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POOLING AND SERVICING AGREEMENT

Pooling and Servicing Agreement

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Title: POOLING AND SERVICING AGREEMENT
Governing Law: Delaware     Date: 11/10/2005

POOLING AND SERVICING AGREEMENT, Parties: wamu mortgage pass-throug , lasalle bank national association
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EXHIBIT 4.1

EXECUTION VERSION

  

WaMu ASSET ACCEPTANCE CORP.,

as Depositor

and

WASHINGTON MUTUAL BANK,

as Servicer

and

LASALLE BANK NATIONAL ASSOCIATION,

as Trustee

and

CHRISTIANA BANK & TRUST COMPANY,

as Delaware Trustee

POOLING AND SERVICING AGREEMENT

$1,449,939,912.91

WaMu Mortgage Pass-Through Certificates Series 2005-AR14 Trust

WaMu Asset Acceptance Corp.

WaMu Mortgage Pass-Through Certificates

Series 2005-AR14

Cut-Off Date: October 1, 2005



TABLE OF CONTENTS

 

 

Page

 

 

ARTICLE I

5

Section 1.01  Definitions

5

Adjustment Date

5

Aggregate Certificate Principal Balance

5

Agreement

5

Appraised Value

5

Assignment of Proprietary Lease

5

Authenticating Agent

5

Authorized Denomination

5

Bankruptcy Loss

6

Beneficial Holder

6

Benefit Plan Opinion

6

Book-Entry Certificates

6

Business Day

6

Buydown Agreement

6

Buydown Fund

6

Buydown Fund Account

6

Buydown Loan

7

Carry-Forward Subsequent Recoveries Amount

7

Certificate

7

Certificate Account

7

Certificateholder or Holder

7

Certificate Interest Rate

8

Certificate of Trust

8

Certificate Principal Balance

8

Certificate Register and Certificate Registrar

8

Class

8

Class A Certificates

8

Class B Certificates

8

Class B-1 Certificates

8

Class B-2 Certificates

8

Class B-3 Certificates

9

Class B-4 Certificates

9

Class B-5 Certificates

9

Class B-6 Certificates

9

Class Y Principal Reduction Amounts

9

Class Y Regular Interests

9

Class Y-1 Principal Distribution Amount

9

Class Y-1 Regular Interest

9

Class Y-2 Principal Distribution Amount

9

Class Y-2 Regular Interest

9

Class Z Principal Reduction Amounts

9

Class Z Regular Interests

10

Class Z-1 Principal Distribution Amount

10

Class Z-1 Regular Interest

10

Class Z-2 Principal Distribution Amount

10

Class Z-2 Regular Interest

10

Class Principal Balance

10

Class R Certificates

11

Class R Residual Interests

11

Class R-1 Residual Interest

11

Class R-2 Residual Interest

11

Class 1-A1 Certificates

11

Class 1-A2 Certificates

11

Class 1-A3 Certificates

12

Class 1-A4 Certificates

12

Class 1-A5 Certificates

12

Class 2-A1 Certificates

12

Class 2-A2 Certificates

12

Clean-Up Call Percentage

12

Clearing Agency

12

Closing Date

12

Code

12

Company

12

Compensating Interest

12

Cooperative

12

Cooperative Apartment

12

Cooperative Lease

12

Cooperative Loans

13

Cooperative Stock

13

Cooperative Stock Certificate

13

Corporate Trust Office

13

Corporation

13

Credit Support Depletion Date

13

Cumulative Carry-Forward Subsequent Recoveries Amount

13

Current Loan-to-Value Ratio

13

Curtailment

13

Curtailment Shortfall

13

Custodial Account for P&I

14

Custodial Agreement

14

Custodian

14

Cut-Off Date

14

Definitive Certificates

14

Delaware Trustee

14

Depositary Agreement

14

Destroyed Mortgage Note

14

Determination Date

14

Disqualified Organization

14

Distribution Date

14

DTC

15

DTC Participant

15

Due Date

15

Eligible Institution

15

Eligible Investments

15

ERISA

16

ERISA Restricted Certificate

16

Event of Default

16

Excess Liquidation Proceeds

17

Excess Subsequent Recoveries

17

Fannie Mae

17

FDIC

17

FHA

17

Final Maturity Date

17

Fitch

17

Freddie Mac

17

Group B Percentage

17

Group 1-A Certificates

17

Group 1 Loans

17

Group 1 Senior Liquidation Amount

17

Group 1 Senior Percentage

17

Group 1 Senior Prepayment Percentage or Group 2 Senior Prepayment Percentage

18

Group 1 Senior Principal Distribution Amount

20

Group 1 Subordinate Balance

20

Group 1 Subordinate Percentage

20

Group 1 Subordinate Prepayment Percentage

20

Group 2-A Certificates

20

Group 2 Loans

20

Group 2 Senior Liquidation Amount

21

Group 2 Senior Percentage

21

Group 2 Senior Prepayment Percentage

21

Group 2 Senior Principal Distribution Amount

21

Group 2 Subordinate Balance

21

Group 2 Subordinate Percentage

21

Group 2 Subordinate Prepayment Percentage

21

Index

21

Indirect DTC Participants

21

Initial Custodial Agreement

21

Initial Custodian

21

Insurance Proceeds

21

Interest Distribution Amount

22

Interest Transfer Amount

22

Investment Account

22

Investment Depository

22

Junior Subordinate Certificates

22

Last Scheduled Distribution Date

22

Liquidated Mortgage Loan

22

Liquidation Principal

22

Liquidation Proceeds

23

Loan Group

23

Loan Group 1

23

Loan Group 1 Weighted Average Pass-Through Rate

23

Loan Group 2

23

Loan Group 2 Weighted Average Pass-Through Rate

23

Lowest Class B Owner

23

Margin

23

MERS

23

MERS Loan

23

MERS® System

23

MIN

23

MOM Loan

23

Monthly P&I Advance

23

Monthly Payment

24

Moody’s

24

Mortgage

24

Mortgage File

24

Mortgage Interest Rate

26

Mortgage Loan Purchase Agreement

26

Mortgage Loan Schedule

27

Mortgage Loans

27

Mortgage Note

27

Mortgage Pool

27

Mortgage Pool Assets

27

Mortgaged Property

28

Mortgagor

28

Nonrecoverable Advance

28

Non-U.S. Person

28

Notice Addresses

28

OTS

29

Officer’s Certificate

29

One-Year CMT

29

One-Year LIBOR

29

Opinion of Counsel

29

Original Trust Agreement

29

Overcollateralized Group

29

Ownership Interest

29

Pass-Through Entity

29

Pass-Through Rate

29

Paying Agent

30

Payoff

30

Payoff Earnings

30

Payoff Interest

30

Payoff Period

30

Percentage Interest

30

Periodic Cap

31

Permitted Transferee

31

Person

31

Prepaid Monthly Payment

31

Primary Insurance Policy

31

Principal Balance

31

Principal Payment

32

Principal Payment Amount

32

Principal Prepayment

32

Principal Prepayment Amount

32

Principal Transfer Amount

32

Prior Period

32

Prospectus

33

Rate Ceiling

33

Rate Floor

33

Rating Agency

33

Ratings

33

Reacquired Mortgage Loan

33

Realized Loss

33

Recognition Agreement

35

Recording Documents

35

Record Date

35

Regular Interests

35

Relief Act Shortfall

35

REMIC

35

REMIC Provisions

35

REMIC I

35

REMIC I Assets

35

REMIC I Available Distribution Amount

36

REMIC I Distribution Amount

36

REMIC I Regular Interests

38

REMIC II

38

REMIC II Assets

38

REMIC II Available Distribution Amount

38

REMIC II Distribution Amount

38

REMIC II Regular Interests

43

Repurchase Price

43

Repurchase Proceeds

43

Residual Certificates

43

Residual Distribution Amount

43

Responsible Officer

44

ROV Mortgage Loan

44

S&P

44

Secretary of State

44

Securities Act

44

Security Agreement

44

Seller

44

Senior Certificates

44

Senior Subordinate Certificates

44

Servicer

44

Servicer Business Day

44

Servicing Fee

44

Servicing Fee Rate

45

Servicing Officer

45

Special Primary Insurance Policy

45

Special Primary Insurance Premium

45

Statutory Trust Statute

45

Streamlined Mortgage Loan

45

Subordinate Certificates

45

Subordinate Component Balance

45

Subordinate Liquidation Amount

45

Subordinate Percentage

45

Subordinate Principal Distribution Amount

45

Subordinate Principal Prepayments Distribution Amount

46

Subordination Level

46

Subsequent Recoveries

46

Substitute Mortgage Loan

47

Substitution Price

47

Tax Matters Person

47

Termination Date

47

Termination Payment

47

Total Transfer Amount

47

Transfer

47

Transferee

48

Transferee Affidavit and Agreement

48

Trust

48

Trustee

48

Uncollected Interest

48

Uncompensated Interest Shortfall

48

Undercollateralized Group

48

Underwriters

48

Uninsured Cause

48

U.S. Person

49

VA

49

Weighted Average Pass-Through Rate

49

Withdrawal Date

49

ARTICLE II  Creation of the Trust; Conveyance of the Mortgage Pool Assets and REMIC I Regular Interests; REMIC Election and Designations; Original Issuance of Certificates

49

Section 2.01  Creation of the Trust

49

Section 2.02  Restrictions on Activities of the Trust

50

Section 2.03  Separateness Requirements

51

Section 2.04  Conveyance of Mortgage Pool Assets; Security Interest

52

Section 2.05  Delivery of Mortgage Files

53

Section 2.06  REMIC Election for REMIC I

54

Section 2.07  Acceptance by Trustee

56

Section 2.08  Representation and Warranty of the Company Concerning the Mortgage Loans

57

Section 2.09  Representations and Warranties of Each Seller Concerning the Mortgage Loans

59

Section 2.10  Additional Provisions Relating to Repurchases of and Substitutions for Mortgage Loans by the Company or a Seller

60

Section 2.11  Acknowledgment of Transfer of Mortgage Pool Assets

61

Section 2.12  Conveyance of REMIC II Assets; Security Interest

61

Section 2.13  REMIC Election for REMIC II

62

Section 2.14  Acknowledgement of Transfer of REMIC II Assets

63

Section 2.15  Legal Title

63

Section 2.16  Compliance with ERISA Requirements

63

Section 2.17  Additional Representation Concerning the Mortgage Loans

63

ARTICLE III  Administration and Servicing of Mortgage Loans

64

Section 3.01  The Servicer

64

Section 3.02  The Custodial Accounts for P&I and Buydown Fund Accounts

66

Section 3.03  The Investment Account; Eligible Investments

67

Section 3.04  The Certificate Account

67

Section 3.05  Permitted Withdrawals from the Certificate Account, the Investment Account, the Custodial Accounts for P&I and the Buydown Fund Accounts

68

Section 3.06  Maintenance of Primary Insurance Policies; Collections Thereunder

70

Section 3.07  Maintenance of Hazard Insurance

70

Section 3.08  Enforcement of Due-on-Sale Clauses; Assumption Agreements

71

Section 3.09  Realization Upon Defaulted Mortgage Loans

71

Section 3.10  Trustee to Cooperate; Release of Mortgage Files

73

Section 3.11  Compensation to the Servicer

74

Section 3.12  [Reserved.]

74

Section 3.13  Annual Statement as to Compliance

74

Section 3.14  Access to Certain Documentation and Information Regarding the Mortgage Loans

75

Section 3.15  Annual Independent Public Accountants’ Servicing Report

75

ARTICLE IV  Payments to Certificateholders; Payment of Expenses

75

Section 4.01  Distributions to Holders of REMIC I Regular Interests and Class R-1 Residual Interest

75

Section 4.02  Monthly P&I Advances; Distribution Reports to the Trustee

76

Section 4.03  Nonrecoverable Advances

77

Section 4.04  Distributions to Certificateholders; Payment of Special Primary Insurance Premiums

78

Section 4.05  Statements to Certificateholders

79

ARTICLE V  The Certificates

79

Section 5.01  The Certificates

79

Section 5.02  Certificates Issuable in Classes; Distributions of Principal and Interest; Authorized Denominations

85

Section 5.03  Registration of Transfer and Exchange of Certificates

86

Section 5.04  Mutilated, Destroyed, Lost or Stolen Certificates

86

Section 5.05  Persons Deemed Owners

87

Section 5.06  [Reserved.]

87

Section 5.07  Book-Entry for Book-Entry Certificates

87

Section 5.08  Notices to Clearing Agency

88

Section 5.09  Definitive Certificates

88

Section 5.10  Office for Transfer of Certificates

89

Section 5.11  Nature of Certificates

89

ARTICLE VI  The Company and the Servicer

89

Section 6.01  Liability of the Company and the Servicer

89

Section 6.02  Merger or Consolidation of the Company or the Servicer

89

Section 6.03  Limitation on Liability of the Company, the Servicer and Others

90

Section 6.04  Neither the Company nor the Servicer May Resign

90

Section 6.05  Trustee Access  90

 

ARTICLE VII  Default

91

Section 7.01  Events of Default

91

Section 7.02  Trustee to Act; Appointment of Successor

93

Section 7.03  Notification to Certificateholders

94

ARTICLE VIII  Concerning the Trustees

94

Section 8.01  Duties of Trustees

94

Section 8.02  Certain Matters Affecting the Trustees

96

Section 8.03  Trustees Not Liable for Certificates or Mortgage Loans

97

Section 8.04  Trustees May Own Certificates

97

Section 8.05  The Servicer to Pay Trustees’ Fees and Expenses

98

Section 8.06  Eligibility Requirements for Trustees

98

Section 8.07  Resignation and Removal of Trustees

98

Section 8.08  Successor Trustee

99

Section 8.09  Merger or Consolidation of Trustee

100

Section 8.10  Appointment of Co-Trustee or Separate Trustee

100

Section 8.11  Authenticating Agents

101

Section 8.12  Paying Agents

102

Section 8.13  Duties of Delaware Trustee

102

Section 8.14  Amendment to Certificate of Trust

103

Section 8.15  Limitation of Liability

103

Section 8.16  Trustees Act on Behalf of Trust

103

ARTICLE IX  Termination

103

Section 9.01  Termination Upon Purchase by the Servicer or Liquidation of All Mortgage Loans

103

Section 9.02  Additional Termination Requirements

106

Section 9.03  Trust Irrevocable

106

ARTICLE X  Miscellaneous Provisions

106

Section 10.01  Amendment

106

Section 10.02  Recordation of Agreement

108

Section 10.03  Limitation on Rights of Certificateholders

108

Section 10.04  Access to List of Certificateholders

109

Section 10.05  Governing Law

109

Section 10.06  Notices

109

Section 10.07  Severability of Provisions

110

Section 10.08  Counterpart Signatures

110

Section 10.09  Benefits of Agreement

110

Section 10.10  Notices and Copies to Rating Agencies

110

Section 10.11  Covenant Not to Place Trust Into Bankruptcy

111

Section 10.12  Covenant Not to Place Company Into Bankruptcy

111

 

 


 

 

Exhibit A

Form of Certificates (other than Class R Certificates)

Exhibit B

Form of Class R Certificates

Exhibit C

[Reserved]

Exhibit D

Mortgage Loan Schedule

Exhibit E

[Reserved]

Exhibit F

Form of Transferor Certificate For Junior Subordinate Certificates

Exhibit G

Form of Transferee’s Agreement For Junior Subordinate Certificates

Exhibit H

Form of Additional Matter Incorporated Into the Certificates

Exhibit I

Transferor Certificate

Exhibit J

Transferee Affidavit And Agreement

Exhibit K

[Reserved]

Exhibit L

Form of Investment Letter

Exhibit M

Form of Trustee’s Certification Pursuant to Section 2.07

Exhibit N

Officer’s Certificate With Respect to ERISA Matters Pursuant to Section 5.01(d)

Exhibit O

Officer’s Certificate With Respect to ERISA Matters Pursuant to Section 5.01(g)

 

 

 


 

This Pooling and Servicing Agreement, dated as of October 1, 2005 (this “ Agreement ”), is by and among WaMu Asset Acceptance Corp., as depositor (the “ Company ”), Washington Mutual Bank, as Servicer, LaSalle Bank National Association, as Trustee, and Christiana Bank & Trust Company, as Delaware Trustee.  Capitalized terms used in this Agreement and not otherwise defined have the meanings ascribed to such terms in Article I hereof.

PRELIMINARY STATEMENT

The Company at the Closing Date is the owner of the Mortgage Loans and the other property being conveyed by it to the Trust. On the Closing Date, the Company will sell the Mortgage Loans and certain other assets to the Trust in return for the REMIC I Regular Interests and the Class R-1 Residual Interest and will be the owner of the REMIC I Regular Interests and the Class R-1 Residual Interest.  Thereafter on the Closing Date, the Company will acquire the Certificates (other than the Class R Certificates) and the Class R-2 Residual Interest from the Trust as consideration for its transfer to the Trust of the REMIC I Regular Interests and will be the owner of the Certificates.  The Company has duly authorized the execution and delivery of this Agreement to provide for (i) the sale to the Trust of the Mortgage Loans and certain other assets, (ii) the issuance to the Company of the REMIC I Regular Interests and the Class R-1 Residual Interest representing in the aggregate the entire beneficial interest in REMIC I, (iii) the conveyance to the Trust of the REMIC I Regular Interests and (iv) the issuance to the Company of the Certificates, such Certificates (other than the portion of the Class R Certificates representing ownership of the Class R-1 Residual Interest) representing in the aggregate the entire beneficial interest in REMIC II. The Company and the Servicer are entering into this Agreement, and the Trustee and the Delaware Trustee are each accepting the trust created hereby, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged.

The Certificates issued hereunder, other than the Junior Subordinate Certificates, have been offered for sale pursuant to a Prospectus, dated October 21, 2005, and a Prospectus Supplement, dated October 24, 2005, of the Company (together, the “ Prospectus ”). The Junior Subordinate Certificates have been offered for sale pursuant to a Private Placement Memorandum, dated October 26, 2005.  The Trust created hereunder is the “Trust” described in the Prospectus and the Private Placement Memorandum and the Certificates are the “Certificates” described therein. The following tables set forth the designation, type of interest, Certificate Interest Rate, initial Class Principal Balance and Final Maturity Date for the REMIC I Regular Interests, the Class R Residual Interests and the Certificates:


 

REMIC I Interests

 

Class Designation for each REMIC I Regular Interest and the Class R-1 Residual Interest

 

Type of Interest

 

Certificate Interest Rate (1)

 

 Initial Class Principal Balance

 

Final Maturity Date*

Class Y-1

 

Regular

 

Variable (2)

 

$649,988.41

 

December 2035

Class Y-2

 

Regular

 

Variable (3)

 

74,976.56

 

December 2035

Class Z-1

 

Regular

 

Variable (2)

 

1,299,326,934.57

 

December 2035

Class Z-2

 

Regular

 

Variable (3)

 

149,888,013.37

 

December 2035

Class R-1†

 

Residual

 

5.086%

 

100.00

 

December 2035

 

 

 

 

 

 

 

 

 

*             The Distribution Date in the specified month, which is the month following the month in which the latest maturing Mortgage Loan in the related Loan Group matures. For federal income tax purposes, for each Class of REMIC I Regular and Residual Interests, the “latest possible maturity date” shall be the Final Maturity Date.

 

†              The Class R-1 Residual Interest is entitled to receive the applicable Residual Distribution Amount and any Excess Liquidation Proceeds.

 

(1)           Interest distributed to the REMIC I Regular Interests and the Class R-1 Residual Interest on each Distribution Date will have accrued at the applicable per annum Certificate Interest Rate on the applicable Class Principal Balance outstanding immediately before such Distribution Date.

 

(2)           For each Distribution Date, the Certificate Interest Rate on the Class Y-1 and Class Z-1 Regular Interests shall equal the Loan Group 1 Weighted Average Pass-Through Rate for such Distribution Date.

 

(3)           For each Distribution Date, the Certificate Interest Rate on the Class Y-2 and Class Z-2 Regular Interests shall equal the Loan Group 2 Weighted Average Pass-Through Rate for such Distribution Date.

 

 

 

 

 

 

 

 

 

 

 

 

 

As provided herein, with respect to REMIC I, the Servicer will cause an election to be made on behalf of REMIC I to be treated for federal income tax purposes as a REMIC. The REMIC I Regular Interests will be designated regular interests in REMIC I and the Class R-1 Residual Interest will be designated the sole class of residual interest in REMIC I, for purposes of the REMIC Provisions.



REMIC II Interests

 

Class Designation for each Class of Certificates and the Class R-2 Residual Interest

 

Type of Interest

 

Certificate Interest Rate (1)

 

Initial Class
Principal
Balance

 

Final Maturity
Date*

 

Class 1-A1

 

Regular

 

Variable (2)

 

$591,750,000.00

 

December 2035

 

Class 1-A2

 

Regular

 

       Variable (2)

 

158,860,000.00

 

December 2035

 

Class 1-A3

 

Regular

 

       Variable (2)

 

185,000,000.00

 

December 2035

 

Class 1-A4

 

Regular

 

       Variable (2)

 

250,000,000.00

 

December 2035

 

Class 1-A5

 

Regular

 

       Variable (2)

 

55,867,000.00

 

December 2035

 

Class 2-A1

 

Regular

 

Variable (3)

 

136,768,000.00

 

December 2035

 

Class 2-A2

 

Regular

 

Variable (3)

 

6,447,000.00

 

December 2035

 

Class B-1

 

Regular

 

Variable (4)

 

34,799,000.00

 

December 2035

 

Class B-2

 

Regular

 

Variable (4)

 

11,600,000.00

 

December 2035

 

Class B-3

 

Regular

 

Variable (4)

 

5,800,000.00

 

December 2035

 

Class B-4

 

Regular

 

Variable (4)

 

5,800,000.00

 

December 2035

 

Class B-5

 

Regular

 

Variable (4)

 

4,350,000.00

 

December 2035

 

Class B-6

 

Regular

 

Variable (4)

 

2,898,812.91

 

December 2035

 

Class R-2 (5)

 

Residual

 

   -----

 

-----

 

December 2035

 

 

 

 

 

 

 

 

 

 

*             The Distribution Date in the specified month, which is the month following the month in which the latest maturing Mortgage Loan matures.  For federal income tax purposes, for each Class of REMIC II Regular and Residual Interests, the “latest possible maturity date” shall be the Final Maturity Date.

 

 

(1)           Interest distributed on each Distribution Date to the REMIC II Regular Interests will have accrued at the applicable per annum Certificate Interest Rate on the applicable Class Principal Balance outstanding immediately before such Distribution Date.

 

(2)           The Certificate Interest Rate for the Class 1-A1, Class 1-A2, Class 1-A3, Class 1-A4 and Class 1-A5 Certificates for each Distribution Date shall equal the Loan Group 1 Weighted Average Pass-Through Rate.

 

(3)           The Certificate Interest Rate for the Class 2-A1 and Class 2-A2 Certificates for each Distribution Date shall equal the Loan Group 2 Weighted Average Pass-Through Rate.

 

(4)           The Certificate Interest Rate for each Class of the Class B Certificates for each Distribution Date shall equal the weighted average of the Certificate Interest Rates for the Class Y-1 and Class Y-2 Regular Interests.

 

(5)           The Class R‑2 Residual Interest shall be entitled to receive the applicable Residual Distribution Amount.  The Class R‑2 Residual Interest shall not be entitled to receive any distributions of interest or principal.

 

 

 

 

 

 

 

 

 

 

 

 

As provided herein, with respect to REMIC II, the Servicer will cause an election to be made on behalf of REMIC II to be treated for federal income tax purposes as a REMIC. The Certificates (other than the Class R Certificates) will be designated regular interests in REMIC II, and the Class R-2 Residual Interest will be designated the sole class of residual interest in REMIC II, for purposes of the REMIC Provisions. 

In addition, the Trust will issue the Class R Certificates, which will represent ownership of the Class R-1 and Class R-2 Residual Interests.

As of the Cut-Off Date, the Mortgage Loans have an aggregate Principal Balance of $1,449,939,912.91 and, as of the Closing Date, the Certificates have an Aggregate Certificate Principal Balance of $1,449,939,912.91.

 

W I T N E S S E T H :

WHEREAS, the Company is a corporation duly organized and existing under and by virtue of the laws of the State of Delaware and has full corporate power and authority to enter into this Agreement and to undertake the obligations undertaken by it herein;

WHEREAS, the Servicer is a federal savings association and has full power and authority to enter into this Agreement and to undertake the obligations undertaken by it herein;

WHEREAS, the Trustee is a national banking association duly organized and existing under the laws of the United States of America and has full power and authority to enter into this Agreement;

WHEREAS, the Delaware Trustee is a banking corporation duly organized and existing under the laws of the State of Delaware and has full power and authority to enter into this Agreement;

WHEREAS, prior to the execution and delivery hereof, the Company and the Delaware Trustee have entered into the Original Trust Agreement, and the Delaware Trustee has filed the Certificate of Trust;

WHEREAS, it is the intention of the Company, the Servicer, the Trustee and the Delaware Trustee that the Trust created by this Agreement constitute a statutory trust under the Statutory Trust Statute, that this Agreement constitute the governing instrument of the Trust, and that this Agreement amend and restate the Original Trust Agreement;

WHEREAS, the Company is the owner of the Mortgage Loans identified in the Mortgage Loan Schedule hereto having unpaid Principal Balances on the Cut-Off Date as stated therein; and

WHEREAS, the Company has been duly authorized to create the Trust to (i) hold the Mortgage Loans and certain other property, (ii) issue the REMIC I Regular Interests and the Class R-1 Residual Interest, (iii) hold the REMIC I Regular Interests and (iv) issue the Certificates.

NOW, THEREFORE, in order to declare the terms and conditions upon which the REMIC I Regular Interests, the Class R Residual Interests and the Certificates are to be issued, and in consideration of the premises and of the purchase and acceptance of the Certificates by the Holders thereof, the Company covenants and agrees with the Trustee, the Servicer and the Delaware Trustee, for the equal and proportionate benefit of the respective Holders from time to time of the REMIC I Regular Interests and the Certificates, as applicable, as follows:

ARTICLE I

Section 1.01.        Definitions .

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

Adjustment Date:   As to each Mortgage Loan, a Due Date on or about the fifth anniversary (in the case of the Group 1 Loans) and on or about the seventh anniversary (in the case of the Group 2 Loans) of the first Due Date and annually thereafter, as set forth in the related Mortgage Note, on which date an adjustment to the Mortgage Interest Rate of such Mortgage Loan becomes effective.

Aggregate Certificate Principal Balance : At any given time, the sum of the then current Class Principal Balances of the Certificates.

Agreement : The meaning specified in the introductory paragraph hereof.

Appraised Value :  With respect to any (i) Mortgage Loan that is not a Streamlined Mortgage Loan or ROV Mortgage Loan, the lesser of (a) the value set forth on the appraisal made in connection with the origination of such Mortgage Loan as the value of the related Mortgaged Property and (b) the purchase price paid for the Mortgaged Property; provided, however , that if such Mortgage Loan was originated in connection with the refinance of a mortgage loan, the Appraised Value shall be the value set forth on the appraisal made in connection with the origination of such Mortgage Loan as the value of the related Mortgaged Property; (ii) ROV Mortgage Loan, the lesser of (a) the value set forth on the residential appraisal review made in connection with the origination of such Mortgage Loan as the value of the related Mortgaged Property and (b) the purchase price paid for the Mortgaged Property; provided, however , that if such ROV Mortgage Loan was originated in connection with the refinance of a mortgage loan, the Appraised Value shall be the value set forth on the residential appraisal review made in connection with the origination of such ROV Mortgage Loan as the value of the related Mortgaged Property; and (iii) Streamlined Mortgage Loan, the value set forth in the appraisal made in connection with the origination of the mortgage loan being refinanced.

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

Authenticating Agent : Any authenticating agent appointed by the Trustee pursuant to Section 8.11.

Authorized Denomination :  With respect to each Class of Certificates (other than the Class R Certificates), an initial Certificate Principal Balance equal to $25,000 and multiples of $1 in excess thereof, except that one Certificate of each Class of the Junior Subordinate Certificates may be issued in an amount that is not an integral multiple of $1.  With respect to the Class R Certificates, one Certificate with a Percentage Interest equal to 0.01% and one Certificate with a Percentage Interest equal to 99.99%.

Bankruptcy Loss : For any Distribution Date and any Mortgage Loan, (i) the amount of any permanent forgiveness of principal with respect to such Mortgage Loan by a court of competent jurisdiction in a case under the United States Bankruptcy Code as of the related Due Date, other than any such forgiveness of principal that arises out of clause (ii) of this definition of “Bankruptcy Loss,” or (ii) the amount, if any, by which the then outstanding principal balance of such Mortgage Loan exceeds any valuation, as of the related Due Date, by a court of competent jurisdiction in a case under the United States Bankruptcy Code, of the related Mortgaged Property, in each case, to the extent not previously allocated to the Certificates as a Realized Loss.

Beneficial Holder : A Person holding a beneficial interest in any Book-Entry Certificate as or through a DTC Participant or an Indirect DTC Participant or a Person holding a beneficial interest in any Definitive Certificate.

Benefit Plan Opinion : With respect to any Certificate presented for registration in the name of any Person, an Opinion of Counsel acceptable to and in form and substance satisfactory to the Trustee and the Company to the effect that the purchase or holding of such Certificate is permissible under applicable law, will not constitute or result in a non-exempt prohibited transaction under Section 406 of ERISA or Section 4975 of the Code, and will not subject the Trust, the Trustee, the Delaware Trustee, the Servicer or the Company to any obligation or liability (including obligations or liabilities under Section 406 of ERISA or Section 4975 of the Code) in addition to those undertaken in this Agreement, which Opinion of Counsel shall not be an expense of the Trust, the Trustee, the Delaware Trustee, the Servicer or the Company.

Book-Entry Certificates : The Class A and Senior Subordinate Certificates, beneficial ownership and transfers of which shall be made through book entries as described in Section 5.07.

Business Day : Any day other than a Saturday, a Sunday or a day on which banking institutions in Stockton, California, Chicago, Illinois, New York, New York, Seattle, Washington or any city in which the Corporate Trust Office is located are authorized or obligated by law or executive order to be closed.

Buydown Agreement : An agreement between a Person and a Mortgagor pursuant to which such Person has provided a Buydown Fund.

Buydown Fund : A fund provided by the originator of a Mortgage Loan or another Person with respect to a Buydown Loan which provides an amount sufficient to subsidize regularly scheduled principal and interest payments due on such Buydown Loan for a period. Buydown Funds may be (i) funded at the par values of future payment subsidies, or (ii) funded in an amount less than the par values of future payment subsidies, and determined by discounting such par values in accordance with interest accruing on such amounts, in which event they will be deposited in an account bearing interest. Buydown Funds may be held in a separate Buydown Fund Account or may be held in a Custodial Account for P&I and monitored by the Servicer.

Buydown Fund Account : A separate account created and maintained pursuant to Section 3.02 (a) with the corporate trust department of the Trustee or another financial institution approved by the Servicer, (b) within FDIC insured accounts (or other accounts with comparable insurance coverage acceptable to the Rating Agencies) created, maintained and monitored by the Servicer or (c) in a separate non-trust account in an Eligible Institution. Such account may be non-interest bearing or may bear interest. In the event that a Buydown Fund Account is established pursuant to clause (b) of the preceding sentence, amounts held in such Buydown Fund Account shall not exceed the level of deposit insurance coverage on such account; accordingly, more than one Buydown Fund Account may be established.

Buydown Loan : A Mortgage Loan for which the Mortgage Interest Rate has been subsidized through a Buydown Fund provided at the time of origination of such Mortgage Loan.

Carry-Forward Subsequent Recoveries Amount : For any Distribution Date and any Loan Group, the excess, if any, of (i) the Subsequent Recoveries for such Distribution Date for such Loan Group over (ii) the amount by which the Class Principal Balance of the Class of Subordinate Certificates with the lowest priority is increased in respect of Subsequent Recoveries for such Loan Group on such Distribution Date pursuant to the definition of “Class Principal Balance” herein.

Certificate : Any one of the Certificates issued pursuant to this Agreement, executed by the Trustee on behalf of the Trust and authenticated by or on behalf of the Trustee hereunder in substantially one of the forms set forth in Exhibit A and B hereto. The additional matter appearing in Exhibit H shall be deemed incorporated into Exhibit A as though set forth at the end of such Exhibit.

Certificate Account : The separate trust account created pursuant to Section 3.04 and maintained with the Trustee, the Investment Depository 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, which account shall be entitled “WaMu Mortgage Pass-Through Certificates Series 2005-AR14 Trust Certificate Account,” or any other account serving a similar function acceptable to the Rating Agencies. Funds in the Certificate Account in respect of the Mortgage Loans in each of the Loan Groups and amounts withdrawn from the Certificate Account attributable to each of such Loan Groups shall be accounted for separately. Funds in the Certificate Account may be invested in Eligible Investments pursuant to Section 3.04(d) and reinvestment earnings thereon shall be paid to the Servicer as additional servicing compensation. Funds deposited in the Certificate Account (exclusive of the Servicing Fee) shall be held in trust for the Certificateholders and for the uses and purposes set forth in Section 2.01, Section 3.04, Section 3.05, Section 4.01 and Section 4.04.

Certificateholder or Holder : With respect to the Certificates, the Person in whose name a Certificate is registered in the Certificate Register, except that, solely for the purposes of giving any consent pursuant to this Agreement, any Certificate registered in the name of the Company, the Servicer or any affiliate thereof shall be deemed not to be outstanding and the Percentage Interest evidenced thereby shall not be taken into account in determining whether the requisite percentage of Percentage Interests necessary to effect any such consent has been obtained; provided , that the Trustee may conclusively rely upon an Officer’s Certificate to determine whether any Person is an affiliate of the Company or the Servicer. With respect to the REMIC I Regular Interests, the owner of the REMIC I Regular Interests, which as of the Closing Date shall be the Trust.

Certificate Interest Rate : For each Class of Certificates and REMIC I Regular Interests and the Class R-1 Residual Interest, the per annum rate set forth as the Certificate Interest Rate for such Class in the Preliminary Statement hereto.

Certificate of Trust : The certificate of trust filed with respect to the Trust with the Secretary of State in accordance with Section 3810(a) of the Statutory Trust Statute.

Certificate Principal Balance : For each Certificate of any Class, the portion of the related Class Principal Balance, if any, represented by such Certificate.

Certificate Register and Certificate Registrar : The register maintained and the registrar appointed, respectively, pursuant to Section 5.03.

Class : All REMIC I Regular Interests or the Class R-1 Residual Interest having the same priority and rights to payments on the Mortgage Loans from the REMIC I Available Distribution Amount, and all REMIC II Regular Interests or the Class R-2 Residual Interest having the same priority and rights to payments on the REMIC I Regular Interests from the REMIC II Available Distribution Amount, as applicable, which REMIC I Regular Interests, REMIC II Regular Interests and Class R Residual Interests, as applicable, shall be designated as a separate Class, and which, in the case of the Certificates (including the Class R Certificates representing ownership of the Class R Residual Interests), shall be set forth in the applicable forms of Certificates attached hereto as Exhibits A and B. Each Class of REMIC I Regular Interests and the Class R-1 Residual Interest shall be entitled to receive the amounts allocated to such Class pursuant to the definition of “REMIC I Distribution Amount” only to the extent of the REMIC I Available Distribution Amount for such Distribution Date remaining after distributions in accordance with prior clauses of the definition of “REMIC I Distribution Amount,” and each Class of REMIC II Regular Interests and the Class R-2 Residual Interest shall be entitled to receive the amounts allocated to such Class pursuant to the definition of “REMIC II Distribution Amount” only to the extent of the REMIC II Available Distribution Amount for such Distribution Date remaining after distributions in accordance with prior clauses of the definition of “REMIC II Distribution Amount.”

Class A Certificates :  The Class 1-A1, Class 1-A2, Class 1-A3, Class 1-A4, Class 1-A5, Class 2-A1 and Class 2-A2 Certificates.

Class B Certificates :  The Class B-1, Class B-2, Class B-3, Class B-4, Class B-5 and Class B-6 Certificates.

Class B-1 Certificates :  The Certificates designated as “Class B-1” on the face thereof in substantially the form attached hereto as Exhibit A.

Class B-2 Certificates :  The Certificates designated as “Class B-2” on the face thereof in substantially the form attached hereto as Exhibit A.

Class B-3 Certificates :  The Certificates designated as “Class B-3” on the face thereof in substantially the form attached hereto as Exhibit A.

Class B-4 Certificates :  The Certificates designated as “Class B-4” on the face thereof in substantially the form attached hereto as Exhibit A.

Class B-5 Certificates :  The Certificates designated as “Class B-5” on the face thereof in substantially the form attached hereto as Exhibit A.

Class B-6 Certificates :  The Certificates designated as “Class B-6” on the face thereof in substantially the form attached hereto as Exhibit A.

Class Y Principal Reduction Amounts For any Distribution Date, the amounts by which the Class Principal Balances of the Class Y-1 and Class Y-2 Regular Interests, respectively, will be reduced on such Distribution Date by the allocation of Realized Losses and the distribution of principal, determined as described in Appendix 1.

Class Y Regular Interests : The Class Y-1 and Class Y-2 Regular Interests.

Class Y-1 Principal Distribution Amount For any Distribution Date, the sum of (A) the excess, if any, of the Class Y-1 Principal Reduction Amount for such Distribution Date over the principal portion of Realized Losses allocated to the Class Y-1 Regular Interest on such Distribution Date and (B) an amount equal to the lesser of (i) the portion, if any, of the Subsequent Recoveries for Loan Group 1 for such Distribution Date not included in the Class Z-1 Principal Distribution Amount pursuant to clause (B) of the definition thereof and (ii) the amount of Realized Losses allocated to the Class Y-1 Regular Interest on previous Distribution Dates (the amount in this clause (B)(ii) reduced by the amount, if any, calculated pursuant to this clause (B) for prior Distribution Dates).

Class Y-1 Regular Interest : The uncertificated undivided beneficial interest in REMIC I which constitutes a REMIC I Regular Interest and is entitled to distributions as set forth herein.

Class Y-2 Principal Distribution Amount For any Distribution Date, the sum of (A) the excess, if any, of the Class Y-2 Principal Reduction Amount for such Distribution Date over the principal portion of Realized Losses allocated to the Class Y-2 Regular Interest on such Distribution Date and (B) an amount equal to the lesser of (i) the portion, if any, of the Subsequent Recoveries for Loan Group 2 for such Distribution Date not included in the Class Z-2 Principal Distribution Amount pursuant to clause (B) of the definition thereof and (ii) the amount of Realized Losses allocated to the Class Y-2 Regular Interest on previous Distribution Dates (the amount in this clause (B)(ii) reduced by the amount, if any, calculated pursuant to this clause (B) for prior Distribution Dates).

Class Y-2 Regular Interest : The uncertificated undivided beneficial interest in REMIC I which constitutes a REMIC I Regular Interest and is entitled to distributions as set forth herein.

Class Z Principal Reduction Amounts : For any Distribution Date, the amounts by which the Class Principal Balances of the Class Z-1 and Class Z-2 Regular Interests, respectively, will be reduced on such Distribution Date by the allocation of Realized Losses and the distribution of principal, which shall be in each case the excess of (A) the sum of (x) the excess of the REMIC I Available Distribution Amount for the related Loan Group (i.e. the “related Loan Group” for the Class Z-1 Regular Interest is Loan Group 1 and the “related Loan Group” for the Class Z-2 Regular Interest is Loan Group 2) over the sum of the amounts thereof distributable (i) in the case of Loan Group 1, to the Class R-1 Regular Interests, (ii) in respect of interest on such Class Z Regular Interest and the related Class Y Regular Interest and (iii) to such Class Z Regular Interest and the related Class Y Regular Interest pursuant to clause (c)(ii) of the definition of “REMIC I Distribution Amount” and (y) the amount of Realized Losses allocable to principal for the related Loan Group over (B) the Class Y Principal Reduction Amount for the related Loan Group.

Class Z Regular Interests : The Class Z-1 and Class Z-2 Regular Interests.

Class Z-1 Principal Distribution Amount : For any Distribution Date, the sum of (A) the excess, if any, of the Class Z-1 Principal Reduction Amount for such Distribution Date over the principal portion of Realized Losses allocated to the Class Z-1 Regular Interest on such Distribution Date and (B) an amount equal to the lesser of (i) the Subsequent Recoveries for Loan Group 1 for such Distribution Date and (ii) the amount of Realized Losses allocated to the Class Z-1 Regular Interest on previous Distribution Dates (the amount in this clause (B)(ii) reduced by the amount, if any, calculated pursuant to this clause (B) for prior Distribution Dates).

Class Z-1 Regular Interest : The uncertificated undivided beneficial interest in REMIC I which constitutes a REMIC I Regular Interest and is entitled to distributions as set forth herein.

Class Z-2 Principal Distribution Amount : For any Distribution Date, the sum of (A) the excess, if any, of the Class Z-2 Principal Reduction Amount for such Distribution Date over the principal portion of Realized Losses allocated to the Class Z-2 Regular Interest on such Distribution Date and (B) an amount equal to the lesser of (i) the Subsequent Recoveries for Loan Group 2 for such Distribution Date and (ii) the amount of Realized Losses allocated to the Class Z-2 Regular Interest on previous Distribution Dates (the amount in this clause (B)(ii) reduced by the amount, if any, calculated pursuant to this clause (B) for prior Distribution Dates).

Class Z-2 Regular Interest : The uncertificated undivided beneficial interest in REMIC I which constitutes a REMIC I Regular Interest and is entitled to distributions as set forth herein.

Class Principal Balance :  For any Class of Certificates, for any Class of REMIC I Regular Interests and for the Class R-1 Residual Interest, the applicable initial Class Principal Balance therefor set forth in the Preliminary Statement hereto (or, in the case of the Class R Certificates, the Class Principal Balance of the Class R-1 Residual Interest), corresponding to the rights of such Class in payments of principal due to be passed through to the Certificateholders or the Holders of the REMIC I Regular Interests from principal payments on the Mortgage Loans or the REMIC I Regular Interests, as applicable, as reduced from time to time by (x) distributions of principal to the Certificateholders or the Holders of the REMIC I Regular Interests of such Class and (y) the portion of Realized Losses allocated to the Class Principal Balance of such Class pursuant to the definition of “Realized Loss” with respect to a given Distribution Date. For any Distribution Date, the reduction of the Class Principal Balance of any Class of Certificates and REMIC I Regular Interests pursuant to the definition of “Realized Loss” shall be deemed effective after the determination and distribution of principal on such Class pursuant to the definitions of “REMIC I Distribution Amount” and “REMIC II Distribution Amount.”

Notwithstanding the foregoing, (A) any amounts distributed in respect of Realized Losses allocable to principal pursuant to paragraph (I)(c)(xix), (II)(a)(v) or (II)(b)(v) of the definition of “REMIC II Distribution Amount” shall not cause a reduction in the Class Principal Balances of the REMIC II Regular Interests and (B) any amounts distributed in respect of Realized Losses allocable to principal pursuant to paragraph (c)(i) of the definition of “REMIC I Distribution Amount” shall not cause a reduction in the Class Principal Balances of the REMIC I Regular Interests.

In addition to the foregoing, on each Distribution Date, the Class Principal Balance of the Class of Subordinate Certificates with the lowest priority then outstanding shall be increased by an amount, for each Loan Group, equal to the lesser of (i) the Subsequent Recoveries for such Distribution Date for such Loan Group and (ii) the amount of Realized Losses for Mortgage Loans in such Loan Group allocated to such Class on previous Distribution Dates (the amount in this clause (ii) reduced by the amount, if any, by which such Class Principal Balance has been increased on prior Distribution Dates pursuant to this paragraph in respect of Subsequent Recoveries for such Loan Group).

The Class Principal Balance for the Class 1-A1 Certificates shall be referred to as the “Class 1-A1 Principal Balance,” the Class Principal Balance for the Class 1-A2 Certificates shall be referred to as the “Class 1-A2 Principal Balance” and so on.

Class R Certificates :  The Certificates designated as “Class R” on the face thereof in substantially the form attached hereto as Exhibit B, representing ownership of the Class R-1 and Class R-2 Residual Interests, each of which Class of Residual Interests has been designated as the sole class of “residual interest” in REMIC I and REMIC II, respectively, pursuant to Section 2.06 and Section 2.13, respectively, for purposes of Section 860G(a)(2) of the Code.

Class R Residual Interests :  The Class R-1 and Class R-2 Residual Interests (which shall be transferable only as a unit evidenced by the Class R Certificates, in accordance with the applicable provisions of Section 5.01).

Class R-1 Residual Interest : The uncertificated undivided beneficial interest in REMIC I which has been designated as the single class of “residual interest” in REMIC I pursuant to Section 2.06. 

Class R-2 Residual Interest : The uncertificated undivided beneficial interest in REMIC II which has been designated as the single class of “residual interest” in REMIC II pursuant to Section 2.13. 

Class 1-A1 Certificates :  The Certificates designated as “Class 1-A1” on the face thereof in substantially the form attached hereto as Exhibit A.

Class 1-A2 Certificates :  The Certificates designated as “Class 1-A2” on the face thereof in substantially the form attached hereto as Exhibit A.

Class 1-A3 Certificates :  The Certificates designated as “Class 1-A3” on the face thereof in substantially the form attached hereto as Exhibit A.

Class 1-A4 Certificates :  The Certificates designated as “Class 1-A4” on the face thereof in substantially the form attached hereto as Exhibit A.

Class 1-A5 Certificates :  The Certificates designated as “Class 1-A5” on the face thereof in substantially the form attached hereto as Exhibit A.

Class 2-A1 Certificates :  The Certificates designated as “Class 2-A1” on the face thereof in substantially the form attached hereto as Exhibit A.

Class 2-A2 Certificates :  The Certificates designated as “Class 2-A2” on the face thereof in substantially the form attached hereto as Exhibit A.

Clean-Up Call Percentage : 10%.

Clearing Agency : An organization registered as a “clearing agency” pursuant to Section 17A of the Securities Exchange Act of 1934, as amended, which initially shall be DTC.

Closing Date : October 26, 2005.

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

Company : The meaning specified in the introductory paragraph hereof.

Compensating Interest : For any Distribution Date with respect to each Loan Group and the Mortgage Loans contained therein, the least of (i) the sum of (a) 1/12 of 0.050% of the aggregate Principal Balance of such Mortgage Loans immediately before such Distribution Date , (b) the aggregate Payoff Earnings with respect to such Mortgage Loans for such Distribution Date and (c) the aggregate Payoff Interest with respect to such Mortgage Loans for such Distribution Date, (ii) the aggregate Uncollected Interest with respect to such Mortgage Loans for such Distribution Date and (iii) 1/12 of 0.125% of the aggregate Principal Balance of such Mortgage Loans immediately before such Distribution Date.

Cooperative : A private cooperative housing corporation which owns or leases land and all or part of a building or buildings, including apartments, spaces used for commercial purposes and common areas therein and whose board of directors authorizes, among other things, the sale of Cooperative Stock.

Cooperative Apartment : A dwelling unit in a multi-dwelling building owned or leased by a Cooperative, which unit the Mortgagor has an exclusive right to occupy pursuant to the terms of a proprietary lease or occupancy agreement.

Cooperative Lease : With respect to a Cooperative Loan, the proprietary lease or occupancy agreement with respect to the Cooperative Apartment occupied by the Mortgagor and relating to the related Cooperative Stock, which lease or agreement confers an exclusive right to the holder of such Cooperative Stock to occupy such apartment.

Cooperative Loans :  Any of the Mortgage Loans made in respect of a Cooperative Apartment, evidenced by a Mortgage Note and secured by the related Cooperative Stock and the related Cooperative Lease, together with (i) the related Security Agreement, (ii) the related Cooperative Stock Certificate, (iii) the related assignment or mortgage of the Cooperative Lease, (iv) the related financing statements, (v) the related stock power or other similar instrument and (vi) the related Recognition Agreement

Cooperative Stock :  With respect to a Cooperative Loan, the stock, partnership interest or other ownership instrument in the related Cooperative.

Cooperative Stock Certificate :  With respect to a Cooperative Loan, the stock certificate or other instrument evidencing the related Cooperative Stock.

Corporate Trust Office : The corporate trust 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 135 South LaSalle Street, Suite 1625, Chicago, Illinois, 60603, Attention: Global Securities and Trust Services/WaMu Series 2005-AR14.

Corporation : Any Person (other than an individual, partnership, joint venture or unincorporated organization) incorporated, associated, organized, chartered or existing under the laws of any state or under the federal laws of the United States of America; provided , that such Person have indefinite existence under the law of its domicile.

Credit Support Depletion Date : The first Distribution Date on which the aggregate Class Principal Balance of the Class B Certificates has been or will be reduced to zero as a result of principal distributions thereon and the allocation of Realized Losses on such Distribution Date.

Cumulative Carry-Forward Subsequent Recoveries Amount : For any Distribution Date and any Loan Group, the sum of (i) the Carry-Forward Subsequent Recoveries Amount for such Distribution Date for such Loan Group and (ii) the Carry-Forward Subsequent Recoveries Amounts for prior Distribution Dates for such Loan Group to the extent such Carry-Forward Subsequent Recoveries Amounts have not been applied in reduction of Realized Losses on prior Distribution Dates pursuant to the first paragraph of the definition of “Realized Loss” herein.

Current Loan-to-Value Ratio : The Principal Balance of a Mortgage Loan as of the applicable date of substitution divided by the Appraised Value.

Curtailment : Any payment of principal on a Mortgage Loan, made by or on behalf of the related Mortgagor, other than a Monthly Payment, a Prepaid Monthly Payment or a Payoff, which is applied to reduce the outstanding principal balance of the Mortgage Loan. (Prepayment penalties are not payments of principal and hence Curtailments do not include prepayment penalties.)

Curtailment Shortfall : For any Distribution Date and for any Curtailment received in the Prior Period, an amount equal to one month’s interest on such Curtailment at the Pass-Through Rate for the applicable Mortgage Loan.

Custodial Account for P&I : A custodial account for principal and interest established and maintained by the Servicer pursuant to Section 3.02 either (a) with the corporate trust department of the Trustee or another financial institution approved by the Servicer such that the rights of the Servicer, the Trustee, the Trust, the Delaware Trustee and the Certificateholders thereto shall be fully protected against the claims of any creditors or depositors of the institution in which such account is maintained, (b) within FDIC insured accounts (or other accounts with comparable insurance coverage acceptable to the Rating Agencies) created, maintained and monitored by the Servicer or (c) as a separate account at an Eligible Institution. In the event that a Custodial Account for P&I is established pursuant to clause (b) of the preceding sentence, amounts held in such Custodial Account for P&I shall not exceed the level of deposit insurance coverage on such account; accordingly, more than one Custodial Account for P&I may be established. In the event that a Custodial Account for P&I is established pursuant to clause (c) it shall be entitled "[Name of Servicer] in trust for holders of WaMu Mortgage Pass-Through Certificates, Series 2005-AR14."

Custodial Agreement : The agreement, if any, between the Trustee and a Custodian (or the Trustee, a Custodian and the Servicer) providing for the safekeeping of the Mortgage Files on behalf of the Trust.

Custodian : The Initial Custodian and any other custodian which is appointed by the Trustee with the consent of the Servicer, as provided in Article II hereof, pursuant to a Custodial Agreement. Any Custodian so appointed shall act as agent on behalf of the Trustee.  The reasonable fees and expenses of the Custodian shall be paid by the Servicer.

Cut-Off Date : October 1, 2005.

Definitive Certificates : Certificates in definitive, fully registered and certificated form.

Delaware Trustee : Christiana Bank & Trust Company, or its successor-in-interest as provided in Section 8.09, or any successor trustee appointed as herein provided.

Depositary Agreement : The Letter of Representations, dated October 25, 2005 by and among DTC, the Trust and the Trustee. The Trustee is authorized to enter into the Depositary Agreement on behalf of the Trust.

Destroyed Mortgage Note : A Mortgage Note the original of which (or a portion of the original of which) was permanently lost or destroyed and has not been replaced.

Determination Date : A day not later than the 10th day preceding a related Distribution Date, as determined by the Servicer.

Disqualified Organization :  Any Person which is not a Permitted Transferee, but does not include any Pass-Through Entity which owns or holds a Residual Certificate and of which a Disqualified Organization, directly or indirectly, may be a stockholder, partner or beneficiary.

Distribution Date : With respect to distributions on the REMIC I Regular Interests and the Certificates, the 25th day (or, if such 25th day is not a Business Day, the Business Day immediately succeeding such 25th day) of each month, with the first such date being November 25, 2005.  The “related Due Date” for any Distribution Date is the Due Date immediately preceding such Distribution Date.

DTC : The Depository Trust Company.

DTC Participant : A Person for whom DTC effects book-entry transfers and pledges of securities deposited with DTC.

Due Date : The day on which the Monthly Payment for each Mortgage Loan is due.

Eligible Institution : An institution having (i) the highest short-term debt rating, and one of the two highest long-term debt ratings, of the Rating Agencies, (ii) with respect to any Custodial Account for P&I, an unsecured long-term debt rating of at least one of the two highest unsecured long-term debt ratings of the Rating Agencies, (iii) with respect to any Buydown Fund Account or Custodial Account which also serves as a Buydown Fund Account, the highest unsecured long-term debt rating by the Rating Agencies, or (iv) the approval of the Rating Agencies. Notwithstanding the foregoing, Washington Mutual Bank shall be an “Eligible Institution” if the following conditions are satisfied: (i) Washington Mutual Bank is acting as Servicer, (ii) if S&P is a Rating Agency as defined herein, the long-term unsecured debt obligations of Washington Mutual Bank are rated no lower than “A-” by S&P and the short-term unsecured debt obligations of Washington Mutual Bank are rated no lower than “A-2” by S&P, (iii) if Fitch is a Rating Agency as defined herein, the long-term unsecured debt obligations of Washington Mutual Bank are rated no lower than “A” by Fitch and the short-term unsecured debt obligations of Washington Mutual Bank are rated no lower than “F1” by Fitch and (iv) if Moody’s is a Rating Agency as defined herein, the long-term unsecured debt obligations of Washington Mutual Bank are rated no lower than “A2” by Moody’s and the short-term unsecured debt obligations of Washington Mutual Bank are rated no lower than “P-1” by Moody’s; provided, that if the long-term or short-term unsecured debt obligations of Washington Mutual Bank are downgraded by any of the Rating Agencies to a rating lower than the applicable rating specified in this sentence, Washington Mutual Bank shall cease to be an “Eligible Institution” ten Business Days after it receives notification of such downgrade.

Eligible Investments : The investment property or other property listed below:

(i)                  Obligations of, or guaranteed as to principal and interest by, the United States or any agency or instrumentality thereof when such obligations are backed by the full faith and credit of the United States;

(ii)                Repurchase agreements on obligations described in clause (i) of this definition of “Eligible Investments,” provided that the unsecured obligations of the party (including the institution acting as Trustee) agreeing to repurchase such obligations have at the time one of the two highest short term debt ratings  of the Rating Agencies and provided that such repurchaser’s unsecured long term debt has one of the two highest unsecured long term debt ratings of the Rating Agencies;

(iii)               Federal funds, certificates of deposit, time deposits and bankers’ acceptances of the institution acting as Trustee or any bank or trust company incorporated under the laws of the United States or any state, provided that the debt obligations of such bank or trust company (or, in the case of the principal bank in a bank holding company system, debt obligations of the bank holding company) at the date of acquisition thereof have one of the two highest short term debt ratings of the Rating Agencies and unsecured long term debt has one of the two highest unsecured long term debt ratings of the Rating Agencies;

(iv)              Obligations of, or obligations guaranteed by, any state of the United States or the District of Columbia, provided that such obligations at the date of acquisition thereof shall have the highest long-term debt ratings available for such securities from the Rating Agencies;

(v)                Commercial paper of any corporation incorporated under the laws of the United States or any state thereof, which on the date of acquisition has the highest commercial paper rating of the Rating Agencies, provided that the corporation has unsecured long term debt that has one of the two highest unsecured long term debt ratings of the Rating Agencies;

(vi)              Securities (other than stripped bonds or stripped coupons) bearing interest or sold at a discount that are issued by any corporation incorporated under the laws of the United States or any state thereof and have the highest long-term unsecured rating available for such securities from the Rating Agencies; provided, however, that securities issued by any such corporation will not be Eligible Investments to the extent that investment therein would cause the outstanding principal amount of securities issued by such corporation that are then held as part of the Investment Account or the Certificate Account to exceed 20% of the aggregate principal amount of all Eligible Investments then held in the Investment Account and the Certificate Account; and

(vii)             Units of taxable 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), which funds have the highest rating available for such securities from the Rating Agencies or which have been designated in writing by the Rating Agencies as Eligible Investments;

provided, however , that such investment property or other property is held for a temporary period pursuant to Section 1.860G-2(g)(1) of the Treasury Regulations, and that such period can in no event exceed thirteen months.

In no event shall an instrument or security be an Eligible Investment if such instrument or security (a) evidences a right to receive only interest payments with respect to the obligations underlying such instrument or (b) has been purchased at a price greater than the outstanding principal balance of such instrument.

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

ERISA Restricted Certificate : Any Senior Subordinate Certificate.

Event of Default : The meaning specified in Section 7.01.

Excess Liquidation Proceeds : With respect to any Distribution Date, the sum of (i) the excess, if any, of aggregate Liquidation Proceeds and Insurance Proceeds received during the Prior Period over the amount that would have been received if Payoffs had been made with respect to such Mortgage Loans during such Prior Period and (ii) any Excess Subsequent Recoveries for any Loan Group for such Distribution Date.

Excess Subsequent Recoveries : For any Distribution Date and any Loan Group, the excess, if any, of (i) amounts received by the Servicer during the Prior Period in connection with the liquidation of defaulted Mortgage Loans in such Loan Group after such Mortgage Loans became Liquidated Mortgage Loans over (ii) the Subsequent Recoveries for such Distribution Date for such Loan Group.

Fannie Mae : The Federal National Mortgage Association and any successor thereto.

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

FHA : The Federal Housing Administration, or any successor thereto.

Final Maturity Date With respect to each Class of the REMIC I Regular Interests, the REMIC II Regular Interests and the Certificates, the date set forth in the applicable table contained in the Preliminary Statement hereto.

Fitch : Fitch Ratings, provided that at the applicable time it is a Rating Agency.

Freddie Mac : The Federal Home Loan Mortgage Corporation and any successor thereto.

Group B Percentage :  For any date of determination, the aggregate Class Principal Balance of the Class B Certificates divided by the then outstanding aggregate Principal Balance of the Mortgage Loans.

Group 1-A Certificates :  The Class 1-A1, Class 1-A2, Class 1-A3, Class 1-A4 and Class 1-A5 Certificates.

Group 1 Loans :  The Mortgage Loans designated on the Mortgage Loan Schedule as Group 1 Loans.

Group 1 Senior Liquidation Amount : For any Distribution Date, the sum of (A) the aggregate, for each Group 1 Loan which became a Liquidated Mortgage Loan during the Prior Period, of the lesser of: (i) the Group 1 Senior Percentage of the Principal Balance of such Mortgage Loan and (ii) the Group 1 Senior Prepayment Percentage of the Liquidation Principal with respect to such Mortgage Loan and (B) the Group 1 Senior Prepayment Percentage of any Subsequent Recoveries for Loan Group 1 for such Distribution Date.

Group 1 Senior Percentage : For any Distribution Date, the lesser of (i) 100% and (ii) the aggregate Class Principal Balance of the Group 1-A and Residual Certificates divided by the aggregate Principal Balance of the Group 1 Loans, in each case immediately before such Distribution Date.

Group 1 Senior Prepayment Percentage or Group 2 Senior Prepayment Percentage :  Subject to the immediately succeeding paragraph, (A) for any Distribution Date prior to the seventh anniversary of the first Distribution Date, each of the Group 1 Senior Prepayment Percentage and the Group 2 Senior Prepayment Percentage shall equal 100% and (B) for any Distribution Date on or after the seventh anniversary of the first Distribution Date, the Group 1 Senior Prepayment Percentage and the Group 2 Senior Prepayment Percentage shall be calculated as follows: (1) for any such Distribution Date on or after the seventh anniversary but before the eighth anniversary of the first Distribution Date, the Group 1 Senior Percentage or the Group 2 Senior Percentage, as applicable, for such Distribution Date plus 70% of the Subordinate Percentage for the related Loan Group for such Distribution Date; (2) for any such Distribution Date on or after the eighth anniversary but before the ninth anniversary of the first Distribution Date, the Group 1 Senior Percentage or the Group 2 Senior Percentage, as applicable, for such Distribution Date plus 60% of the Subordinate Percentage for the related Loan Group for such Distribution Date; (3) for any such Distribution Date on or after the ninth anniversary but before the tenth anniversary of the first Distribution Date, the Group 1 Senior Percentage or the Group 2 Senior Percentage, as applicable, for such Distribution Date plus 40% of the Subordinate Percentage for the related Loan Group for such Distribution Date; (4) for any such Distribution Date on or after the tenth anniversary but before the eleventh anniversary of the first Distribution Date, the Group 1 Senior Percentage or the Group 2 Senior Percentage, as applicable, for such Distribution Date plus 20% of the Subordinate Percentage for the related Loan Group for such Distribution Date; and (5) for any such Distribution Date thereafter, the Group 1 Senior Percentage or the Group 2 Senior Percentage, as applicable, for such Distribution Date; provided, however, that (x) for any Distribution Date on or prior to the Distribution Date in August 2008, if (i) the Group B Percentage for such Distribution Date is greater than or equal to twice the Group B Percentage as of the Closing Date and (ii) cumulative Realized Losses on the Mortgage Loans allocated to the Class B Certificates, as a percentage of the aggregate Class Principal Balance of the Class B Certificates as of the Closing Date, do not exceed 20%, then the Group 1 Senior Prepayment Percentage and the Group 2 Senior Prepayment Percentage shall equal the Group 1 Senior Percentage or the Group 2 Senior Percentage, as applicable, for such Distribution Date plus 50% of the Subordinate Percentage for the related Loan Group for such Distribution Date and (y) for any Distribution Date after the Distribution Date in August 2008, if (i) the Group B Percentage for such Distribution Date is greater than or equal to twice the Group B Percentage as of the Closing Date and (ii) cumulative Realized Losses on the Mortgage Loans allocated to the Class B Certificates, as a percentage of the aggregate Class Principal Balance of the Class B Certificates as of the Closing Date, do not exceed 30%, then the Group 1 Senior Prepayment Percentage and the Group 2 Senior Prepayment Percentage shall equal the Group 1 Senior Percentage or the Group 2 Senior Percentage, as applicable, for such Distribution Date.

Notwithstanding the immediately preceding paragraph, (A) for any Distribution Date, if the Group 1 Senior Percentage for such Distribution Date is greater than the Group 1 Senior Percentage as of the Closing Date or the Group 2 Senior Percentage for such Distribution Date is greater than the Group 2 Senior Percentage as of the Closing Date, then each of the Group 1 Senior Prepayment Percentage and Group 2 Senior Prepayment Percentage shall equal 100%, (B) for any Distribution Date on or before the seventh anniversary of the first Distribution Date, if any of the tests specified in clauses (a) through (d) below is met, then each of the Group 1 Senior Prepayment Percentage and Group 2 Senior Prepayment Percentage shall equal 100% and (C) for any Distribution Date after the seventh anniversary of the first Distribution Date, if any of the tests specified in clauses (a) through (d) below is met (unless either (w) the Group 1 Senior Percentage for such Distribution Date is greater than the Group 1 Senior Percentage as of the Closing Date, (x) the Group 2 Senior Percentage for such Distribution Date is greater than the Group 2 Senior Percentage as of the Closing Date or (y) there is no Earlier Distribution Date (as defined below), in each of which case each of the Group 1 Senior Prepayment Percentage and the Group 2 Senior Prepayment Percentage shall equal 100%), then each of the Group 1 Senior Prepayment Percentage and the Group 2 Senior Prepayment Percentage shall be calculated as follows:  (1) if the most recent preceding Distribution Date on which none of the tests specified in clauses (a) through (d) below was met (such date referred to as the “ Earlier Distribution Date ”) is on or after the seventh anniversary but before the eighth anniversary of the first Distribution Date, then the Group 1 Senior Prepayment Percentage and the Group 2 Senior Prepayment Percentage shall equal the Group 1 Senior Percentage or the Group 2 Senior Percentage, as applicable, for the current Distribution Date plus 70% of the Subordinate Percentage for the related Loan Group for the current Distribution Date, (2) if the Earlier Distribution Date is on or after the eighth anniversary but before the ninth anniversary of the first Distribution Date, then the Group 1 Senior Prepayment Percentage and the Group 2 Senior Prepayment Percentage shall equal the Group 1 Senior Percentage or the Group 2 Senior Percentage, as applicable, for the current Distribution Date plus 60% of the Subordinate Percentage for the related Loan Group for the current Distribution Date, (3) if the Earlier Distribution Date is on or after the ninth  anniversary but before the tenth anniversary of the first Distribution Date, then the Group 1 Senior Prepayment Percentage and the Group 2 Senior Prepayment Percentage shall equal the Group 1 Senior Percentage or the Group 2 Senior Percentage, as applicable, for the current Distribution Date plus 40% of the Subordinate Percentage for the related Loan Group for the current Distribution Date, (4) if the Earlier Distribution Date is on or after the tenth anniversary but before the eleventh anniversary of the first Distribution Date, then the Group 1 Senior Prepayment Percentage and the Group 2 Senior Prepayment Percentage shall equal the Group 1 Senior Percentage or the Group 2 Senior Percentage, as applicable, for the current Distribution Date plus 20% of the Subordinate Percentage for the related Loan Group for the current Distribution Date, and (5) if the Earlier Distribution Date is on or after the eleventh anniversary of the first Distribution Date, then the Group 1 Senior Prepayment Percentage and the Group 2 Senior Prepayment Percentage shall equal the Group 1 Senior Percentage or the Group 2 Senior Percentage, as applicable, for the current Distribution Date:

(a)        the mean aggregate Principal Balance, as of the Distribution Date in each of the immediately preceding six calendar months, of the Group 1 Loans which were 60 or more days delinquent as of such date (including Mortgage Loans in foreclosure and Mortgaged Properties held by REMIC I) is greater than 50% of the Subordinate Component Balance for Loan Group 1 as of the current Distribution Date,

(b)        the mean aggregate Principal Balance, as of the Distribution Date in each of the immediately preceding six calendar months, of the Group 2 Loans which were 60 or more days delinquent as of such date (including Mortgage Loans in foreclosure and Mortgaged Properties held by REMIC I) is greater than 50% of the Subordinate Component Balance for Loan Group 2 as of the current Distribution Date,

(c)        cumulative Realized Losses on the Group 1 Loans allocated to the Class B Certificates, as a percentage of the Subordinate Component Balance for Loan Group 1 as of the Closing Date, are greater than, for any Distribution Date (1) before the eighth anniversary of the first Distribution Date, 30%, (2) on or after the eighth anniversary but before the ninth anniversary of the first Distribution Date, 35%, (3) on or after the ninth anniversary but before the tenth anniversary of the first Distribution Date, 40%, (4) on or after the tenth anniversary but before the eleventh anniversary of the first Distribution Date, 45%, and (5) on or after the eleventh anniversary of the first Distribution Date, 50% or

(d)        cumulative Realized Losses on the Group 2 Loans allocated to the Class B Certificates, as a percentage of the Subordinate Component Balance for Loan Group 2 as of the Closing Date, are greater than, for any Distribution Date (1) before the eighth anniversary of the first Distribution Date, 30%, (2) on or after the eighth anniversary but before the ninth anniversary of the first Distribution Date, 35%, (3) on or after the ninth anniversary but before the tenth anniversary of the first Distribution Date, 40%, (4) on or after the tenth anniversary but before the eleventh anniversary of the first Distribution Date, 45%, and (5) on or after the eleventh anniversary of the first Distribution Date, 50%.

If on any Distribution Date the allocation to the Group 1-A or Group 2-A Certificates of Principal Prepayments in the percentage required would reduce the aggregate Class Principal Balance of such Certificates below zero, the Group 1 Senior Prepayment Percentage or the Group 2 Senior Prepayment Percentage, as applicable, for such Distribution Date shall be limited to the percentage necessary to reduce such aggregate Class Principal Balance to zero.

Group 1 Senior Principal Distribution Amount : For any Distribution Date, an amount equal to the sum of (a) the Group 1 Senior Percentage of the Principal Payment Amount for Loan Group 1, (b) the Group 1 Senior Prepayment Percentage of the Principal Prepayment Amount for Loan Group 1 and (c) the Group 1 Senior Liquidation Amount.

Group 1 Subordinate Balance :  For any date of determination, an amount equal to the then outstanding aggregate Principal Balance of the Group 1 Loans reduced by the aggregate Class Principal Balance of the Group 1-A and Residual Certificates.

Group 1 Subordinate Percentage : For any Distribution Date, the excess of 100% over the Group 1 Senior Percentage for such date.

Group 1 Subordinate Prepayment Percentage : For any Distribution Date, the excess of 100% over the Group 1 Senior Prepayment Percentage for such Distribution Date; provided, however, that if the aggregate Class Principal Balance of the Group 1-A and Residual Certificates has been reduced to zero, then the Group 1 Subordinate Prepayment Percentage shall equal 100%.

Group 2-A Certificates :  The Class 2-A1 and Class 2-A2 Certificates.

Group 2 Loans :  The Mortgage Loans designated on the Mortgage Loan Schedule as Group 2 Loans.

Group 2 Senior Liquidation Amount : For any Distribution Date, the sum of (A) the aggregate, for each Group 2 Loan which became a Liquidated Mortgage Loan during the Prior Period, of the lesser of: (i) the Group 2 Senior Percentage of the Principal Balance of such Mortgage Loan and (ii) the Group 2 Senior Prepayment Percentage of the Liquidation Principal with respect to such Mortgage Loan and (B) the Group 2 Senior Prepayment Percentage of any Subsequent Recoveries for Loan Group 2 for such Distribution Date.

Group 2 Senior Percentage : For any Distribution Date, the lesser of (i) 100% and (ii) the aggregate Class Principal Balance of the Group 2-A Certificates divided by the aggregate Principal Balance of the Group 2 Loans, in each case immediately before such Distribution Date.

Group 2 Senior Prepayment Percentage : See the definition of “Group 1 Senior Prepayment Percentage or Group 2 Senior Prepayment Percentage.”

Group 2 Senior Principal Distribution Amount : For any Distribution Date, an amount equal to the sum of (a) the Group 2 Senior Percentage of the Principal Payment Amount for Loan Group 2, (b) the Group 2 Senior Prepayment Percentage of the Principal Prepayment Amount for Loan Group 2 and (c) the Group 2 Senior Liquidation Amount.

Group 2 Subordinate Balance :  For any date of determination, an amount equal to the then outstanding aggregate Principal Balance of the Group 2 Loans reduced by the aggregate Class Principal Balance of the Group 2-A Certificates.

Group 2 Subordinate Percentage : For any Distribution Date, the excess of 100% over the Group 2 Senior Percentage for such date.

Group 2 Subordinate Prepayment Percentage : For any Distribution Date, the excess of 100% over the Group 2 Senior Prepayment Percentage for such Distribution Date; provided, however, that if the aggregate Class Principal Balance of the Group 2-A Certificates has been reduced to zero, then the Group 2 Subordinate Prepayment Percentage shall equal 100%.

Index :  Initially, either One-Year CMT or One-Year LIBOR, as set forth on the Mortgage Loan Schedule.  In the event such initial Index is no longer available, the Servicer will select a substitute Index in accordance with the terms of the related Mortgage Note and in compliance with applicable law.

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

Initial Custodial Agreement :  The Custodial Agreement, dated the date hereof, among the Trustee, the Servicer and the Initial Custodian.

Initial Custodian Washington Mutual Bank fsb .

Insurance Proceeds : Amounts paid or payable by the insurer under any Primary Insurance Policy or any other insurance policy (including any replacement policy permitted under this Agreement) covering any Mortgage Loan or Mortgaged Property, including, without limitation, any hazard insurance policy required pursuant to Section 3.07, any title insurance policy and any FHA insurance policy or VA guaranty, to the extent such amounts are not released to the Mortgagor in accordance with prudent mortgage loan servicing practices.

Interest Distribution Amount : For any Distribution Date, for any Class of REMIC I Regular Interests, the Class R-1 Residual Interest and the Certificates, the amount of interest accrued during the Prior Period, at the related Certificate Interest Rate for such Class for such Distribution Date, on the respective Class Principal Balance immediately before such Distribution Date, reduced by Uncompensated Interest Shortfall and the interest portion of Realized Losses allocated to such Class on such Distribution Date pursuant to the definitions of “Uncompensated Interest Shortfall” and “Realized Loss,” respectively. 

The computation of interest accrued shall be made on the basis of a 360-day year of twelve 30-day months. 

Interest Transfer Amount : On any Distribution Date for an Undercollateralized Group, an amount equal to one month’s interest on the applicable Principal Transfer Amount at the Loan Group 1 Weighted Average Pass-Through Rate if the Undercollateralized Group is Loan Group 1 and at the Loan Group 2 Weighted Average Pass-Through Rate if the Undercollateralized Group is Loan Group 2 plus any interest accrued on the Senior Certificates related to such Undercollateralized Group remaining unpaid from prior Distribution Dates.

Investment Account : The commingled account (which shall be commingled only with investment accounts related to series of pass-through certificates with a class of certificates which has a rating equal to the highest of the Ratings of the Certificates) maintained by the Servicer in the trust department of the Investment Depository pursuant to Section 3.03 and which bears a designation acceptable to the Rating Agencies.

Investment Depository : JPMorgan Chase Bank, or another bank or trust company designated from time to time by the Servicer. The Investment Depository shall at all times be an Eligible Institution.

Junior Subordinate Certificates : The Class B-4, Class B-5 and Class B-6 Certificates.

Last Scheduled Distribution Date With respect to any Class of Certificates, the Final Maturity Date for such Class.

Liquidated Mortgage Loan : A Mortgage Loan (other than a Mortgage Loan with respect to which a Payoff has been made) for which the Servicer has determined in accordance with its customary servicing practices that it has received all amounts which it expects to recover from or on account of such Mortgage Loan, whether from Insurance Proceeds, Liquidation Proceeds or otherwise. For purposes of this definition, acquisition of a Mortgaged Property by the Trust shall not constitute final liquidation of the related Mortgage Loan.

Liquidation Principal : The principal portion of Liquidation Proceeds and Insurance Proceeds received with respect to each Mortgage Loan which became a Liquidated Mortgage Loan during the Prior Period (but not in excess of the principal balance thereof).

Liquidation Proceeds : Amounts received and retained in connection with the liquidation of defaulted Mortgage Loans, whether through foreclosure or otherwise, other than Insurance Proceeds and other than Subsequent Recoveries, and (except for purposes of the definition of “Realized Loss”) after deduction of amounts reimbursable under Section 3.05(a)(i) and (ii).

Loan Group : Loan Group 1 or Loan Group 2, as applicable.

Loan Group 1 : The group of Mortgage Loans comprised of the Group 1 Loans.

Loan Group 1 Weighted Average Pass-Through Rate :  For any Distribution Date, the weighted average of the Pass-Through Rates on the Group 1 Loans as of the second preceding Due Date (after giving effect to the payments due on the Group 1 Loans on that Due Date and after giving effect to any Payoffs on the Group 1 Loans received on or before the 14th day of the calendar month immediately preceding the calendar month of that Distribution Date).

Loan Group 2 : The group of Mortgage Loans comprised of the Group 2 Loans.

Loan Group 2 Weighted Average Pass-Through Rate :  For any Distribution Date, the weighted average of the Pass-Through Rates on the Group 2 Loans as of the second preceding Due Date (after giving effect to the payments due on the Group 2 Loans on that Due Date and after giving effect to any Payoffs on the Group 2 Loans received on or before the 14th day of the calendar month immediately preceding the calendar month of that Distribution Date).

Lowest Class B Owner : An owner unaffiliated with the Company or the Servicer of (i) a 100% interest in the Class of Class B Certificates with the lowest priority or (ii) a 100% interest in a class of securities representing such interest in such Class specified in clause (i) above.

Margin :  For each Mortgage Loan, the applicable fixed per annum percentage rate specified in the applicable Mortgage Note and designated as such in the Mortgage Loan Schedule.

MERS : Mortgage Electronic Registration Systems, Inc., a Delaware corporation, or any successor thereto.

MERS Loan : Any Mortgage Loan registered on the MERS® System for which MERS appears as the mortgagee of record on the related Mortgage or on an assignment thereof.

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

MIN : The Mortgage Identification Number for a MERS Loan.

MOM Loan : A MERS Loan that was registered on the MERS® System at the time of origination thereof and for which MERS appears as the mortgagee of record on the related Mortgage.

Monthly P&I Advance : An advance of funds by the Servicer pursuant to Section 4.02 to cover delinquent principal and interest installments.

Monthly Payment : The scheduled payment of principal (if any) and interest on a Mortgage Loan (including any amounts due from a Buydown Fund, if any) which is due on the related Due Date for such Mortgage Loan.

Moody’s :  Moody’s Investors Service, Inc., provided that at the applicable time it is a Rating Agency.

Mortgage : The mortgage, deed of trust or other instrument securing a Mortgage Note.

Mortgage File : The following documents or instruments with respect to each Mortgage Loan, (X) with respect to each Mortgage Loan that is not a Cooperative Loan:

(i)                  The original Mortgage Note endorsed (A) in blank, without recourse, (B) to the Trustee, without recourse, or (C) to the Trust, without recourse, and all intervening endorsements evidencing a complete chain of endorsements from the originator to the endorser last endorsing the Mortgage Note , or, in the event of any Destroyed Mortgage Note, a copy or a duplicate original of the Mortgage Note (or portion thereof, as applicable), together with an original lost note affidavit from the originator of the Mortgage Loan, the applicable Seller or the Company stating that the original Mortgage Note (or portion thereof, as applicable) was lost, misplaced or destroyed, together with a copy of the Mortgage Note (or portion thereof, as applicable); provided, however, that in the event that either (a) Washington Mutual Bank or Washington Mutual Bank fsb is the Seller of the Mortgage Loan or (b) Washington Mutual Mortgage Securities Corp. is the Seller of the Mortgage Loan and purchased the Mortgage Loan from Washington Mutual Bank or Washington Mutual Bank fsb, then the Mortgage Note need not be endorsed in blank or to the Trustee or the Trust as provided above, but, if not so endorsed, shall be made payable to, or properly endorsed to, Washington Mutual Bank or Washington Mutual Bank fsb, as applicable;

(ii)                The Buydown Agreement, if applicable;

(iii)               (1)        (x) the original recorded Mortgage with evidence of recording thereon for the jurisdiction in which the Mortgaged Property is located (which original recorded Mortgage, in the case of a MOM Loan, shall set forth the MIN and shall indicate that the Mortgage Loan is a MOM Loan), (y) unless the Mortgage Loan is a MERS Loan, an original assignment of the Mortgage duly executed and acknowledged in recordable form (A) in blank, (B) to the Trustee or (C) to the Trust, and (z) unless the Mortgage Loan is a MOM Loan, recorded originals of all intervening assignments evidencing a complete chain of assignment from the originator to the person executing the assignment described in clause (y); or

(2)        (x) a copy (which may be in electronic form) of the Mortgage (which Mortgage, in the case of a MOM Loan, shall set forth the MIN and shall indicate that the Mortgage Loan is a MOM Loan) which represents a true and correct reproduction of the original Mortgage and which has either been certified (i) on the face thereof by the public recording office in the appropriate jurisdiction in which the Mortgaged Property is located, or (ii) by the originator, the applicable Seller, the Servicer or the escrow or title company which provided closing services in connection with such Mortgage Loan as a true and correct copy the original of which has been sent for recordation, (y) unless the Mortgage Loan is a MERS Loan, an original assignment of the Mortgage duly executed and acknowledged in recordable form (A) in blank, (B) to the Trustee or (C) to the Trust, and (z) unless the Mortgage Loan is a MOM Loan, true and correct copies, certified by the applicable county recorder or by the originator, the applicable Seller or the Servicer as described above, of all intervening assignments evidencing a complete chain of assignment from the originator to the person executing the assignment described in clause (y);

provided, however, that in the event that either (a) Washington Mutual Bank or Washington Mutual Bank fsb is the Seller of the Mortgage Loan or (b) Washington Mutual Mortgage Securities Corp. is the Seller of the Mortgage Loan and purchased the Mortgage Loan from Washington Mutual Bank or Washington Mutual Bank fsb, then the Mortgage File need not include an assignment of the Mortgage executed in blank or to the Trustee or the Trust as provided in clause (X)(iii)(1)(y) or (X)(iii)(2)(y) above, as applicable, but the Mortgage File shall, unless the Mortgage Loan was originated by Washington Mutual Bank or Washington Mutual Bank fsb, include a complete chain of assignments of the related Mortgage from the originator of such Mortgage Loan to Washington Mutual Bank or Washington Mutual Bank fsb, as applicable; and

(iv)              For any Mortgage Loan that has been modified or amended, the original instrument or instruments effecting such modification or amendment;

and (Y) with respect to each Cooperative Loan:

(i)                  the original Mortgage Note endorsed (A) in blank, without recourse, (B) to the Trustee, without recourse, or (C) to the Trust, without recourse, and all intervening endorsements evidencing a complete chain of endorsements from the originator to the endorser last endorsing the Mortgage Note , or, in the event of any Destroyed Mortgage Note, a copy or a duplicate original of the Mortgage Note (or portion thereof, as applicable), together with an original lost note affidavit from the originator of the Cooperative Loan, the applicable Seller or the Company, as applicable, stating that the original Mortgage Note (or portion thereof, as applicable) was lost, misplaced or destroyed, together with a copy of the Mortgage Note (or portion thereof, as applicable); provided, however, that in the event that either (a) Washington Mutual Bank or Washington Mutual Bank fsb is the Seller of the Mortgage Loan or (b) Washington Mutual Mortgage Securities Corp. is the Seller of the Mortgage Loan and purchased the Mortgage Loan from Washington Mutual Bank or Washington Mutual Bank fsb, then the Mortgage Note need not be endorsed in blank or to the Trustee or the Trust as provided above, but, if not so endorsed, shall be made payable to, or properly endorsed to, Washington Mutual Bank or Washington Mutual Bank fsb, as applicable;

(ii)                A counterpart of the Cooperative Lease and the Assignment of Proprietary Lease;

(iii)               The Cooperative Stock Certificate, together with an undated stock power or other similar instrument executed in blank;

(iv)              The Recognition Agreement;

(v)                The Security Agreement;

(vi)              Copies of the original UCC financing statement, and any continuation statements or amendments thereof, each with evidence of recording thereof, perfecting the security interest granted under the Security Agreement and the Assignment of Proprietary Lease;

(vii)             Copies of the filed UCC assignments or amendments of the UCC financing statements described in clause (vi) above showing an unbroken chain of assignments from the originator to the Trustee or the Trust, each with evidence of recording thereof;

(viii)           Executed assignments of the interest of the originator in the Security Agreement, the Assignment of Proprietary Lease and the Recognition Agreement, showing an unbroken chain of assignments from the originator to the Trustee or the Trust; and

(ix)              For any Cooperative Loan that has been modified or amended, the original instrument or instruments effecting such modification or amendment;

provided, however, that in the event that either (a) Washington Mutual Bank or Washington Mutual Bank fsb is the Seller of the Mortgage Loan or (b) Washington Mutual Mortgage Securities Corp. is the Seller of the Mortgage Loan and purchased the Mortgage Loan from Washington Mutual Bank or Washington Mutual Bank fsb, then the Mortgage File need not include (1) a UCC assignment or amendment of the UCC financing statement referenced in clause (Y)(vi) above to the Trustee or the Trust as provided in clause (Y)(vii) above, but the Mortgage File shall, unless the Cooperative Loan was originated by Washington Mutual Bank or Washington Mutual Bank fsb, include a UCC assignment or amendment of such UCC financing statement to Washington Mutual Bank or Washington Mutual Bank fsb, as applicable, or (2) an assignment of the interest of the originator in the Security Agreement, the Assignment of Proprietary Lease and the Recognition Agreement to the Trustee or the Trust as provided in clause (Y)(viii) above, but the Mortgage File shall, unless the Cooperative Loan was originated by Washington Mutual Bank or Washington Mutual Bank fsb, include an assignment of such interest to Washington Mutual Bank or Washington Mutual Bank fsb, as applicable.

Mortgage Interest Rate : For any Mortgage Loan, the per annum rate at which interest accrues on such Mortgage Loan pursuant to the terms of the related Mortgage Note.

Mortgage Loan Purchase Agreement : The Mortgage Loan Purchase and Sale Agreement, dated as of October 25, 2005, among the Company, Washington Mutual Bank and Washington Mutual Bank fsb, as supplemented and amended by the Term Sheet, dated the Closing Date, between the Company and Washington Mutual Bank and relating to the Certificates.

Mortgage Loan Schedule : The schedule, as amended from time to time, of Mortgage Loans attached hereto as Exhibit D, which shall set forth as to each Mortgage Loan the following, among other things:

(i)                  its loan number,

(ii)                the city, state and zip code of the Mortgaged Property,

(iii)               the Monthly Payment as of the Cut-Off Date,

(iv)              the Appraised Value of the property subject to the Mortgage,

(v)                the Principal Balance as of the Cut-Off Date,

(vi)              the Mortgage Interest Rate, as of the Cut-Off Date, under the Mortgage Note and the Rate Ceiling and Mortgage Loan Margin under the Mortgage Note,

(vii)             whether a Primary Insurance Policy is in effect as of the Cut-Off Date, and, if so, whether such Primary Insurance Policy is a Special Primary Insurance Policy,

(viii)           the maturity of the Mortgage Note,

(ix)              the Servicing Fee Rate, and

(x)                its Loan Group.

Mortgage Loans : The mortgage loans and cooperative loans (if any), including each Substitute Mortgage Loan, listed on the Mortgage Loan Schedule. With respect to each Mortgage Loan that is a Cooperative Loan, “Mortgage Loan” shall include, but not be limited to, the Mortgage Note and the related Security Agreement, Assignment of Proprietary Lease, Recognition Agreement, Cooperative Stock Certificate and Cooperative Lease and, with respect to each Mortgage Loan other than a Cooperative Loan, “Mortgage Loan” shall include, but not be limited to, the Mortgage Note and the related Mortgage.

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

Mortgage Pool : All of the Mortgage Loans.

Mortgage Pool Assets : (i) The Mortgage Loans (including all Substitute Mortgage Loans) identified on the Mortgage Loan Schedule, and all rights pertaining thereto, including the related Mortgage Notes, Mortgages, Cooperative Stock Certificates, Cooperative Leases, Security Agreements, Assignments of Proprietary Lease, and Recognition Agreements, and all Monthly Payments due after the Cut-Off Date and all other payments and distributions collected with respect to the Mortgage Loans on or after the Cut-Off Date; (ii) the Certificate Account, the Investment Account, and all money, instruments, investment property, and other property credited thereto, carried therein, or deposited therein (except amounts constituting the Servicing Fee); (iii) the Custodial Accounts for P&I and any Buydown Fund Account (to the extent of the amounts on deposit or other property therein attributable to the Mortgage Loans), and all money, instruments, investment property, and other property credited thereto, carried therein, or deposited therein (except amounts constituting the Servicing Fee); (iv) all property that secured a Mortgage Loan and that has been acquired by foreclosure or deed in lieu of foreclosure or, in the case of a Cooperative Loan, a similar form of conversion, after the Cut-Off Date; and (v) each FHA insurance policy, Primary Insurance Policy, VA guaranty, and other insurance policy related to any Mortgage Loan, and all amounts paid or payable thereunder and all proceeds thereof.

Mortgaged Property : With respect to any Mortgage Loan, other than a Cooperative Loan, the real property, together with improvements thereto, and, with respect to any Cooperative Loan, the related Cooperative Stock and Cooperative Lease, securing the indebtedness of the Mortgagor under the related Mortgage Note.  “Mortgaged Property” shall also refer to property which once secured the indebtedness of a Mortgagor under the related Mortgage Loan but which was acquired by the Trust upon foreclosure or other liquidation of such Mortgage Loan.

Mortgagor : The obligor on a Mortgage Note.

Nonrecoverable Advance : With respect to any Mortgage Loan, any advance which the Servicer shall determine to be a Nonrecoverable Advance pursuant to Section 4.03 and which was, or is proposed to be, made by the Servicer.

Non-U.S. Person : A Person that is not a U.S. Person.

Notice Addresses : (a) In the case of the Company, 1201 Third Avenue, WMT 1706A, Seattle, WA 98101, or such other address as may hereafter be furnished to the Trustee in writing by the Company, (b) in the case of the Servicer, 19850 Plummer St. (Mail Stop N070205) Chatsworth, California 91311, Fax No: (818) 775-2815, Attention: Vice President Investor Reporting, with a copy to: Washington Mutual Legal Department, 1201 Third Avenue, WMT 1706, Seattle, WA 98101, Fax No: (206) 377-6244, Attention: WaMu, and with a copy to Washington Mutual Mortgage Securities Corp., 75 North Fairway Drive, Vernon Hills, Illinois 60061, Attention: Bond Administration, or such other address and fax number as may hereafter be furnished in writing by the Servicer, (c) in the case of the Trustee, at its Corporate Trust Office, or such other address as may hereafter be furnished to the Servicer in writing by the Trustee, (d) in the case of the Delaware Trustee, 1314 King Street, Wilmington, DE  19801, or such other address as may hereafter be furnished to the Servicer in writing by the Delaware Trustee, (e) in the case of the Trust, c/o LaSalle Bank National Association, at the Corporate Trust Office, or such other address as may hereafter be furnished to the Servicer in writing by the Trustee, (f) in the case of the Certificate Registrar, at its Corporate Trust Office, or such other address as may hereafter be furnished to the Trustee in writing by the Certificate Registrar, (g) in the case of S&P, 55 Water Street, 41st Floor, New York, New York 10041-0003, Attention:  Residential Mortgage Backed Securities Surveillance Group, or such other address as may hereafter be furnished to the Trustee and Servicer in writing by S&P and (h) in the case of Fitch, 1 State Street Plaza, New York, New York 10004, Attention: Glenn Costello, or such other address as may hereafter be furnished to the Trustee and Servicer in writing by Fitch.

OTS : The Office of Thrift Supervision, or any successor thereto.

Officer’s Certificate : A certificate signed by the Chairman of the Board, the President, a Vice President, or the Treasurer of the Servicer and delivered to the Trustee or the Delaware Trustee, as applicable.

One-Year CMT :  The weekly average yield on United States Treasury Securities adjusted to a constant maturity of one year, as made available by the Federal Reserve Board, published in Federal Reserve Statistical Release H.15(519) most recently available as of 45 days before the applicable Adjustment Date.

One-Year LIBOR : The average of interbank offered rates for one-year U.S. dollar-denominated deposits in the London market, as published in The Wall Street Journal and most recently available as of the date 45 days before the applicable Adjustment Date.

Opinion of Counsel : A written opinion of counsel, who shall be reasonably acceptable to the Trustee or the Delaware Trustee, as applicable, and who may be counsel (including in-house counsel) for the Company or the Servicer.