FINANCIAL GUARANTY INSURANCE POLICY

Exhibit 10.6

FINANCIAL SECURITY ASSURANCE INC. (“Financial Security”), for consideration received, hereby UNCONDITIONALLY AND IRREVOCABLY GUARANTEES to each Holder, subject only to the terms of this Policy (which includes each endorsement hereto), the full and complete payment by the Obligor of Scheduled Payments of principal of, and interest on, the Obligations.

For the further protection of each Holder, Financial Security irrevocably and unconditionally guarantees:

(a) payment of the amount of any distribution of principal of, or interest on, the Obligations made during the Term Of This Policy to such Holder that is subsequently avoided in whole or in part as a preference payment under applicable law (such payment to be made by Financial Security in accordance with Endorsement No. 1 hereto).

(b) payment of any amount required to be paid under this Policy by Financial Security following Financial Security’s receipt of notice as described in Endorsement No. 1 hereto.

Financial Security shall be subrogated to the rights of each Holder to receive payments under the Obligations to the extent of any payment by Financial Security hereunder.

Except to the extent expressly modified by an endorsement hereto, the following terms shall have the meanings specified for all purposes of this Policy. “Holder” means the registered owner of any Obligation as indicated on the registration books maintained by or on behalf of the Obligor for such purpose or, if the Obligation is in bearer form, the holder of the Obligation. “Scheduled Payments” means payments which are scheduled to be made during the Term Of This Policy in accordance with the original terms of the Obligations when issued and without regard to any amendment or modification of such Obligations thereafter; payments which become due on an accelerated basis as a result of (a) a default by the Obligor, (b) an election by the Obligor to pay principal on an accelerated basis or (c) any other cause, shall not constitute “Scheduled Payments” unless Financial Security shall elect, in its sole discretion, to pay such principal due upon such acceleration together with any accrued interest to the date of acceleration. “Term Of This Policy” shall have the meaning set forth in Endorsement No. 1 hereto.

This Policy sets forth in full the undertaking of Financial Security, and shall not be modified, altered or affected by any other agreement or instrument, including any modification or amendment thereto, or by the merger, consolidation or dissolution of the Obligor. Except to the extent expressly modified by an endorsement hereto, the premiums paid in respect of this Policy are nonrefundable for any reason whatsoever, including payment, or provision being made for payment, of the Obligations prior to maturity. This Policy may not be canceled or revoked during the Term Of This Policy. THIS POLICY IS NOT COVERED BY THE PROPERTY/CASUALTY INSURANCE SECURITY FUND SPECIFIED IN ARTICLE 76 OF THE NEW YORK INSURANCE LAW.

In witness whereof, FINANCIAL SECURITY ASSURANCE INC. has caused this Policy to be executed on its behalf by its Authorized Officer.

ENDORSEMENT NO. 1 TO

FINANCIAL GUARANTY INSURANCE POLICY

(NOTES POLICY)

Policy No.: 51831A-N

Date of Issuance: April 19, 2007

1. Definitions . For all purposes of this Policy, the terms specified below shall have the meanings or constructions provided below. Capitalized terms used herein and not otherwise defined herein shall have the meanings provided in the Indenture or the Sale and Servicing Agreement unless otherwise specified.

“ Business Day ” means any day other than a Saturday, Sunday, legal holiday or other day on which commercial banking institutions in Wilmington, Delaware, Fort Worth, Texas, New York City, New York, Minneapolis, Minnesota or any other location of any successor Servicer, successor Owner Trustee or successor Trust Collateral Agent are authorized or obligated by law, executive order or governmental decree to be closed.

“ Financial Security ” means Financial Security Assurance Inc., a New York stock insurance company.

“ Holder ” shall have the meaning set forth in the Indenture; provided , however that “Holder” shall not include the Obligor or any affiliates or successors thereof in the event the Obligor, or any such affiliate or successor, is a registered or beneficial owner of the Obligations.

“ Indenture ” means the Indenture, dated as of April 11, 2007, between the Obligor and Wells Fargo Bank, National Association, as Trustee and Trust Collateral Agent, as amended from time to time with the consent of Financial Security.

“ Indenture Trustee ” means Wells Fargo Bank, National Association, in its capacity as Trustee under the Indenture and any successor in such capacity.

“ Policy ” means this Financial Guaranty Insurance Policy and includes each endorsement thereto.

“ Receipt ” and “ Received ” mean actual delivery to Financial Security and to the Fiscal Agent (as defined below), if any, prior to 12:00 noon, New York City time, on a Business Day; delivery either on a day that is not a Business Day, or after 12:00 noon, New York City time, shall be deemed to be receipt on the next succeeding Business Day. If any notice or certificate given hereunder by the Trust Collateral Agent is not in proper form or is not properly completed, executed or delivered, or contains any misstatement, it shall be deemed not to have been Received, and Financial Security or its Fiscal Agent shall promptly so advise the Trust Collateral Agent and the Trust Collateral Agent may submit an amended notice.

“ Sale and Servicing Agreement ” means the Sale and Servicing Agreement dated as of April 11, 2007 among the Obligor, AmeriCredit Financial Services, Inc., as Servicer, AFS SenSub Corp., as Seller and Wells Fargo Bank, National Association, as Backup Servicer and Trust Collateral Agent, as such agreement may be amended, supplemented or otherwise modified from time to time in accordance with the terms thereof.

“ Scheduled Payments ” means, as to each Insured Distribution Date, payments which are required to be made to Holders in accordance with the original terms of the Obligations when issued and without regard to any subsequent amendment or modification of the Obligations or of the Indenture except amendments or modifications to which Financial Security has given its prior written consent, which payments are (i) the Noteholders’ Interest Distributable Amount with respect to the related Distribution Date, (ii) the Noteholders’ Remaining Parity Deficit Amount with respect to the related Distribution Date and (iii) with respect to the Final Scheduled Distribution Date for any class of Obligations, the outstanding principal amount of such class on such Final Scheduled Distribution Date, after taking into account reductions on such date of such outstanding principal amount from all sources other than this Policy. Scheduled Payments do not include payments which become due on an accelerated basis as a result of (a) a default by the Obligor, (b) an election by the Obligor to pay principal on an accelerated basis, (c) the occurrence of an Event of Default under the Indenture or (d) any other cause, unless Financial Security elects, in its sole discretion, to pay in whole or in part such principal due upon acceleration, together with any accrued interest to the date of acceleration. In the event Financial Security does not so elect, this Policy will continue to guarantee payment on the Obligations in accordance with their original terms. Scheduled Payments shall not include (x) any portion of a Noteholders’ Interest Distributable Amount or of a Noteholders’ Interest Carryover Amount due to Holders because the appropriate notice and certificate for payment in proper form as required by paragraph 2 hereof was not timely Received by Financial Security or (y) any portion of a Noteholders’ Interest Distributable Amount due to Holders representing interest on any Noteholders’ Interest Carryover Amount accrued from and including the date of payment of the amount of such Noteholders’ Interest Carryover Amount, unless in each case, Financial Security elects, in its sole discretion, to pay such amount in whole or in part, pursuant hereto. Scheduled Payments shall not include any amounts due in respect of the

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Obligations attributable to any increase in interest rate, penalty or other sum payable by the Obligor by reason of any default or event of default in respect of the Obligations, or by reason of any deterioration of the credit worthiness of the Obligor, nor shall Scheduled Payments include, nor shall coverage be provided under this Policy in respect of, any taxes, withholding or other charge with respect to any Holder imposed by any governmental authority due in connection with the payment of any Scheduled Payment to a Holder.

“ Term Of This Policy ” means the period from and including the Date of Issuance to and including the date on which (i) all Scheduled Payments have been paid or deemed to be paid within the meaning of Section 4.1 of the Indenture; (ii) any period during which any Scheduled Payment coul