Exhibit 10.21

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| |  |                                            
| |  | -------------------------------------------
| |  | Ambac Assurance Corporation                
| |  | One State Street Plaza                     
| |  | New York, NY 10004                         
| |  | 212.208.3249 Fax: 212.363.9049             
| |  | dadams@ambac.com                           
| | 
| |  | A member of the Ambac Financial Group, Inc.
| | 
| |  | Diana N.Adams                              
| |  | Senior Managing Director                   

September 21, 2009

Mr. Douglas C. Renfield-Miller

888 Park Avenue

New York, NY 10075

Dear Doug:

This agreement (the Agreement) sets forth our agreement concerning the terms and conditions of your Retirement from employment at Ambac
Financial Group, Inc. (Ambac or the Company).



|1. | Effective Date of Retirement
|-- | ----------------------------

Your last day of employment with Ambac (the Retirement Date) will be December 31, 2009.



|2. | Employment Period & Payments
|-- | ----------------------------



| | (a) | During the period from the date of this Agreement (Agreement Date or Date of Agreement) through the Retirement Date (the Employment
Period), you will continue to report to Ambacs CEO. You will not be required to report to the office or perform your full-time duties but will be required to provide transition and consulting services to and on behalf of Ambac as
reasonably requested by the CEO or his designee.
| | --- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (b) | During the Employment Period, you will continue to receive your regular salary at the rate in effect as of June 30, 2009. Such salary will be paid to you in
accordance with Ambacs normal payroll practices and procedures.
| | --- | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (c) | Subject to Section 4, you will be paid severance in the amount of $231,000 in consideration of your signing this Agreement. The fee will be paid within ten
business days of the date you execute this Agreement and Waiver and General Release Agreement annexed hereto as Exhibit A on or following the Retirement Date.
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|3. | Legal and Outplacement Expenses
|-- | -------------------------------

Ambac will pay or reimburse you for up to a total of $25,000 for (i) legal expenses in reviewing this document and (ii) outplacement, career counseling and/or coaching services to be provided to you until the date on which you
secure new employment. You must engage at least the initial provider of such outplacement, career counseling and/or coaching services by March 15, 2010 otherwise you forfeit the right to the payment arrangement set forth in clause (ii) of
the preceding sentence. The selection of the service providers, dates and scope of services will be as you elect. All invoices for legal fees and/or outplacement must be provide detail of the services provided and must note that the services are for
Douglas Renfield-Miller.



|4. | Release Obligations
|-- | -------------------

Ambacs obligations under this Agreement, including its obligation to provide you with the payments set forth in sections 2 and 3, are contingent on the execution, delivery and non-revocation of this Agreement and the Waiver and
General Release Agreement in the form set forth as Exhibit A hereto and, in addition, the execution, delivery and non-revocation, on or as of the Retirement Date, of a second Waiver and General Release Agreement in the form set forth as Exhibit A
hereto in respect of the period from the date you initially sign the Waiver and General Release Agreement through the Retirement Date. In the event the agreement described in the preceding sentence is not executed and delivered, or revoked,
(a) any option and/or restricted stock unit award that has vested from the date hereof through the Retirement Date will be forfeited and (b) you will be required to reimburse Ambac the entire amount of the payments set forth in paragraphs
2 and 3 within ten business days of the revocation date.

Ambac, for and on behalf of itself and the other Released Parties (as
such term is defined in the form of Waiver and General Release Agreement attached hereto as Exhibit A) further hereby waives and releases you and the other Releasors (as such term is also defined in the form of Waiver and General Release Agreement
attached hereto as Exhibit A), from any and all Claims related to any event, condition, circumstance or obligation that occurred, existed or arose on or prior to the date hereof that Ambac is aware of, or should have been aware of, that it or any
other Released Party has, may have or in the future may possess against you or any other such Releasor, arising or accruing on or prior to the date hereof, and Ambac shall, concurrent with your execution and delivery to Ambac on, after or as of the
Retirement Date of the additional Waiver and General Release Agreement, execute and deliver to you a second release in your favor, in a form consistent with and no less favorable to you than the forgoing release set forth in this paragraph, covering
the period between the date Ambac executes this Agreement and the date you execute such second release in favor of Ambac.



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|5. | Accrued Obligations
|-- | -------------------

Ambac will timely pay you for any unreimbursed business expenses incurred by you for the period through the Retirement Date in accordance with its normal business expense reimbursement policy, provided, that all of your reimbursable
business expenses are submitted in accordance with Ambacs business expense reimbursement policy. Such reimbursement(s), if any, shall be paid in accordance with Ambacs normal practices and procedures.

Ambac will continue to provide you with and timely pay for all tax consulting and return preparation services of Grant Thornton for both U.K.
and U.S. income tax purposes in respect of all periods through and/or which include December 31, 2009, in connection with your employment in both the U.K. and the U.S. As previously agreed, Ambac will also cover the cost (by timely paying or
reimbursing you) for your own accountants review of Grant Thorntons work up to $25,000, with such obligation to survive the date of December 31, 2009 and any revocation or cancellation of this Agreement.



|6. | Welfare Benefits
|-- | ----------------



| | (a) | Through June 30, 2010, you will continue be eligible to participate in all medical, dental and prescription drug programs available to Ambacs full-time
employees in accordance with the terms of such programs. You will be required to make premium contributions as applicable to all full-time employees with like coverage. If you obtain and commence alternative coverage, you are required to advise
Ambac and terminate the Ambac coverage. During the period through the Retirement Date, you will also continue to receive and participate in all other insurance and employee benefits consistent with past practice.
| | --- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (b) | On and after July 1, 2010, you will be entitled to receive continuation coverage pursuant to Ambacs retirement benefits as detailed in Exhibit B
attached hereto.
| | --- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (c) | Nothing herein contained shall limit any of your rights to elect continuation coverage under Section 4980 (f) of the Internal Revenue Code of 1986, as amended
(relating to COBRA coverage).
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|7. | Retirement Benefits
|-- | -------------------

Through and including the Retirement Date, Company-match and profit-sharing contributions will be credited on your behalf to the Ambac Savings Incentive Plan in accordance with the terms and conditions of such plan at substantially the same
time(s) that the Company funds such contributions for its other employees, regardless of when paid (it being understood that all or a portion of such contributions may be funded on your behalf after the Retirement Date).



|8. | Other Benefits
|-- | --------------

Ambac
will pay you all vested amounts, if any, due but not previously paid to you, pursuant to the terms of any welfare, deferred compensation or other benefit plan as of the Retirement Date, or which by their terms extend to or beyond the Retirement
Date. Notwithstanding the foregoing, any amount due under the Non-Qualified Savings Incentive Plan will be paid to you no sooner than six months and one day from the Retirement Date.

Inasmuch as it is and has been the expressed mutual intention of the parties that your entering into this Agreement shall not affect any or
all of your rights under that certain Amended and Restated Management Retention Agreement, dated as of 2007, between you and Ambac (the Management Retention Agreement), it is agreed that notwithstanding anything to the contrary contained
in this Agreement, in the event that there shall be a Change of Control of Ambac on or prior to the Retirement Date, as such term Change in Control is defined in the Management Retention Agreement, or there shall be a proposed or pending
Change in Control of Ambac reported in any newspaper of general circulation or business publication on or before the Retirement Date, you shall have the right (but not the obligation) to rescind and cancel your retirement and this Agreement,
together with the related Waiver and General Release Agreement (the form of which is set forth in Exhibit A), as if neither such document had ever been executed (i.e., and such that you shall have no further obligations hereunder or thereunder), and
as if your employment had continued in the ordinary course through such date, whereupon the parties hereto shall then promptly cooperate and negotiate, in good faith, a written agreement between them, effective as of such date, such that your
employment with Ambac shall further continue in a manner substantially consistent with past practice and so as to afford you the ability to fully participate in (i.e., and not deprive you from) all of the benefits to which you would otherwise be
entitled under the Change in Control Agreement should the Change in Control be (or have been) consummated. In furtherance of the foregoing, it is understood and agreed that the forfeiture and reimbursement provisions of the first paragraph of
Section 4 above would not apply to or with respect to any rescission and/or cancellation by you of this Agreement pursuant to the provisions of this paragraph.



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In the event of your death or disability prior to the date any or all payments or benefits under
this Agreement shall be paid or become payable to you, all such benefits and payments shall instead be paid by Ambac to your heirs, executors, administrators, trustees, legal representatives, successors or assigns, as applicable.



|9. | Stock Options and Restricted Stock Units
|-- | ----------------------------------------

All of your outstanding stock options, as set forth in Exhibit C hereto, will vest on the Retirement Date. The terms of the 1997 Equity Plan as Amended and the General Terms and Conditions of the
respective stock option grants shall govern. Any vested options not exercised within the time frame(s) set forth in the above documents will be forfeited.

All restricted stock units, as set forth in Exhibit C hereto, will vest on the Retirement Date. All restricted stock units will be settled six months and one day following the Retirement Date. The terms
of the 1997 Equity Plan as Amended and the General Terms and Conditions of the respective restricted stock unit grants shall govern.



|10. | Return of Property
|--- | ------------------

The
parties hereby mutually acknowledge that any Ambac property in your possession and any property made available to you in connection with your employment relationship with Ambac has heretofore been returned by you to Ambac.



|11. | Confidentiality & Competition
|--- | -----------------------------

In consideration for the payments described above, you agree to the following:



| | (a) | Ambac (for purposes of this Section 11, Ambac refers to Ambac and all of its affiliates) is engaged in a highly competitive business and that, in connection with
your employment, you have access to information relating to Ambacs business that provides Ambac with a competitive advantage, that is not generally known by persons not employed by Ambac, and that could not easily be determined or learned by
someone outside Ambac (collectively, Confidential Information). Subject to the foregoing, such Confidential Information may include, but is not limited to, the characteristics and preferences of Ambacs Customers
(as defined below) and accounts, matters relating to information, pricing, fee and commission structures, trading policies and procedures, trade secrets, records, files, memoranda, documents, reports, and other written, printed or recorded materials
and data, regardless of data storage method (collectively Documents) received, created, or used by you during the course of your employment and other methods of doing business, whether or not marketed as confidential or secret. As
used herein, Customer shall mean all clients and actively pursued prospective clients of Ambac with whom or which you actively worked during the period of your employment with Ambac.
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| | (b) | You agree that before and after the Retirement Date, you shall not, directly or indirectly, use or disclose such Confidential Information, except as may be necessary in
the good faith performance of your duties to Ambac. You acknowledge that all Confidential Information will remain the sole property of Ambac and all such documents (if any, that have not yet been returned by you to Ambac) constituting Confidential
Information, other than intellectual knowledge, will be returned by you to Ambac within five business days of the Retirement Date. The terms and conditions of this Section 11(a) and (b) are in addition to and do not supersede or replace
the terms and obligations of Ambacs Code of Business Conduct.
| | --- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (c) | You further agree that from the Agreement Date through the six-month anniversary of the Retirement Date (i.e., through June 30, 2010), you will not, for any
reason, unless Ambac consents in writing, which consent shall not be unreasonably withheld or delayed, (i) solicit the business of or encourage or assist any other party in competition with Ambac to solicit any such Customer of Ambac in
connection with the municipal bond insurance business, or (ii) assist any party engaged in municipal bond insurance with raising capital for such municipal bond insurance business, or seeking a rating for such municipal bond insurance business
from a Nationally Recognized Statistical Rating Agency, or (iii) hire or seek to hire, whether on your own behalf or on behalf of any other person or entity, any person who is an employee of Ambac at the Retirement Date, or who left the employ
of Ambac within three months prior to such date unless such person was terminated by Ambac.
| | --- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Paragraph
11(c) and the associated restrictions contained herein shall supersede and cancel any similar restrictions contained in any and all documents relating to Ambacs stock options and/or restricted stock units, and Ambac hereby waives any
objections thereto.

If you breach the terms of this Section 11(c), you forfeit your right to future payments provided for
herein from the date of such breach, and, to the extent any payments have been made, you agree to return all payments made pursuant to this Agreement including, but not limited to, the gross payments provided for in paragraph 2. The return of the
aforementioned payments must be made within ten business days of the breach of this Section 11(c).



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| | (d) | In the event that (A) the Wisconsin Office of the Commissioner of Insurance: (i) appoints a custodian, trustee, agent or receiver for Ambac Assurance
Corporation (AAC) or for all or any material portion of its Property or (ii) authorizes the taking of possession by a custodian, trustee, agent or receiver of AAC (or the taking of possession of all or a substantial portion of
AACs property), or (B) Ambac abandons efforts to recapitalize and launch Everspan Financial Guarantee Corporation, the provisions of this Section 11 will become null and void, except solely for the provisions of the second paragraph
of this Section 11(c) which shall remain in full force and effect. In view of the nature of Ambacs business, you also acknowledge that the restrictions contained in this Section 11 are fair, reasonable and necessary to protect the
legitimate business interests of Ambac and that Ambac may suffer irreparable harm in the event of any actual or intended violation by you of this paragraph. You, therefore, agree that, in the event of any actual or intended violation by you of
Section 11(b) or 11(c), Ambac shall be entitled to apply for a court order requiring you to cease any such violations in addition to and without prejudice to any other rights or remedies which may be available to Ambac through the legal
system.
| | --- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (e) | You shall not be deemed to be in breach of any covenant set forth in this Agreement on the basis of any communications you may have with third parties relating to:
(i) the fact and circumstances of your employment and Retirement by/from Ambac; (ii) your job titles at Ambac; (iii) the dates of your employment by Ambac; (iv) the responsibilities and authorities of your positions at Ambac;
(v) the nature and extent of your achievements during employment by Ambac; (vi) the names and positions of individuals with whom you worked during your employment at Ambac; and (vii) the restrictions on your post-Retirement date
employment activities. You hereby authorize Ambac to provide the information responsive to items (i) through (iv) and (vi) to prospective employers.
| | --- | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (f) | You shall not be deemed in breach of the confidentiality obligations set forth in this Section 11 if, compelled by legal process or court order, you are to
participate in any administrative, judicial or criminal investigation, probe, grand jury proceeding or other demand for testimony, information or documentation.
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| | (g) | In the event of any breach of this paragraph 11, Ambac shall provide you with written notice (to the address set forth on page one of this Agreement) and you will have
ten business days from the date of receipt of said written notice to cure any curable breach. If you fail to cure any such breach or the breach is not curable, Ambac shall be released from any obligation to make any payment to you or on your behalf
and provide any benefits, other than retirement benefits, under this Agreement. Ambac shall be further entitled to pursue any and all of its remedies under the law arising out of such breach including, but not limited to, recoupment as outlined in
Section 11(c). In any action alleging breach of this Agreement, the prevailing party shall be entitled to recover reasonable costs and/or attorneys fees incurred to enforce this Agreement. Upon written request, you will promptly receive
Ambacs determination, made in good faith, in writing regarding whether a particular activity or act would be deemed in breach of your obligations and/or covenants under this Agreement.
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|12. | Withholding
|--- | -----------

Any payments
made or benefits provided to you under this Agreement will be reduced by any applicable legally required withholding taxes.



|13. | Cooperation
|--- | -----------



| | (a) | For a period of 12 months after the Retirement Date, you agree to make yourself reasonably available to Ambac (for purposes of this Section 13, Ambac refers to
Ambac and all of its affiliates at reasonable times and places and subject to non-interference with your then employment or business activities, to provide information to Ambac or its representatives in connection with any matters relating to the
business or affairs of Ambac, and any pending or future governmental or regulatory investigation, civil or administrative proceeding, litigation, arbitration or other proceeding related to the business of Ambac during your term as an officer of
Ambac or your employment with Ambac. Ambac will reimburse you at your then daily rate of base compensation, certified by you in writing, for any lost wages and/or reasonable out-of-pocket expenses incurred in connection with the provision of such
cooperation and assistance, provided that Ambacs prior written approval for such expenses have been obtained, which shall not be unreasonably withheld or delayed. Such expenses will include reasonable attorneys fees only in the
event representation by Ambacs counselcould reasonably be deemed to be a conflict of interest. You agree to reasonable requests by Ambac to travel in performing services pursuant to this Section 13(a).
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| | (b) | In addition to, and not in limitation of, any and all other rights of indemnification or advancement of expenses to which you are or may be entitled, if and to the
extent you already have been and/or hereafter are, or threatened to be, a named party to any action, suit, claim or proceeding as a result of your being or having been an officer, director, employee or agent of Ambac or any of its subsidiaries or
affiliates, or your serving or having served any other enterprise as a director, officer, employee or agent at the request of Ambac, or any of your acts or omissions in connection with any of the foregoing or pursuant to or in connection with this
Agreement or your obligations hereunder, Ambac will indemnify you to the fullest extent permitted (including payment of expenses and attorneys and other fees in advance of final disposition of a proceeding) by the laws of the State of
Delaware, or by the Certificate of Incorporation or By-Laws or other governing documents of Ambac, in each case as in effect at the time of the subject act or omission, the date of this Agreement or the date of such action, suit, claim or
proceeding, whichever affords or afforded the greatest protection to you, and you shall be entitled to the protection of any insurance policies that Ambac maintains or may elect to maintain generally for the benefit of its directors, officers or
employees (and to the extent Ambac maintains such an insurance policy or policies, you shall be covered by such policy or policies, in accordance with its or their terms, to the maximum extent of the coverage provided for any officer, director or
employee of Ambac), against all costs, charges and expenses whatsoever incurred or sustained by you or your legal representatives at the time such costs, charges and expenses are incurred or sustained, in connection with any such action, suit, claim
or proceeding, to which you may be made a party by reason of your being or having been a director, officer, employee or agent of Ambac or any subsidiary or affiliate thereof, or your serving or having served any other enterprise as a director,
officer, employee or agent at the request of Ambac. The indemnification, advancement of expenses and other provisions contained in this paragraph shall survive the Retirement Date and any termination or expiration of this Agreement, and shall inure
to your benefit, as well as to the benefit of your heirs, executors, administrators and legal representatives.
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|14. | Non-Disparagement
|--- | -----------------

You
and Ambac each agree with respect to the other to refrain from making, directly or indirectly, now or at any time in the future, whether in writing, orally or electronically: (i) any defamatory or product disparaging comment concerning the you
and Ambac or any of its current or former directors, officers or employees, or (ii) any other comment that could reasonably be expected to be detrimental to you or Ambacs business or financial prospects or reputation. In furtherance of
the foregoing, Ambac additionally agrees to cause its affiliates to be bound by the provisions of this Section 14 (i.e., as if they were Ambac under the provisions of this Section 14).



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|15. | Entire Agreement
|--- | ----------------

This
Agreement sets forth the entire agreement and understanding of the parties hereto and supersedes and replaces all prior or contemporaneous agreements or understandings, oral or written, negotiations, or discussions relating to the subject matter of
this Agreement. This Agreement may be amended only by written document signed by the parties hereto. It is understood that you shall have no further obligations to Ambac from and after the date hereof except as otherwise expressly set forth herein.



|16. | Severability
|--- | ------------

In the
event that any one or more of the provisions of this Agreement shall be held invalid, illegal or unenforceable, the validity and enforceability of the remainder of the Agreement shall not in any way be affected or impaired thereby.



|17. | Governing Law
|--- | -------------

This
Agreement will be governed by, and construed in accordance with, the laws of the State of New York.



|18. | Revocation
|--- | ----------



| | (a) | You are required to execute and deliver the Waiver and General Release Agreement in the form set forth as Exhibit A hereto at the two times heretofore set forth.
| | --- | -----------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (b) | Either or both of the aforementioned Waiver and General Release Agreements, once signed by you, may be revoked by you within the 7-day period described therein. In the
event of any such revocation by you, all of Ambacs obligations under this Agreement will terminate and be of no further force and effect as of the date of such revocation. No such revocation by you will be effective unless it is in writing and
signed by you and received by Ambac prior to the expiration of the Revocation Period. The revocation must be mailed or delivered to Diana Adams, Senior Managing Director, Ambac Financial Group, Inc., One State Street Plaza, New York, New York 10004.
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IN WITNESS WHEREOF,Ambac has executed this Agreement as of the date first set forth above
and you have executed this Agreement as of the date set forth below (or, if you do not include a date under your signature line, the date set forth shall be the date this Agreement, signed by you, is received by the Ambac.



AMBAC FINANCIAL GROUP, INC.By:

/s/ Diana N. AdamsDiana N. AdamsSenior Managing Director




|                     |  |                               
|-------------------- |  | ------------------------------
|ACCEPTED AND AGREED:
|                     | 
|By:                  |  | /s/ Douglas C. Renfield-Miller
|                     |  | Douglas C. Renfield-Miller    
|                    
|Date: Sept 22, 2009 



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EXHIBIT A

WAIVER AND GENERAL RELEASE AGREEMENT

This Waiver and
General Release Agreement (this Release) is entered into as of the date indicated on the signature page of this Release by Douglas C. Renfield-Miller (Executive). Executive has been employed by Ambac Financial
Group, Inc. (the Company), and in connection with Executives Retirement and for the consideration of the payments and benefits set forth in the Agreement between Executive and the Company dated as of September 21, 2009
(the Agreement), the receipt and adequacy of which are herein acknowledged, Executive agrees as follows:



|1. | General Release
|-- | ---------------

Executive, on behalf of himself and Executives heirs, executors, administrators, trustees, legal representatives and assigns (hereinafter collectively referred to as the Releasors), hereby irrevocably and
unconditionally release and forever discharge Ambac, and any and all of its parent corporations, shareholders, subsidiaries, divisions, affiliated and related entities, employee benefit and/or pension plans or funds, successors and assigns, and any
and all of its or their past, present or future officers, directors, agents, stockholders, fiduciaries, administrators, employees or assigns (whether acting as agents for Ambac or in their individual capacities, but in any case not in their
capacities, if applicable, as stockholders) (hereinafter collectively referred to as the Released Parties), of and from any and from any and all claims, actions, causes of action, rights, judgments, obligations, damages, demands,
accountings or liabilities of whatever kind or character (collectively, Claims), including, without limitation, any Claims under any federal, state, local or foreign law, that the Releasors may have, or in the future may possess,
arising out of (i) the Executives employment relationship with and service as an employee, officer or director of the Company, and the termination of such relationship or service, and (ii) any event, condition, circumstance or
obligation that occurred, existed or arose on or prior to the date hereof; provided, however, that notwithstanding the foregoing, the Executive does not release, discharge or waive any rights: (i) under or to enforce the
Agreement, or to payments and benefits provided under the Agreement that are contingent upon the execution, delivery and non-revocation by the Executive of this Release; (ii) any rights to vested pension or 401k benefits; or (iii) to
indemnification, whether pursuant to (a) the Agreement or any other agreement between the parties, including, without limitation, the Change In Control Agreement, (b) the charter, by-laws or other governing documents of Ambac or any of its
affiliates, (c) insurance policies, (d) applicable law, or (e) otherwise.



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|2. | ADEA Release
|-- | ------------

The
Releasors hereby unconditionally release and forever discharge Ambac, its subsidiaries and affiliates and each of their respective officers, employees, directors, shareholders and agents from any and all Claims that the Releasors may have arising
under the Federal Age Discrimination in Employment Act of 1967, as amended, and the applicable rules and regulations promulgated thereunder (ADEA). By signing this Release, you hereby acknowledge and confirm the following:



| | (a) | Executive was advised by Ambac in connection with his Retirement to consult with an attorney of his choice prior to signing this Release and to have such attorney
explain to you the terms of this Release, including, without limitation, the terms relating to your release of claims arising under ADEA;
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| | (b) | Executive was given a period of not fewer than 21 days to consider the terms of this Release and to consult with an attorney of her choosing with respect thereto;
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| | (c) | Executive is providing the release and discharge set forth in this Section 2 only in exchange for consideration in addition to anything of value to which he is
already entitled; and
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| | (d) | that Executive knowingly and voluntarily accept the terms of this Release.
| | --- | --------------------------------------------------------------------------



|3. | No Legal Claim
|-- | --------------



| | (a) | Executive represents and warrants that he will not commence, maintain, prosecute or participate in any action or proceeding of any kind (judicial or administrative)
against any of the Released Parties, arising out of any act, omission, transaction or occurrence happening up to and including the Effective Date (as defined below) of this Release and released hereunder, and has not done so as of the Effective Date
of this Release.
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| | (b) | If Executive is named as a party or included in a class action against any Released Party, Executive agrees to execute a waiver of rights and release of any such claims
against such Released Party; provided, however, that any such waiver and release shall not apply to any of Executives rights of indemnification from such Released Party.
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|4. | Continuing Obligations
|-- | ----------------------

This Release shall not supersede any continuing obligations Executive may have under the terms of the Agreement or any other agreement between Executive and the Company.



|5. | Governing Law
|-- | -------------

This
Release will be governed by, and construed in accordance with, the laws of the State of New York.



|6. | Effective Date
|-- | --------------

This
Release shall not become effective until the day following the last day of the Revocation Period (as defined below) (the Effective Date).

* * *

Executive shall have the right to revoke this Release during the seven-day period (the
Revocation Period) commencing immediately following the date Executive signs and delivers this Release to the Company. The Revocation Period shall expire at 5:00 p.m. New York City Time on the last day of the Revocation
Period; provided, however, that if such seventh day is not a business day, the Revocation Period shall extend to 5:00 p.m. New York City Time on the next succeeding business day. In the event Executive revokes this Release, all
obligations of the Company under the Agreement shall terminate and be of no further force and effect as of the date of such revocation. No such revocation by Executive shall be effective unless it is in writing and signed by Executive and received
by the Company prior to the expiration of the Revocation Period.



|      |  |                               
|----- |  | ------------------------------
|By:   |  | /s/ Douglas C. Renfield-Miller
|      |  | Douglas C. Renfield-Miller    
|      | 
|Date: |  | Sept 22, 2009                 



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EXHIBIT B

RETIREMENT HEALTHCARE BENEFIT*

As a retiree from Ambac, you
have the option to elect to receive medical, dental and prescription drug coverage (coverage or healthcare coverage). The cost the retiree pays for that coverage is based on a formula that considers their years of service at
Ambac beyond their fortieth birthday and the actual cost of such coverage. The actual formula is set forth below:



|           |  |                         |  |                                     
|---------- |  | ----------------------- |  | ------------------------------------
|Name:      |  | Douglas Renfield-Miller |  |                                     
|           |  |                        
|Birth date |  | 06/24/53                |  | 56.56 age at retirement             
|           |  |                         |  | 46.85 age at beginning of employment
|Hire date  |  | 04/17/00                |  | 9.71 years employed at Ambac        



|                                                                       |  |   |                  |  
|---------------------------------------------------------------------- |  | - | ---------------- | -
|Total Health Care Premium per month for:         PPO Employee + Family |  | $ | 1,765.33         |  
|Number of full years worked for Ambac over the age of 40               |  |   | 9                |  
|Multiplied by                                                          |  |   | 4                | %
|% of healthcare premium paid by Ambac                                  |  |   | 36               | %
|% of healthcare premium paid by Retiree                                |  |   | 64               | %
|Monthly premium paid by retiree                                        |  | $ | 1,129.81         |  
|                                                                       |  | $ | 13,557.73 annual |  
|                                                                       |  | $ | 37.14 daily      |  

Monthly premium subject to change as Ambacs premium changes.



4



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LOGO

EXHIBIT C

STOCK OPTIONS AND RESTRICTED STOCK UNITS

Stock Options:



|                |  |                 |  |         |  |                          |  |             |  |         |  |             |  |             |  |             
|--------------- |  | --------------- |  | ------- |  | ------------------------ |  | ----------- |  | ------- |  | ----------- |  | ----------- |  | ------------
|Grant Date      |  | Expiration Date |  | Plan ID |  | Granted orTransferred To |  | Grant Price |  | Granted |  | Outstanding |  | Exercisable
|1/21/2003       |  | 1/21/2010       |  | 01b     |  | Non-Qualified            |  | $  56.1350  |  | 20,000  |  | 20,000      |  | 20,000      |  | current     
|1/26/2004       |  | 1/26/2011       |  | 01b     |  | Non-Qualified            |  | $  73.7100  |  | 20,000  |  | 20,000      |  | 10,000      |  | current     
|                |  |                 |  |         |  |                          |  |             |  |         |  |             |  | 10,000      |  | on 1/26/2010
|1/26/2004       |  | 1/26/2011       |  | 01b     |  | Non-Qualified            |  | $  73.7100  |  | 4,700   |  | 4,700       |  | 2,350       |  | current     
|                |  |                 |  |         |  |                          |  |             |  |         |  |             |  | 2,350       |  | on 1/26/2010
|1/24/2005       |  | 1/24/2012       |  | 01b     |  | Non-Qualified            |  | $  79.3000  |  | 25,000  |  | 25,000      |  | 0           |  | current     
|                |  |                 |  |         |  |                          |  |             |  |         |  |             |  | 25,000      |  | on 1/24/2011
|1/23/2006       |  | 1/23/2013       |  | 01b     |  | Non-Qualified            |  | $  74.4250  |  | 25,000  |  | 25,000      |  | 12,500      |  | current     
|                |  |                 |  |         |  |                          |  |             |  |         |  |             |  | 12,500      |  | on 1/23/2012
|1/29/2007       |  | 1/29/2014       |  | 01b     |  | Non-Qualified            |  | $  87.2700  |  | 35,000  |  | 35,000      |  | 0           |  | current     
|                |  |                 |  |         |  |                          |  |             |  |         |  |             |  | 35,000      |  | on 1/29/2012
|1/28/2008       |  | 1/28/2015       |  | 01      |  | Non-Qualified            |  | $  11.1300  |  | 64,000  |  | 64,000      |  | 21,334      |  | current     
|                |  |                 |  |         |  |                          |  |             |  |         |  |             |  | 21,333      |  | on 1/28/2010
|                |  |                 |  |         |  |                          |  |             |  |         |  |             |  | 21,333      |  | on 1/28/2011
|                |  |                 |  |         |  |                          |  |             |  |         |  |             |  |             |  |             
|Optionee Totals |  |                 |  |         |  |                          |  |             |  | 193,700 |  | 193,700     |  | 66,184      |  |             



5



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LOGO

Restricted Stock Units



|                |  |                 |  |         |  |                          |  |         |  |             |  |             |  |             |  |             
|--------------- |  | --------------- |  | ------- |  | ------------------------ |  | ------- |  | ----------- |  | ----------- |  | ----------- |  | ------------
|Grant Date      |  | Expiration Date |  | Plan ID |  | Granted orTransferred To |  | Granted |  | Grant Price |  | Outstanding |  | Exercisable
|1/22/2001       |  | 4/22/2084       |  | 02B     |  | Restricted               |  | 3,467   |  | $0,0000     |  | 3,467       |  | 0           |  | current     
|                |  |                 |  |         |  |                          |  |         |  |             |  |             |  | 3,467       |  | on 4/22/2084
|1/22/2001       |  | 4/22/2084       |  | 02C     |  | Restricted               |  | 1,155   |  | $0,0000     |  | 1,155       |  | 0           |  | current     
|                |  |                 |  |         |  |                          |  |         |  |             |  |             |  | 1,155       |  | on 4/22/2084
|1/22/2002       |  | 4/22/2085       |  | 02B     |  | Restricted               |  | 2,732   |  | $0,0000     |  | 2,732       |  | 0           |  | current     
|                |  |                 |  |         |  |                          |  |         |  |             |  |             |  | 2,732       |  | on 4/22/2085
|1/22/2002       |  | 4/22/2085       |  | 02C     |  | Restricted               |  | 910     |  | $0,0000     |  | 910         |  | 0           |  | current     
|                |  |                 |  |         |  |                          |  |         |  |             |  |             |  | 910         |  | on 4/22/2085
|1/21/2003       |  | 4/21/2086       |  | 02B     |  | Restricted               |  | 3,136   |  | $0,0000     |  | 3,136       |  | 0           |  | current     
|                |  |                 |  |         |  |                          |  |         |  |             |  |             |  | 3,136       |  | on 4/21/2086
|1/21/2003       |  | 4/21/2086       |  | 02C     |  | Restricted               |  | 1,045   |  | $0,0000     |  | 1,045       |  | 0           |  | current     
|                |  |                 |  |         |  |                          |  |         |  |             |  |             |  | 1,045       |  | on 4/21/2086
|1/26/2004       |  | 4/26/2087       |  | 02B     |  | Restricted               |  | 2,516   |  | $0,0000     |  | 2,516       |  | 0           |  | current     
|                |  |                 |  |         |  |                          |  |         |  |             |  |             |  | 2,516       |  | on 1/26/2086
|1/26/2004       |  | 4/26/2087       |  | 02C     |  | Restricted               |  | 837     |  | $0,0000     |  | 837         |  | 0           |  | current     
|                |  |                 |  |         |  |                          |  |         |  |             |  |             |  | 837         |  | on 1/26/2086
|1/24/2005       |  | 4/24/2088       |  | 02B     |  | Restricted               |  | 2,605   |  | $0,0000     |  | 2,605       |  | 0           |  | current     
|                |  |                 |  |         |  |                          |  |         |  |             |  |             |  | 2,605       |  | on 4/24/2088
|1/24/2005       |  | 4/24/2088       |  | 02C     |  | Restricted               |  | 868     |  | $0,0000     |  | 868         |  | 0           |  | current     
|                |  |                 |  |         |  |                          |  |         |  |             |  |             |  | 868         |  | on 4/24/2088
|1/23/2006       |  | 4/23/2089       |  | 02B     |  | Restricted               |  | 2,615   |  | $0,0000     |  | 2,615       |  | 0           |  | current     
|                |  |                 |  |         |  |                          |  |         |  |             |  |             |  | 2,615       |  | on 4/23/2089
|1/23/2006       |  | 4/23/2089       |  | 02C     |  | Restricted               |  | 871     |  | $0,0000     |  | 871         |  | 0           |  | current     
|                |  |                 |  |         |  |                          |  |         |  |             |  |             |  | 871         |  | on 4/23/2089
|1/29/2007       |  | 1/29/2014       |  | 02      |  | Restricted               |  | 4,751   |  | $0,0000     |  | 4,751       |  | 0           |  | current     
|                |  |                 |  |         |  |                          |  |         |  |             |  |             |  | 4,751       |  | on 1/29/2010
|1/29/2007       |  | 4/29/2090       |  | 02B     |  | Restricted               |  | 2,673   |  | $0,0000     |  | 2,673       |  | 0           |  | current     
|                |  |                 |  |         |  |                          |  |         |  |             |  |             |  | 2,673       |  | on 4/29/2090
|1/29/2007       |  | 4/29/2090       |  | 02C     |  | Restricted               |  | 890     |  | $0,0000     |  | 890         |  | 0           |  | current     
|                |  |                 |  |         |  |                          |  |         |  |             |  |             |  | 890         |  | on 4/29/2090
|1/28/2008       |  | 1/28/2015       |  | 02      |  | Restricted               |  | 58,639  |  | $0,0000     |  | 58,639      |  | 0           |  | current     
|                |  |                 |  |         |  |                          |  |         |  |             |  |             |  | 58,639      |  | on 1/28/2011
|                |  |                 |  |         |  |                          |  |         |  |             |  |             |  |             |  |             
|Optionee Totals |  |                 |  |         |  | 89,710                   |  |         |  | 89,710      |  | 0           |  |            



6