UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q/A

Amendment No. 1

x QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the Quarterly Period Ended June 30, 2011

¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

Commission File Number: 1-10777

Ambac Financial Group, Inc.

(Debtor-in-possession as of November 8, 2010)

(Exact name of Registrant as specified in its charter)

Delaware	13-3621676
(State of incorporation)	(I.R.S. employer identification no.)
One State Street Plaza New York, New York	10004
(Address of principal executive offices)	(Zip code)

(212) 668-0340

(Registrant’s telephone number, including area code)

Indicate by check mark whether the Registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the Registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the Registrant was required to submit and post such files).    Yes  ¨    No  ¨

Indicate by check mark whether the Registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See definition of “large accelerated filer”, “accelerated filer”, and “smaller reporting company” in Rule 12b-2 of the Exchange Act): (Check one):

Large accelerated filer	¨	Accelerated filer	x
Non-accelerated filer	¨	Smaller reporting company	x

Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes  ¨    No  x

As of July 31, 2011, 302,428,811 shares of Common Stock, par value $0.01 per share, (net of 5,587,953 treasury shares) of the Registrant were outstanding.

Explanatory Note

The purpose of this Amendment No. 1 to our Quarterly Report on Form 10-Q for the period ended June 30, 2011 (the “Form 10-Q”), as filed with the Securities and Exchange Commission on August 9, 2011, is to furnish Exhibit 101 to the Form 10-Q as required by Rule 405 of Regulation S-T. Exhibit 101 to this report provides the following items from the Form 10-Q formatted in eXtensible Business Reporting Language (XBRL): (i) the unaudited Consolidated Balance Sheets, (ii) the unaudited Consolidated Statements of Income, (iii) the unaudited Consolidated Statements of Cash Flows, (iv) the unaudited Consolidated Statements of Stockholders’ Equity, and (v) the Notes to the unaudited Consolidated Financial Statements, tagged as blocks of text.

Users of this data are advised that pursuant to Rule 406T of Regulation S-T these interactive data files are deemed not filed or part of a registration statement or prospectus for purposes of Sections 11 or 12 of the Securities Act of 1933, as amended, are deemed not filed for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, and otherwise are not subject to liability under those sections. No other changes have been made to the Form 10-Q other than those described above. This Amendment No. 1 speaks as of the original filing date of the Form 10-Q, and does not modify or update in any way disclosures made in the Form 10-Q.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this Report to be signed on its behalf by the undersigned thereunto duly authorized.

	Ambac Financial Group, Inc. (Registrant)
Dated: September 8, 2011	By:	/S/    DAVID TRICK
		David Trick
		Senior Managing Director, Chief Financial Officer and Treasurer (Principal Financial Officer and Duly Authorized Officer)

Item 6 – Exhibits

The following are annexed as exhibits:

Exhibit Number	Description
31.1*	Certification of CEO Pursuant to Exchange Act Rules 13a-14 and 15d-14, as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
31.2*	Certification of CFO Pursuant to Exchange Act Rules 13A-14 and 15D-14, as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
32.1*	Certification of CEO Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.
32.2*	Certification of CFO Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.
101.INS**	XBRL Instance Document.
101.SCH**	XBRL Taxonomy Extension Schema Document.
101.CAL**	XBRL Taxonomy Extension Calculation Linkbase Document.
101.LAB**	XBRL Taxonomy Extension Label Linkbase Document.
101.PRE**	XBRL Taxonomy Extension Presentation Linkbase Document.
101.DEF**	XBRL Taxonomy Extension Definition Linkbase Document.

* Previously filed as an exhibit to the Company’s Quarterly Report on Form 10-Q for the three months ended June 30, 2011, filed with the Securities and Exchange Commission on August 9, 2011.

** Furnished herewith.