Exhibit 10.8

EXECUTION COPY

TRUST GUARANTEE AGREEMENT

CAPMARK TRUST

Dated as of March 23, 2006

CROSS REFERENCE TABLE*

*                                          This Cross-Reference Table does not constitute part of the Agreement and shall not have any bearing upon the interpretation of any of its terms or provisions.

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Table of Contents

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TRUST GUARANTEE AGREEMENT

This TRUST GUARANTEE AGREEMENT (the “ Trust Guarantee ”), dated as of March 23, 2006, is executed and delivered by GMAC Commercial Holding Corp., a Nevada corporation (the “ Guarantor ”), and Law Debenture Trust Company of New York, as trustee (the “ Trust Guarantee Trustee ”), for the benefit of the Holders (as defined herein) from time to time of the Trust Securities (as defined herein) of Capmark Trust, a Delaware statutory trust (the “ Trust ”).

WHEREAS, pursuant to the Declaration of Trust (as defined herein), the Trust is issuing preferred securities, having a liquidation amount of $5,000,000 per security, designated the Floating Rate Trust Preferred Securities (the “ Trust Preferred Securities ”) to the Purchaser pursuant to the Purchase Agreement, and common securities, having a liquidation amount of $1,000 per security and designated the Trust Common Securities (the “ Trust Common Securities ” and together with the Trust Preferred Securities, the “ Trust Securities ”);

WHEREAS, as incentive for the Holders to purchase the Trust Securities, the Guarantor desires irrevocably and unconditionally to agree, to the extent set forth in this Trust Guarantee, to pay to the Holders of the Trust Securities the Guarantee Payments (as defined herein) and to make certain other payments on the terms and conditions set forth herein.

NOW, THEREFORE, in consideration of the purchase by each Holder of Trust Securities, which purchase the Guarantor hereby agrees shall benefit the Guarantor, the Guarantor executes and delivers this Trust Guarantee for the benefit of the Holders.

ARTICLE I

INTERPRETATION AND DEFINITIONS

SECTION 1.1.                                           Interpretation and Definitions

In this Trust Guarantee, unless the context otherwise requires:

(a)           capitalized terms used in this Trust Guarantee but not defined in the preamble above have the respective meanings assigned to them in this Section 1.1;

(b)           capitalized terms used in this Trust Guarantee but not otherwise defined herein shall have the meanings assigned to them in the Declaration of Trust or the Indenture;

(c)           a term defined anywhere in this Trust Guarantee has the same meaning throughout;

(d)           all references to “the Trust Guarantee” or “this Trust Guarantee” are to this Trust Guarantee as modified, supplemented or amended from time to time;

(e)           all references in this Trust Guarantee to Articles and Sections are to Articles and Sections of this Trust Guarantee, unless otherwise specified;

(f)            unless otherwise defined in this Trust Guarantee, a term defined in the Trust Indenture Act has the same meaning when used in this Trust Guarantee;

(g)           a reference to the singular includes the plural and vice versa and a reference to any masculine form of a term shall include the feminine form of such term, as applicable; and

(h)           the following terms have the following meanings:

“ Affiliate ” means, with respect to any specified Person, any other Person that directly or indirectly controls or is controlled by, or is under common control with such specified Person. For the purposes of this definition, “control” when used with respect to any specified Person means the power to direct the management and policies of such Person, directly or indirectly, whether through the ownership of voting securities, by contract or otherwise; and the terms “controlling” and “controlled” have meanings correlative to the foregoing.

“ Business Day ” means any day other than a Saturday or Sunday or a day on which banking institutions in the City of New York are authorized or required by law, regulation or executive order to close.

“ Covered Person ” means any Holder or beneficial owner of Trust Securities.

“ Declaration of Trust ” means the Amended and Restated Declaration of Trust by and among GMAC Commercial Holding Corp., as Sponsor, Law Debenture Trust Company of New York, as Property Trustee, Deutsche Bank Trust Company Delaware, as the Delaware Trustee, Deutsche Bank Trust Company Americas, as Agent and the Regular Trustees named therein, dated as of March 23, 2006, as it may be amended, modified or supplemented from time to time.

“ Event of Default ” means a default by the Guarantor on any of its payment or other obligations under this Trust Guarantee.

“ Guarantee Payments ” means the following payments or distributions, without duplication, with respect to the Trust Securities, to the extent not paid by or on behalf of the Trust: (i) any accumulated and unpaid distributions on such Trust Securities to the extent the Trust has sufficient funds available therefor at the time, (ii) the Redemption Price with respect to any Trust Securities called for redemption by the Trust to the extent the Trust has sufficient funds available therefor at the time and (iii) upon a voluntary or involuntary dissolution, winding up or termination of the Trust (other than in connection with the redemption of all of the Trust Preferred Securities), the lesser of (a) the aggregate of the liquidation amount and all accumulated and unpaid Distributions (as defined in the Declaration of Trust) on the Trust Securities to the date of payment, to the extent the Trust has sufficient funds available therefor at the time and (b) the amount of assets of the Trust, after satisfaction of all liabilities, remaining available for distribution to Holders upon dissolution of the Trust (the “ Liquidation Distribution ”).

“ Holder ” means any holder of Trust Securities, as registered on the books and records of the Trust; provided , however , that, in determining whether the Holders of the requisite

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percentage of Trust Preferred Securities have given any request, notice, consent or waiver hereunder, “Holder” shall not include the Guarantor or any Affiliate of the Guarantor or any other obligor on the Trust Securities.

“ Indemnified Person ” means the Trust Guarantee Trustee, any Affiliate of the Trust Guarantee Trustee, or any officers, directors, shareholders, members, partners, employees, representatives, nominees, custodians or agents of the Trust Guarantee Trustee.

“ Indenture ” means the Floating Rate Junior Subordinated Indenture, dated as of March 23, 2006, among the Guarantor, Law Debenture Trust Company of New York, as Trustee, and Deutsche Bank Trust Company Americas, as Agent.

“ Majority in Liquidation Amount of the Trust Preferred Securities ” means, except as provided in the terms of the Trust Preferred Securities or by the Trust Indenture Act, Holder(s) of outstanding Trust Preferred Securities, voting together as a single class, of more than 50% of the aggregate liquidation amount of all outstanding Trust Preferred Securities. In determining whether the Holders of the requisite amount of Trust Preferred Securities have voted, Trust Preferred Securities that are owned by the Guarantor or any Affiliate of the Guarantor or any other obligor on the Trust Securities shall be disregarded for the purpose of any such determination; provided that in determining whether the Trust Guarantee Trustee is entitled to rely on any instructions received from a Majority in Liquidation Amount, only Trust Securities that it knows to be so owned shall be disregarded.

“ Officers’ Certificate ” means, with respect to any Person, a certificate signed on behalf of such Person by two Authorized Officers of such Person. Any Officers’ Certificate delivered with respect to compliance with a condition or covenant provided for in this Trust Guarantee shall include:

(a)           a statement that each officer signing the Officers’ Certificate has read the covenant or condition and the definitions relating thereto;

(b)           a brief statement of the nature and scope of the examination or investigation undertaken by each officer on behalf of such Person in rendering the Officers’ Certificate;

(c)           a statement that each such officer has made such examination or investigation as, in such officer’s opinion, is necessary to enable such officer on behalf of such Person to express an informed opinion as to whether or not such covenant or condition has been complied with; and

(d)           a statement as to whether, in the opinion of each such officer on behalf of such Person, such condition or covenant has been complied with.

“ Person ” means a legal person, including any individual, corporation, estate, partnership, joint venture, association, joint stock company, limited liability company, trust, unincorporated association, or government or any agency or political subdivision thereof, or any other entity of whatever nature.

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“ Property Trustee ” means the Trustee meeting the eligibility requirements set forth in Section 6.3 of the Declaration of Trust until a Successor Property Trustee has been appointed and has accepted such appointment pursuant to the terms of the Declaration of Trust and thereafter means each such Successor Property Trustee. The Property Trustee shall initially be Law Debenture Trust Company of New York.

“ Purchase Agreement ” means the Purchase Agreement dated as of March 23, 2006 by and among the Guarantor, the Trust and the Purchaser.

“ Purchaser ” means General Motors Acceptance Corporation

“ Registration Rights Agreement ” means the Registration Rights Agreement dated as of March 23, 2006 by and among the Guarantor, the Trust and the Purchaser.

“ Responsible Officer ” means, with respect to the Trust Guarantee Trustee, any officer with direct responsibility for the administration of this Trust Guarantee and also means, with respect to a particular corporate trust matter, any other officer to whom such matter is referred because of that officer’s knowledge of and familiarity with the particular subject.

“ Successor Trust Guarantee Trustee ” means a successor Trust Guarantee Trustee possessing the qualifications to act as Trust Guarantee Trustee under Section 4.1.

“ Trust Indenture Act ” means the Trust Indenture Act of 1939, as amended from time to time, or any successor legislation.

ARTICLE II

TRUST INDENTURE ACT

SECTION 2.1.                                           Trust Indenture Act; Application

(a)           This Trust Guarantee is subject to the provisions of the Trust Indenture Act that are required to be part of this Trust Guarantee and shall, to the extent applicable, be governed by such provisions.

(b)           If and to the extent that any provision of this Trust Guarantee limits, qualifies or conflicts with the duties imposed by Sections 310 to 317, inclusive, of the Trust Indenture Act, such imposed duties shall control.

(c)           The Guarantor and the Trust Guarantee Trustee shall not be required to comply with any provisions of this Trust Guarantee that referred to the Trust Indenture Act unless this Trust Guarantee shall have been qualified under the Trust Indenture Act.

SECTION 2.2.                                           Lists of Holders

(a)           The Guarantor shall provide the Trust Guarantee Trustee (i) except while the Trust Preferred Securities are represented by one or more Global Securities at least one Business Day prior to the date for payment of distributions, a list, in such form as the Trust Guarantee Trustee may reasonably require, of the names and addresses of the Holders of the

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Trust Preferred Securities (“ List of Holders ”) as of the record date relating to the payment of such distributions and (ii) at any other time, within 30 days of receipt by the Guarantor of a written request from the Trust Guarantee Trustee for a List of Holders as of a date no more than 15 days before such List of Holders is given to the Trust Guarantee Trustee; provided that the Guarantor shall not be obligated to provide such List of Holders at any time the List of Holders does not differ from the most recent List of Holders given to the Trust Guarantee Trustee by the Guarantor. The Trust Guarantee Trustee shall preserve, in as current a form as is reasonably practicable, all information contained in Lists of Holders given to it, provided that the Trust Guarantee Trustee may destroy any List of Holders previously given to it on receipt of a new List of Holders.

(b)           The Trust Guarantee Trustee shall comply with its obligations under Sections 311(a), 311(b) and 312(b) of the Trust Indenture Act.

SECTION 2.3.                                           Reports by the Trust Guarantee Trustee

Within 60 days after May 15 of each year, the Trust Guarantee Trustee shall provide to the Holders such reports as are required by Section 313 of the Trust Indenture Act, if any, in the form and in the manner provided by Section 313 of the Trust Indenture Act. The Trust Guarantee Trustee shall also comply with the requirements of Section 313(d) of the Trust Indenture Act.

SECTION 2.4.                                           Periodic Reports to Trust Guarantee Trustee

The Guarantor shall provide to the Trust Guarantee Trustee such documents, reports and information as required by Section 314(a) of the Trust Indenture Act (if any) and the compliance certificate required by Section 314(a) of the Trust Indenture Act in the form, in the manner and at the times required by Section 314(a) of the Trust Indenture Act.

SECTION 2.5.                                           Evidence of Compliance with Conditions Precedent

The Guarantor shall provide to the Trust Guarantee Trustee such evidence of compliance with any conditions precedent, if any, provided for in this Trust Guarantee that relate to any of the matters set forth in Section 314(c) of the Trust Indenture Act. Any certificate or opinion required to be given by an officer pursuant to Section 314(c)(1) may be given in the form of an Officers’ Certificate.

SECTION 2.6.                                           Events of Default; Waiver

The Holders of a Majority in Liquidation Amount of Trust Preferred Securities may, by vote or written consent, on behalf of the Holders of all of the Trust Securities, waive any past Event of Default and its consequences. Upon such waiver, any such Event of Default shall cease to exist, and any Event of Default arising therefrom shall be deemed to have been cured, for every purpose of this Trust Guarantee, but no such waiver shall extend to any subsequent or other default or Event of Default or impair any right consequent thereon.

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SECTION 2.7.                                           Event of Default; Notice

(a)           The Trust Guarantee Trustee shall, within 90 days after the occurrence of an Event of Default, transmit by mail, first class postage prepaid, to the Holders of the Trust Preferred Securities, notices of all Events of Default actually known to a Responsible Officer of the Trust Guarantee Trustee, unless such defaults have been cured before the giving of such notice; provided that the Trust Guarantee Trustee shall be protected in withholding such notice if and so long as a Responsible Officer of the Trust Guarantee Trustee in good faith determines that the withholding of such notice is in the interests of the Holders of the Trust Preferred Securities.

(b)           The Trust Guarantee Trustee shall not be deemed to have knowledge of any Event of Default unless the Trust Guarantee Trustee shall have received written notice, or of which a Responsible Officer of the Trust Guarantee Trustee charged with the administration of the Declaration of Trust shall have obtained actual knowledge.

SECTION 2.8.                                           Conflicting Interests

The Declaration of Trust shall be deemed to be specifically described in this Trust Guarantee for the purposes of clause (i) of the first proviso contained in Section 310(b)(1) of the Trust Indenture Act.

SECTION 2.9.              Disclosure of Information

The disclosure of information as to the names and addresses of the Holders in accordance with Section 312 of the Trust Indenture Act, regardless of the source from which such information was derived, shall not be deemed to be a violation of any existing law, or any law hereafter enacted which does not specifically refer to Section 312 of the Trust Indenture Act, nor shall the Trust Guarantee Trustee be held accountable by reason of mailing any material pursuant to a request made under Section 312(b) of the Trust Indenture Act.

SECTION 2.10.                                     Trust Guarantee Trustee May File Proofs of Claim

Upon the occurrence