NOTE GUARANTY INSURANCE POLICY

Exhibit 4.3

NOTE GUARANTY INSURANCE POLICY

POLICY NUMBER: 490190

IndyMac Home Equity Mortgage Loan Asset-Backed Trust, Series 2006-H4

Home Equity Mortgage Loan Asset-Backed Notes, Series 2006-H4

MBIA Insurance Corporation (the “Insurer”), in consideration of the payment of the premium and subject to the terms of this Note Guaranty Insurance Policy (this “Policy”), hereby unconditionally and irrevocably guarantees to any Owner that an amount equal to each full and complete Insured Payment will be received from the Insurer by Deutsche Bank National Trust Company, or its successors, as indenture trustee for the Owners (the “Indenture Trustee”), on behalf of the Owners, for distribution by the Indenture Trustee to each Owner of each Owner’s proportionate share of the Insured Payment. The Insurer’s obligations hereunder with respect to a particular Insured Payment shall be discharged to the extent funds equal to the applicable Insured Payment are received by the Indenture Trustee, whether or not those funds are properly applied by the Indenture Trustee. Insured Payments will be made only at the time set forth in this Policy, and no accelerated Insured Payments will be made regardless of any acceleration of the Obligations, unless the acceleration is at the sole option of the Insurer.

Notwithstanding the foregoing, this Policy does not cover shortfalls, if any, attributable to the liability of the Issuer, any REMIC or the Indenture Trustee for withholding taxes, if any (including interest and penalties in respect of any such liability).

The Insurer will pay any Insured Payment that is a Preference Amount on the Business Day following receipt on a Business Day by the Fiscal Agent (as described below) of (a) a certified copy of the order requiring the return of a preference payment, (b) an opinion of counsel satisfactory to the Insurer that such order is final and not subject to appeal, (c) an assignment in such form as is reasonably required by the Insurer, irrevocably assigning to the Insurer all rights and claims of the Owner relating to or arising under the Obligations against the debtor which made such preference payment or otherwise with respect to such preference payment and (d) appropriate instruments to effect the appointment of the Insurer as agent for such Owner in any legal proceeding related to such preference payment, such instruments being in a form satisfactory to the Insurer, provided that if such documents are received after 12:00 noon, New York City time, on such Business Day, they will be deemed to be received on the following Business Day. Such payments shall be disbursed to the receiver or trustee in bankruptcy named in the final order of the court exercising jurisdiction on behalf of the Owner and not to any Owner directly unless such Owner has returned principal or interest paid on the Obligations to such receiver or trustee in bankruptcy, in which case such payment shall be disbursed to such Owner.

The Insurer will pay any other amount payable hereunder no later than 12:00 noon, New York City time, on the later of the Payment Date on which the related Deficiency Amount is due or the first Business Day following receipt in New York, New York on a Business Day by

U.S. Bank Trust National Association, as Fiscal Agent for the Insurer, or any successor fiscal agent appointed by the Insurer (the “Fiscal Agent”), of a Notice (as described below), provided that if such Notice is received after 12:00 noon, New York City time, on such Business Day, it will be deemed to be received on the following Business Day. If any such Notice received by the Fiscal Agent is not in proper form or is otherwise insufficient for the purpose of making claim hereunder, it shall be deemed not to have been received by the Fiscal Agent for purposes of this paragraph, and the Insurer or the Fiscal Agent, as the case may be, shall promptly so advise the Indenture Trustee and the Indenture Trustee may submit an amended Notice.

Insured Payments due hereunder, unless otherwise stated herein, will be disbursed by the Fiscal Agent to the Indenture Trustee on behalf of the Owners by wire transfer of immediately available funds in the amount of the Insured Payment less, in respect of Insured Payments related to Preference Amounts, any amount held by the Indenture Trustee for the payment of such Insured Payment and legally available therefor.

The Fiscal Agent is the agent of the Insurer only, and the Fiscal Agent shall in no event be liable to Owners for any acts of the Fiscal Agent or any failure of the Insurer to deposit, or cause to be deposited, sufficient funds to make payments due under this Policy.

Subject to the terms of the Agreement, the Insurer shall be subrogated to the rights of each Owner to receive payments under the Obligations to the extent of any payment by the Insurer hereunder.

As used herein, the following terms shall have the following meanings:

“ Agreement ” means, collectively, the Indenture, dated as of December 21, 2006, between IndyMac Home Equity Mortgage Loan Asset-Backed Trust, Series 2006-H4, as Issuer, and the Indenture Trustee, as indenture trustee, and the Sale and Servicing Agreement, dated as of December 12, 2006, among the Issuer, IndyMac Bank, F.S.B., as Seller and Servicer, IndyMac ABS, Inc., as Depositor, and the Indenture Trustee, as indenture trustee, in each case without regard to any amendment or supplement thereto, unless such amendment or supplement has been approved in writing by the Insurer.

“ Available Funds ” means, with respect