

The Class A-1-B, Class A-1-C, Class A-1-D, Class A-2-B, Class A-3, Class M-1-B, Class M-2, Class M-3, Class M-5, Class M-6, Class M-7 and Class M-8 Certificates.

Senior Certificates

The Class A Certificates.

Subordinate Certificates

The Class M-1-A, Class M-1-B, Class M-2, Class M-3, Class M-4, Class M-5, Class M-6, Class M-7, Class M-8 and Class X Certificates.

Insured Certificates

The Class A-4 Certificates.

LIBOR Certificates

The Floating Rate Certificates.

Lockout Certificates

The Class A-6-A and A-6-B Certificates.

Notional Amount Certificates

The Class X Certificates.

Offered Certificates

All Classes of Certificates other than the Private Certificates.

Physical Certificates

The Residual Certificates and the Private Certificates.

Private Certificates

The Class X and Class P Certificates.

Regular Certificates

All Classes of Certificates other than the Residual Certificates.

Residual Certificates

The Class AR Certificates.

All covenants and agreements made by the Depositor herein are for the benefit and security of the Certificateholders and Certificate Insurer.  The Depositor is entering into this Agreement, and the Trustee is accepting the trusts created hereby and thereby, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged.  The principal balance of the Mortgage Loans as of the Cut-off Date is 748,985,360.51.

The parties hereto intend to effect an absolute sale and assignment of the Mortgage Loans to the Trustee for the benefit of Certificateholders under this Agreement.  However, the Depositor and the Seller will hereunder absolutely assign and, as a precautionary matter grant a security interest, in and to its rights, if any, in the related Mortgage Loans to the Trustee on behalf of Certificateholders to ensure that the interest of the Certificateholders hereunder in the Mortgage Loans is fully protected.

W I T N E S S E T H   T H A T:

In consideration of the mutual agreements herein contained, the Depositor, the Seller, the Master Servicer, the Servicers, the Trustee and the Trust Administrator agree as follows:

ARTICLE I

DEFINITIONS

Whenever used in this Agreement, the following words and phrases, unless the context otherwise requires, shall have the following meanings:

Accepted Servicing Practices :  With respect to any Mortgage Loan, those mortgage servicing practices of prudent mortgage lending institutions which service mortgage loans of the same type as such Mortgage Loan in the jurisdiction where the related Mortgaged Property is located.

Accountant’s Attestation :  The attestation required from an accountant pursuant to Section 14.08.

Accrual Period :  For any interest-bearing Class of Certificates (other than the LIBOR Certificates) and for each Class of Lower Tier Interests, and any Distribution Date, the calendar month immediately preceding that Distribution Date.   For the LIBOR Certificates, the period from and including the Distribution Date immediately preceding that Distribution Date (or the Closing Date, in the case of the first Accrual Period) to and including the day immediately preceding that Distribution Date.

Additional Data Remittance Date :  With respect to any Distribution Date and the Master Servicer, SPS or Wells Fargo, no later than twelve noon, five Business Days before the related Distribution Date.  

Additional Disclosure Notification :  As defined in Section 14.02.

Additional Form 10-D Disclosure :  As defined in Section 14.02.

Additional Form 10-K Disclosure :  As defined in Section 14.03.

Additional Servicer :  Each affiliate of the Depositor that Services any of the Mortgage Loans and each Person who is not an affiliate of the Depositor, who Services 10% or more of the Mortgage Loans (measured by aggregate Stated Principal Balance of the Mortgage Loans, annually at the commencement of the calendar year prior to the year in which an Item 1123 Certificate is required to be delivered).  For clarification purposes, the Master Servicer and the Trust Administrator are Additional Servicers.

Advance :  With respect to any Non-Designated Mortgage Loan, the payment required to be made by a Servicer or the Master Servicer, as applicable, with respect to any Distribution Date pursuant to Section 5.01.

With respect to any Countrywide Serviced Mortgage Loan, the payment required to be made by (i) Countrywide with respect to any Distribution Date pursuant to Section 11.19 of the Countrywide Servicing Agreement or (ii) the Master Servicer with respect to any Distribution Date pursuant to Section 3.20(b) of this Agreement.

Adjusted Subsidiary REMIC 1 WAC :  For any Distribution Date (and the related Accrual Period) the product of (i) two and (ii) the weighted average of the interest rates for such Distribution Date for the Class LT1-A-1-A, Class LT1-A-1-B, Class LT1-A-1-C, Class LT1-A-1-D, Class LT1-A-2-A, Class LT1-A-2-B, Class LT1-A-3, Class LT1-A-4, Class LT1-A-5, Class LT1-A-6-A, Class LT1-A-6-B, Class LT1-M-1-A, Class LT1-M-1-B, Class LT1-M-2, Class LT1-M-3, Class LT1-M-4, Class LT1-M-5, Class LT1-M-6, Class LT1-M-7, Class LT1-M-8, Class LT1-AR and Class LT1-Q Interests, weighted in proportion to their class principal balance as of the beginning of the related Accrual Period and computed by subjecting the rate on the Class LT1-Q to a cap of 0.00%, and by subjecting the rate on each of the Class LT1-A-1-A, Class LT1-A-1-B, Class LT1-A-1-C, Class LT1-A-1-D, Class LT1-A-2-A, Class LT1-A-2-B, Class LT1-A-3, Class LT1-A-4, Class LT1-A-5, Class LT1-A-6-A, Class LT1-A-6-B, Class LT1-M-1-A, Class LT1-M-1-B, Class LT1-M-2, Class LT1-M-3, Class LT1-M-4, Class LT1-M-5, Class LT1-M-6, Class LT1-M-7, Class LT1-M-8 and Class LT1-AR Interests to a cap that corresponds to the Pass-Through Rate for the Corresponding Class of Master REMIC Certificates; provided, however , that for each Class of LIBOR Certificates the Pass-Through Rate shall be multiplied by the quotient of (a) the actual number of days in the Accrual Period divided by (b) 30.

Adverse REMIC Event :  As defined in Section 2.07(f).

Aggregate Loan Balance:   As of any date of determination, the aggregate of the Stated Principal Balances of the Mortgage Loans, except as otherwise provided herein, as of the last day of the related Collection Period.

Agreement :  This Pooling and Servicing Agreement and all amendments or supplements hereto.

Ancillary Income :  All income derived from the Non-Designated Mortgage Loans, other than Servicing Fees, including but not limited to, late charges, Prepayment Premiums (other than Assigned Prepayment Premiums), fees received with respect to checks or bank drafts returned by the related bank for non-sufficient funds, assumption fees, optional insurance administrative fees and all other incidental fees and charges, and only with respect to SPS, any Qualified Substitute Mortgage Loan Excess Interest with respect to any Qualified Substitute Mortgage Loan for which a payment has been received or advanced during the related Collection Period.

Applied Loss Amount :  As to any Distribution Date, an amount equal to the excess, if any of (i) the aggregate Class Principal Balance of the Offered Certificates, after giving effect to all Realized Losses incurred with respect to Mortgage Loans during the Collection Period for such Distribution Date, payments of principal on such Distribution Date and any additions to the Class Principal Balance of the Offered Certificates on such Distribution Date pursuant to Section 4.03 over (ii) the Aggregate Loan Balance for such Distribution Date.

Appraised Value :  The appraised value of the Mortgaged Property based upon the appraisal made for the originator at the time of the origination of the related Mortgage Loan or the sales price of the Mortgaged Property at the time of such origination, whichever is less, or (i) with respect to any Mortgage Loan that represents a refinancing other than a Streamlined Mortgage Loan, the appraised value of the Mortgaged Property based upon the appraisal made at the time of such refinancing and (ii) with respect to any Streamlined Mortgage Loan, the appraised value of the Mortgaged Property based upon the appraisal made in connection with the origination of the Mortgage Loan being refinanced.

Assessment of Compliance :  The certification required pursuant to Section 14.07.

Assigned Prepayment Premium :  Any Prepayment Premium on a SPS Serviced Mortgage Loan, Wells Fargo Serviced Mortgage Loan and Wells Fargo Serviced CORE Mortgage Loans.

Assignment and Assumption Agreement :  That certain assignment and assumption agreement dated as of November 1, 2006, by and between DLJMC, as assignor and the Depositor, as assignee, relating to the Mortgage Loans.

Assignment of Mortgage : An assignment of mortgage, notice of transfer or equivalent instrument, in recordable form (excepting therefrom, if applicable, the mortgage recordation information which has not been required pursuant to Section 2.01 hereof or returned by the applicable recorder’s office and/or the assignee’s name), which is sufficient under the laws of the jurisdiction wherein the related Mortgaged Property is located to reflect of record the sale of the Mortgage, which assignment, notice of transfer or equivalent instrument may be in the form of one or more blanket assignments covering Mortgages secured by Mortgaged Properties located in the same county, if permitted by law.

Assignment of Proprietary Lease :  With respect to a Cooperative Loan, the assignment or mortgage of the related Proprietary Lease from the Mortgagor to the originator of the Cooperative Loan.

Auction Purchaser :  As defined in Section 11.01.

Balloon Loan :  Any Mortgage Loan that, by its terms, does not fully amortize the principal balance thereof by its stated maturity and requires a payment at the stated maturity larger than the monthly payments due thereunder.

Bankruptcy Code :  The United States Bankruptcy Code, as amended from time to time (11 U.S.C. §§ 101 et seq.).

Basis Risk Reserve Fund :  The separate Eligible Account created and initially maintained by the Trust Administrator pursuant to Section 4.07 in the name of the Trust Administrator for the benefit of the Certificateholders and designated "Wells Fargo Bank, N.A. in trust for registered holders of Credit Suisse First Boston Mortgage Securities Corp., CSAB Mortgage-Backed Trust 2006-4, CSAB Mortgage-Backed Pass-Through Certificates, Series 2006-4."  The Basis Risk Reserve Fund shall not be part of any REMIC.  Funds in the Basis Risk Reserve Fund shall be held in trust for the Certificateholders for the uses and purposes set forth in this Agreement.

Basis Risk Shortfall :  For any Class of Offered Certificates (other than the Class AR Certificates) and any Distribution Date, the sum of (i) the excess, if any, of the related Current Interest calculated on the basis of the applicable Pass-Through Rate of such Class of Certificates without regard to the application of the Net Funds Cap over the related Current Interest for that Distribution Date; (ii) any Basis Risk Shortfall remaining unpaid from prior Distribution Dates; and (iii) interest accrued during the related Accrual Period on the amount in clause (ii) calculated at a per annum rate equal to the applicable Pass-Through Rate of such Class of Certificates without regard to the application of the Net Funds Cap.

Beneficial Holder :  A Person holding a beneficial interest in any Certificate through a Participant or an Indirect Participant or a Person holding a beneficial interest in any Definitive Certificate.

Book-Entry Certificates :  As specified in the Preliminary Statement.

Book-Entry Form :  Any Certificate held through the facilities of the Depository.

Business Day :  Any day other than (i) a Saturday or a Sunday or (ii) a day on which banking institutions in New York or the state in which the office of the Master Servicer or any Servicer or the Corporate Trust Office of the Trustee or Trust Administrator are located are authorized or obligated by law or executive order to be closed.

Capitalization Reimbursement Amount :  For any Distribution Date, the aggregate of the amounts added to the Stated Principal Balances of the Mortgage Loans during the preceding calendar month representing reimbursements made to a Servicer on or prior to such Distribution Date in connection with the modification of such Mortgage Loan pursuant to Section 3.05.

Carryforward Interest :  For any Class of Offered Certificates and any Distribution Date, the sum of (1) the amount, if any, by which (x) the sum of (A) Current Interest for such Class for the immediately preceding Distribution Date and (B) any unpaid Carryforward Interest from the immediately preceding Distribution Date exceeds (y) the amount paid in respect of interest on such Class on such immediately preceding Distribution Date, and (2) interest on such amount for the related Accrual Period at the applicable Pass-Through Rate for such Distribution Date.

Cash Remittance Date :  With respect to any Distribution Date and (A) SPS, by 1:00 p.m. New York City time on the 7th calendar day preceding such Distribution Date, or if such 7th calendar day is not a Business Day, the Business Day immediately preceding such 7th calendar day, (B) Wells Fargo, by 4:00  p.m. New York City Time on the 18th calendar day of the month in which that Distribution Date occurs or, if such day is not a Business Day, the immediately following Business Day or (C) the Master Servicer, by 1:00 p.m. New York City time two Business Days preceding such Distribution Date.

Certificate :  Any Certificates executed and authenticated by the Trust Administrator on behalf of the Trustee for the benefit of the Certificateholders in substantially the form or forms attached as Exhibits A through H hereto.

Certificate Account :  The separate Eligible Account created and maintained with the Trust Administrator, or any other bank or trust company acceptable to the Rating Agencies which is incorporated under the laws of the United States or any state thereof pursuant to Section 3.05, which account shall bear a designation clearly indicating that the funds deposited therein are held in trust for the benefit of the Trust Administrator, as agent for the Trustee, on behalf of the Certificateholders or any other account serving a similar function acceptable to the Rating Agencies. Funds in the Certificate Account may (i) be held uninvested without liability for interest or compensation thereon or (ii) be invested at the direction of the Trust Administrator in Eligible Investments and reinvestment earnings thereon (net of investment losses) shall be paid to the Trust Administrator.  Funds deposited in the Certificate Account (exclusive of the amounts permitted to be withdrawn pursuant to Section 3.08(b)) shall be held in trust for the Certificateholders.

Certificate Balance :  With respect to any Certificate at any date, the maximum dollar amount of principal to which the Holder thereof is then entitled hereunder, such amount being equal to the Denomination thereof minus all distributions of principal previously made with respect thereto and, in the case of any Subordinate Certificates, reduced by any Applied Loss Amounts allocated to such Class on prior Distribution Dates pursuant to Section 4.02(a) plus the amount of any increase to the Certificate Balance of such Certificate pursuant to Section 4.03; provided , however , that solely for purposes of determining the Certificate Insurer Premium payable to the Certificate Insurer and the Certificate Insurer’s rights as subrogee to the Holders of the Insured Certificates, the Certificate Principal Balance of any Insured Certificate shall be deemed not to be reduced by any principal amounts paid to the Holder thereof from payments made by the Certificate Insurer under the Policy, unless such amounts have been reimbursed to the Certificate Insurer.

Certificate Index :  With respect to each Distribution Date and the LIBOR Certificates, the rate for one-month United States dollar deposits quoted on Telerate Page 3750 as of 11:00 A.M., London time, on the related Interest Determination Date relating to each Class of LIBOR Certificates.  If such rate does not appear on such page (or such other page as may replace that page on that service, or if such service is no longer offered, such other service for displaying LIBOR or comparable rates as may be reasonably selected by the Trust Administrator after consultation with DLJMC), the rate will be the Reference Bank Rate.  If no such quotations can be obtained and no Reference Bank Rate is available, the Certificate Index will be the Certificate Index applicable to the preceding Distribution Date.  On the Interest Determination Date immediately preceding each Distribution Date, the Trust Administrator shall determine the Certificate Index for the Accrual Period commencing on such Distribution Date and inform the Master Servicer of such rate.

Certificate Insurer :  Financial Security Assurance Inc., a financial guaranty insurance company, organized and created under the laws of the State of New York and its successors in interest.

Certificate Insurer Default :  As defined in Section 13.04(j).

Certificate Insurer Premium :  The Policy premium payable pursuant to Section 4.01 hereof for each Distribution Date in an amount equal to (i) the product of the Certificate Insurer Premium Rate and  the aggregate Class Principal Balance of the Insured Certificates immediately prior to such Distribution Date, divided by (ii) 12; provided that the Certificate Insurer Premium payable on the December 2006 Distribution Date is $3,246.08.

Certificate Insurer Premium Rate :  The per annum rate at which the Certificate Insurer Premium for the Policy is calculated, which shall be 0.07% per annum.

Certificate Register :  The register maintained pursuant to Section 6.02(a) hereof.

Certificateholder or Holder :  The Person in whose name a Certificate is registered in the Certificate Register.

Certification Parties :  As defined in Section 14.09.

Certifying Person :  As defined in Section 14.09.

Class :  All Certificates bearing the same Class designation as set forth in the Preliminary Statement.

Class A-1-B/A-1-C Interest Rate Cap Account :  The separate Eligible Account designated as such and created and maintained by the Trust Administrator pursuant to Section 4.08 hereof.  The Class A-1-B/A-1-C Interest Rate Cap Account shall be treated as an "outside reserve fund" under Treasury regulation Section 1.860G-2(h) and shall not be part of any REMIC.  Funds in the Class A-1-B/A-1-C Interest Rate Cap Account shall be held in trust in the Supplemental Interest Trust for the uses and purposes set forth in this Agreement.

Class A-1-B/A-1-C Interest Rate Cap Agreement :  The interest rate cap agreement relating to the Class A-1-B and Class A-1-C Certificates consisting of the ISDA Master Agreement (Multicurrency Cross-Border) and a schedule dated as of the Closing Date and the related confirmation thereto, between the Supplemental Interest Trust Trustee, on behalf of the Supplemental Interest Trust and the Interest Rate Cap Agreement Counterparty, and acknowledged and agreed by the Trust Administrator, which supplements, forms a part of, is subject to, and is governed by such ISDA Master Agreement, as such agreement may be amended and supplemented in accordance with its terms.

Class A-1-D Interest Rate Cap Account :  The separate Eligible Account designated as such and created and maintained by the Trust Administrator pursuant to Section 4.08 hereof.  The Class A-1-D Interest Rate Cap Account shall be treated as an "outside reserve fund" under Treasury regulation Section 1.860G-2(h) and shall not be part of any REMIC.  Funds in the Class A-1-D Interest Rate Cap Account shall be held in trust in the Supplemental Interest Trust for the uses and purposes set forth in this Agreement.

Class A-1-D Interest Rate Cap Agreement:   The interest rate cap agreement relating to the Class A-1-D Certificates consisting of the ISDA Master Agreement (Multicurrency Cross-Border) and a schedule dated as of the Closing Date and the related confirmation thereto, between the Supplemental Interest Trust Trustee, on behalf of the Supplemental Interest Trust and the Interest Rate Cap Agreement Counterparty, and acknowledged and agreed by the Trust Administrator, which supplements, forms a part of, is subject to, and is governed by such ISDA Master Agreement, as such agreement may be amended and supplemented in accordance with its terms.  

Class A-2-B  Interest Rate Cap Account :  The separate Eligible Account designated as such and created and maintained by the Trust Administrator pursuant to Section 4.08 hereof.  The Class A-2-B Interest Rate Cap Account shall be treated as an "outside reserve fund" under Treasury regulation Section 1.860G-2(h) and shall not be part of any REMIC.  Funds in the Class A-2-B Interest Rate Cap Account shall be held in trust in the Supplemental Interest Trust for the uses and purposes set forth in this Agreement.

Class A-2-B Interest Rate Cap Agreement:   The interest rate cap agreement relating to the Class A-2-B Certificates consisting of the ISDA Master Agreement (Multicurrency Cross-Border) and a schedule dated as of the Closing Date and the related confirmation thereto, between the Supplemental Interest Trust Trustee, on behalf of the Supplemental Interest Trust and the Interest Rate Cap Agreement Counterparty,  and acknowledged and agreed by the Trust Administrator, which supplements, forms a part of, is subject to, and is governed by such ISDA Master Agreement,  as such agreement may be amended and supplemented in accordance with its terms.

Class A-3 Interest Rate Cap Account :  The separate Eligible Account designated as such and created and maintained by the Trust Administrator pursuant to Section 4.08 hereof.  The Class A-3 Interest Rate Cap Account shall be treated as an "outside reserve fund" under Treasury regulation Section 1.860G-2(h) and shall not be part of any REMIC.  Funds in the Class A-3 Interest Rate Cap Account shall be held in trust in the Supplemental Interest Trust for the uses and purposes set forth in this Agreement.

Class A-3 Interest Rate Cap Agreement :  The interest rate cap agreement relating to the Class A-3 Certificates consisting of the ISDA Master Agreement (Multicurrency Cross-Border) and a schedule dated as of the Closing Date and the related confirmation thereto, between the Supplemental Interest Trust Trustee, on behalf of the Supplemental Interest Trust and the Interest Rate Cap Agreement Counterparty,  and acknowledged and agreed by the Trust Administrator, which supplements, forms a part of, is subject to, and is governed by such ISDA Master Agreement,  as such agreement may be amended and supplemented in accordance with its terms.

Class A-6 Available Principal Amount :  With respect to any Distribution Date, an amount equal to (i) if such Distribution Date is prior to the Stepdown Date or occurs when a Trigger Event is in effect, the Principal Payment Amount for that Distribution Date and (ii) if such Distribution Date is on or after the Stepdown Date and a Trigger Event is not in effect, the Senior Principal Payment Amount for that Distribution Date.

Class A-6 Calculation Percentage :  With respect to any Distribution Date, a fraction expressed as a percentage, the numerator of which is the aggregate Class Principal Balance of the Class A-6-A and Class A-6-B Certificates and the denominator of which is the aggregate Class Principal Balance of the Senior Certificates, in each case prior to giving effect to the distributions of principal on that Distribution Date.

Class A-6 Lockout Distribution Amount :  With respect to any Distribution Date, an amount equal to the product of (1) the applicable Class A-6 Lockout Percentage for that Distribution Date, (2) the Class A-6 Calculation Percentage for that Distribution Date and (3) the Class A-6 Available Principal Amount for that Distribution Date, but in no event will the Class A-6 Lockout Distribution Amount exceed (a) the outstanding aggregate Class Principal Balance of the Class A-6-A and Class A-6-B Certificates or (b) the Class A-6 Available Principal Amount for that Distribution Date.

Class A-6 Lockout Percentage :  With respect to any Distribution Date, the applicable percentage set forth below for that Distribution Date:

Class M-1 Principal Payment Amount :  For any Distribution Date on or after the Stepdown Date and as long as a Trigger Event is not in effect with respect to such Distribution Date, will be the amount, if any, by which (x) the sum of (i) the aggregate Class Principal Balance of the Senior Certificates after giving effect to payments on such Distribution Date and (ii) the aggregate Class Principal Balance of the Class M-1-A and Class M-1-B Certificates immediately prior to such Distribution Date exceeds (y) the lesser of (A) the product of (i) 91.48% and (ii) the Aggregate Loan Balance for such Distribution Date and (B) the amount, if any, by which (i) the Aggregate Loan Balance for such Distribution Date exceeds (ii) 0.50% of the Aggregate Loan Balance as of the Cut-off Date.

 Class M-1-B Interest Rate Cap Account :  The separate Eligible Account designated as such and created and maintained by the Trust Administrator pursuant to Section 4.08 hereof.  The Class M-1-B Interest Rate Cap Account shall be treated as an "outside reserve fund" under applicable treasury regulations and shall not be part of any REMIC.  Funds in the Class M-1-B Interest Rate Cap Account shall be held in trust in the Supplemental Interest Trust for the uses and purposes set forth in this Agreement.

Class M-1-B Interest Rate Cap Agreement:   The interest rate cap agreement relating to the Class M-1-B Certificates consisting of the ISDA Master Agreement (Multicurrency Cross-Border) and a schedule dated as of the Closing Date and the related confirmation thereto, between the Supplemental Interest Trust Trustee, on behalf of the Supplemental Interest Trust and the Interest Rate Cap Agreement Counterparty, and acknowledged and agreed by the Trust Administrator, which supplements, forms a part of, is subject to, and is governed by such ISDA Master Agreement, as such agreement may be amended and supplemented in accordance with its terms.

Class M-2 Interest Rate Cap Account :  The separate Eligible Account designated as such and created and maintained by the Trust Administrator pursuant to Section 4.08 hereof.  The Class M-2 Interest Rate Cap Account shall be treated as an "outside reserve fund" under applicable treasury regulations and shall not be part of any REMIC.  Funds in the Class M-2 Interest Rate Cap Account shall be held in trust in the Supplemental Interest Trust for the uses and purposes set forth in this Agreement.

Class M-2 Interest Rate Cap Agreement:   The interest rate cap agreement relating to the Class M-2 Certificates consisting of the ISDA Master Agreement (Multicurrency Cross-Border) and a schedule dated as of the Closing Date and the related confirmation thereto, between the Supplemental Interest Trust Trustee, on behalf of the Supplemental Interest Trust and the Interest Rate Cap Agreement Counterparty, and acknowledged and agreed by the Trust Administrator, which supplements, forms a part of, is subject to, and is governed by such ISDA Master Agreement, as such agreement may be amended and supplemented in accordance with its terms.

Class M-2 Principal Payment Amount:   For any Distribution Date on or after the Stepdown Date and as long as a Trigger Event is not in effect with respect to such Distribution Date, will be the amount, if any, by which (x) the sum of (i) the aggregate Class Principal Balance of the Senior Certificates and the Class M-1-A Certificates and Class M-1-B Certificates, in each case, after giving effect to payments on such Distribution Date and (ii) the aggregate Class Principal Balance of the Class M-2 Certificates immediately prior to such Distribution Date exceeds (y) the lesser of (A) the product of (i) 93.78% and (ii) the Aggregate Loan Balance for such Distribution Date and (B) the amount, if any, by which (i) the Aggregate Loan Balance for such Distribution Date exceeds (ii) 0.50% of the Aggregate Loan Balance as of the Cut-off Date.

Class M-3 Interest Rate Cap Account :  The separate Eligible Account designated as such and created and maintained by the Trust Administrator pursuant to Section 4.08 hereof.  The Class M-3 Interest Rate Cap Account shall be treated as an "outside reserve fund" under applicable treasury regulations and shall not be part of any REMIC.  Funds in the Class M-3 Interest Rate Cap Account shall be held in trust in the Supplemental Interest Trust for the uses and purposes set forth in this Agreement.

Class M-3 Interest Rate Cap Agreement:   The interest rate cap agreement relating to the Class M-3 Certificates consisting of the ISDA Master Agreement (Multicurrency Cross-Border) and a schedule dated as of the Closing Date and the related confirmation thereto, between the Supplemental Interest Trust Trustee, on behalf of the Supplemental Interest Trust and the Interest Rate Cap Agreement Counterparty, and acknowledged and agreed by the Trust Administrator, which supplements, forms a part of, is subject to, and is governed by such ISDA Master Agreement, as such agreement may be amended and supplemented in accordance with its terms.

Class M-3 Principal Payment Amount:   For any Distribution Date on or after the Stepdown Date and as long as a Trigger Event is not in effect with respect to such Distribution Date, will be the amount, if any, by which (x) the sum of (i) the aggregate Class Principal Balance of the Senior Certificates and the Class M-1-A Certificates, Class M-1-B Certificates and Class M-2 Certificates, in each case, after giving effect to payments on such Distribution Date and (ii) the Class Principal Balance of the Class M-3 Certificates immediately prior to such Distribution Date exceeds (y) the lesser of (A) the product of (i) 94.78% and (ii) the Aggregate Loan Balance for such Distribution Date and (B) the amount, if any, by which (i) the Aggregate Loan Balance for such Distribution Date exceeds (ii) 0.50% of the Aggregate Loan Balance as of the Cut-off Date.

Class M-4 Principal Payment Amount :  For any Distribution Date on or after the Stepdown Date and as long as a Trigger Event is not in effect with respect to such Distribution Date, will be the amount, if any, by which (x) the sum of (i) the aggregate Class Principal Balance of the Senior Certificates and the Class M-1-A Certificates, Class M-1-B Certificates, Class M-2 Certificates and Class M-3 Certificates, in each case, after giving effect to payments on such Distribution Date and (ii) the Class Principal Balance of the Class M-4 Certificates immediately prior to such Distribution Date exceeds (y) the lesser of (A) the product of (i) 95.58% and (ii) the Aggregate Loan Balance for such Distribution Date and (B) the amount, if any, by which (i) the Aggregate Loan Balance for such Distribution Date exceeds (ii) 0.50% of the Aggregate Loan Balance as of the Cut-off Date.

Class M-5 Interest Rate Cap Account :  The separate Eligible Account designated as such and created and maintained by the Trust Administrator pursuant to Section 4.08 hereof.  The Class M-5 Interest Rate Cap Account shall be treated as an "outside reserve fund" under applicable treasury regulations and shall not be part of any REMIC.  Funds in the Class M-5 Interest Rate Cap Account shall be held in trust in the Supplemental Interest Trust for the uses and purposes set forth in this Agreement.

Class M-5 Interest Rate Cap Agreement:   The interest rate cap agreement relating to the Class M-5 Certificates consisting of the ISDA Master Agreement (Multicurrency Cross-Border) and a schedule dated as of the Closing Date and the related confirmation thereto, between the Supplemental Interest Trust Trustee, on behalf of the Supplemental Interest Trust and the Interest Rate Cap Agreement Counterparty, and acknowledged and agreed by the Trust Administrator, which supplements, forms a part of, is subject to, and is governed by such ISDA Master Agreement, as such agreement may be amended and supplemented in accordance with its terms.

Class M-5 Principal Payment Amount :  For any Distribution Date on or after the Stepdown Date and as long as a Trigger Event is not in effect with respect to such Distribution Date, will be the amount, if any, by which (x) the sum of (i) the aggregate Class Principal Balance of the Senior Certificates and the Class M-1-A Certificates, Class M-1-B Certificates, Class M-2 Certificates, Class M-3 Certificates and Class M-4 Certificates, in each case, after giving effect to payments on such Distribution Date and (ii) the Class Principal Balance of the Class M-5 Certificates immediately prior to such Distribution Date exceeds (y) the lesser of (A) the product of (i) 96.28% and (ii) the Aggregate Loan Balance for such Distribution Date and (B) the amount, if any, by which (i) the Aggregate Loan Balance for such Distribution Date exceeds (ii) 0.50% of the Aggregate Loan Balance as of the Cut-off Date.

Class M-6 Interest Rate Cap Account :  The separate Eligible Account designated as such and created and maintained by the Trust Administrator pursuant to Section 4.08 hereof.  The Class M-6 Interest Rate Cap Account shall be treated as an "outside reserve fund" under applicable treasury regulations and shall not be part of any REMIC.  Funds in the Class M-6 Interest Rate Cap Account shall be held in trust in the Supplemental Interest Trust for the uses and purposes set forth in this Agreement.

Class M-6 Interest Rate Cap Agreement:   The interest rate cap agreement relating to the Class M-6 Certificates consisting of the ISDA Master Agreement (Multicurrency Cross-Border) and a schedule dated as of the Closing Date and the related confirmation thereto, between the Supplemental Interest Trust Trustee, on behalf of the Supplemental Interest Trust and the Interest Rate Cap Agreement Counterparty, and acknowledged and agreed by the Trust Administrator, which supplements, forms a part of, is subject to, and is governed by such ISDA Master Agreement, as such agreement may be amended and supplemented in accordance with its terms.

Class M-6 Principal Payment Amount :  For any Distribution Date on or after the Stepdown Date and as long as a Trigger Event is not in effect with respect to such Distribution Date, will be the amount, if any, by which (x) the sum of (i) the aggregate Class Principal Balance of the Senior Certificates and the Class M-1-A Certificates, Class M-1-B Certificates, Class M-2 Certificates, Class M-3 Certificates, Class M-4 Certificates and Class M-5 Certificates, in each case, after giving effect to payments on such Distribution Date and (ii) the Class Principal Balance of the Class M-6 Certificates immediately prior to such Distribution Date exceeds (y) the lesser of (A) the product of (i) 96.97% and (ii) the Aggregate Loan Balance for such Distribution Date and (B) the amount, if any, by which (i) the Aggregate Loan Balance for such Distribution Date exceeds (ii) 0.50% of the Aggregate Loan Balance as of the Cut-off Date.

Class M-7 Interest Rate Cap Account :  The separate Eligible Account designated as such and created and maintained by the Trust Administrator pursuant to Section 4.08 hereof.  The Class M-7 Interest Rate Cap Account shall be treated as an "outside reserve fund" under applicable treasury regulations and shall not be part of any REMIC.  Funds in the Class M-7 Interest Rate Cap Account shall be held in trust in the Supplemental Interest Trust for the uses and purposes set forth in this Agreement.

Class M-7 Interest Rate Cap Agreement:   The interest rate cap agreement relating to the Class M-7 Certificates consisting of the ISDA Master Agreement (Multicurrency Cross-Border) and a schedule dated as of the Closing Date and the related confirmation thereto, between the Supplemental Interest Trust Trustee, on behalf of the Supplemental Interest Trust and the Interest Rate Cap Agreement Counterparty, and acknowledged and agreed by the Trust Administrator, which supplements, forms a part of, is subject to, and is governed by such ISDA Master Agreement, as such agreement may be amended and supplemented in accordance with its terms.

Class M-7 Principal Payment Amount :  For any Distribution Date on or after the Stepdown Date and as long as a Trigger Event is not in effect with respect to such Distribution Date, will be the amount, if any, by which (x) the sum of (i) the aggregate Class Principal Balance of the Senior Certificates and the Class M-1-A Certificates, Class M-1-B Certificates, Class M-2 Certificates, Class M-3 Certificates, Class M-4 Certificates, Class M-5 Certificates and Class M-6 Certificates, in each case, after giving effect to payments on such Distribution Date and (ii) the Class Principal Balance of the Class M-7 Certificates immediately prior to such Distribution Date exceeds (y) the lesser of (A) the product of (i) 97.77% and (ii) the Aggregate Loan Balance for such Distribution Date and (B) the amount, if any, by which (i) the Aggregate Loan Balance for such Distribution Date exceeds (ii) 0.50% of the Aggregate Loan Balance as of the Cut-off Date.

Class M-8 Interest Rate Cap Account :  The separate Eligible Account designated as such and created and maintained by the Trust Administrator pursuant to Section 4.08 hereof.  The Class M-8 Interest Rate Cap Account shall be treated as an "outside reserve fund" under applicable treasury regulations and shall not be part of any REMIC.  Funds in the Class M-8 Interest Rate Cap Account shall be held in trust in the Supplemental Interest Trust for the uses and purposes set forth in this Agreement.

Class M-8 Interest Rate Cap Agreement:   The interest rate cap agreement relating to the Class M-8 Certificates consisting of the ISDA Master Agreement (Multicurrency Cross-Border) and a schedule dated as of the Closing Date and the related confirmation thereto, between the Supplemental Interest Trust Trustee, on behalf of the Supplemental Interest Trust and the Interest Rate Cap Agreement Counterparty, and acknowledged and agreed by the Trust Administrator, which supplements, forms a part of, is subject to, and is governed by such ISDA Master Agreement, as such agreement may be amended and supplemented in accordance with its terms.

Class M-8 Principal Payment Amount :  For any Distribution Date on or after the Stepdown Date and as long as a Trigger Event is not in effect with respect to such Distribution Date, will be the amount, if any, by which (x) the sum of (i) the aggregate Class Principal Balance of the Senior Certificates and the Class M-1-A Certificates, Class M-1-B Certificates, Class M-2 Certificates, Class M-3 Certificates, Class M-4 Certificates, Class M-5 Certificates, Class M-6 Certificates and Class M-7 Certificates, in each case, after giving effect to payments on such Distribution Date and (ii) the Class Principal Balance of the Class M-8 Certificates immediately prior to such Distribution Date exceeds (y) the lesser of (A) the product of (i) 98.90% and (ii) the Aggregate Loan Balance for such Distribution Date and (B) the amount, if any, by which (i) the Aggregate Loan Balance for such Distribution Date exceeds (ii) 0.50% of the Aggregate Loan Balance as of the Cut-off Date.

Class P Certificates :  As set forth in the Preliminary Statement.

Class P Reserve Fund :  The Eligible Account established pursuant to Section 4.01(f).

Class Principal Balance :  With respect to any Class of Certificates, other than the Notional Amount Certificates, and as to any date of determination, the aggregate of the Certificate Balances of all Certificates of such Class as of such date.

Class X Distributable Amount :  With respect to any Distribution Date, the excess of (i) the sum of (a) the amounts distributable on the Class X Interest on such Distribution Date, as described in the Preliminary Statement, and (b) amounts so distributable in all prior Accrual Periods over (ii) the sum of (a) amounts distributed with respect to the Class X Certificate pursuant to Section 4.01(d)(xii) on prior Distribution Dates (other than amounts distributed pursuant to Sections 4.07 through 4.08), and (b) any amounts deposited into the Basis Risk Reserve Fund on such Distribution Date or any prior Distribution Date.

Class X Interest :  As defined in the Preliminary Statement.

Clearing Agency :  An organization registered as a "clearing agency" pursuant to Section 17A of the Exchange Act, which initially shall be DTC.

Closing Date :  November 29, 2006.

Code :  The Internal Revenue Code of 1986, as amended.

Collection Account :  The separate accounts established and maintained by each Servicer in accordance with Section 3.05.

Collection Period :  With respect to each Distribution Date, the period commencing on the second day of the month preceding the month of the Distribution Date and ending on the first day of the month of the Distribution Date.

Commission :  The U.S. Securities and Exchange Commission.

Compensating Interest Payment :   

For any Distribution Date and SPS, with respect to the SPS Serviced Mortgage Loans, the lesser of (i) the aggregate Servicing Fee payable to SPS (for the purposes of this definition only the Servicing Fee Rate shall equal 0.25% per annum) in respect of the SPS Serviced Mortgage Loans for such Distribution Date and (ii) the aggregate Prepayment Interest Shortfall allocable to Payoffs and Curtailments with respect to SPS Serviced Mortgage Loans.

For any Distribution Date and Wells Fargo, with respect to the Wells Fargo Serviced Mortgage Loans or Wells Fargo Serviced CORE Mortgage Loan, the lesser of (i) the aggregate Servicing Fee payable to Wells Fargo (for purposes of this definition only the Servicing Fee Rate shall equal 0.25% per annum) in respect of the Wells Fargo Serviced Mortgage Loans or Wells Fargo Serviced CORE Mortgage Loans, as applicable, for such Distribution Date and (ii) the aggregate Prepayment Interest Shortfall allocable to Payoffs and Curtailments with respect to Wells Fargo Serviced Mortgage Loans or Wells Fargo Serviced CORE Mortgage Loans, as applicable.

For any Distribution Date and the Master Servicer, the Compensating Interest Payment shall be equal to:  

(a)

with respect to the SPS Serviced Mortgage Loans, the excess of (i) the Compensating Interest Payment required to be remitted by SPS for such Distribution Date over (ii) the amount of the Compensating Interest Payment actually remitted by SPS for such Distribution Date; and

(b)

with respect to the Wells Fargo Serviced Mortgage Loans, the excess of (i) the Compensating Interest Payment required to be remitted by Wells Fargo for such Distribution Date over (ii) the amount of the Compensating Interest Payment actually remitted by Wells Fargo for such Distribution Date.

(c)

with respect to the Wells Fargo Serviced CORE Mortgage Loans, the excess of (i) the Compensating Interest Payment required to be remitted by Wells Fargo for such Distribution Date over (ii) the amount of the Compensating Interest Payment actually remitted by Wells Fargo for such Distribution Date; and

(d)

with respect to the Countrywide Serviced Mortgage Loans, the excess of (i) the Prepayment Interest Shortfall Amount (as defined in the Countrywide Servicing Agreement) required to be remitted by Countrywide on the Remittance Date (as defined in the Countrywide Servicing Agreement) immediately preceding such Distribution Date over (ii) the amount of the Prepayment Interest Shortfall Amount (as defined in the Countrywide Servicing Agreement) actually remitted by Countrywide for such Distribution Date.

Controlling Person :  With respect to any Person, any other Person who "controls" such Person within the meaning of the Securities Act.

Cooperative Corporation :  With respect to any Cooperative Loan, the cooperative apartment corporation that holds legal title to the related Cooperative Property and grants occupancy rights to units therein to stockholders through Proprietary Leases or similar arrangements.

Cooperative Lien Search:  A search for (a) federal tax liens, mechanics’ liens, lis pendens, judgments of record or otherwise against (i) the Cooperative Corporation and (ii) the seller of the Cooperative Unit, (b) filings of Financing Statements and (c) the deed of the Cooperative Property into the Cooperative Corporation.

Cooperative Loan:  A Mortgage Loan that is secured by a first lien on and a perfected security interest in Cooperative Shares and the related Proprietary Lease granting exclusive rights to occupy the related Cooperative Unit in the building owned by the related Cooperative Corporation.

Cooperative Property:  With respect to any Cooperative Loan, all real property and improvements thereto and rights therein and thereto owned by a Cooperative Corporation including without limitation the land, separate dwelling units and all common elements.

Cooperative Shares:  With respect to any Cooperative Loan, the shares of stock issued by a Cooperative Corporation and allocated to a Cooperative Unit and represented by stock certificates.

Cooperative Unit :  With respect to any Cooperative Loan, a specific unit in a Cooperative Property.

Corporate Trust Office :  With respect to the Trustee, the designated office of the Trustee at which at any particular time its corporate trust business with respect to this Agreement shall be administered, which office at the date of the execution of this Agreement is located at 60 Livingston Avenue, Structured Finance EP-MN-WS3D, St. Paul, Minnesota 55107-2292, Attention:  Corporate Trust—Structured Finance.  With respect to the Trust Administrator, the designated office of the Trust Administrator at which at any particular time its corporate trust business with respect to this Agreement shall be administered, which office at the date of the execution of this Agreement is located at 9062 Old Annapolis Road, Columbia, Maryland 21045, Attention:  CSAB 2006-4, except for purposes of Section 6.06 and certificate transfer purposes, such term shall mean the office or agency of the Trust Administrator located at Wells Fargo Bank, National Association, Sixth Street and Marquette Avenue, Minneapolis, Minnesota  55479, Attention:  CSAB 2006-4.

Corresponding Classes of Certificates :  With respect to each Lower Tier Interest, any Class of Certificates appearing opposite such Lower Tier Interest in the Preliminary Statement.  

Countrywide :  Countrywide Home Loans Servicing LP, a Texas limited partnership, and its successors and assigns.

Countrywide Serviced Mortgage Loans :  The Mortgage Loans identified as such on the Mortgage Loan Schedule.

Countrywide Servicing Agreement : That certain Reconstituted Servicing Agreement dated as of November 1, 2006 among DLJMC, Countrywide, the Master Servicer, the Trustee and the Trust Administrator.

Current Interest :  For any Class of Offered Certificates (other than the Class AR Certificates) and any Distribution Date, the amount of interest accruing at the applicable Pass-Through Rate on the related Class Principal Balance of such Class during the related Accrual Period; provided , that if and to the extent that on any Distribution Date the Interest Remittance Amount is less than the aggregate distributions required pursuant to Section 4.01(a) without regard to this proviso as a result of Interest Shortfalls, then the Current Interest on each Class will be reduced, on a pro rata basis in proportion to the amount of Current Interest for each Class without regard to this proviso, by such Interest Shortfalls for such Distribution Date.

Curtailment :  Any payment of principal on a Mortgage Loan, made by or on behalf of the related Mortgagor, other than a Scheduled Payment, a prepaid Scheduled Payment or a Payoff, which is applied to reduce the outstanding Stated Principal Balance of the Mortgage Loan.

Custodial Agreements :  Those certain custodial agreements each dated as of November 1, 2006 among the Trustee, the Trust Administrator and either LaSalle Bank, National Association and Wells Fargo Bank, N.A, as applicable, pursuant to which the Custodian agrees to hold any of the documents or instruments referred to in Section 2.01 of this Agreement as agent for the Trustee.

Custodians :  LaSalle Bank, National Association and Wells Fargo Bank, N.A., each of which shall act as agent on behalf of the Trustee, and shall be compensated by the Trust Administrator or as otherwise specified therein.  

Cut-off Date :  November 1, 2006.

Cut-off Date Pool Principal Balance :  748,985,360.51.

Cut-off Date Principal Balance :  As to any Mortgage Loan, the Stated Principal Balance thereof as of the close of business on the Cut-off Date.

Data Remittance Date :  With respect to any Distribution Date and the Master Servicer, SPS or Wells Fargo, the 10th calendar day of the month in which such Distribution Date occurs, or if such 10th day is not a Business Day, the Business Day immediately following such 10th day.

Deferred Amount :  For any Class of Subordinate Certificates (other than the Class X Certificates) and any Distribution Date, the amount by which (x) the aggregate of the Applied Loss Amounts previously applied in reduction of the Class Principal Balance thereof exceeds (y) the sum of (i) the aggregate of amounts previously paid in reimbursement thereof and (ii) any additions to the Class Principal Balance pursuant to Section 4.03 on such Distribution Date or any previous Distribution Date.  Any payment of Deferred Amount pursuant to Section 4.01(d) shall not result in a reduction to the Class Principal Balance of the Class of Certificate to which it is distributed.

Definitive Certificate :  As defined in Section 6.07.

Deleted Mortgage Loan:   As defined in Section 2.03(c).

Delinquency Rate :  For any month will be, generally, the fraction, expressed as a percentage, the numerator of which is the aggregate outstanding principal balance of all Mortgage Loans 60 or more days delinquent (including all foreclosures, bankruptcies and REO Properties) as of the close of business on the last day of such month, and the denominator of which is the Aggregate Loan Balance as of the close of business on the last day of such month.

Denomination :  With respect to each Certificate, the amount set forth on the face thereof as the "Initial Certificate Balance of this Certificate" or the "Initial Notional Amount of this Certificate" or, if neither of the foregoing, the Percentage Interest appearing on the face thereof.

Depositor :  Credit Suisse First Boston Mortgage Securities Corp., a Delaware corporation, or its successor in interest.

Depository Agreement :  The Letter of Representation dated as of the Closing Date by and among DTC, the Depositor and the Trust Administrator for the benefit of the Trustee.

Designated Mortgage Loans :  The Countrywide Serviced Mortgage Loans, unless any such Mortgage Loan is no longer serviced by Countrywide under the Countrywide Servicing Agreement.

Designated Servicer :  Countrywide.

Designated Servicing Agreement :  The Countrywide Servicing Agreement.

Determination Date :  With respect to each Distribution Date and (A) the Master Servicer or any Servicer (other than Wells Fargo), the 10th day of the calendar month in which such Distribution Date occurs or, if such 10th day is not a Business Day, the Business Day immediately succeeding such Business Day and (B) Wells Fargo, the Business Day immediately preceding the Cash Remittance Date related to such Distribution Date.

Disqualified Organization :  Any organization defined as a "disqualified organization" under Section 860E(e)(5) of the Code, which includes any of the following:  (i) the United States, any state or political subdivision thereof, any possession of the United States, or any agency or instrumentality of any of the foregoing (other than an instrumentality which is a corporation if all of its activities are subject to tax and, except for the FHLMC, a majority of its board of directors is not selected by such governmental unit), (ii) a foreign government, any international organization, or any agency or instrumentality of any of the foregoing, (iii) any organization (other than certain farmers’ cooperatives described in Section 521 of the Code) which is exempt from the tax imposed by Chapter 1 of the Code (including the tax imposed by Section 511 of the Code on unrelated business taxable income), (iv) rural electric and telephone cooperatives described in Section 1381(a)(2)(C) of the Code, (v) an "electing large partnership" within the meaning of Section 775 of the Code, and (vi) any other Person so designated by the Trust Administrator based upon an Opinion of Counsel that the holding of an Ownership Interest in a Residual Certificate by such Person may cause any REMIC formed hereby or any Person having an ownership interest in any Class of Certificates (other than such Person) to incur a liability for any federal tax imposed under the Code that would not otherwise be imposed but for the transfer of an ownership interest in a Residual Certificate to such Person.  The terms "United States", "State" and "international organization" shall have the meanings set forth in Section 7701 of the Code or successor provisions.

Distribution Date :  The 25 ^th day of any month, or if such 25 ^th day is not a Business Day, the Business Day immediately following such 25 ^th day, commencing in December 2006.

DLJMC :  DLJ Mortgage Capital, Inc., a Delaware corporation, and its successors and assigns.

DTC :  The Depository Trust Company.

Due Date :  With respect to each Mortgage Loan and any Distribution Date, the date on which Scheduled Payments on such Mortgage Loan are due which is either the first day of the month of such Distribution Date, or if Scheduled Payments on such Mortgage Loan are due on a day other than the first day of the month, the date in the calendar month immediately preceding the Distribution Date on which such Scheduled Payments are due, exclusive of any days of grace.

Eligible Account :  Either (i) an account or accounts maintained with a federal or state chartered depository institution or trust company acceptable to the Rating Agencies or (ii) an account or accounts the deposits in which are insured by the FDIC to the limits established by such corporation, provided that any such deposits not so insured shall be maintained in an account at a depository institution or trust company whose commercial paper or other short term debt obligations (or, in the case of a depository institution or trust company which is the principal subsidiary of a holding company, the commercial paper or other short term debt obligations of such holding company) have been rated by each Rating Agency in its highest short-term rating category, or (iii) a segregated trust account or accounts (which shall be a "special deposit account") maintained with the Trustee, the Trust Administrator or any other federal or state chartered depository institution or trust company, acting in its fiduciary capacity, in a manner acceptable to the Trustee, the Trust Administrator and the Rating Agencies.  Eligible Accounts may bear interest.  

Eligible Institution :  An institution having the highest short-term debt rating, and one of the two highest long-term debt ratings of the Rating Agencies or the approval of the Rating Agencies.

Eligible Investments :  Any one or more of the obligations and securities listed below:

1.

direct obligations of, and obligations fully guaranteed by, the United States of America, or any agency or instrumentality of the United States of America the obligations of which are backed by the full faith and credit of the United States of America; or obligations fully guaranteed by, the United States of America, the FHLMC, FNMA, the Federal Home Loan Banks or any agency or instrumentality of the United States of America rated AA (or the equivalent) or higher by the Rating Agencies;

2.

federal funds, demand and time deposits in, certificates of deposits of, or bankers’ acceptances issued by, any depository institution or trust company incorporated or organized under the laws of the United States of America or any state thereof and subject to supervision and examination by federal and/or state banking authorities, so long as at the time of such investment or contractual commitment providing for such investment the commercial paper or other short-term debt obligations of such depository institution or trust company (or, in the case of a depository institution or trust company which is the principal subsidiary of a holding company, the commercial paper or other short-term debt obligations of such holding company) are rated in one of two of the highest ratings by each of the Rating Agencies, and the long-term debt obligations of such depository institution or trust company (or, in the case of a depository institution or trust company which is the principal subsidiary of a holding company, the long-term debt obligations of such holding company) are rated in one of two of the highest ratings, by each of the Rating Agencies;

3.

repurchase obligations with a term not to exceed 30 days with respect to any security described in clause (1) above and entered into with a depository institution or trust company (acting as a principal) rated "A-1+" by the Rating Agencies; provided, however , that collateral transferred pursuant to such repurchase obligation must be of the type described in clause (1) above and must (A) be valued daily at current market price plus accrued interest, (B) pursuant to such valuation, be equal, at all times, to 105% of the cash transferred by the Trustee or the Trust Administrator in exchange for such collateral, and (C) be delivered to the Trustee or the Trust Administrator or, if the Trustee or the Trust Administrator, as applicable, is supplying the collateral, an agent for the Trustee or the Trust Administrator, in such a manner as to accomplish perfection of a security interest in the collateral by possession of certificated securities;

4.

securities bearing interest or sold at a discount issued by any corporation incorporated under the laws of the United States of America or any state thereof which has a long-term unsecured debt rating in the highest available rating category of each of the Rating Agencies at the time of such investment;

5.

commercial paper having an original maturity of less than 365 days and issued by an institution having a short-term unsecured debt rating in the highest available rating category of each of the Rating Agencies at the time of such investment;

6.

a guaranteed investment contract approved by each of the Rating Agencies and issued by an insurance company or other corporation having a long-term unsecured debt rating in the highest available rating category of each of the Rating Agencies at the time of such investment;

7.

money market funds (which may be 12b-1 funds as contemplated under the rules promulgated by the Securities and Exchange Commission under the Investment Company Act of 1940) having ratings in the highest available rating category of Moody’s and one of the two highest available rating categories of S&P at the time of such investment (any such money market funds which provide for demand withdrawals being conclusively deemed to satisfy any maturity requirements for Eligible Investments set forth herein) including money market funds of the Master Servicer, a Servicer, the Trustee or the Trust Administrator and any such funds that are managed by the Master Servicer, a Servicer, the Trustee or the Trust Administrator or their respective Affiliates or for the Master Servicer, a Servicer, the Trustee or the Trust Administrator or any Affiliate of such Person acts as advisor, as long as such money market funds satisfy the criteria of this subparagraph (7); and

8.

such other investments the investment in which will not, as evidenced by a letter from each of the Rating Agencies, result in the downgrading or withdrawal of the Ratings of the any of Certificates, without respect to the Policy.

provided, however , that no such instrument shall be an Eligible Investment if such instrument evidences either (i) a right to receive only interest payments with respect to the obligations underlying such instrument, or (ii) both principal and interest payments derived from obligations underlying such instrument and the principal and interest payments with respect to such instrument provide a yield to maturity of greater than 120% of the yield to maturity at par of such underlying obligations.

ERISA :  The Employee Retirement Income Security Act of 1974, as amended.

ERISA-Qualifying Underwriting :  A best efforts or firm commitment underwriting or private placement that meets the requirements (without regard to the ratings requirements) of an Underwriter’s Exemption.

ERISA-Restricted Certificate :  As set forth in the Preliminary Statement.

Escrow Account :  The separate account or accounts created and maintained by the Master Servicer or a Servicer pursuant to Section 3.06.

Escrow Payments :  With respect to any Mortgage Loan, the amounts constituting ground rents, taxes, mortgage insurance premiums, fire and hazard insurance premiums, and any other payments required to be escrowed by the Mortgagor with the mortgagee pursuant to the Mortgage, applicable law or any other related document.

Event of Default :  As defined in Section 8.01 hereof.

Exchange Act :  The Securities Exchange Act of 1934, as amended, and the rules and regulations thereunder.

Expense Fee Rate :  As to each Mortgage Loan, the sum of the related Servicing Fee Rate, the Trust Administrator Fee Rate, the rate at which any lender paid primary mortgage guaranty insurance fee accrues, if applicable, and the Qualified Substitute Mortgage Loan Excess Interest Rate, if applicable.

Expense Fees :  As to each Mortgage Loan, the sum of the related Servicing Fee,  the Trust Administrator Fee, any lender paid primary mortgage guaranty insurance premium, if applicable, and any Qualified Substitute Mortgage Loan Excess Interest, if applicable.

Fair Credit Reporting Act :  The Fair Credit Reporting Act of 1970, as amended.

FDIC :  The Federal Deposit Insurance Corporation, or any successor thereto.

Federal Funds Rate :  The interest rate at which depository institutions lend balances at the Federal Reserve to other depository institutions overnight.

FHLMC :  The Federal Home Loan Mortgage Corporation, a corporate instrumentality of the United States created and existing under Title III of the Emergency Home Finance Act of 1970, as amended, or any successor thereto.

Financing Statement :  A financing statement in the form of a UCC-1 or UCC-3, as applicable, filed pursuant to the Uniform Commercial Code to perfect a security interest in the Cooperative Shares and Pledge Instruments.

Fitch Ratings:   Fitch, Inc., or any successor thereto.

FNMA :  The Federal National Mortgage Association, a federally chartered and privately owned corporation organized and existing under the Federal National Mortgage Association Charter Act, or any successor thereto.

Form 8-K Disclosure Information :  As defined in Section 14.04.

Indemnification Agreement :  Indemnification Agreement dated as of November 28, 2006, among the Certificate Insurer, the Depositor and the Seller.

Independent :  When used with respect to any accountants, a Person who is "independent" within the meaning of Rule 2-01(B) of the Securities and Exchange Commission’s Regulation S-X.  Independent means, when used with respect to any other Person, a Person who (A) is in fact independent of another specified Person and any affiliate of such other Person, (B) does not have any material direct or indirect financial interest in such other Person or any affiliate of such other Person, (C) is not connected with such other Person or any affiliate of such other Person as an officer, employee, promoter, underwriter, trust administrator, partner, director or Person performing similar functions and (D) is not a member of the immediate family of a Person defined in clause (B) or (C) above.

Indirect Participants :  Entities, such as banks, brokers, dealers and trust companies, that clear through or maintain a custodial relationship with a Participant, either directly or indirectly.

Initial Class Principal Balance :  As set forth in the Preliminary Statement.

Insolvency Proceeding ;  As defined in Section 13.04(e) of this Agreement.

Insurance Policy :  With respect to any Mortgage Loan included in the Trust Fund, any Mortgage Guaranty Insurance Policy, standard hazard insurance policy, flood insurance policy or title insurance policy, including all riders and endorsements thereto in effect, including any replacement policy or policies for any Insurance Policies.

Insurance Proceeds :  Amounts paid pursuant to any Insurance Policy with respect to a Mortgage Loan that have not been used to restore the related Mortgaged Property or released to the Mortgagor in accordance with the related Servicer’s or the Designated Servicer’s normal servicing procedures.

Insured Amounts :  With respect to the Insured Certificates, it has the same meaning assigned to "Guaranteed Distributions" in the Policy.

Insured Certificates :  The Class A-4 Certificates.

Insured Payments :  The aggregate amount actually paid by the Certificate Insurer to the Trust Administrator in respect of Insured Amounts.

Interest Determination Date :  With respect to the LIBOR Certificates and for each Accrual Period, the second LIBOR Business Day preceding the commencement of such Accrual Period.

Interest Rate :  With respect to each Subsidiary REMIC Regular Interest, the applicable rate set forth or calculated in the manner described in the Preliminary Statement.

Interest Rate Cap Account(s) :

 The Class A-1-B/A-1-C Interest Rate Cap Account, Class A-1-D Interest Rate Cap Account, the Class A-2-B Interest Rate Cap Account, the Class A-3 Interest Rate Cap Account, the Class M-1-B Interest Rate Cap Account, the Class M-2 Interest Rate Cap Account, the Class M-3 Interest Rate Cap Account, the Class M-5 Interest Rate Cap Account, the Class M-6 Interest Rate Cap Account, the Class M-7 Interest Rate Cap Account or the Class M-8 Interest Rate Cap Account, respectively.

Interest Rate Cap Agreement Counterparty :  Credit Suisse International.

Interest Rate Cap Agreement Termination Date :  With respect to each Interest Rate Cap Agreement, the related Distribution Date as specified in the table below, after any required payment is made.  

Interest Rate Cap Agreements :  The Class A-1-B/A-1-C Interest Rate Cap Agreement, the Class A-1-D Interest Rate Cap Agreement, the Class A-2-B Interest Rate Cap Agreement, the Class A-3 Interest Rate Cap Agreement, the Class M-1-B Interest Rate Cap Agreement, the Class M-2 Interest Rate Cap Agreement, the Class M-3 Interest Rate Cap Agreement, the Class M-5 Interest Rate Cap Agreement, the Class M-6 Interest Rate Cap Agreement, the Class M-7 Interest Rate Cap Agreement or the Class M-8 Interest Rate Cap Agreement.

Interest Remittance Amount :  For any Distribution Date, an amount equal to the sum, without duplication, of (1) all interest collected (other than related Payaheads, if applicable) or advanced in respect of Scheduled Payments on the Mortgage Loans during the related Collection Period, the interest portion of Payaheads previously received and intended for application in the related Collection Period and the interest portion of all Payoffs and Curtailments received on the Mortgage Loans during the related Prepayment Period (other than interest on Principal Prepayments in full that occur during the portion of the Prepayment Period that is in the same calendar month as the related Distribution Date), less (x) the Servicing Fees and any Lender Paid Mortgage Guaranty Insurance Policy premiums with respect to the Mortgage Loans and (y) unreimbursed Advances and other amounts due to the Servicers, the Master Servicer, the Trust Administrator or the Trustee with respect to the Mortgage Loans and (2) all Compensating Interest Payments paid by the Servicers or the Master Servicer with respect to the Mortgage Loans with respect to such Distribution Date, (3) the portion of any Substitution Adjustment Amount and Purchase Price paid with respect to the Mortgage Loans during the calendar month immediately preceding the Distribution Date, in each case allocable to interest, and the proceeds of any purchase of the Mortgage Loans by the Terminating Entity pursuant to Section 9.01 allocable to interest and (4) all Net Liquidation Proceeds and Recoveries collected with respect to the Mortgage Loans during the prior calendar month, to the extent allocable to interest.

Interest Shortfall :  For any Distribution Date, an amount equal to the aggregate shortfall, if any, in collections of interest (adjusted to the related Net Mortgage Rate) on the Mortgage Loans resulting from (a) Prepayment Interest Shortfalls to the extent not covered by a Compensating Interest Payment and (b) interest payments on certain of the Mortgage Loans being limited pursuant to the provisions of the Relief Act.

ISDA :  International Swaps and Derivatives Association, Inc.

ISDA Master Agreement :  An ISDA Master Agreement (Multicurrency-Cross Border) in the form published by ISDA in 1992 including the schedule thereto.

Item 1123 Certificate :  As defined in Section 14.06.

Late Payment Rate :  With respect to any Distribution Date, the greater of (i) the per annum rate of interest, publicly announced from time to time by JPMorgan Chase Bank, National Association at its principal office in the City of New York as its prime or base lending rate (any change in such rate of interest to be effective on the date such change is announced by JPMorgan Chase Bank, National Association) plus 3% and (ii) the then applicable highest rate of interest on the Insured Certificates, in each case, computed on the basis of a year of 360 days and the actual number of days elapsed and in no event shall the Late Payment Rate exceed the maximum rate permissible under any applicable law limiting interest rates.

Lender Paid Mortgage Guaranty Insurance Policy :  Any lender paid Mortgage Guaranty Insurance Policy.

LIBOR Business Day :  Any day other than (i) a Saturday or a Sunday or (ii) a day on which banking institutions in the State of New York or in the City of London, England are required or authorized by law to be closed.

LIBOR Certificates :  As set forth in the Preliminary Statement.

Liquidated Mortgage Loan :  With respect to any Distribution Date, a defaulted Mortgage Loan (including any REO Property) which was liquidated in the calendar month preceding the month of such Distribution Date and as to which the related Servicer has determined (with respect to the Non-Designated Mortgage Loans, in accordance with this Agreement, or with respect to the Designated Mortgage Loans, in accordance with the Designated Servicing Agreement) that it has received all amounts it expects to receive in connection with the liquidation of such Mortgage Loan, including the final disposition of the related REO Property.

Liquidation Expenses :  Customary and reasonable "out of pocket" expenses incurred by a Servicer (or the related Sub-Servicer) in connection with the liquidation of any defaulted Mortgage Loan and not recovered by such Servicer (or the related Sub-Servicer) under a Mortgage Guaranty Insurance Policy for reasons other than such Servicer’s failure to comply with Section 3.09 hereof, such expenses including, without limitation, legal fees and expenses, any unreimbursed amount expended by a Servicer pursuant to Section 3.11 hereof respecting the related Mortgage and any related and unreimbursed expenditures for real estate property taxes or for property restoration or preservation to the extent not previously reimbursed under any hazard insurance policy for reasons other than such Servicer’s failure to comply with Section 3.11 hereof.

Liquidation Proceeds :  Amounts, including Insurance Proceeds, received in connection with the partial or complete liquidation of defaulted Mortgage Loans, whether through trustee’s sale, foreclosure sale or otherwise or amounts received in connection with any condemnation or partial release of a Mortgaged Property related to a Mortgage Loan and any other proceeds received in connection with an REO Property, other than Recoveries.

Loan Level Data :  As defined in Section 4.04(c).

Loan-to-Value Ratio :  As of any date, the fraction, expressed as a percentage, the numerator of which is the Stated Principal Balance of the related Mortgage Loan at the date of determination and the denominator of which is the Appraised Value of the Mortgaged Property.

Lost Mortgage Note :  Any Mortgage Note the original of which was permanently lost or destroyed and has not been replaced.

Lower Tier Interest :  As described in the Preliminary Statement.

Majority Servicer :  The Servicer servicing the largest percentage of Mortgage Loans by Stated Principal Balance of outstanding Mortgage Loans on the Optional Termination Date.

Master REMIC :  As described in the Preliminary Statement.

Master Servicer :  Wells Fargo.

Master Servicer Employees :  As defined in Section 3.18.

MERS :  Mortgage Electronic Registration Systems, Inc., a corporation organized and existing under the laws of the State of Delaware, or any successor thereto.

MERS Mortgage Loan :  Any Mortgage Loan registered with MERS on the MERS System.

MERS® System :  The system of recording transfers of mortgages electronically maintained by MERS.

MIN :  The mortgage identification number for any MERS Mortgage Loan.

Modification Oversight Agent :  SPS and any successor, as modification oversight agent hereunder.

MOM Loan :  Any Mortgage Loan as to which MERS is acting as mortgagee, solely as nominee for the originator of such Mortgage Loan and its successors and assigns.

Monthly Excess Cashflow :  For any Distribution Date, an amount equal to the sum of the Monthly Excess Interest and Overcollateralization Release Amount, if any, for such date.

Monthly Excess Interest :  As to any Distribution Date, the Interest Remittance Amount remaining after the application of payments pursuant to clauses (i) through (x) of Section 4.01(a) and the Principal Payment Amount remaining after the application of payments pursuant to clauses (i) through (ix) of Section 4.01(b) or 4.01(c), as applicable.

Moody’s :  Moody’s Investors Service, Inc., or any successor thereto.

Mortgage :  With respect to a Mortgage Loan, the mortgage, deed of trust or other instrument creating a first lien on a fee simple or leasehold estate in real property securing a Mortgage Note.

Mortgage File :  For each Mortgage Loan, the Trustee Mortgage File.

Mortgage Guaranty Insurance Policy :  Each policy of primary mortgage guaranty insurance or any replacement policy therefor with respect to any Mortgage Loan.

Mortgage Loans :  Such of the mortgage loans and cooperative loans transferred and assigned to the Trustee pursuant to the provisions hereof as from time to time are held as a part of the Trust Fund (including any REO Property), the mortgage loans so held being identified in the Mortgage Loan Schedule, notwithstanding foreclosure or other acquisition of title of the related Mortgaged Property.  With respect to each Mortgage Loan that is a Cooperative Loan, if any, "Mortgage Loan" shall include, but not be limited to, the related Mortgage Note, Security Agreement, Assignment of Proprietary Lease, Recognition Agreement, Cooperative Shares and Proprietary Lease and, with respect to each Mortgage Loan other than a Cooperative Loan, "Mortgage Loan" shall include, but not be limited to the related Mortgages and the related Mortgage Notes.

Mortgage Loan Auction Price :  The price, calculated as set forth in Section 11.01, to be paid in connection with the purchase of the Mortgage Loans by the Auction Purchaser.

Mortgage Loan Purchase Price :  The price, calculated as set forth in Section 11.01, to be paid in connection with the purchase of the Mortgage Loans pursuant to an Optional Termination.

Mortgage Loan Schedule :  The list of Mortgage Loans (as from time to time amended by the Seller to reflect the addition of Qualified Substitute Mortgage Loans and the purchase of Mortgage Loans pursuant to Section 2.02 or 2.03) transferred to the Trustee as part of the Trust Fund and from time to time subject to this Agreement, attached hereto as Schedule I, setting forth the following information with respect to each Mortgage Loan and applicable Servicer:

1.

the Mortgage Loan identifying number;

2.

a code indicating the type of Mortgaged Property (detached single family dwelling, PUD, condominium unit, two- to four-unit residential property or Cooperative Unit) and the occupancy status;

3.

the original months to maturity or the remaining months to maturity from the Cut-off Date, in any case based on the original amortization schedule and, if different, the maturity expressed in the same manner but based on the actual amortization schedule;

4.

the Loan-to-Value Ratio at origination;

5.

a code indicating the existence of a subordinate lien for the related Mortgaged Property;

6.

the combined Loan-to-Value Ratio at origination;

7.

the related borrower’s debt-to-income ratio;

8.

the related borrower’s credit score at origination;

9.

the Mortgage Rate as of the Cut-off Date;

10.

the stated maturity date;

11.

the amount of the Scheduled Payment as of the Cut-off Date;

12.

the original principal amount of the Mortgage Loan;

13.

the principal balance of the Mortgage Loan as of the close of business on the Cut-off Date, after deduction of payments of principal due on or before the Cut-off Date whether or not collected;

14.

a code indicating the purpose of the Mortgage Loan (i.e., purchase, rate and term refinance, equity take-out refinance);

15.

a code indicating whether an Assigned Prepayment Premium is required to be paid in connection with a prepayment of the Mortgage Loan and the term and the amount of the Assigned Prepayment Premium;

16.

the Expense Fee Rate as of the Cut-off Date;

17.

the Servicing Fee Rate (which may be disclosed on the Mortgage Loan Schedule in two parts identified as the servicing fee and the master servicing fee or in two parts identified as the "Lender Fee" and the "Mgmt Fee" or in two parts identified as "service fee" and "excess fee");

18.

the Servicer of the Mortgage Loan;

19.

a code indicating whether the Mortgage Loan is covered under a borrower paid or lender paid Mortgage Guaranty Insurance Policy (and, if so, the name of the insurance carrier) and the rate at which any lender paid Mortgage Guaranty Insurance Policy premium is calculated, if applicable; and

20.

a code indicating whether the Mortgage Loan is a MERS Mortgage Loan and, if so, its corresponding MIN.

With respect to the Mortgage Loans in the aggregate, the Mortgage Loan Schedule shall set forth the following information, as of the Cut-off Date:

1.

the number of Mortgage Loans;

2.

the current aggregate principal balance of the Mortgage Loans as of the close of business on the Cut-off Date, after deduction of payments of principal due on or before the Cut-off Date whether or not collected; and

3.

the weighted average Mortgage Rate of the Mortgage Loans.

Mortgage Note :  The original executed note or other evidence of the indebtedness of a Mortgagor under a Mortgage Loan.

Mortgage Rate :  The annual rate of interest borne by a Mortgage Note.

Mortgaged Property :  The underlying real property securing a Mortgage Loan or, with respect to a Cooperative Loan, the related Cooperative Shares and Proprietary Lease.

Mortgagor :  The obligor on a Mortgage Note.

Most Senior Enhancement Percentage :  With respect to any Distribution Date and any Class of Certificates, a fraction, expressed as a percentage, the numerator of which is the sum of (i) the aggregate Class Principal Balance of those Classes of Certificates which are lower in priority than such Class of Certificates and (ii) the Overcollateralization Amount (which, for purposes of this definition only, shall not be less than zero), in each case prior to giving effect to payments on such Distribution Date, and the denominator of which is the Aggregate Loan Balance as of the first day of the related Collection Period.

Net Funds Cap :  For any Distribution Date and each Class of Offered Certificates (other than the Class AR Certificates), a per annum rate equal to (a) a fraction, expressed as a percentage, the numerator of which is the product of (1) the Optimal Interest Remittance Amount on such date (adjusted to account for the Certificate Insurer Premium with respect to the Insured Certificates) and (2) 12, and the denominator of which is the Aggregate Loan Balance for the immediately preceding Distribution Date, multiplied by, (b) with respect to the LIBOR Certificates only, a fraction, the numerator of which is 30 and the denominator of which is the actual number of days in the immediately preceding Accrual Period.

Net Liquidation Proceeds :  With respect to any Liquidated Mortgage Loan, the excess of the related Liquidation Proceeds over the sum of Recoveries, Liquidation Expenses, Expense Fees, unreimbursed Advances and Servicing Advances.

Net Mortgage Rate :  As to each Mortgage Loan, and at any time, the per annum rate equal to the Mortgage Rate for such Mortgage Loan less the related Expense Fee Rate.

Net Prepayment Interest Shortfall :  For any Distribution Date, the amount by which the aggregate of Prepayment Interest Shortfalls during the related Prepayment Period exceeds the Compensating Interest Payments.

NIM Note :  Any debt instrument secured by distributions on any of the Certificates issued by the Trust Fund.

NIM Trust :  Any trust created to hold the Class X Certificates that issues notes that are secured by distributions on the Class X Certificates.

Non-Designated Mortgage Loans :  The Mortgage Loans that are not Designated Mortgage Loans.

Nonrecoverable Advance :  Any portion of an Advance or Servicing Advance previously made or proposed to be made by the Master Servicer or a Servicer that, in the good faith judgment of the Master Servicer or a Servicer, will not be ultimately recoverable by the Master Servicer or a Servicer from the related Mortgagor, related Liquidation Proceeds or otherwise from proceeds or collections on the related Mortgage Loan.

Notional Amount Certificates :  As set forth in the Preliminary Statement.

Offered Certificates :  As set forth in the Preliminary Statement.

Officer’s Certificate :  A certificate signed by the Chairman of the Board, any Vice Chairman of the Board, the President, an Executive Vice President, Senior Vice President, a Vice President, the Treasurer, the Secretary, one of the Assistant Treasurers or Assistant Secretaries or other authorized officer of the Depositor, the Seller, the Master Servicer, the Servicers, any Special Servicer, a Sub-Servicer, the Trustee or the Trust Administrator, as the case may be, and delivered to the Depositor, the Seller, the Master Servicer, any Special Servicer, the Servicers, the Trustee or the Trust Administrator, as required by this Agreement.

Opinion of Counsel :  A written opinion of counsel, who may be counsel for the Depositor, the Master Servicer or a Servicer, reasonably acceptable to the Trustee and the Trust Administrator.  With respect to the definition of Eligible Account in this Article I and Sections 2.05 and 7.04 hereof and any opinion dealing with the qualification of the REMIC or compliance with the REMIC Provisions, such counsel must (i) in fact be independent of the Depositor, the Master Servicer and such Servicer, (ii) not have any direct financial interest in the Depositor, the Master Servicer or such Servicer or in any affiliate of either of them and (iii) not be connected with Depositor, the Master Servicer or such Servicer as an officer, employee, promoter, underwriter, trustee, partner, director or Person performing similar functions; provided, that with respect to Wells Fargo Bank, N.A., as a Servicer, such counsel may be in-house counsel for Wells Fargo Bank, N.A., as a Servicer.

Optimal Interest Remittance Amount :  With respect to any Distribution Date, an amount equal to the excess of (i) the product of (1) (x) the weighted average Net Mortgage Rate of the Mortgage Loans as of the first day of the related Collection Period divided by (y) 12 and (2) the Aggregate Loan Balance for the immediately preceding Distribution Date, over (ii) any expenses that reduce the Interest Remittance Amount which did not arise as a result of a default or delinquency of the Mortgage Loans or were not taken into account in computing the Expense Fee Rate.

Optional Termination :  Any purchase of the Mortgage Loans by a Terminating Entity or an Auction Purchaser, pursuant to Section 11.01.

Optional Termination Date :  As defined in Section 11.01(A).

Optional Termination Notice Period :  The period during which notice of an Optional Termination is to be given to the affected Certificateholders of an Optional Termination pursuant to Section 11.03(e).

OTS :  The Office of Thrift Supervision.

Overcollateralization Amount :  For any Distribution Date, an amount equal to the amount, if any, by which (x) the Aggregate Loan Balance for such Distribution Date exceeds (y) the aggregate Class Principal Balance of the Offered Certificates after giving effect to payments on such Distribution Date.

Overcollateralization Commencement Date :  The Distribution Date in January 2007.

Overcollateralization Deficiency :  For any Distribution Date will be equal to the amount, if any, by which (x) the Targeted Overcollateralization Amount for such Distribution Date exceeds (y) the Overcollateralization Amount for such Distribution Date, calculated for this purpose after giving effect to the reduction on such Distribution Date of the aggregate Class Principal Balance of the Offered Certificates resulting from the payment of the Principal Payment Amount on such Distribution Date, but prior to allocation of any Applied Loss Amount on such Distribution Date.

Overcollateralization Release Amount :  For any Distribution Date, an amount equal to the lesser of (x) the Principal Remittance Amount for such Distribution Date and (y) the amount, if any, by which (1) the Overcollateralization Amount for such date, calculated for this purpose on the basis of the assumption that 100% of the aggregate Principal Remittance Amount for such date is applied on such date in reduction of the aggregate of the Class Principal Balances of the Certificates, exceeds (2) the Targeted Overcollateralization Amount for such date.

Participant :  A broker, dealer, bank, other financial institution or other Person for whom DTC effects book-entry transfers and pledges of securities deposited with DTC.

Pass-Through Entity :  (a) a regulated investment company described in Section 851 of the Code, a real estate investment trust described in Section 856 of the Code, a common trust fund or an organization described in Section 1381(a) of the Code, (b) any partnership, trust or estate or (c) any person holding a Class A Certificate as nominee for another person.

Pass-Through Rate :  For any interest-bearing Class of Certificates, the per annum rate set forth or calculated in the manner described in the Preliminary Statement.  Interest on the Certificates (other than the LIBOR Certificates) will be computed on the basis of a 360-day year comprised of twelve 30-day months.  Interest on the LIBOR Certificates shall be calculated on the basis of a 360-day year and the actual number of days elapsed in each Accrual Period.

Payahead :  Any scheduled principal payment intended by the related Mortgagor to be applied in a Collection Period subsequent to the Collection Period in which such payment was received.

Payoff :  Any payment of principal on a Mortgage Loan equal to the entire outstanding Stated Principal Balance of such Mortgage Loan, if received in advance of the last scheduled Due Date for such Mortgage Loan and accompanied by an amount of interest equal to accrued unpaid interest on the Mortgage Loan to the date of such payment-in-full.

Payoff Interest :  For any Distribution Date with respect to each SPS Serviced Mortgage Loan, the Wells Fargo Serviced CORE Mortgage Loan and the Wells Fargo Serviced Mortgage Loan for which a Payoff was received on or after the first calendar day of the month of such Distribution Date and before the 15th calendar day, 14th calendar day and 14th calendar day, respectively, of such month, an amount of interest thereon at the applicable Net Mortgage Rate from the first day of such month through the day of receipt thereof.

PCAOB :  The Public Company Accounting Oversight Board.

Percentage Interest :  As to any Certificate, either the percentage set forth on the face thereof or equal to the percentage obtained by dividing the Denomination of such Certificate by the aggregate of the Denominations of all Certificates of the same Class.

Person :  Any individual, corporation, partnership, joint venture, association, joint-stock company, trust, unincorporated organization or government, or any agency or political subdivision thereof.

Physical Certificates :  As set forth in the Preliminary Statement.

Pledge Instruments :  With respect to each Cooperative Loan, the Stock Power, the Assignment of Proprietary Lease and the Security Agreement.

Policy : Financial Guaranty Insurance Policy No. 51781-N issued by the Certificate Insurer with respect to the Insured Certificates, including any endorsements thereto.

Policy Payments Account :  As defined in Section 13.04(b) of this Agreement.

Prepayment Interest Shortfall :  As to any Mortgage Loan, Distribution Date and Principal Prepayment (other than Payoffs with respect to a SPS Serviced Mortgage Loan received during the period from and including the first day to and including the 14th day of the month of such Distribution Date and with respect to a Wells Fargo Serviced Mortgage Loan or Wells Fargo Serviced CORE Mortgage Loan received during the period from and including the first day to and including the 13th day of the month of such Distribution Date) received during the related Prepayment Period, the difference between (i) one full month’s interest at the applicable Mortgage Rate (giving effect to any applicable Relief Act Reduction, Debt Service Reduction and Deficient Valuation), as reduced by the Servicing Fee Rate, on the outstanding principal balance of such Mortgage Loan immediately prior to such prepayment or, if such Principal Prepayment is a Curtailment, the principal amount of such Curtailment and (ii) the amount of interest actually received with respect to such Mortgage Loan in connection with such Principal Prepayment, net of the Servicing Fee.

Prepayment Premium :  With respect to any Mortgage Loan, any penalty, fee or premium required to be paid if the Mortgagor prepays such Mortgage Loan as provided in the related Mortgage Note or Mortgage.

Prepayment Period :  With respect to each Distribution Date and each Payoff with respect to a SPS Serviced Mortgage Loan, the related "Prepayment Period" will commence on the 15th day of the month preceding the month in which the related Distribution Date occurs (or, in the case of the first Distribution Date, commencing on the Cut-off Date) and will end on the 14th day of the month in which such Distribution Date occurs.  With respect to each Distribution Date and any Payoff with respect to a Wells Fargo Serviced Mortgage Loan or a Wells Fargo Serviced CORE Mortgage Loan, the related "Prepayment Period" will commence on the 14 ^th day of the month preceding the month in which the related Distribution Date occurs (or, in the case of the first Distribution Date, commencing on the Cut-off Date) and will end on the 13 ^th day of month in which such Distribution Date occurs.  With respect to each Distribution Date and any Curtailment on any Wells Fargo Serviced Mortgage Loan, Wells Fargo Serviced CORE Mortgage Loan and SPS Serviced Mortgage Loan, the related "Prepayment Period" will commence on the first day of the month preceding the month in which the related Distribution Date occurs and will end on the last day of such month.  With respect to each Distribution Date and each Payoff and Curtailment with respect to any other Mortgage Loan, the related "Prepayment Period" will be as defined in the Designated Servicing Agreement.

Principal Payment Amount :  For any Distribution Date, the excess of the Principal Remittance Amount for such date minus the Overcollateralization Release Amount, if any, for such date.

Principal Prepayment :  Any payment of principal on a Mortgage Loan that constitutes a Payoff or Curtailment.  

Principal Remittance Amount :  For any Distribution Date, an amount equal to (A) the sum, without duplication, of (1) all principal collected (other than Payaheads) or advanced in respect of Scheduled Payments on the Mortgage Loans during the related Collection Period (less unreimbursed Advances, Servicing Advances and other amounts due to the Servicers, the Master Servicer, the Trust Administrator and the Trustee with respect to the Mortgage Loans, to the extent allocable to principal or to the extent the Interest Remittance Amount is insufficient) and the principal portion of Payaheads previously received and intended for application in the related Collection Period, (2) all Principal Prepayments on the Mortgage Loans received during the related Prepayment Period, (3) the outstanding principal balance of each Mortgage Loan that was repurchased by the Seller or purchased by the Servicer during the calendar month immediately preceding such Distribution Date, (4) the principal portion of the Mortgage Loan Purchase Price received in connection with an Optional Termination pursuant to Section 11.01, (5) the principal portion of the Mortgage Loan Auction Price received in connection with an Auction Sale pursuant to Section 11.01, (6) the portion of any Substitution Adjustment Amount paid with respect to any Deleted Mortgage Loans during the calendar month immediately preceding such Distribution Date allocable to principal and (7) all Net Liquidation Proceeds and any Recoveries collected with respect to the Mortgage Loans during the prior calendar month, to the extent allocable to principal or to the extent the Interest Remittance Amount is insufficient less (B) the Capitalization Reimbursement Amount for such Distribution Date.

Private Certificates :  As set forth in the Preliminary Statement.

Proprietary Lease :  The lease on a Cooperative Unit evidencing the possessory interest of the owner of the Cooperative Shares in such Cooperative Unit.

Prospectus :  The Prospectus, dated October 27, 2006, relating to the offering by the Depositor from time to time of its CSAB Mortgage-Backed Pass-Through Certificates (Issuable in Series) in the form in which it was or will be filed with the Securities and Exchange Commission pursuant to Rule 424(b) under the 1933 Act with respect to the offer and sale of the Offered Certificates.

Prospectus Supplement :  The Prospectus Supplement, dated November 28, 2006, relating to the offering of the Offered Certificates in the form in which it was or will be filed with the Securities and Exchange Commission pursuant to Rule 424(b) under the Securities Act with respect to the offer and sale of the Offered Certificates.

Purchase Price :  With respect to any Mortgage Loan required to be purchased by the Seller pursuant to Section 2.02 or 2.03 or purchased by an entity pursuant to Section 3.11(f) or purchased at the option of any Special Servicer pursuant to Section 3.19(c), the sum of (i) 100% of the unpaid principal balance of the Mortgage Loan on the date of such purchase, (ii) accrued and unpaid interest on the Mortgage Loan at the applicable Mortgage Rate (reduced by the related Servicing Fee Rate, if the purchaser is also the Servicer thereof) from the date through which interest was last paid by the Mortgagor to the Due Date in the month in which the Purchase Price is to be distributed to Certificateholders, (iii) in the case of a Mortgage Loan purchased by the Seller, the amount of any unreimbursed Servicing Advances made by a Servicer, other than the Seller, with respect to such Mortgage Loan or, in the case of a Mortgage Loan purchased by a Special Servicer, any unreimbursed Servicing Advances payable to any Servicer other than SPS and (iv) any costs and damages (including, without limitation, late fees) actually incurred and paid by or on behalf of the Trust Fund in connection with the fact that such Mortgage Loan at the time it was made failed to comply in all material respects with applicable federal, state or local predatory and abusive lending laws, to the extent such costs and damages result from a breach by the Seller of the representation and warranty set forth in Schedule III(viii).  With respect to any Mortgage Loan required or allowed to be purchased, the related Servicer or the Seller, as applicable, shall deliver to the Trustee and the Trust Administrator an Officer’s Certificate as to the calculation of the Purchase Price.

Qualified Insurer :  A mortgage guaranty insurance company duly qualified as such under the laws of the state of its principal place of business and each state having jurisdiction over such insurer in connection with the insurance policy issued by such insurer, duly authorized and licensed in such states to transact a mortgage guaranty insurance business in such states and to write the insurance provided by the insurance policy issued by it, approved as a FNMA- or FHLMC-approved mortgage insurer or having a claims paying ability rating of at least "AA" or equivalent rating by a nationally recognized statistical rating organization.  Any replacement insurer with respect to a Mortgage Loan must have at least as high a claims paying ability rating as the insurer it replaces had on the Closing Date.

Qualified Substitute Mortgage Loan :  One or more Mortgage Loans substituted by the Seller for one or more Deleted Mortgage Loans which must, on the date of such substitution, as confirmed in a Request for Release, substantially in the form of Exhibit L, individually or in the aggregate and on a weighted average basis, as applicable, (i) have a Stated Principal Balance, after deduction of the principal portion of the Scheduled Payment due in the month of substitution, not in excess of, and not more than 10% less than the Stated Principal Balance of the Deleted Mortgage Loan; (ii) be accruing interest at a rate no lower than and not more than 1% per annum higher than, that of the Deleted Mortgage Loan; (iii) have a Loan-to-Value Ratio no higher than that of the Deleted Mortgage Loan; (iv) have a remaining term to maturity not more than one year greater than or less than that of the Deleted Mortgage Loan; provided that the remaining term to maturity of any such Mortgage Loan shall be no greater than the last maturing Mortgage Loan in the Trust Fund immediately prior to any substitution; (v) not be a Cooperative Loan unless the Deleted Mortgage Loan was a Cooperative Loan; (vi) have the same Due Date as the Due Date on the Deleted Mortgage Loan; (vii) have a risk grading at least equal to the risk grading assigned on the Deleted Mortgage Loan, (viii) be a "qualified mortgage" as defined in the REMIC Provisions and (ix) comply with each representation and warranty set forth in Section 2.03(b).  In the event that one or more mortgage loans are substituted for one or more Deleted Mortgage Loans, the amounts described in clause (i) hereof shall be determined on the basis of aggregate principal balances, the Mortgage Interest Rates described in clause (ii) hereof shall be determined on the basis of weighted average Mortgage Interest Rates, the terms described in clause (iv) hereof shall be determined on the basis of weighted average remaining term to maturity, the Loan-to-Value Ratios described in clause (iii) hereof shall be satisfied as to each such Qualified Substitute Mortgage Loan, the risk gradings described in clause (vii) hereof shall be satisfied as to each such Qualified Substitute Mortgage Loan and, except to the extent otherwise provided in this sentence, the representations and warranties described in clause (ix) hereof must be satisfied as to each Qualified Substitute Mortgage Loan or in the aggregate, as the case may be.

Qualified Substitute Mortgage Loan Excess Interest :  For any Qualified Substitute Mortgage Loan and Distribution Date, the product of (x) the Stated Principal Balance, as of the second preceding Due Date after giving effect to scheduled payments for that Due Date, whether or not received, of such Mortgage Loan and (y) the Qualified Substitute Mortgage Loan Excess Interest Rate for such Mortgage Loan and Distribution Date.

Qualified Substitute Mortgage Loan Excess Interest Rate :  For any Qualified Substitute Mortgage Loan and Distribution Date, the excess of the rate at which such Mortgage Loan is accruing interest over the rate at which the related Deleted Mortgage Loan was accruing interest on the date of substitution.

Rating Agency :  Moody’s or S&P, or any successor to either of them.

Ratings :  As of any date of determination, the ratings, if any, of the Certificates as assigned by the Rating Agencies.

Realized Loss :  With respect to any Liquidated Mortgage Loan, an amount (not less than zero or more than the Stated Principal Balance of the Mortgage Loan) as of the date of such liquidation, equal to (i) the Stated Principal Balance of the Liquidated Mortgage Loan as of the date of such liquidation, plus (ii) interest at the applicable Net Mortgage Rate from the related Due Date as to which interest was last paid or advanced (and not reimbursed) to Certificateholders up to the related Due Date in the month in which Liquidation Proceeds are required to be distributed on the Stated Principal Balance of such Liquidated Mortgage Loan from time to time, minus (iii) the Net Liquidation Proceeds, if any, received during the month in which such liquidation occurred, to the extent applied as recoveries of interest at the Net Mortgage Rate and to principal of the Liquidated Mortgage Loan.

Recognition Agreement :  An Agreement among a Cooperative Corporation, a lender and a Mortgagor with respect to a Cooperative Loan whereby such parties (i) acknowledge that such lender may make, or intends to make, such Cooperative Loan, (ii) make certain agreements with respect to such Cooperative Loan.

Record Date :  With respect to any Distribution Date and the LIBOR Certificates, the Business Day immediately preceding that Distribution Date so long as the Certificates remain Book-Entry Certificates, or otherwise on the close of business on the last Business Day of the month preceding the month in which the applicable Distribution Date occurs, and with respect to any other Class of Certificates, the close of business on the last Business Day of the month preceding the month in which the applicable Distribution Date occurs.

Recovery :  With respect to any Distribution Date and Mortgage Loan that became a Liquidated Mortgage Loan in a month preceding the month prior to that Distribution Date, an amount received in respect of such Liquidated Mortgage Loan during the prior calendar month which has previously been allocated as a Realized Loss to a Class or Classes of Certificates, net of any reimbursable expenses.

Reference Bank Rate :  As to any Accrual Period relating to the LIBOR Certificates as follows:  the arithmetic mean (rounded upwards, if necessary, to the nearest one sixteenth of a percent) of the offered rates for United States dollar deposits for one month which are offered by the Reference Banks as of 11:00 A.M., London time, on the Interest Determination Date prior to the first day of such Accrual Period to prime banks in the London interbank market for a period of one month in amounts approximately equal to the aggregate Class Principal Balance of the LIBOR Certificates; provided that at least two such Reference Banks provide such rate.  If fewer than two offered rates appear, the Reference Bank Rate will be the arithmetic mean of the rates quoted by one or more major banks in New York City, selected by the Trust Administrator after consultation with DLJMC, as of 11:00 A.M., New York City time, on such date for loans in U.S. Dollars to leading European banks for a period of one month in amounts approximately equal to the aggregate Class Principal Balance of the LIBOR Certificates.  If no such quotations can be obtained, the Reference Bank Rate shall be the Reference Bank Rate applicable to the preceding Accrual Period.

Reference Banks :  Three major banks that are engaged in the London interbank market, selected by the Trust Administrator after consultation with DLJMC.

Reimbursement Amount :  As to any Distribution Date, the sum of (i)(a) all Insured Payments paid by the Certificate Insurer, but for which the Certificate Insurer has not been reimbursed prior to such Distribution Date pursuant to this Agreement, plus (b) interest accrued thereon, calculated at the related Late Payment Rate from the date the Certificate Insurer paid the Insured Payment to the Trust Administrator and (ii) without duplication, (a) any other amounts owing to the Certificate Insurer under this Agreement and the Indemnification Agreement, as certified to the Trust Administrator by the Certificate Insurer plus (b) interest accrued thereon calculated at the related Late Payment Rate.

Registration Statement :  That certain registration statement on Form S-3, as amended (Registration No. 333-135481), relating to the offering by the Depositor from time to time of its CSAB Mortgage-Backed Pass-Through Certificates (Issuable in Series) as heretofore declared effective by the Securities and Exchange Commission.

Regular Certificates :  All of the Certificates other than the Residual Certificates.

Regulation AB :  Subpart 229.1100 – Asset Backed Securities (Regulation AB), 17 C.F.R. §§229.1100 - 229.1123, as such may be amended from time to time, and subject to such clarification and interpretation as have been provided by the Commission in the adopting release (Asset-Backed Securities, Securities Act Release No. 33-8518, 70 Red. Reg. 1,506, 1,531 (Jan. 7, 2005)) or by the staff of the Commission, or as may be provided by the Commission or its staff from time to time.  

Regulation S :  Regulation S promulgated under the Securities Act or any successor provision thereto, in each case as the same may be amended from time to time; and all references to any rule, section or subsection of, or definition or term contained in, Regulation S means such rule, section, subsection, definition or term, as the case may be, or any successor thereto, in each case as the same may be amended from time to time.

Relevant Servicing Criteria :  The Servicing Criteria applicable to the various parties, as set forth on Exhibit Q.  For clarification purposes, multiple parties can have responsibility for the same Relevant Servicing Criteria.  With respect to a Servicing Function Participant engaged by the Master Servicer, each Servicer, the Trust Administrator, the Trustee or each Servicer, the term "Relevant Servicing Criteria" may refer to a portion of the Relevant Servicing Criteria applicable to such parties.

Relief Act :  The Servicemembers Civil Relief Act of 1940, as amended, and any similar state or local law.

Relief Act Reductions :  With respect to any Distribution Date and any Mortgage Loan as to which there has been a reduction in the amount of interest collectible thereon for the most recently ended calendar month as a result of the application of the Relief Act, the amount, if any, by which (i) interest collectible on such Mortgage Loan for the most recently ended calendar month is less than (ii) interest accrued thereon for such month pursuant to the Mortgage Note.

REMIC :  A "real estate mortgage investment conduit", within the meaning of Section 860D of the Code.  Reference herein to REMIC refers to the Master REMIC and Subsidiary REMIC 1, as the context requires.

REMIC Election :  An election, for federal income tax purposes, to treat certain assets as a REMIC.

REMIC Provisions :  Provisions of the federal income tax law relating to real estate mortgage investment conduits, which appear at sections 860A through 860G of Subchapter M of Chapter 1 of the Code, and related provisions, and regulations promulgated thereunder, as the foregoing may be in effect from time to time.

REO Disposition :  The final sale by Wells Fargo, as a Servicer, of any REO Property.

REO Disposition Fee :  With respect to each REO Disposition, the greater of (i) $1,200 or (ii) one percent (1%) of the final sales price of such REO Disposition; provided that the real estate broker commission with respect to the liquidation of the REO property is equal to or less than 5% except in such cases where the property value is less than $100,000 or the property is located in a rural area and market conditions require the related Servicer to pay a real estate broker commission greater than 5% or prior written consent has been obtained from DLJMC or its authorized representative.

REO Property :  A Mortgaged Property acquired by the Trust Fund through foreclosure or deed-in-lieu of foreclosure in connection with a defaulted Mortgage Loan.

Representatives :  As defined in Section 3.05(b).

Required Basis Risk Reserve Fund Amount :  With respect to any Distribution Date, $5,000.

Required Basis Risk Reserve Fund Deposit :  With respect to any Distribution Date, the sum of (i) any Basis Risk Shortfall for such date (net of amounts available to pay Basis Risk Shortfalls on deposit in the Interest Rate Cap Accounts on such date) and (ii) the excess, if any, of the Required Basis Risk Reserve Fund Amount for such Distribution Date over the amount on deposit in the Basis Risk Reserve Fund at the close of business on the Business Day immediately preceding such Distribution Date.

Required Insurance Policy :  With respect to any Non-Designated Mortgage Loan, any insurance policy that is required to be maintained from time to time under this Agreement in respect of such Mortgage Loan or the related Mortgaged Property.

Reportable Event :  As defined in Section 14.04.

Reporting Servicer :  As defined in Section 14.03.

Residual Certificates :  The Class AR Certificates.

Responsible Officer :  When used with respect to the Trustee or the Trust Administrator, shall mean any officer within the corporate trust department of the Trustee or the Trust Administrator, respectively, including any Assistant Vice President, the Secretary, any Assistant Secretary, the Treasurer, any Assistant Treasurer, any Trust Officer or any other officer of the Trustee or the Trust Administrator customarily performing functions similar to those performed by any of the above designated officers and also, with respect to a particular matter, any other officer to whom such matter is referred because of such officer’s knowledge of and familiarity with the particular subject.

Rolling Three Month Delinquency Rate :  For any Distribution Date will be the fraction, expressed as a percentage, equal to the average of the related Delinquency Rates for each of the three (or one and two, in the case of the first and second Distribution Dates) immediately preceding months.

Rule 144A :  Rule 144A under the Securities Act, as in effect from time to time.

S&P :  Standard & Poor’s Ratings Services, a division of The McGraw-Hill Companies, Inc., or any successor thereto.

Scheduled Payment :  The scheduled monthly payment on a Mortgage Loan due on any Due Date allocable to principal and/or interest on such Mortgage Loan pursuant to the terms of the related Mortgage Note.

Sarbanes-Oxley Act :  The Sarbanes-Oxley Act of 2002 and the rules and regulations of the Commission promulgated thereunder (including any interpretations thereof by the Commission’s staff).

Sarbanes-Oxley Certification :  As defined in Section 14.09.

Securities Act :  means the Securities Act of 1933, as amended, and the rules and regulations thereunder.

Security Agreement :  With respect to a Cooperative Loan, the agreement or mortgage creating a security interest in favor of the originator of the Cooperative Loan in the related Cooperative Shares.

Seller :  DLJMC.

Senior Certificates :  As set forth in the Preliminary Statement.

Senior Enhancement Percentage :  For any Distribution Date, the fraction, expressed as a percentage, the numerator of which is the sum of the aggregate Class Principal Balance of the Subordinate Certificates (other than the Class X Certificates) and the Overcollateralization Amount (which, for purposes of this definition only, shall not be less than zero), in each case prior to giving effect to payments on such Distribution Date (assuming no Trigger Event has occurred), and the denominator of which is the Aggregate Loan Balance as of the first day of the related Collection Period.

Senior Principal Payment Amount :  For any Distribution Date on or after the Stepdown Date and as long as a Trigger Event has not occurred with respect to such Distribution Date, will be the amount, if any, by which (x) the aggregate Class Principal Balance of the Senior Certificates immediately prior to such Distribution Date exceeds (y) the lesser of (A) the product of (i) 86.47% and (ii) the Aggregate Loan Balance for such Distribution Date and (B) the amount, if any, by which (i) the Aggregate Loan Balance for such Distribution Date exceeds (ii) 0.50% of the Aggregate Loan Balance as of the Cut-off Date.

Servicer(s) :  SPS, Countrywide, Wells Fargo and any successor in interest thereto or any successor servicer appointed as provided herein.

Servicer Employee :  As defined in Section 3.18.

Service(s)(ing) :  In accordance with Regulation AB, the act of servicing and administering the Mortgage Loans or any other assets of the Trust Fund by an entity that meets the definition of "servicer’ set forth in Item 1101 of Regulation AB and is subject to the disclosure requirements set forth in 1108 of Regulation AB.  For clarification purposes, any uncapitalized occurrence of this term shall have the meaning commonly understood by participants in the residential mortgage-backed securitization market.

Servicing Advance :  With respect to the Non-Designated Mortgage Loans, all customary, reasonable and necessary "out of pocket" costs and expenses incurred in the performance by a Servicer of its servicing obligations related to such Mortgage Loans, including, but not limited to, the cost (including reasonable attorneys’ fees and disbursements) of (i) the preservation, restoration and protection of a Mortgaged Property, (ii) compliance with the obligations under Section 3.11 and any enforcement or judicial proceedings, including foreclosures, (iii) any litigation related to a Mortgage Loan, (iv) the management and liquidation of any REO Property (including default management and similar services, appraisal services and real estate broker services), (v) any expenses incurred by a Servicer in connection with obtaining an environmental inspection or review pursuant to the second paragraph of Section 3.11(a), (vi) compliance with the obligations under Section 3.09, (vii) locating any documents missing from the Trustee’s Mortgage File and (viii) obtaining broker price opinions.

With respect to the Designated Mortgage Loans, Servicing Advance shall have the meaning assigned to such term in the Designated Servicing Agreement.

Servicing Criteria :  The "servicing criteria" set forth in Item 1122(d) of Regulation AB, as such may be amended from time to time.

Servicing Fee :  As to each Mortgage Loan and any Distribution Date, an amount equal to one month’s interest at the Servicing Fee Rate on the Stated Principal Balance of such Mortgage Loan as of the Due Date in the month of such Distribution Date (prior to giving effect to any Scheduled Payments due on such Mortgage Loan on such Due Date), subject to reduction as provided in Section 3.14.

Servicing Fee Rate :  The per annum rate set forth on the Mortgage Loan Schedule.

Servicing Function Participant :  Any Sub-Servicer, Subcontractor or any other Person, other than each Servicer, the Master Servicer, the Trustee and the Trust Administrator, that is performing activities addressed by the Servicing Criteria, unless such Person’s activities relate only to 5% or less of the Mortgage Loans (measured as the weighted average of the monthly percentages of the aggregate Stated Principal Balance of the Mortgage Loans serviced by such participant during the commencement of the calendar year prior to the year in which an Assessment of Compliance is required to be delivered, multiplied by a fraction, the numerator of which is the number of months in such year during which such Servicing Function Participant Services the related Mortgage Loans and the denominator of which is 12, or, in the case of the year in which the Closing Date occurs, the number of months elapsed from the Cut-Off Date to the end of such calendar year).  For clarification purposes, each of the Custodians are Servicing Function Participants.

Servicing Officer :  Any officer of the Master Servicer, Servicer or Modification Oversight Agent involved in, or responsible for, the administration and servicing of the related Mortgage Loans whose name and specimen signature appear on a list of servicing officers furnished to the Trustee and the Trust Administrator by the Master Servicer, a Servicer or the Modification Oversight Agent on the Closing Date pursuant to this Agreement, as such list may from time to time be amended and delivered to the Trustee and Trust Administrator.

Special Payoff Mortgage Loan :  With respect to any Distribution Date, any Mortgage Loan (i) that was subject to a Payoff in the month preceding the month of such Distribution Date and (ii) the principal of which was distributed on the Distribution Date immediately preceding such Distribution Date.

Special Servicer :  Any special servicer appointed by the Class X Certificateholder pursuant to Section 3.19.

Special Serviced Mortgage Loan :  The Mortgage Loans for which any Special Servicer acts as servicer pursuant to Section 3.19.

SPS :  Select Portfolio Servicing, Inc., a Utah corporation, and its successors and assigns.

SPS Mortgage Loans :  Any SPS Serviced Mortgage Loans for which SPS has not entered into a sub-servicing arrangement for such Mortgage Loan pursuant to Section 3.02 hereof.

SPS Serviced Mortgage Loans :  The Mortgage Loans identified as such on the Mortgage Loan Schedule, for which SPS is the applicable Servicer.

Standard Hazard Policy :  Each standard hazard insurance policy or replacement therefor referred to in Section 3.09.

Startup Day :  The Closing Date.

Stated Principal Balance :  As to any Mortgage Loan and date of determination, the principal balance of such Mortgage Loan as of the Cut-off Date, after application of the principal portion of all Scheduled Payments due on or before the Cut-off Date, whether or not received, increased by the portion of any Capitalization Reimbursement Amount allocable to such Mortgage Loan, if any, minus the sum of (i) all amounts allocable to principal that have been distributed to Certificateholders with respect to such Mortgage Loan on or before that date of determination and (ii) any Realized Losses on such Mortgage Loan that have been allocated to one or more Classes of Certificates on or before that date of determination.

Stepdown Date :  The date occurring on the earlier of (i) the first Distribution Date following the Distribution Date on which the aggregate principal balance of the Senior Certificates is reduced to zero and later of (x) the Distribution Date in December 2009 and (y) the first Distribution Date on which the Senior Enhancement Percentage (calculated for this purpose after giving effect to payments or other recoveries in respect of the Mortgage Loans during the related Collection Period but before giving effect to payments on the Certificates on such Distribution Date) is greater than or equal to 13.53%.

Streamlined Mortgage Loan :  A Mortgage Loan originated in connection with the refinance of a mortgage loan pursuant to the Seller’s streamlined documentation program then in effect.

Stock Power :  With respect to a Cooperative Loan, an assignment of the stock certificate or an assignment of the Cooperative Shares issued by the Cooperative Corporation.

Subcontractor :  Any vendor, subcontractor or other Person that (i) is a Servicing Function Participant and (ii) is not responsible for the overall servicing of Mortgage Loans but performs one or more discrete functions identified in Item 1122(d) of Regulation AB with respect to Mortgage Loans under the direction or authority of any Servicer (or a Sub-Servicer of any Servicer), the Master Servicer, the Trustee or the Trust Administrator.

Subordinate Certificates :  As set forth in the Preliminary Statement.

Subsidiary REMIC 1 :  As described in the Preliminary Statement.

Subsidiary REMIC :  Subsidiary REMIC 1.

Subsidiary REMIC Regular Interest :  Any one of the "regular interests" in the Subsidiary REMIC as described in the Preliminary Statement.

Substitution Adjustment Amount :  As defined in Section 2.03.

Sub-Servicer :  Any Person that (i) is a Servicing Function Participant, (ii) services Mortgage Loans on behalf of any Servicer, and (iii) is responsible for the performance (whether directly or through sub-servicers or Subcontractors) of Servicing functions required to be performed under this Agreement, the Designated Servicing Agreement or any sub-servicing agreement that are identified in Item 1122(d) of Regulation AB.

Sub-Servicing Agreement :  Any servicing agreement between a Servicer and a Sub-Servicer pursuant to which such Servicer delegates any of its servicing responsibilities with respect to any of the Non-Designated Mortgage Loans.

Supplemental Interest Trust :  A trust created pursuant to this Agreement, (which is separate from the Trust Fund) consisting of the Interest Rate Cap Agreements, the Interest Rate Cap Accounts and the right to receive payments from the Interest Rate Cap Agreement Counterparty.

Supplemental Interest Trust Trustee :  The Trustee acting not in its individual capacity, but solely as trustee of the Supplemental Interest Trust.

Targeted Overcollateralization Amount :  The Targeted Overcollateralization Amount shall equal (1) with respect to any Distribution Date prior to the Stepdown Date, 0.55% of the Aggregate Loan Balance as of the Cut-off Date; (2) with respect to any Distribution Date on or after the Stepdown Date and with respect to which a Trigger Event is not in effect, the greater of (a) 1.10% of the Aggregate Loan Balance for such Distribution Date, and (b) 0.50% of the Aggregate Loan Balance as of the Cut-off Date; and (3) with respect to any Distribution Date on or after the Stepdown Date with respect to which a Trigger Event has occurred and is continuing, the Targeted Overcollateralization Amount for the Distribution Date immediately preceding such Distribution Date.

Tax Matters Person :  The person designated as "tax matters person" in the manner provided under treasury regulation § 1.860F-4(d) and temporary treasury regulation § 301.6231(a)(7)-1T.  Initially, the Tax Matters Person shall be the Trust Administrator.

Terminating Entity :  As determined by the Trust Administrator pursuant to Section 11.02(a).

Transferee Affidavit and Agreement :  As defined in Section 6.02(g)(i)(2).

Trigger Event :  A Trigger Event will occur for any Distribution Date if either (i) the Rolling Three Month Delinquency Rate as of the last day of the related Collection Period equals or exceeds the applicable percentage (as set forth in the table immediately below) of the Most Senior Enhancement Percentage for the most senior Class of Certificates then outstanding :

or (ii) the cumulative Realized Losses with respect to Mortgage Loans as a percentage of the original Aggregate Loan Balance on the Closing Date for such Distribution Date is greater than the percentage set forth in the following table:  

* The percentages set forth above are the percentages applicable for the first Distribution Date in the corresponding range of Distribution Dates.  The percentage for each succeeding Distribution Date in a range increases incrementally by 1/12 of the positive difference between the percentage applicable to the first Distribution Date in that range and the percentage applicable to the first Distribution Date in the succeeding range.

Trust :  CSAB Mortgage Backed Trust 2006-4.

Trust Administrator :  Wells Fargo Bank, N.A. a national banking association, not in its individual capacity, but solely in its capacity as trust administrator for the benefit of the Certificateholders under this Agreement, and any successor thereto, as provided herein.

Trust Administrator Fee :  As to any Distribution Date, an amount equal to one month’s interest at the Trust Administrator Fee Rate on the aggregate Stated Principal Balance of the Mortgage Loans calculated as of the first day of the related Collection Period.

Trust Administrator Fee Rate :  As to each Mortgage Loan, a per annum rate equal to 0.00%.

Trust Collateral:  As defined in Section 11.01(C).

Trust Fund :  The corpus of the trust created by this Agreement consisting of (a) the Mortgage Loans listed in the Mortgage Loan Schedule, including all interest and principal received on or with respect to the Mortgage Loans after the Cut-off Date, but not including payments of principal and interest due and payable on the Mortgage Loans on or before the Cut-off Date, together with the Mortgage Files relating to the Mortgage Loans, (b) REO Property, (c) the Collection Account, the Certificate Account, the Interest Rate Cap Accounts (subject to Section 4.08(b)), the Interest Rate Cap Agreements and the Basis Risk Reserve Fund and all amounts deposited therein pursuant to the applicable provisions of this Agreement, (d) any Insurance Policies with respect to the Mortgage Loans, (e) the Depositor’s rights under the Assignment and Assumption Agreement, (f) the Policy and (g) all proceeds of the conversion, voluntary or involuntary, of any of the foregoing into cash or other liquid property.  

Trust Receipt and Final Certification :  As defined in Section 2.02(a).

Trust Receipt and Initial Certification :  As defined in Section 2.02(a).

Trustee :  U.S. Bank National Association, a national banking association, not in its individual capacity, but solely in its capacity as trustee for the benefit of the Certificateholders under this Agreement, and any successor thereto, as provided herein.

Trustee Mortgage File :  The mortgage documents listed in Section 2.01 hereof pertaining to a particular Mortgage Loan and any additional documents required to be added to the Trustee Mortgage File pursuant to this Agreement.

Underwriter’s Exemption :  Prohibited Transaction Exemption 2002-41, 67 Fed. Reg. 54487 (2002), as amended (or any successor thereto), or any substantially similar administrative exemption granted by the U.S. Department of Labor.

U.S. Bank :  U.S. Bank National Association.

U.S. Person :  A citizen or resident of the United States, a corporation, partnership or other entity treated as a corporation or partnership for federal income tax purposes created or organized in, or under the laws of, the United States, any state thereof or the District of Columbia, or an estate or trust whose income from sources without the United States is includible in gross income for United States federal income tax purposes regardless of its connection with the conduct of a trade or business within the United States, and any trust that elects to be treated as a United States Person that is eligible to make such election under Code Section 7701(a)(30).

Voting Rights :  The portion of the voting rights of all the Certificates that is allocated to any Certificate for purposes of the voting provisions of this Agreement.  At all times during the term of this Agreement, 99% of all Voting Rights shall be allocated among the Holders of the Certificates, except for the Class P, Class X and Class AR Certificates.  The portion of such 99% Voting Rights allocated to each of the Certificates, except for the Class P, Class X and Class AR Certificates, shall be based on the fraction, expressed as a percentage, the numerator of which is the aggregate Class Principal Balance then outstanding and the denominator of which is the Class Principal Balance of all such Classes then outstanding.  The Class X Certificates shall be allocated 1% of the Voting Rights; provided, however, for so long as the Class X Certificates, or any portion thereof, are held in a NIM Trust, the holders of the Class X Certificates shall not be entitled to exercise any Voting Rights with respect to their  Certificates and the Voting Rights otherwise allocable to the Class X Certificates shall be allocated to the other Classes of Certificates other than the Class P and Class AR Certificates.  Voting Rights shall be allocated among the Certificates within each such Class in proportion to their respective Percentage Interests.  The Class P and Class AR Certificates shall have no Voting Rights.  Notwithstanding any of the foregoing, unless a Certificate Insurer Default is continuing, on any date on which any Insured Certificates are outstanding, or any amounts are owed to the Certificate Insurer under this Agreement, the Certificate Insurer will have all Voting Rights of the Insured Certificates.  So long as the Certificate Insurer has the Voting Rights pursuant to the preceding sentence, the reference to holders of the Class A-4 Certificates in this definition shall be deemed to refer to the Certificate Insurer.

Wells Fargo :  Wells Fargo Bank, N.A., a national banking association, and its successors and assigns.

Wells Fargo Serviced CORE Mortgage Loans :  The Mortgage Loans identified as such on the Mortgage Loan Schedule, for which Wells Fargo is the applicable Servicer and the owner of the related servicing rights.

Wells Fargo Serviced Mortgage Loans :  The Mortgage Loans identified as such on the Mortgage Loan Schedule, for which Wells Fargo is the applicable Servicer.

ARTICLE II

CONVEYANCE OF MORTGAGE LOANS;
REPRESENTATIONS AND WARRANTIES

SECTION 2.01

Conveyance of Trust Fund.

(a)

The Depositor hereby sells, transfers, assigns, delivers, sets over and otherwise conveys to the Trustee in trust for the benefit of the Certificateholders and the Certificate Insurer, without recourse, the Depositor’s right, title and interest in and to (a) the Mortgage Loans listed in the Mortgage Loan Schedule, including all interest and principal received or receivable by the Depositor on or with respect to the Mortgage Loans after the Cut-off Date and any Assigned Prepayment Premiums, but not including payments of principal and interest due and payable on the Mortgage Loans on or before the Cut-off Date, together with the Mortgage Files relating to the Mortgage Loans, (b) REO Property related to the Mortgage Loans, (c) the Collection Account, the Certificate Account and the Basis Risk Reserve Fund and all amounts deposited therein pursuant to the applicable provisions of this Agreement, (d) any Insurance Policies with respect to the Mortgage Loans, (e) the Depositor’s rights under the Assignment and Assumption Agreement and (f) all proceeds of the conversion, voluntary or involuntary, of any of the foregoing into cash or other liquid property.  In addition, on or prior to the Closing Date, the Depositor shall cause the Supplemental Interest Trust Trustee, on behalf of the Trust Fund, to enter into each of the Interest Rate Cap Agreements with the Interest Rate Cap Agreement Counterparty and shall cause the Trust Administrator to acknowledge and agree to each Interest Rate Cap Agreement and the Depositor shall pay or cause to be paid on behalf of the Trust Fund the payments owed to the Interest Rate Cap Agreement Counterparty as of the Closing Date under the Interest Rate Cap Agreements.    

It is agreed and understood by the Depositor, the Seller, the Modification Oversight Agent, the Servicers, the Master Servicer, the Trust Administrator and the Trustee that it is not intended that any Mortgage Loan be included in the Trust Fund that is a "High-Cost Home Loan" as defined in the New Jersey Home Ownership Act, effective as of November 27, 2003, or The Home Loan Protection Act of New Mexico, effective as of January 1, 2004, or that is a "High Cost Home Mortgage Loan" as defined in the Massachusetts Predatory Home Loan Practices Act, effective as of November 7, 2004, or that is an "Indiana High Cost Home Mortgage Loan" as defined in the Indiana High Cost Home Loan Act, effective as of January 1, 2005 or a "High Cost Loan" or "Covered Loan", as applicable, as such terms are defined in the Standard & Poor’s LEVELS® Glossary, Appendix E, in effect as of the Closing Date.

(b)

In connection with the transfer and assignment set forth in clause (a) above, the Depositor has delivered or caused to be delivered to the Custodian for the benefit of the Certificateholders and the Certificate Insurer, the documents and instruments with respect to each Mortgage Loan as assigned:

(i)

(A) the original Mortgage Note bearing all intervening endorsements and including any riders to the Mortgage Note, endorsed "Pay to the order of ________________, without recourse" and signed in the name of the last named endorsee by an authorized officer or (B) with respect to any Lost Mortgage Note, a lost note affidavit and indemnity from the Seller stating that the original Mortgage Note was lost or destroyed, (together with a copy of such Mortgage Note, if available) and indemnifying the Trust Fund against any loss, cost or liability resulting from the failure to deliver the original Mortgage Note;

(ii)

the original of any guarantee executed in connection with the Mortgage Note (if any);

(iii)

for each Mortgage Loan that is not a MERS Mortgage Loan, the original Mortgage, with evidence of recording thereon, or copies certified by the related recording office or if the original Mortgage has not yet been returned from the recording office, a copy certified by or on behalf of the Seller indicating that such Mortgage has been delivered for recording (the return directions for the original Mortgage should indicate, when recorded, mail to the Seller) and in the case of each MERS Mortgage Loan, the original Mortgage, noting the presence of the MIN of the related Mortgage Loan and either language indicating that the Mortgage Loan is a MOM Loan if the Mortgage Loan is a MOM Loan or if the Mortgage Loan was not a MOM Loan at origination, the original Mortgage and the assignment thereof to MERS, with evidence of recording indicated thereon or a copy of the Mortgage certified by the public recording office in which such Mortgage has been recorded;

(iv)

the originals of all assumption, modification, consolidation or extension agreements, (or, if an original of any of these documents has not been returned from the recording office, a copy thereof certified by or on behalf of the Seller, the original to be delivered to the Seller forthwith after return from such recording office) with evidence of recording thereon, if any;

(v)

for each Mortgage Loan that is not a MERS Mortgage Loan, the original Assignment of Mortgage as appropriate, in recordable form, for each Mortgage Loan from the last assignee assigned in blank;

(vi)

for each Mortgage Loan that was not a MERS Mortgage Loan at its origination, the originals of any intervening recorded Assignments of Mortgage, showing a complete chain of assignment from origination to the last assignee, including warehousing assignments, with evidence of recording thereon (or, if an original intervening Assignment of Mortgage has not been returned from the recording office, a copy thereof certified by or on behalf of the Seller, the original to be delivered to the Custodian forthwith after return from such recording office);

(vii)

the original mortgage title insurance policy, or copy of title commitment (or in appropriate jurisdictions, attorney’s opinion of title and abstract of title); and

(viii)

with respect to a Cooperative Loan, if any, the originals of the following documents or instruments:

(A)

the Cooperative Shares, together with the Stock Power in blank;

(B)

the executed Security Agreement;

(C)

the executed Proprietary Lease and the Assignment of Proprietary Lease to the originator of the Cooperative Loan;

(D)

the executed Recognition Agreement;

(E)

Copies of the original UCC financing statement, and any continuation statements, filed by the originator of such Cooperative Loan as secured party, each with evidence of recording thereof, evidencing the interest of the originator under the Security Agreement and the Assignment of Proprietary Lease;

(F)

Copies of the filed UCC assignments or amendments of the security interest referenced in clause (E) above showing an unbroken chain of title from the originator to the Trust Fund, each with evidence of recording thereof, evidencing the interest of the assignee under the Security Agreement and the Assignment of Proprietary Lease;

(G)

An executed assignment of the interest of the originator in the Security Agreement, the Assignment of Proprietary Lease and the Recognition Agreement, showing an unbroken chain of title from the originator to the Trust Fund; and

(H)

For any Cooperative Loan that has been modified or amended, the original instrument or instruments effecting such modification or amendment.

In addition, in connection with the assignment of any MERS Mortgage Loan, the related Servicer agrees that it will cause, at the Seller’s direction and expense, the MERS® System to indicate that such Mortgage Loans have been assigned by the Seller to the Trustee in accordance with this Agreement for the benefit of the Certificateholders and the Certificate Insurer by including (or deleting, in the case of Mortgage Loans which are repurchased or substituted in accordance with this Agreement) the information required by the MERS® System to (a) identify the Trustee and (b) identify the series of the Certificates issued in connection with such Mortgage Loans.  The related Servicer shall report to the Depositor, the Certificate Insurer and the Custodian the status of updating all applicable assignments with MERS within 60 days of the Closing Date and shall confirm in writing to the applicable Custodian and the Certificate Insurer (which may be furnished electronically) once all assignments are updated with MERS.  The Seller further agrees that it will not, and will not permit a Servicer to, and each related Servicer agrees that it will not, alter the information referenced in this paragraph with respect to any Mortgage Loan during the term of this Agreement unless and until such Mortgage Loan is repurchased or substituted in accordance with the terms of this Agreement.

In the event the Depositor delivers to the Custodian certified copies of any document or instrument set forth in 2.01(b) because of a delay caused by the public recording office in returning any recorded document, the Depositor shall deliver or cause to be delivered to the Custodian, within 60 days of the Closing Date, an Officer’s Certificate which shall (i) identify the recorded document, (ii) state that the recorded document has not been delivered to the Custodian due solely to a delay caused by the public recording office, and (iii) state the amount of time generally required by the applicable recording office to record and return a document submitted for recordation.

In the event that in connection with any Mortgage Loan the Depositor cannot deliver (a) for a Mortgage Loan that is not a MERS Mortgage Loan, the original recorded Mortgage, (b) all interim recorded assignments or (c) the lender’s title policy (together with all riders thereto) satisfying the requirements set forth above, concurrently with the execution and delivery hereof because such document or documents have not been returned from the applicable public recording office in the case of clause (a) or (b) above, or because the title policy has not been delivered to the Seller or the Depositor by the applicable title insurer in the case of clause (c) above, the Depositor shall promptly deliver to the Custodian, in the case of clause (a) or (b) above, such original Mortgage or such interim assignment, as the case may be, with evidence of recording indicated thereon upon receipt thereof from the public recording office, or a copy thereof, certified, if appropriate, by the relevant recording office.

As promptly as practicable subsequent to such transfer and assignment, and in any event, within thirty (30) days thereafter, DLJMC shall, at its expense, (i) affix or cause to be affixed the Trustee’s name to each Assignment of Mortgage, as the assignee thereof, (ii) cause such assignment to be in proper form for recording in the appropriate public office for real property records within thirty (30) days after receipt thereof and (iii) cause to be delivered for recording in the appropriate public office for real property records the assignments of the Mortgages to the Trustee, except that, with respect to any assignment of a Mortgage as to which DLJMC has not received the information required to prepare such assignment in recordable form, DLJMC’s obligation to do so and to deliver the same for such recording shall be as soon as practicable after receipt of such information and in any event within thirty (30) days after the receipt thereof, and DLJMC need not cause to be recorded any assignment which relates to a Mortgage Loan in any jurisdiction under the laws of which, as evidenced by an Opinion of Counsel delivered by the Depositor (at the Depositor’s expense) to the Trustee, the Trust Administrator, the Certificate Insurer and DLJMC, acceptable to the Rating Agencies, the recordation of such assignment is not necessary to protect the Trustee’s, the Certificate Insurer’s and the Certificateholders’ interest in the related Mortgage Loan.

If any original Mortgage Note referred to in Section 2.01(b)(i) above cannot be located, the obligations of the Depositor to deliver such documents shall be deemed to be satisfied upon delivery to the Custodian of a photocopy of such Mortgage Note, if available, with a lost note affidavit and indemnity.  If any of the original Mortgage Notes for which a lost note affidavit and indemnity was delivered to the Custodian is subsequently located, such original Mortgage Note shall be delivered to the Custodian within three Business Days.

(c)

The Trustee is authorized to enter into the Custodial Agreements, at the direction of the Depositor, for the purpose of having a Custodian maintain custody of the documents and instruments referred to in this Section 2.01, and any documents delivered thereunder shall be delivered to the Custodian and any Officer’s Certificates delivered with respect thereto shall be delivered to the Trustee, the Certificate Insurer, the Trust Administrator and the Custodian.

(d)

It is the express intent of the parties to this Agreement that the conveyance of the Mortgage Loans by the Depositor to the Trustee as provided in this Section 2.01 be, and be construed as, a sale of the Mortgage Loans by the Depositor to the Trustee.  It is, further, not the intention of the parties to this Agreement that such conveyance be deemed a pledge of the Mortgage Loans by the Depositor to the Trustee to secure a debt or other obligation of the Depositor.  However, in the event that, notwithstanding the intent of the parties to this Agreement, the Mortgage Loans are held to be the property of the Depositor, or if any for any other reason this Agreement is held or deemed to create a security interest in the Mortgage Loans then (a) this Agreement shall also be deemed to be a security agreement within the meaning of Articles 8 and 9 of the New York Uniform Commercial Code; (b) the conveyance provided for in this Section 2.01 shall be deemed to be a grant by the Depositor to the Trustee for the benefit of the Certificateholders and the Certificate Insurer of a security interest in all of the Depositor’s right, title and interest in and to the Mortgage Loans and all amounts payable to the holders of the Mortgage Loans in accordance with the terms thereof and all proceeds of the conversion, voluntary or involuntary, of the foregoing into cash, instruments, securities or other property, including without limitation all amounts, other than investment earnings, from time to time held or invested in the Certificate Account, whether in the form of cash, instruments, securities or other property; (c) the possession by the Trustee or the Custodian of such items of property and such other items of property as constitute instruments, money, negotiable documents or chattel paper shall be deemed to be "in possession by the secured party" for purposes of perfecting the security interest pursuant to Section 9-313 of the New York Uniform Commercial Code; and (d) notifications to persons holding such property, and acknowledgments, receipts or confirmations from persons holding such property, shall be deemed notifications to, or acknowledgments, receipts or confirmations from, financial intermediaries, bailees or agents (as applicable) of the Trustee for the benefit of the Certificateholders and the Certificate Insurer for the purpose of perfecting such security interest under applicable law (except that nothing in this clause (d) shall cause any person to be deemed to be an agent of the Trustee for any purpose other than for perfection of such security interests unless, and then only to the extent, expressly appointed and authorized by the Trustee in writing).  The Depositor and the Trustee, upon directions from the Depositor, shall, to the extent consistent with this Agreement, take such actions as may be necessary to ensure that, if this Agreement were deemed to create a security interest in the Mortgage Loans, such security interest would be deemed to be a perfected security interest of first priority under applicable law and will be maintained as such throughout the term of this Agreement.  

SECTION 2.02

Acceptance by the Trustee.

(a)

The Trustee shall require the Custodian, pursuant to the Custodial Agreement, to execute and deliver on the Closing Date to the Depositor, the Certificate Insurer, the Master Servicer, Wells Fargo, the Seller, the Trustee and the Trust Administrator a Trust Receipt and Initial Certification with respect to the Mortgage Loans in the form annexed hereto as Exhibit J.  Such Trust Receipt and Initial Certification shall require the Custodian, based on its review and examination, and only as to the documents identified in such Trust Receipt and Initial Certification, to acknowledge that such documents appear regular on their face and relate to such Mortgage Loan.  The Custodian shall not be required to inspect, review or examine said documents, instruments, certificates or other papers to determine that the same are genuine, enforceable or appropriate for the represented purpose or that they have actually been recorded in the real estate records or that they are other than what they purport to be on their face.

Pursuant to Section 6 of the Custodial Agreement, not later than 90 days after the Closing Date, the Custodian shall deliver to the Depositor, Wells Fargo, as servicer, the Certificate Insurer, the Trustee and the Trust Administrator a Trust Receipt and Final Certification with respect to the Mortgage Loans in the form annexed hereto as Exhibit K, with any applicable exceptions noted thereon.

Based solely upon the Trust Receipt and Initial Certification received from the Custodian, and subject to the provisions of Section 2.01 and any exceptions noted on the exception report described in the next paragraph below, the Trustee acknowledges receipt of the documents referred to in Section 2.01 above and declares that it holds and will hold such documents and the other documents delivered to it constituting the Mortgage File, and that it holds or will hold all such assets and such other assets included in the definition of the Trust Fund in trust for the exclusive use and benefit of all present and future Certificateholders and the Certificate Insurer.

If, in the course of such review, the Custodian finds any document constituting a part of a Mortgage File which does not meet the requirements of Section 2.01, the Custodian shall list such as an exception in the Trust Receipt and Final Certification pursuant to Section 6 of the Custodial Agreement; provided, however , that the Custodian shall not make any determination as to whether (i) any endorsement is sufficient to transfer all right, title and interest of the party so endorsing, as noteholder or assignee thereof, in and to that Mortgage Note or (ii) any assignment is in recordable form or is sufficient to effect the assignment of and transfer to the assignee thereof under the mortgage to which the assignment relates.

The Seller shall promptly correct or cure such defect within 90 days from the date it was so notified of such defect and, if the Seller does not correct or cure such defect within such period and such defect materially and adversely affects the interests of Certificateholders or the Certificate Insurer in the related Mortgage Loan, the Seller shall either (a) substitute for the related Mortgage Loan a Qualified Substitute Mortgage Loan, which substitution shall be accomplished in the manner and subject to the conditions set forth in Section 2.03, or (b) repurchase such Mortgage Loan within 90 days from the date the Seller was notified of such defect in writing at the Purchase Price of such Mortgage Loan, or such longer period not to exceed 720 days from the Closing Date if the substitution or repurchase of a Mortgage Loan pursuant to this provision is required by reason of a delay in delivery of any documents by the appropriate recording office; provided, however, except as required by Section 2.01, that the Seller shall have no liability for recording any Assignment of Mortgage in favor of the Trustee or for the Custodian’s failure to record such Assignment of Mortgage, and provided, further, that the Seller shall not be obligated to repurchase or cure any Mortgage Loan solely as a result of the Custodian’s failure to record such Assignment of Mortgage.  The Trust Administrator shall direct the Custodian to deliver to each Rating Agency and the Certificate Insurer written notice within 270 days from the Closing Date indicating each Mortgage Loan (i) for which a mortgage or assignment of mortgage required to be recorded hereunder has not been returned by the appropriate recording office or (ii) as to which there is a dispute as to location or status of such Mortgage Loan.  Such notice shall be delivered every 90 days thereafter until the related Mortgage Loan is returned to the Custodian.  Any such substitution pursuant to (a) above or purchase pursuant to (b) above shall not be effected prior to the delivery to the Trustee, the Certificate Insurer and the Trust Administrator of the Opinion of Counsel required by Section 2.05 hereof, if any, and any substitution pursuant to (a) above shall not be effected prior to the additional delivery to the Trustee or the Trust Administrator of a Request for Release substantially in the form of Exhibit L. No substitution is permitted to be made in any calendar month after the Determination Date for such month.  The Purchase Price for any such Mortgage Loan shall be deposited by the Seller in the Certificate Account on or prior to the Business Day immediately preceding such Distribution Date in the month following the month of repurchase and, upon receipt of such deposit and certification with respect thereto in the form of Exhibit L hereto, the Custodian shall release the related Mortgage File to the Seller and shall execute and deliver at such entity’s request such instruments of transfer or assignment prepared by such entity, in each case without recourse, as shall be necessary to vest in such entity, or a designee, the Trustee’s interest in any Mortgage Loan released pursuant hereto.

If pursuant to the preceding paragraph the Seller repurchases a Mortgage Loan that is a MERS Mortgage Loan, the related Servicer shall, at the Seller’s expense, either (i) cause MERS to execute and deliver an Assignment of Mortgage in recordable form to transfer the Mortgage from MERS to the Seller and shall cause such Mortgage to be removed from registration on the MERS® System in accordance with MERS’ rules and regulations or (ii) cause MERS to designate on the MERS® System the Seller as the beneficial holder of such Mortgage Loan.

With respect to any Mortgage Loan the Seller reasonably believes breaches a representation, warranty or covenant under a mortgage loan purchase agreement pursuant to which the Seller purchased such Mortgage Loan from the originator or prior holder of such Mortgage Loan, the Seller shall have the right to repurchase such Mortgage Loan from the Trust Fund at any time in order to facilitate its rights against such originator or prior holder of such Mortgage Loan at a price equal to the Purchase Price; provided, however , that in no event shall such repurchase take place with respect to Mortgage Loans constituting more than 5% of the aggregate Cut-off Date Principal Balance of the Mortgage Loans, and provided further that such limitation does not affect the Seller’s obligation to repurchase any Mortgage Loan pursuant to Section 2.03.  Any such repurchase by the Seller pursuant to this provision shall be effected in accordance with the provisions of Section 2.03(c).  

In the event that DLJMC exercises such option, the Purchase Price therefor shall be deposited in the Certificate Account and upon such deposit of the Purchase Price and receipt of a Request for Release in the form of Exhibit L hereto, the Custodian shall release the related Mortgage File held for the benefit of the Certificateholders and the Certificate Insurer to DLJMC, and the Trustee shall execute and deliver at DLJMC’s direction such instruments of transfer or assignment prepared by DLJMC, in each case without recourse, as shall be necessary to transfer title from the Trustee to DLJMC.

(b)

It is understood and agreed that the obligation of the Seller to cure, substitute for or to repurchase any Mortgage Loan which does not meet the requirements of Section 2.01 shall constitute the sole remedy respecting such defect available to the Trustee, the Trust Administrator, the Certificate Insurer, the Depositor and any Certificateholder against the Seller.

SECTION 2.03

Representations and Warranties of the Seller, Master Servicer the Modification Oversight Agent and Servicers.

(a)

Each of DLJMC, in its capacity as Seller, Wells Fargo, in its capacity as the Master Servicer, SPS, in its capacity as a Servicer and as Modification Oversight Agent and Wells Fargo, in its capacity as a Servicer hereby makes the representations and warranties applicable to it set forth in Schedules IIA, IIB, IIC and IID, respectively, as applicable, hereto, and by this reference incorporated herein, to the Depositor, the Certificate Insurer, the Trustee and the Trust Administrator, as of the Closing Date, or if so specified therein, as of the Cut-off Date or such other date as may be specified.  In addition, SPS and Wells Fargo, in their respective capacities as Servicers, hereby make the representations and warranties applicable to it set forth in Schedules IIC and IID hereto, and by this reference incorporated herein, to the Master Servicer, as of the Closing Date, or if so specified therein, as of the Cut-off Date or such other date as may be specified.

(b)

DLJMC, in its capacity as Seller, hereby makes the representations and warranties set forth in Schedule III, applicable to the Mortgage Loans and by this reference incorporated herein, to the Depositor, the Servicers, the Trustee, the Certificate Insurer and the Trust Administrator, as of the Closing Date, or if so specified therein, as of the Cut-off Date or such other date as may be specified, with respect to the Mortgage Loans identified on Schedule I hereto.

(c)

Upon discovery by any of the parties hereto of a breach of a representation or warranty made pursuant to Section 2.03(b) that materially and adversely affects the interests of the Certificateholders or the Certificate Insurer in any Mortgage Loan, the party discovering such breach shall give prompt notice thereof to the other parties and the Certificate Insurer.  The Seller hereby covenants that within 90 days of the earlier of its discovery or its receipt of written notice from any party of a breach of any representation or warranty made by it pursuant to Section 2.03(b) which materially and adversely affects the interests of the Certificateholders or the Certificate Insurer in any Mortgage Loan sold by the Seller to the Trust Fund, it shall cure such breach in all material respects, and if such breach is not so cured, shall, (i) if such 90-day period expires prior to the second anniversary of the Closing Date, remove such Mortgage Loan (a "Deleted Mortgage Loan") from the Trust Fund and substitute in its place a Qualified Substitute Mortgage Loan, in the manner and subject to the conditions set forth in this Section; or (ii) repurchase the affected Mortgage Loan or Mortgage Loans at the Purchase Price in the manner set forth below; provided, however, that any such substitution pursuant to (i) above shall not be effected prior to the delivery to the Certificate Insurer, the Trustee and the Trust Administrator of the Opinion of Counsel required by Section 2.05 hereof, if any, and any such substitution pursuant to (i) above shall not be effected prior to the additional delivery to the Trustee or the Trust Administrator of a Request for Release substantially in the form of Exhibit L relating to the Deleted Mortgage Loan and the Mortgage File for any such Qualified Substitute Mortgage Loan.  The Seller shall promptly reimburse the Trustee, the Trust Administrator and the related Servicer for any actual out-of-pocket expenses reasonably incurred by the Trustee, the Trust Administrator and such related Servicer in respect of enforcing the remedies for such breach.  With respect to any representation and warranties described in this Section which are made to the best of the Seller’s knowledge if it is discovered by any of the Depositor, the Master Servicer, Seller, the Certificate Insurer, any Servicer, any Special Servicer, the Trustee or the Trust Administrator that the substance of such representation and warranty is inaccurate and such inaccuracy materially and adversely affects the value of the related Mortgage Loan or the interests of the Certificateholders or the Certificate Insurer therein, notwithstanding the Seller’s lack of knowledge with respect to the substance of such representation or warranty, such inaccuracy shall be deemed a breach of the applicable representation or warranty.

With respect to any Qualified Substitute Mortgage Loan or Loans, the Seller shall deliver to the Custodian for the benefit of the Certificateholders and the Certificate Insurer, the Mortgage Note, the Mortgage, the related assignment of the Mortgage, and such other documents and agreements as are required by Section 2.01(b), with the Mortgage Note endorsed and the Mortgage assigned as required by Section 2.01.  No substitution is permitted to be made in any calendar month after the Determination Date for such month.  Scheduled Payments due with respect to Qualified Substitute Mortgage Loans in the month of substitution shall not be part of the Trust Fund and will be retained by the Seller on the next succeeding Distribution Date.  For the month of substitution, distributions to Certificateholders will include the monthly payment due on any Deleted Mortgage Loan for such month and thereafter the Seller shall be entitled to retain all amounts received in respect of such Deleted Mortgage Loan.  The Seller shall amend the Mortgage Loan Schedule for the benefit of the Certificateholders and the Certificate Insurer to reflect the removal of such Deleted Mortgage Loan and the substitution of the Qualified Substitute Mortgage Loan or Loans and the Seller shall deliver the amended Mortgage Loan Schedule to the Trustee, the related Servicer and the Trust Administrator.  Upon such substitution, the Qualified Substitute Mortgage Loan or Loans shall be subject to the terms of this Agreement in all respects, and the Seller shall be deemed to have made with respect to such Qualified Substitute Mortgage Loan or Loans, as of the date of substitution, the representations and warranties made pursuant to Section 2.03(b) with respect to such Mortgage Loan.  Upon any such substitution and the deposit to the Collection Account of the amount required to be deposited therein in connection with such substitution as described in the following paragraph, the Trustee shall instruct the Custodian to release the Mortgage File held for the benefit of the Certificateholders relating to such Deleted Mortgage Loan to the Seller and the Trustee shall execute and deliver at the Seller’s direction such instruments of transfer or assignment prepared by the Seller, in each case without recourse, as shall be necessary to vest title in the Seller, or its designee, the Trustee’s interest in any Deleted Mortgage Loan substituted for pursuant to this Section 2.03.

For any month in which the Seller substitutes one or more Qualified Substitute Mortgage Loans for one or more Deleted Mortgage Loans, the related Servicer shall determine the amount (if any) by which the aggregate principal balance of all such Qualified Substitute Mortgage Loans as of the date of substitution is less than the aggregate Stated Principal Balance of all such Deleted Mortgage Loans (after application of the scheduled principal portion of the monthly payments due in the month of substitution).  The amount of such shortage (the "Substitution Adjustment Amount") plus an amount equal to the aggregate of any unreimbursed Advances and Servicing Advances and unpaid Servicing Fees with respect to such Deleted Mortgage Loans and any amount owed under clause (iv) of the definition of Purchase Price shall be deposited in the Collection Account by the Seller on or before the Business Day immediately preceding the Distribution Date in the month succeeding the calendar month during which the related Mortgage Loan became required to be repurchased or replaced hereunder.

One or more Mortgage Loans may be substituted for one or more Deleted Mortgage Loans.  The determination of whether a Mortgage Loan is a Qualified Substitute Mortgage Loan may be satisfied on an individual basis.  Alternatively, if more than one Mortgage Loan is to be substituted for one or more Deleted Mortgage Loans, the characteristics of such Mortgage Loans and Deleted Mortgage Loans shall be aggregated or calculated on a weighted average basis, as applicable, in determining whether such Mortgage Loans are Qualified Substitute Mortgage Loans.

In the event that the Seller shall have repurchased a Mortgage Loan, the Purchase Price therefor shall be deposited in the Collection Account on or before the Business Day immediately preceding the Distribution Date in the month following the month during which the Seller became obligated hereunder to repurchase or replace such Mortgage Loan and upon such deposit of the Purchase Price, the delivery of the Opinion of Counsel if required by Section 2.05 and receipt of a Request for Release in the form of Exhibit L hereto, the Custodian shall release the related Mortgage File held for the benefit of the Certificateholders to such Person, and the Trustee shall execute and deliver at such Person’s direction such instruments of transfer or assignment prepared by such Person, in each case without recourse, as shall be necessary to transfer title from the Trustee.  It is understood and agreed that the obligation under this Agreement of any Person to cure, repurchase or substitute any Mortgage Loan as to which a breach has occurred and is continuing shall constitute the sole remedy against such Persons respecting such breach available to Certificateholders, the Depositor, the Trustee or the Trust Administrator on their behalf.

The representations and warranties made pursuant to this Section 2.03 shall survive delivery of the respective Mortgage Files to the Trustee, the Trust Administrator or the Custodian for the benefit of the Certificateholders and the Certificate Insurer.

SECTION 2.04

Representations and Warranties of the Depositor as to the Mortgage Loans.

The Depositor hereby represents and warrants to the Trustee with respect to the Mortgage Loans that, as of the Closing Date, assuming good title has been conveyed to the Depositor, the Depositor had good title to the Mortgage Loans and Mortgage Notes, and did not encumber the Mortgage Loans during its period of ownership thereof, other than as contemplated by this Agreement.

It is understood and agreed that the representations and warranties set forth in this Section 2.04 shall survive delivery of the Mortgage Files to the Custodian.

SECTION 2.05

Delivery of Opinion of Counsel in Connection with Substitutions.

Notwithstanding any contrary provision of this Agreement, no substitution pursuant to Section 2.02 shall be made more than ninety (90) days after the Closing Date unless the Seller delivers to the Certificate Insurer, the Trustee and the Trust Administrator an Opinion of Counsel, which Opinion of Counsel shall not be at the expense of any of the Certificate Insurer, the Trustee, the Trust Administrator or the Trust Fund, addressed to the Trustee and the Trust Administrator, to the effect that such substitution will not (i) result in the imposition of the tax on "prohibited transactions" on the Trust Fund or contributions after the Startup Date, as defined in Sections 860F(a)(2) and 860G(d) of the Code, respectively, or (ii) cause any REMIC created hereunder to fail to qualify as a REMIC at any time that any Certificates are outstanding; provided, however , that no Opinion of Counsel shall be required if (A) the substitution occurs within two years of the Closing Date and (B) the substitution occurs with respect to Mortgage Loans that are "defective" under the Code and the Seller delivers to the Trustee and the Trust Administrator an Officer's Certificate substantially in the form of Exhibit Y.

SECTION 2.06

Issuance of Certificates.

The Trustee acknowledges the assignment to it of the Mortgage Loans together with the assignment to it of all other assets included in the Trust Fund, receipt of which, subject to the provisions of Section 2.02(a), is hereby acknowledged.  Concurrently with such assignment and delivery and in exchange therefor, the Trust Administrator, pursuant to the written request of the Depositor executed by an officer of the Depositor, has executed the Certificates and caused them to be authenticated and delivered to or upon the order of the Depositor in authorized denominations which evidence ownership of the Trust Fund.  The rights of the Holders of such Certificates to receive distributions from the Trust Fund and all ownership interests of the Holders of the Certificates in such distributions shall be as set forth in this Agreement.

SECTION 2.07

REMIC Provisions.  

(a)

The Depositor hereby elects and authorizes the Trust Administrator to treat the Trust Fund as the number of separate REMICs specified in the Preliminary Statement (each, a "REMIC") under the Code and, if necessary, under applicable state law.  Each such election will be made on Form 1066 or other appropriate federal tax or information return (including Form 8811) or any appropriate state return (x) for the taxable year ending on the last day of the calendar year in which the Certificates are issued and (y) for the taxable year ending on the last day of the calendar year in which Certificates are first sold to a third party.  The Closing Date is hereby designated as the "startup day" of each REMIC created hereunder within the meaning of Section 860G(a)(9) of the Code.  Except as provided in Section 2.07(o), the "regular interests" (within the meaning of Section 860G of the Code) in the Master REMIC shall consist of the Class X Interest and the Certificates (other than the Class X and Class AR Certificates).  Class AR Certificates shall represent the beneficial ownership of the "residual interest" in Subsidiary REMIC 1 and the Master REMIC.  Neither the Depositor nor the Trust Administrator nor the Trustee shall permit the creation of any "interests" (within the meaning of Section 860G of the Code) in any REMIC other than the Certificates and the Subsidiary REMIC Regular Interests.

(b)

The Trust Administrator on behalf of the Holders of the Class AR Certificates, shall act as agent for the Class AR Certificateholder as the "tax matters person" (within the meaning of the REMIC Provisions) for each REMIC, in the manner provided under Treasury regulations section 1.860F-4(d) and temporary Treasury regulations section 301.6231(a)(7)-1T.  By its acceptance of a Class AR Certificate, each Holder thereof shall have agreed to such appointment and shall have consented to the appointment of the Trust Administrator as its agent to act on behalf of each REMIC pursuant to the specific duties outlined herein.

(c)

A Holder of the Class AR Certificates, by the purchase of such Certificates, shall be deemed to have agreed to timely pay, upon demand by the Trust Administrator, the amount of any minimum California state franchise taxes due with respect to each REMIC created hereunder under Sections 23151(a) and 23153(a) of the California Revenue and Taxation Code.  Notwithstanding the foregoing, the Trust Administrator shall be authorized to retain the amount of such tax from amounts otherwise distributable to such Holder in the event such Holder does not promptly pay such amount upon demand by the Trust Administrator.  In the event that any other federal, state or local tax is imposed, including without limitation taxes imposed on a "prohibited transaction" of a REMIC as defined in Section 860F of the Code, such tax shall be charged against amounts otherwise available for distribution to the applicable Holder of a Class AR Certificate and then against amounts otherwise available for distribution to the Holders of Regular Certificates in accordance with the provisions set forth in Section 4.01.  The Trust Administrator or the Trustee shall promptly deposit in the Certificate Account any amount of "prohibited transaction" tax that results from a breach of the Trust Administrator’s or the Trustee’s duties, respectively, under this Agreement.  The Master Servicer or the related Servicer shall promptly deposit in the Certificate Account any amount of "prohibited transaction" tax that results from a breach of the Master Servicer’s or such Servicer’s duties, respectively, under this Agreement.

(d)

The Trust Administrator shall act as attorney-in-fact and as agent on behalf of the tax matters person of each REMIC created hereunder and in such capacity the Trust Administrator shall:  (i) prepare and file, or cause to be prepared and filed, federal and state tax returns (which returns the Trustee shall sign) using a calendar year as the taxable year for each REMIC created hereunder when and as required by the REMIC Provisions and other applicable federal income tax laws as the direct representative of each such REMIC in compliance with the Code and shall provide copies of such returns as required by the Code; (ii) make an election, on behalf of each REMIC created hereunder, to be treated as a REMIC on the federal tax return of such REMIC for its first taxable year, in accordance with the REMIC Provisions; and (iii) prepare and forward, or cause to be prepared and forwarded, to the Certificateholders and to any governmental taxing authority all information reports as and when required to be provided to them in accordance with the REMIC Provisions.  The expenses of preparing and filing such returns shall be borne by the Trust Administrator.  The Depositor, the Master Servicer and the related Servicer shall provide on a prompt and timely basis to the Trust Administrator or its designee such information with respect to each REMIC created hereunder as is in their possession and reasonably required or requested by the Trust Administrator to enable it to perform its obligations under this subsection.

In its capacity as attorney-in-fact and as agent on behalf of the tax matters person, the Trust Administrator shall also:  (A) act on behalf of each REMIC created hereunder in relation to any tax matter or controversy involving the Trust Fund, (B) represent the Trust Fund in any administrative or judicial proceeding relating to an examination or audit by any governmental taxing authority with respect thereto and (C) cause to be paid solely from the sources provided herein the amount of any taxes imposed on each REMIC created hereunder when and as the same shall be due and payable (but such obligation shall not prevent the Trust Administrator or any other appropriate Person from contesting any such tax in appropriate proceedings and shall not prevent the Trust Administrator from withholding payment of such tax, if permitted by law, pending the outcome of such proceedings).

(e)

The Trust Administrator shall provide (i) to any transferor of a Residual Certificate such information as is necessary for the application of any tax relating to the transfer of such Residual Certificate to any Person who is not a permitted transferee, (ii) to the Certificateholders such information or reports as are required by the Code or the REMIC Provisions including reports relating to interest, original issue discount and market discount or premium and (iii) to the Internal Revenue Service the name, title, address and telephone number of the person who will serve as the representative of each REMIC created hereunder.

(f)

The Trustee, to the extent directed by the Trust Administrator, the Depositor and the Holder of the Class AR Certificates (with respect to each REMIC) shall take any action or cause the Trust Fund to take any action necessary to create or maintain the status of each REMIC created hereunder as a REMIC under the REMIC Provisions and shall assist each other as necessary to create or maintain such status.  Neither the Trustee, to the extent directed or (in the case of a failure to act) not directed by the Trust Administrator, nor the Holders of the Residual Certificates shall take any action, cause the Trust Fund to take any action or fail to take (or fail to cause the Trust Fund to take) any action that, under the REMIC Provisions, if taken or not taken, as the case may be, could (i) endanger the status of each REMIC created hereunder as a REMIC or (ii) result in the imposition of a tax upon a REMIC (including, but not limited to, the tax on prohibited transactions as defined in Code Section 860F(a)(2) and the tax on prohibited contributions set forth in Section 860G(d) of the Code) (either such event, an "Adverse REMIC Event") unless the Certificate Insurer, the Trustee and the Trust Administrator have received an Opinion of Counsel (at the expense of the party seeking to take such action) to the effect that the contemplated action will not endanger such status or result in the imposition of such a tax.

The Trustee, the Certificate Insurer and the Trust Administrator shall not take or fail to take any action (whether or not authorized hereunder) as to which the Master Servicer, a Servicer or the Depositor has advised it in writing that it has received an Opinion of Counsel to the effect that an Adverse REMIC Event could occur with respect to such action.  In addition, prior to taking any action with respect to a REMIC or their assets, or causing any REMIC created hereunder to take any action, which is not expressly permitted under the terms of this Agreement, the Trustee and the Trust Administrator will consult with the Master Servicer, the Servicers and the Depositor or their designees, in writing, with respect to whether such action could cause an Adverse REMIC Event to occur with respect to any REMIC created hereunder and the Certificate Insurer, the Trustee and the Trust Administrator shall not take any such action or cause that REMIC to take any such action as to which the Master Servicer, any Servicer or the Depositor has advised it in writing that an Adverse REMIC Event could occur.

In addition, prior to taking any action with respect to any REMIC created hereunder or the assets therein, or causing any REMIC created hereunder to take any action, which is not expressly permitted under the terms of this Agreement, the Holders of the Residual Certificates will consult with the Trust Administrator or its designee, in writing, with respect to whether such action could cause an Adverse REMIC Event to occur with respect to any REMIC created hereunder, and no such Person shall take any action or cause the Trust Fund to take any such action as to which the Trust Administrator has advised it in writing that an Adverse REMIC Event could occur.  The Trust Administrator may consult with counsel to make such written advice, and the cost of same shall be borne by the party seeking to take action not permitted by this Agreement.

At all times as may be required by the Code, the Trust Administrator will to the extent within its control and the scope of its duties more specifically set forth herein, maintain substantially all of the assets of the REMICs as "qualified mortgages" as defined in Section 860G(a)(3) of the Code and "permitted investments" as defined in Section 860G(a)(5) of the Code.

(g)

In the event that any tax is imposed on "prohibited transactions" of any REMIC created hereunder, as defined in Section 860F(a)(2) of the Code, on "net income from foreclosure property" of such REMIC, as defined in Section 860G(c) of the Code, on any contributions to a REMIC after the Startup Day therefor pursuant to Section 860G(d) of the Code, or any other tax is imposed by the Code or any applicable provisions of state or local tax laws, such tax shall be charged (i) to the related Servicer, if such Servicer has in its sole discretion determined to indemnify the Trust Fund against such tax or if such tax arises out of or results from a breach of such Servicer’s duties under (x) Section 2.07(j) of this Agreement to not enter into any arrangement by which a REMIC would receive a fee or other compensation for services or to permit such REMIC to receive any income from assets other than "qualified mortgages" or "permitted investments", (y) Section 3.01 of this Agreement to not make or any modification, waiver or amendment of any Mortgage Loan which would cause any REMIC created hereunder to fail to qualify as a REMIC or result in the imposition of any tax under Section 860F(a) or Section 860G(d) of the Code or (z) Section 3.11(d) of this Agreement to not cause any REO Property to fail to qualify as "foreclosure property" within the meaning of Section 860G(a)(8) of the Code or to subject any REMIC created hereunder to the imposition of any federal, state or local income taxes on the income earned from such Mortgaged Property under Section 860G(c) of the Code of otherwise, (ii) to the Master Servicer, if such tax arises out of or results from a breach by the Master Servicer of any of its obligations under this Agreement or if the Master Servicer has in its sole discretion determined to indemnify the Trust Fund against such tax, (iii) to the Trust Administrator, if such tax arises out of or results from a breach by the Trust Administrator of any of its obligations under this Article II, (iv) to the Trustee, if such tax arises out of or results from a breach by the Trustee of any of its obligations under this Article II, or (v) otherwise against amounts on deposit in the Collection Account as provided by Section 3.08 and on the Distribution Date(s) following such reimbursement the aggregate of such taxes shall be allocated in reduction of the Interest Distribution Amount on each Class entitled thereto in the same manner as if such taxes constituted a Prepayment Interest Shortfall.

In accordance with Section 2.07(c), the related Servicer, the Master Servicer, the Trust Administrator or the Trustee, as applicable, shall promptly deposit in the Certificate Account any amount of such tax.

For purposes of this Section 2.07(g), a tax is imposed following the final and unappealable determination under the Code of the amount of such tax and written notice thereof by the Tax Matters Person to the party to be charged.

(h)

The failure of the related Servicer to promptly deposit in the Certificate Account any amount of such tax shall be an Event of Default, as provided in Section 8.01(b).  

(i)

The Trust Administrator shall, for federal income tax purposes, maintain books and records with respect to each REMIC created hereunder on a calendar year and on an accrual basis or as otherwise may be required by the REMIC Provisions.

(j)

Following the Startup Day, none of any Servicer, the Trustee (which will act only at the direction of the Trust Administrator or as otherwise specifically provided in this Agreement) or the Trust Administrator shall accept any contributions of assets to any REMIC created hereunder unless (subject to Section 2.05) such Servicer, the Trustee or the Trust Administrator shall have received an Opinion of Counsel (at the expense of the party seeking to make such contribution) to the effect that the inclusion of such assets in a REMIC will not cause that REMIC to fail to qualify as a REMIC at any time that any Certificates are outstanding, or subject that REMIC to any tax under the REMIC Provisions or other applicable provisions of federal, state and local law or ordinances.

(k)

None of any Servicer, the Trustee (which will act only at the direction of the Trust Administrator or as otherwise specifically provided in this Agreement) or the Trust Administrator shall (subject to Section 2.05) enter into any arrangement by which a REMIC will receive a fee or other compensation for services nor permit such REMIC to receive any income from assets other than "qualified mortgages" as defined in Section 860G(a)(3) of the Code or "permitted investments" as defined in Section 860G(a)(5) of the Code.

(l)

Within 30 days after the Closing Date, the Trust Administrator shall apply to the Internal Revenue Service for an employer identification number for each REMIC created hereunder by means of a Form SS-4 or other acceptable means and prepare and file with the Internal Revenue Service Form 8811, "Information Return for Real Estate Mortgage Investment Conduits (REMIC) and Issuers of Collateralized Debt Obligations" for each REMIC.

(m)

None of the Trustee (which will act only at the direction of the Trust Administrator or as otherwise specifically provided in this Agreement), the Trust Administrator, the Master Servicer or any Servicer shall sell, dispose of or substitute for any of the Mortgage Loans (except in connection with (i) the default, imminent default or foreclosure of a Mortgage Loan, including but not limited to, the acquisition or sale of a Mortgaged Property acquired by deed in lieu of foreclosure, (ii) the bankruptcy of any REMIC created hereunder, (iii) the termination of any REMIC created hereunder pursuant to Article X of this Agreement or (iv) a purchase of Mortgage Loans pursuant to Article II or III of this Agreement) nor acquire any assets for a REMIC, nor sell or dispose of any investments in the Collection Account or the Certificate Account for gain nor accept any contributions to a REMIC after the Closing Date (a) unless it has received an Opinion of Counsel that such sale, disposition, substitution or acquisition will not affect adversely the status of any REMIC created hereunder as a REMIC or (b) unless the Master Servicer or such Servicer has determined in its sole discretion to indemnify the Trust Fund against such tax.

(n)

In order to enable the Trust Administrator to perform its duties as set forth herein, the Depositor shall provide, or cause to be provided to the Trust Administrator, within ten days after the Closing Date, all information or data that the Trust Administrator determines to be relevant for tax purposes to the valuations and offering prices of the Certificates, including, without limitation, the price, yield, prepayment assumption and projected cash flows of the Certificates and the Mortgage Loans and the Trust Administrator shall be entitled to rely upon any and all such information and data in the performance of its duties set forth herein.  Thereafter, the Master Servicer shall provide, promptly upon request therefor, any such additional information or data that the Trustee or the Trust Administrator may from time to time reasonably request in order to enable the Trustee and the Trust Administrator to perform their duties as set forth herein and the Trustee and the Trust Administrator shall be entitled to rely upon any and all such information and data in the performance of its duties set forth herein.  DLJMC shall indemnify the Trust Administrator and hold it harmless for any loss, liability, damage, claim or expense of the Trust Administrator arising from any failure of the Depositor to provide, or to cause to be provided, accurate information or data to the Trust Administrator on a timely basis. The Master Servicer shall indemnify the Trustee and the Trust Administrator and hold it harmless for any loss, liability, damage, claim or expense of the Trustee and the Trust Administrator arising from any failure of the Master Servicer to provide, or to cause to be provided, accurate information or data required to be provided by the Master Servicer to the Trustee and the Trust Administrator on a timely basis; provided, however, that if any Servicer  shall fail to provide such information to the Master Servicer upon timely request for such information by the Master Servicer, that Servicer shall indemnify the Master Servicer, the Trustee and the Trust Administrator and hold it harmless for any loss, liability, damage, claim or expense of the Master Servicer, the Trustee and the Trust Administrator arising from any failure of that Servicer to provide, or to cause to be provided, the information referred to above on a timely basis.  The indemnification provisions hereunder shall survive the termination of this Agreement and shall extend to any co-trustee and co-trust administrator appointed pursuant to this Agreement.

(o)

The Trust Administrator shall treat each of the Supplemental Interest Trust and the Basis Risk Reserve Fund as an outside reserve fund within the meaning of Treasury Regulation 1.860G-2(h) that is owned by the Class X Certificateholder, and not as an asset of any REMIC.  The Trust Administrator shall treat the rights of the Certificateholders (other than with respect to the Class X, Class P or Class AR Certificates) to receive payments from the Supplemental Interest Trust and the Basis Risk Reserve Fund as rights in an interest rate cap contract written by the Class X Certificateholder in favor of such Certificateholders.  Thus, each Certificate (other than the Class X, Class P or Class AR Certificates) shall be treated as representing ownership of not only REMIC Regular Interests, but also ownership of an interest in interest rate cap contracts or a separate contractual right.  For purposes of determining the issue price of the REMIC Regular interests, the Trust Administrator shall assume that the interest rate cap contract has a value of $10,000.

SECTION 2.08

Covenants of the Master Servicer, the Trust Administrator and each Servicer.

(a)

The Master Servicer and each Servicer, severally and not jointly, hereby covenants to the Depositor, the Certificate Insurer, the Trustee and the Trust Administrator as follows:

(i)

Such Servicer or the Master Servicer shall comply in the performance of its obligations under this Agreement with all reasonable rules and requirements of the insurer under each Mortgage Guaranty Insurance Policy; and

(ii)

No written information, certificate of an officer, statement furnished in writing or written report delivered to the Depositor, any affiliate of the Depositor, the Certificate Insurer, the Trustee or the Trust Administrator and prepared by the Master Servicer or such Servicer pursuant to this Agreement will contain any untrue statement of a material fact.

(b)

The Trust Administrator hereby covenants to the Depositor, the Certificate Insurer, the Trustee and the Master Servicer as follows:

(i)

No written information, certificate of an officer, statement furnished in writing or written report delivered to the Depositor, any affiliate of the Depositor, the Certificate Insurer, the Trustee or the Trust Administrator and prepared by the Trust Administrator pursuant to this Agreement will contain any untrue statement of a material fact.

(c)

The Master Servicer agrees to indemnify the Trust Fund, the Depositor, each Servicer, the Trust Administrator, the Certificate Insurer and the Trustee for losses, damages, penalties, fines, forfeitures, reasonable and necessary legal fees and related costs, judgments and other costs and expenses imposed on or incurred by the Trust Fund, the Servicer, the Depositor, the Securities Administrator or the Trustee, as a result of a breach of the Master Servicer’s covenants set forth above in Section 2.08(a) provided that the Master Servicer shall not provide indemnification for any damages caused by information provided to the Master Servicer by any other party to this Agreement, the Designated Servicer, the Interest Rate Cap Agreement Counterparty, the Certificate Insurer, the Custodians, any Subcontractor or any Sub-Servicer.

(d)

Each Servicer agrees to indemnify the Trust Fund, the Depositor, the Master Servicer, the Trust Administrator, the Certificate Insurer and the Trustee for losses, damages, penalties, fines, forfeitures, reasonable and necessary legal fees and related costs, judgments and other costs and expenses imposed on or incurred by the Trust Fund, the Depositor, the Trust Administrator or the Trustee, as a result of a breach of the Servicer’s covenants set forth above in Section 2.08(a).

(e)

The Trust Administrator agrees to indemnify the Trust Fund, the Depositor, each Servicer, the Master Servicer, the Certificate Insurer and the Trustee for losses, damages, penalties, fines, forfeitures, reasonable and necessary legal fees and related costs, judgments and other costs and expenses imposed on or incurred by the Trust Fund, the Servicer, the Depositor, the Master Servicer or the Trustee, as a result of a breach of the Trust Administrator’s covenants set forth above in Section 2.08(b) provided that the  Trust Administrator shall not provide indemnification for any damages caused by information provided to the  Trust Administrator by any other party to this Agreement, the Designated Servicer, the Interest Rate Cap Agreement Counterparty, the Certificate Insurer, the Custodians, any Subcontractor or any Sub-Servicer.

ARTICLE III

ADMINISTRATION AND SERVICING
OF MORTGAGE LOANS

SECTION 3.01

Master Servicing and Servicing of Mortgage Loans.

For and on behalf of the Certificateholders and the Certificate Insurer, as independent contractors of the Trustee, (i) each Servicer, severally and not jointly, shall service and administer the related Non-Designated Mortgage Loans in accordance with the terms of this Agreement and with Accepted Servicing Practices and with all applicable requirements of the Servicing Criteria, (ii) the Master Servicer shall, in accordance with Section 3.03 of this Agreement, master service and administer the Non-Designated Mortgage Loans  by overseeing and enforcing the servicing of the Non-Designated Mortgage Loans by the related Servicer  according to the terms of this Agreement and (iii) the Master Servicer shall, in accordance with the Section 3.20 of this Agreement, master service and administer the Designated Mortgage Loans by overseeing and enforcing the servicing of the Designated Mortgage Loans by the Designated Servicer according to the terms of the Designated Servicing Agreement.  The obligations of each of SPS and Wells Fargo hereunder to service and administer the Mortgage Loans shall be limited to SPS Serviced Mortgage Loans, Wells Fargo Serviced CORE Mortgage Loans and Wells Fargo Serviced Mortgage Loans, respectively; and with respect to the duties and obligations of each Servicer, references herein to related "Mortgage Loans" shall be limited to the SPS Serviced Mortgage Loans (and the related proceeds thereof and related REO Properties) in the case of SPS and the Wells Fargo Serviced Mortgage Loans and the Wells Fargo Serviced CORE Mortgage Loans (and the related proceeds thereof and related REO Properties) in the case of Wells Fargo; and in no event shall any Servicer have any responsibility or liability with respect to any of the other Mortgage Loans.  The obligations of the Master Servicer to master service and administer the Mortgage Loans shall be limited to the Non-Designated Mortgage Loans and the Designated Mortgage Loans.   In connection with such servicing and administration of the Non-Designated Mortgage Loans, the Master Servicer and each Servicer shall have full power and authority, acting alone and/or, with respect to any Servicer, through Sub-Servicers as provided in Section 3.02 hereof, to do or cause to be done any and all things that it may deem necessary or desirable in connection with such servicing and administration, including but not limited to, the power and authority, subject to the terms hereof (i) to execute and deliver, on behalf of the Certificateholders and the Trustee, customary consents or waivers and other instruments and documents, (ii) to consent to transfers of any Mortgaged Property and assumptions of the Mortgage Notes and related Mortgages (but only in the manner provided in this Agreement), (iii) to collect any Insurance Proceeds and other Liquidation Proceeds, and (iv) to effectuate foreclosure or other conversion of the ownership of the Mortgaged Property securing any Mortgage Loan; provided that neither the Master Servicer nor any Servicer shall take any action that is inconsistent with or prejudices the interests of the Trust Fund or the Certificateholders in any Mortgage Loan or the rights and interests of the Depositor, the Trustee, the Trust Administrator, the Certificate Insurer or the Certificateholders under this Agreement.  The Master Servicer and each Servicer shall represent and protect the interests of the Trust Fund in the same manner as it protects its own interests in mortgage loans in its own portfolio in any claim, proceeding or litigation regarding a Mortgage Loan, and shall not make or permit any modification, waiver or amendment of any Mortgage Loan which would cause any REMIC created hereunder to fail to qualify as a REMIC or result in the imposition of any tax under Section 860F(a) or Section 860G(d) of the Code.  Without limiting the generality of the foregoing, the Master Servicer and each Servicer, in its own name or in the name of the Depositor and the Trustee, is hereby authorized and empowered by the Depositor, the Trustee and the Trust Administrator, when the Master Servicer or such Servicer believes it appropriate in its reasonable judgment, to execute and deliver, on behalf of the Trustee, the Trust Administrator, the Depositor, the Certificateholders or any of them, any and all instruments of satisfaction or cancellation, or of partial or full release or discharge and all other comparable instruments, with respect to the Mortgage Loans, and with respect to the Mortgaged Properties held for the benefit of the Certificateholders.  The Master Servicer and each Servicer shall prepare and deliver to the Depositor and/or the Trustee and/or the Trust Administrator such documents requiring execution and delivery by either or both of them as are necessary or appropriate to enable the Master Servicer or such Servicer to master servicer and administer or service and administer the Mortgage Loans, as applicable, to the extent that the Master Servicer or such Servicer is not permitted to execute and deliver such documents pursuant to the preceding sentence.  Upon receipt of such documents, the Depositor and/or the Trustee or the Trust Administrator shall execute such documents and deliver them to the Master Servicer or such Servicer, as applicable.

In accordance with the standards of the preceding paragraph and unless determined in good faith to be a Nonrecoverable Advance, each Servicer shall advance or cause to be advanced funds, as necessary for the purpose of effecting the payment of taxes and assessments on the Mortgaged Properties related to Non-Designated Mortgage Loans, which advances constitute Servicing Advances and shall be reimbursable in the first instance from related collections from the Mortgagors pursuant to Section 3.06, and further as provided in Section 3.08.  In no event will any Servicer be required to make any Servicing Advance that would constitute a Nonrecoverable Advance.  The costs incurred by a Servicer, if any, in effecting the timely payments of taxes and assessments on the Mortgaged Properties related to Non-Designated Mortgage Loans and related insurance premiums shall not, for the purpose of calculating monthly distributions to the Certificateholders, be added to the Stated Principal Balances of the related Non-Designated Mortgage Loans, notwithstanding that the terms of such Non-Designated Mortgage Loans so permit; provided, however , that the limitations contained in this sentence will not apply to modifications made pursuant to Section 3.05(b).  The parties to this Agreement acknowledge that Servicing Advances shall be reimbursable pursuant to Section 3.08 and agree that no Servicing Advances shall be rejected or disallowed by any party unless such Servicing Advance is not reimbursable under the terms of this Agreement.

Each Servicer hereby acknowledges that, to the extent such Servicer has previously serviced some or all of the Non-Designated Mortgage Loans pursuant to another servicing agreement, the provisions contained in this Agreement shall supersede the provisions contained in such other servicing agreement from and after the Closing Date, except that such other servicing agreement shall survive and govern with respect to excess servicing fees and termination without cause.  In addition, the Master Servicer hereby acknowledges that, to the extent the Master Servicer or Designated Servicer has previously serviced some or all of the Designated Mortgage Loans pursuant to another servicing agreement, the provisions contained in the Designated Servicing Agreement shall supersede the provisions contained in such other servicing agreement from and after the Closing Date.

Notwithstanding anything in this Agreement to the contrary, the purchase of any Wells Fargo Serviced CORE Mortgage Loan by any Person shall be subject to the rights of Wells Fargo to continue servicing such Wells Fargo Serviced CORE Mortgage Loan for the same Servicing Fee substantially in accordance with the terms of this Agreement.

The related Servicer will fully furnish, in accordance with the Fair Credit Reporting Act and its implementing regulations, accurate and complete information (e.g., favorable and unfavorable) on its borrower credit files to Equifax, Experian and Trans Union Credit Information Company, on a monthly basis.

Each Servicer is authorized and empowered, on behalf of the Certificateholders and the Trustee, in its own name or in the name of any Sub-Servicer, when a Servicer or any Sub-Servicer, as the case may be, believes it appropriate in its best judgment to register any related Mortgage Loan on the MERS® System, or cause the removal from the registration of such Mortgage Loan on the MERS® System, to execute and deliver, on behalf of the Trustee and the Certificateholders or any of them, any and all instruments of assignment and other comparable instruments with respect to such assignment or re-recording of a Mortgage in the name of MERS, solely as nominee for the Trustee and its successors and assigns.

SECTION 3.02

Sub-servicing; Enforcement of the Obligations of Sub-Servicers.

(a)

The Non-Designated Mortgage Loans may be subserviced by a Sub-Servicer on behalf of the related Servicer in accordance with the servicing provisions of this Agreement, provided that the Sub-Servicer is a FNMA-approved lender or a FHLMC seller/servicer in good standing.  With respect to the Non-Designated Mortgage Loans, each Servicer may perform any of its servicing responsibilities hereunder or may cause the Sub-Servicer to perform any such servicing responsibilities on its behalf, but the use by such Servicer of the Sub-Servicer shall not release such Servicer from any of its obligations hereunder and such Servicer shall remain responsible hereunder for all acts and omissions of the Sub-Servicer as fully as if such acts and omissions were those of such Servicer.  With respect to the Non-Designated Mortgage Loans, each Servicer shall pay all fees and expenses of any Sub-Servicer engaged by such Servicer from its own funds.

A Servicer shall not permit a Sub-Servicer to perform any servicing responsibilities hereunder with respect to the Non-Designated Mortgage Loans unless that Sub-Servicer first agrees in writing with such Servicer to deliver an Item 1123 Certificate, if applicable, or an Assessment of Compliance and an Accountant’s Attestation in such manner and at such times that permits that Servicer to comply with Sections 14.06, 14.07 and 14.08 of this Agreement.

Each Servicer may in connection with its duties as Servicer hereunder enter into transactions with any of its Affiliates relating to the Mortgage Loans; provided that (a) such Servicer acts (i) in accordance with Accepted Servicing Practices and the terms of this Agreement, and (ii) in the ordinary course of business of such Servicer; and (b) the terms of such transaction are no less favorable to such Servicer than it would obtain in a comparable arm’s-length transaction with a Person that is not an Affiliate of such Servicer.

A Servicer shall not outsource one or more separate servicing functions hereunder with respect to the Non-Designated Mortgage Loans to any Subcontractor unless that Subcontractor first agrees in writing with such Servicer to deliver an Assessment of Compliance and an Accountant’s Attestation in such manner and at such times that permits that Servicer to comply with Sections 14.07 and 14.08 of this Agreement.

(b)

With respect to any Non-Designated Mortgage Loans, at the cost and expense of a Servicer, without any right of reimbursement from the Depositor, the Trustee, the Trust Administrator or the applicable Collection Account, such Servicer shall be entitled to terminate the rights and responsibilities of its Sub-Servicer and arrange for any servicing responsibilities to be performed by a successor Sub-Servicer meeting the requirements set forth in Section 3.02(a), provided, however, that nothing contained herein shall be deemed to prevent or prohibit such Servicer, at such Servicer’s option, from electing to service the related Non-Designated Mortgage Loans itself.  In the event that a Servicer’s responsibilities and duties under this Agreement are terminated pursuant to Section 8.01, and if requested to do so by the Trustee or Trust Administrator, such Servicer shall, at its own cost and expense terminate the rights and responsibilities of its Sub-Servicer as soon as is reasonably possible.  Each Servicer shall pay all fees, expenses or penalties necessary in order to terminate the rights and responsibilities of its Sub-Servicer from such Servicer’s own funds without any right of reimbursement from the Depositor, Trustee, Trust Administrator, or the applicable Collection Account.

(c)

Notwithstanding any of the provisions of this Agreement relating to agreements or arrangements between a Servicer and its Sub-Servicer, or a Servicer and its Subcontractor, or any reference herein to actions taken through the Sub-Servicer, the Subcontractor, or otherwise, the related Servicer shall not be relieved of its obligations to the Depositor, Trustee, the Trust Administrator or Certificateholders and shall be obligated to the same extent and under the same terms and conditions as if it alone were servicing and administering the related Non-Designated Mortgage Loans.  Each Servicer shall be entitled to enter into an agreement with its Sub-Servicer and Subcontractor for indemnification of such Servicer or Subcontractor, as applicable, by such Sub-Servicer and nothing contained in this Agreement shall be deemed to limit or modify such indemnification.

For purposes of this Agreement, a Servicer shall be deemed to have received any collections, recoveries or payments with respect to the related Non-Designated Mortgage Loans that are received by a related Sub-Servicer regardless of whether such payments are remitted by the Sub-Servicer to such Servicer.

Any Sub-servicing Agreement and any other transactions or services relating to the Non-Designated Mortgage Loans involving a Sub-Servicer shall be deemed to be between the Sub-Servicer, and the related Servicer alone, and the Depositor, the Trustee, the Trust Administrator, the Master Servicer, any Special Servicer and the other Servicers shall have no obligations, duties or liabilities with respect to a Sub-Servicer including no obligation, duty or liability of the Depositor, Trustee, the Trust Administrator, the Master Servicer, any Special Servicer or other Servicers to pay a Sub-Servicer’s fees and expenses.

(d)

SPS is hereby authorized to enter into a financing or other facility (any such arrangement, a "Facility") under which (i) SPS assigns or pledges to another person (a "Lender") (A) SPS’ rights under this Agreement to be reimbursed for any Advances or Servicing Advances, and (B) any and all rights of SPS under this Agreement resulting from SPS’ performance of its obligations under this Agreement, including, without limitation, any Servicing Fees, special servicing fees, interest income, Ancillary Income, and other payments received by SPS for servicing the SPS Serviced Mortgage Loans or Special Serviced Mortgage Loans and (ii) the Lender agrees to fund some or all Advances and/or Servicing Advances required to be made by SPS pursuant to this Agreement.  No consent of the Trustee, Trust Administrator, Certificateholders or any other party is required before SPS may enter into a Facility; provided, however, that the consent of the Trust Administrator shall be required before SPS may cause to be outstanding at one time more than one Facility.  Notwithstanding the existence of any Facility, SPS shall remain obligated pursuant to this Agreement to make Advances and Servicing Advances pursuant to and as required by this Agreement, and to perform all duties and obligations of SPS under this Agreement and shall not be relieved of such obligations by virtue of such Facility.  Prior to entering into a Facility, SPS shall notify the Lender under such Facility in writing, and the Facility shall provide, that:  (a) the Advances financed by and/or pledged to the Lender are obligations owed to SPS on a non-recourse basis payable only from the cash flows and proceeds received by SPS under this Agreement for reimbursement of Advances only to the extent provided herein, and the Trust Fund is not obligated or liable to repay any Advances financed by the Lender; (b) SPS will be responsible for remitting to the Lender the applicable amounts collected by it as reimbursement for Advances funded by the Lender, subject to the restrictions and priorities created in this Agreement; and (c) the Trust Fund shall not have any responsibility to track or monitor the administration of the financing arrangement between the Servicer and the Lender.

SECTION 3.03

Master Servicing by Master Servicer.

For and on behalf of the Certificateholders and the Certificate Insurer, the Master Servicer shall oversee and enforce the obligation of SPS to service and administer the SPS Mortgage Loans and Wells Fargo to service and administer the Wells Fargo Serviced CORE Mortgage Loans and Wells Fargo Serviced Mortgage Loans, in accordance with the terms of this Agreement and shall have full power and authority to do any and all things which it may deem necessary or desirable in connection with such master servicing and administration.  In performing its obligations hereunder, the Master Servicer shall act in a manner consistent with this Agreement and with customary and usual standards of practice of prudent mortgage loan master servicers.  Furthermore, the Master Servicer shall oversee and consult with SPS and Wells Fargo as necessary from time-to-time to carry out the Master Servicer’s obligations hereunder, shall receive, review and evaluate all reports, information and other data provided to the Master Servicer by SPS and Wells Fargo and shall cause each of SPS and Wells Fargo to perform and observe the covenants, obligations and conditions to be performed or observed by such Servicer under this Agreement.  

With respect to any Distribution Date, no later than the related Cash Remittance Date, the Master Servicer shall remit to the Trust Administrator for deposit in the Certificate Account the amount of the Compensating Interest Payment for the Master Servicer, with respect to the SPS Serviced Mortgage Loans, the Wells Fargo Serviced CORE Mortgage Loans, the Wells Fargo Serviced Mortgage Loans and the Designated Mortgage Loans, for the related Prepayment Period.  The aggregate of such deposits shall be made from the Master Servicer’s own funds, without reimbursement therefor.

SECTION 3.04

Trustee to Act as Master Servicer or Servicer.

In the event that (A) the Master Servicer shall for any reason no longer be Master Servicer hereunder or (B) any Servicer shall for any reason no longer be a Servicer hereunder and, with respect to any Servicer, the Master Servicer shall for any reason no longer be Master Servicer hereunder (including, in each case, by reason of an Event of Default), the Trustee or its successor shall thereupon assume all of the rights and obligations of the Master Servicer or such Servicer hereunder arising thereafter (except that the Trustee shall not be (i) liable for losses of the Master Servicer or such Servicer pursuant to Section 3.09 hereof or any acts or omissions of the related predecessor of the Master Servicer or such Servicer hereunder, (ii) subject to Section 8.02, obligated to make Advances if it is prohibited from doing so by applicable law, (iii) obligated to effectuate repurchases or substitutions of Mortgage Loans hereunder including, but not limited to, repurchases or substitutions of Mortgage Loans pursuant to Section 2.02 or 2.03 hereof; (iv) deemed to have made any representations and warranties of the Master Servicer or such Servicer hereunder or (v) be obligated to perform any obligation of the Master Servicer or such Servicer under Section 14.06 or Section 14.08 with respect to any period of time during which the Trustee was not acting as the Master Servicer or Servicer).  Any such assumption shall be subject to Section 8.02 hereof.

Each Servicer shall, upon request of the Trust Administrator, but at the expense of such Servicer, deliver to the assuming party all documents and records relating to each Sub-servicing Agreement or substitute Sub-servicing Agreement and the Mortgage Loans then being serviced thereunder and hereunder by such Servicer and an accounting of amounts collected or held by it and otherwise use its best efforts to effect the orderly and efficient transfer of the Sub-servicing Agreement or substitute Sub-servicing Agreement to the assuming party.

SECTION 3.05

Collection of Mortgage Loans; Collection Accounts; Certificate Account.

(a)

Continuously from the date hereof until the principal and interest on all Non-Designated Mortgage Loans have been paid in full or such Non-Designated Mortgage Loans have become Liquidated Mortgage Loans, each Servicer shall proceed in accordance with Accepted Servicing Practices to collect all payments due under each of the related Non-Designated Mortgage Loans when the same shall become due and payable to the extent consistent with this Agreement and the terms and provisions