<SEC-DOCUMENT>0000874501-18-000075.txt : 20180518
<SEC-HEADER>0000874501-18-000075.hdr.sgml : 20180518
<ACCEPTANCE-DATETIME>20180518160738
ACCESSION NUMBER:		0000874501-18-000075
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20180516
FILED AS OF DATE:		20180518
DATE AS OF CHANGE:		20180518

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LeBlanc Claude
		CENTRAL INDEX KEY:			0001380820

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-10777
		FILM NUMBER:		18846677

	MAIL ADDRESS:	
		STREET 1:		ONE BERMUDIANA ROAD
		CITY:			HAMILTON
		STATE:			D0
		ZIP:			HM 11

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			AMBAC FINANCIAL GROUP INC
		CENTRAL INDEX KEY:			0000874501
		STANDARD INDUSTRIAL CLASSIFICATION:	SURETY INSURANCE [6351]
		IRS NUMBER:				133621676
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		ONE STATE ST PLZ
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10004
		BUSINESS PHONE:		2126680340

	MAIL ADDRESS:	
		STREET 1:		ONE STATE ST PLZ
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10004

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	AMBAC INC /DE/
		DATE OF NAME CHANGE:	19930328
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_152667404506180.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-05-16</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000874501</issuerCik>
        <issuerName>AMBAC FINANCIAL GROUP INC</issuerName>
        <issuerTradingSymbol>AMBC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001380820</rptOwnerCik>
            <rptOwnerName>LeBlanc Claude</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O AMBAC FINANCIAL GROUP, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>ONE STATE STREET PLAZA</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10004</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Executive Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2018-05-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2639</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>50139</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2018-05-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2639</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>19.14</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>47500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2018-05-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>55173</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>55173.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>114816</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2018-05-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2639</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2639.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>112177</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">On May 16, 2018, the Grant Date, 2,639 restricted stock units (&quot;RSUs&quot;) vested, and were settled and converted into shares of common stock and withheld by Ambac Financial Group, Inc. (the &quot;Company&quot;) to satisfy certain tax withholding obligations.</footnote>
        <footnote id="F2">Each RSU represents a contingent right to receive one share of the common stock of the Company.</footnote>
        <footnote id="F3">On May 16, 2018, there were 55,173 RSUs granted in recognition of the reporting person's efforts to bring about the successful exit of the Segregated Account of Ambac Assurance Corporation from Rehabilitation. The RSUs shall vest immediately and shall settle and convert into shares of common stock as follows: 50% of the RSUs shall settle and convert into shares of common stock on May 16, 2019, and the remaining 50% of the RSUs shall settle and convert into shares of common stock on May 16, 2020; provided however, that if the reporting person's employment with the Company is terminated for any reason (other than termination for cause), all of the RSUs will settle and convert into shares of common stock immediately. Notwithstanding the foregoing, a number of vested RSUs sufficient to satisfy certain tax withholding obligations imposed upon the Company may be converted into shares of common stock and withheld by the Company to satisfy such tax withholding obligations.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>William J. White, attoney-in-fact</signatureName>
        <signatureDate>2018-05-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24
<SEQUENCE>2
<FILENAME>poa-claudeleblancforedgari.htm
<DESCRIPTION>POWER OF ATTORNEY, EXHIBIT 24
<TEXT>
<!-- Document created using Workiva -->
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<pre>
POWER OF ATTORNEY



            I, Claude LeBlanc, do hereby nominate, constitute and appoint each of  William White, Stephen M. Ksenak and Yolanda Ortiz, as my true and lawful agent and attorney-in-fact, with full power and authority to act hereunder, in his or her discretion, in my name and on my behalf as fully as I could if I were present and acting in person, to make any and all required or voluntary filings under Section 16(a) of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and the applicable rules and regulations thereunder, with the Securities and Exchange Commission, the NASDAQ Stock Exchange, Ambac Financial Group, Inc., a Delaware corporation (the "Company"), and any other person or entity to which such filings may be required under Section 16(a) of the Exchange Act as a result of my service as an officer or director of the Company or beneficial ownership (within the meaning of Section 16(a) of the Exchange Act) of more than ten percent of any class of equity securities of the Company.

            I hereby consent to, ratify and confirm all the said attorney-in-fact shall do or cause to be done by virtue of this Power of Attorney.  I hereby acknowledge the attorney-in-fact, in serving in such capacity at my request, is not assuming, nor is the Company assuming, any of my responsibilities to comply with Section 16 of the Exchange Act.

            This Power of Attorney shall remain in full force and effect from this date forward for so long as I am an officer or director of the Company and for such time thereafter as may be necessary to make any such filings or until revoked or modified by me.  I hereby revoke all prior powers of attorney relating to the foregoing acts.

            IN WITNESS WHEREOF, I have hereunto signed my name this 16th day of December, 2016.






                         ___/s/ Claude LeBlanc __
                        Claude LeBlanc
</pre>
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</SEC-DOCUMENT>
