SCHEDULE 14A
                                 (Rule 14a-101)
                     INFORMATION REQUIRED IN PROXY STATEMENT

                            SCHEDULE 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

Filed by the Registrant  [X]

Filed by a Party other than the Registrant [ ]

Check the appropriate box:

[ ]     Preliminary Proxy Statement

[ ]     CONFIDENTIAL, FOR USE OF THE
        COMMISSION ONLY (AS PERMITTED BY
        RULE 14A-6(E)(2))

[X]     Definitive Proxy Statement

[ ]     Definitive Additional Materials

[ ]     Soliciting Material Under Rule 14a-12



                           AMBAC FINANCIAL GROUP, INC.
 ................................................................................
                (Name of Registrant as Specified In Its Charter)


 ................................................................................
    (Name of Person(s) Filing Proxy Statement, if other than the Registrant)



Payment of Filing Fee (Check the appropriate box):

[X]  No fee required.

[ ]  Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and
     0-11.
     1)   Title of each class of securities to which transaction applies:


- --------------------------------------------------------------------------------
     2)   Aggregate number of securities to which transaction applies:


- --------------------------------------------------------------------------------
     3)   Per unit price or other underlying value of transaction computed
          pursuant to Exchange Act Rule 0-11 (Set forth the amount on which the
          filing fee is calculated and state how it was determined):

- --------------------------------------------------------------------------------

     4)   Proposed maximum aggregate value of transaction:

- --------------------------------------------------------------------------------
     5)   Total fee paid:

- --------------------------------------------------------------------------------

[ ]  Fee paid previously with preliminary materials.

[ ]  Check box if any part of the fee is offset as provided by Exchange Act
     Rule 0-11(a)(2) and identify the filing for which the offsetting fee was
     paid previously. Identify the previous filing by registration statement
     number, or the Form or Schedule and the date of its filing.

     1)  Amount Previously Paid:

- --------------------------------------------------------------------------------
     2)  Form, Schedule or Registration Statement No.:

- --------------------------------------------------------------------------------
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- --------------------------------------------------------------------------------
     4)  Date Filed:

- --------------------------------------------------------------------------------

Notes:

Reg. (S) 240.14a-101

SEC 1913 (3-99)


                                 AMBAC FINANCIAL GROUP, INC.

[LOGO] Ambac                     NOTICE OF
                                 2001 ANNUAL MEETING
                                 OF STOCKHOLDERS
                                 AND
                                 PROXY STATEMENT

                                 Meeting Date:

                                 Tuesday, May 1, 2001
                                 at 11:30 A.M. (local time)

                                 Meeting Place:

                                 Ambac Financial Group, Inc.
                                 One State Street Plaza
                                 New York, New York 10004


                                                          AMBAC FINANCIAL
                                                          GROUP, INC.
                                                          One State Street
                                                          Plaza
                                                          New York, NY 10004
                                                          212.668.0340

                                                          PHILLIP B. LASSITER
                                                          Chairman and
                                                          Chief Executive
                                                          Officer

                         March 28, 2001

[LOGO] Ambac
                         Dear Stockholders:

                         It is my pleasure to invite you to Ambac's 2001 Annual
                         Meeting of Stockholders.

                         We will hold the meeting on Tuesday, May 1, 2001, at
                         11:30 a.m. at our executive offices in New York City.
                         In addition to the formal items of business, I will
                         review the major developments of 2000 and answer your
                         questions.

                         This booklet includes the Notice of Annual Meeting and
                         the Proxy Statement. The Proxy Statement describes the
                         business that we will conduct at the meeting.

                         Your vote is important. Whether you plan to attend the
                         meeting or not, please complete, sign and return the
                         enclosed proxy card in the envelope provided. If you
                         attend the meeting you may vote in person, even if you
                         previously submitted your proxy.
                         We look forward to seeing you at the meeting.

                         Sincerely,

                         /s/ Phillip B. Lassiter


                                                          AMBAC FINANCIAL
                                                          GROUP, INC.
                                                          One State Street
                                                          Plaza
                                                          New York, NY 10004
                                                          212.668.0340

                         NOTICE OF 2001 ANNUAL MEETING OF STOCKHOLDERS

                         March 28, 2001

[LOGO] Ambac
                         Dear Stockholders:

                         We will hold the 2001 Annual Meeting of Stockholders
                         on Tuesday, May 1, 2001 at 11:30 a.m. (local time) at
                         our executive offices at One State Street Plaza in New
                         York City. At our Annual Meeting, we will ask you to:

                         .   Elect seven directors;

                         .   Ratify the selection of KPMG LLP as independent
                             auditors for 2001; and

                         .   Consider any other business that is properly
                             presented at the Annual Meeting.

                         You may vote at the Annual Meeting if you were an
                         Ambac stockholder at the close of business on March
                         14, 2001.

                         Along with the attached Proxy Statement, we are also
                         sending you the Ambac 2000 Annual Report, which
                         includes our financial statements.

                         /s/ Anne G.Gill
                         Anne G. Gill
                         First Vice President, Corporate Secretary
                         and Assistant General Counsel


                               TABLE OF CONTENTS



                                                                                      
INFORMATION ABOUT THE ANNUAL MEETING AND VOTING.........................................  1

   Why Did You Send Me this Proxy Statement?............................................  1
   How Many Votes Do I Have?............................................................  1
   How Do I Vote by Proxy?..............................................................  1
   May I Vote by Telephone or Via the Internet?.........................................  2
   May I Revoke My Proxy?...............................................................  2
   How Do I Vote in Person?.............................................................  2
   How Do Employees in the Ambac Stock Fund Vote?.......................................  3
   What Votes Do We Need to be Present to Hold the Annual Meeting?......................  3
   What Vote Is Required to Approve Each Proposal?......................................  3
   What Is the Effect of Broker Non-Votes?..............................................  3
   Is Voting Confidential?..............................................................  4
   What Are the Costs of Soliciting these Proxies?......................................  4
   How Do I Obtain an Annual Report on Form 10-K?.......................................  4
   Where Can I Find the Voting Results?.................................................  4
   Whom Should I Call If I Have Any Questions?..........................................  4

INFORMATION ABOUT AMBAC COMMON STOCK OWNERSHIP..........................................  5

   Which Stockholders own at least 5% of Ambac?.........................................  5
   How Much Stock is Owned By Directors and Executive Officers?.........................  6
   Did Ambac Insiders Comply with Section 16(a) Beneficial Ownership Reporting in 2000?.  7

INFORMATION ABOUT DIRECTORS.............................................................  8

   The Board of Directors...............................................................  8
   The Committees of the Board..........................................................  8
   How We Compensate Directors..........................................................  9

THE AUDIT COMMITTEE REPORT.............................................................. 11

INFORMATION ABOUT THE EXECUTIVE OFFICERS................................................ 12

   The Executive Officers............................................................... 12
   How We Compensate Executive Officers................................................. 14
   The Pension Plan..................................................................... 16
   Employment Agreement with the Chief Executive Officer................................ 18
   Management Retention Agreements with Executive Officers.............................. 20
   Definitions.......................................................................... 20

REPORT ON EXECUTIVE COMPENSATION FOR 2000 BY THE COMPENSATION AND
  ORGANIZATION COMMITTEE................................................................ 22

   What is Our Executive Compensation Philosophy?....................................... 22
   What is Our Position on Maximizing the Deductibility of Executive Compensation?...... 22
   What are the Elements of Executive Compensation?..................................... 23
   How Did We Determine Base Salaries for 2000?......................................... 23
   How Did We Determine Bonuses for 2000?............................................... 24
   What Were the Long-Term Incentive Awards in 2000?.................................... 25

PERFORMANCE GRAPH....................................................................... 27

DISCUSSION OF PROPOSALS RECOMMENDED BY THE BOARD........................................ 28

   Proposal 1: Elect Seven Directors.................................................... 28
   Proposal 2: Ratify Selection of KPMG LLP as Independent Auditors for 2001............ 30

INFORMATION ABOUT STOCKHOLDER PROPOSALS................................................. 31



              PROXY STATEMENT FOR THE AMBAC FINANCIAL GROUP, INC.
                      2001 ANNUAL MEETING OF STOCKHOLDERS

                INFORMATION ABOUT THE ANNUAL MEETING AND VOTING

WHY DID YOU SEND ME THIS PROXY STATEMENT?

    We sent you this Proxy Statement and the enclosed proxy card because
Ambac's Board of Directors is soliciting your proxy to vote at the 2001 Annual
Meeting of Stockholders.

    This Proxy Statement summarizes the information you need to vote at the
Annual Meeting. You do not need to attend the Annual Meeting to vote your
shares. You may simply complete, sign and return the enclosed proxy card.

    We will begin mailing this Proxy Statement on March 28, 2001 to all
stockholders entitled to vote. If you owned Ambac common stock at the close of
business on March 14, 2001, you are entitled to vote. On that date, there were
105,652,028 shares of Ambac common stock outstanding. Ambac common stock is our
only class of voting stock.

HOW MANY VOTES DO I HAVE?

    You have one vote for each share of Ambac common stock that you owned at
the close of business on March 14, 2001. The proxy card indicates the number.

HOW DO I VOTE BY PROXY?

    If you properly fill in your proxy card and send it to us in time to vote,
your "proxy" (one of the individuals named on your proxy card) will vote your
shares as you have directed. If you sign the proxy card but do not make
specific choices, your proxy will vote your shares as recommended by the Board:

    .  "FOR" Proposal 1 (Elect Seven Directors); and

    .  "FOR" Proposal 2 (Ratify Selection of KPMG LLP as Independent Auditors
       for 2001).

    If any other matter is presented, your proxy will vote in accordance with
his or her best judgment. At the time we began printing this Proxy Statement,
we knew of no matters that needed to be acted on at the Annual Meeting, other
than those discussed in this Proxy Statement.


      Whether you plan to attend the Annual Meeting or not, we urge you to
      complete, sign and date the enclosed proxy card and to return it promptly
      in the envelope provided. Returning the proxy card will not affect your
      right to attend the Annual Meeting and vote.

MAY I VOTE BY TELEPHONE OR VIA THE INTERNET?

    Yes. Instead of submitting your vote by mail on the enclosed proxy card,
you may be able to vote via the Internet or by telephone. Please note that
there are separate Internet and telephone arrangements depending on whether you
are a registered stockholder (that is, if you hold your stock in your own
name), or whether you hold your shares in "street name" (that is, if your stock
is held in the name of your broker or bank).

    If you are a registered stockholder, you may vote by telephone, or
electronically through the Internet, by following the instructions provided on
your proxy card.

    If your shares are held in "street name", you may need to contact your bank
or broker to determine whether you will be able to vote by telephone or
electronically.

    The telephone and Internet voting procedures are designed to authenticate
stockholders' identities, to allow stockholders to give their voting
instructions and to confirm that stockholders' instructions have been recorded
properly. If you vote via the Internet, you may incur costs, such as usage
charges from Internet access providers and telephone companies. You will be
responsible for those costs.

MAY I REVOKE MY PROXY?

    Yes. You may change your mind after you send in your proxy card by
following any of these procedures. To revoke your proxy:

   .   Send in another signed proxy with a later date; or

   .   Send a letter revoking your proxy to Ambac's Corporate Secretary at the
       address indicated on page 31 under "Information about Stockholder
       Proposals"; or

   .   Attend the Annual Meeting and vote in person.

HOW DO I VOTE IN PERSON?

    If you plan to attend the Annual Meeting and vote in person, we will give
you a ballot when you arrive.

    If your shares are held in the name of your broker, bank or other nominee,
you must bring an account statement or letter from the nominee. The account
statement or letter must show that you were the direct or indirect (beneficial)
owner of the shares on March 14, 2001.

                                       2


HOW DO EMPLOYEES IN THE AMBAC STOCK FUND VOTE?

    If you are an employee who participates in our Savings Incentive Plan
("SIP"), you are receiving this material because of shares held for you in the
Ambac Stock Fund in the SIP. The SIP Trustee will send you a voting instruction
card instead of a proxy card. This voting instruction card will indicate the
number of shares of Ambac common stock credited to your account in the Ambac
Stock Fund as of March 14, 2001.

   .   If you complete, sign and return the voting instruction card on time,
       the SIP Trustee will vote the shares as you have directed.

   .   If you do not complete, sign and return the voting instruction card on
       time, the SIP Trustee will not vote the shares credited to your account.

WHAT VOTES DO WE NEED TO BE PRESENT TO HOLD THE ANNUAL MEETING?

    We need a majority of the shares of Ambac common stock outstanding on March
14, 2001 to be present, in person or by proxy, to hold the Annual Meeting.

WHAT VOTE IS REQUIRED TO APPROVE EACH PROPOSAL?

PROPOSAL 1:             The seven nominees for director who receive the most
ELECT SEVEN             votes will be elected. If you do not vote for a
DIRECTORS               nominee, or you indicate "withhold authority to vote"
                        for any nominee on your proxy card, your vote will not
                        count either for or against the nominee.

PROPOSAL 2:             The affirmative vote of a majority of the votes present
RATIFY SELECTION        and entitled to vote at the Annual Meeting is required
OF AUDITORS             to ratify the selection of independent auditors. So, if
                        you "abstain" from voting, it has the same effect as if
                        you voted "against" this proposal.

WHAT IS THE EFFECT OF BROKER NON-VOTES?

    Under the rules of the New York Stock Exchange, if your broker holds your
shares in its "street" name, the broker may vote your shares on both proposals
even if it does not receive instructions from you.

    However, if your broker does not vote on either of the proposals, it will
have no effect on the outcome of the proposal.

                                       3


IS VOTING CONFIDENTIAL?

    We maintain a policy of keeping all the proxies, ballots and voting
tabulations confidential. The Inspectors of Election will forward to management
any written comments that you make on the proxy card.

WHAT ARE THE COSTS OF SOLICITING THESE PROXIES?

    Ambac will pay all the costs of soliciting these proxies. Although we are
mailing these proxy materials, our directors and employees may also solicit
proxies by telephone, by fax or other electronic means of communication, or in
person. We will reimburse banks, brokers, nominees and other fiduciaries for
the expenses they incur in forwarding the proxy materials to you. Georgeson
Shareholder Communications, Inc. is assisting us with the solicitation of
proxies for a fee of $8,500 plus out-of-pocket expenses.

HOW DO I OBTAIN AN ANNUAL REPORT ON FORM 10-K?

    IF YOU WOULD LIKE A COPY OF OUR ANNUAL REPORT ON FORM 10-K FOR THE YEAR
ENDED DECEMBER 31, 2000 THAT WE FILED WITH THE SECURITIES AND EXCHANGE
COMMISSION, WE WILL SEND YOU ONE WITHOUT CHARGE. PLEASE WRITE TO:

                     INVESTOR RELATIONS
                     AMBAC FINANCIAL GROUP, INC.
                     ONE STATE STREET PLAZA
                     NEW YORK, NEW YORK 10004
                     ATTENTION: BRIAN MOORE, MANAGING DIRECTOR, INVESTOR
                     RELATIONS

OR CONTACT MR. MOORE AT (212) 208-3333 OR AT BMOORE@AMBAC.COM.

WHERE CAN I FIND THE VOTING RESULTS?

    We will publish the voting results in our FORM 10-Q for the second quarter
of 2001, which we will file with the SEC in August 2001. You can also find the
results on Ambac's website at WWW.AMBAC.COM.

WHOM SHOULD I CALL IF I HAVE ANY QUESTIONS?

    If you have any questions about the Annual Meeting or voting, please
contact ANNE GILL, OUR CORPORATE SECRETARY, AT (212) 208-3355 OR AT
AGILL@AMBAC.COM.

    If you have any questions about your ownership of Ambac common stock,
please call BRIAN MOORE, MANAGING DIRECTOR, INVESTOR RELATIONS, AT (212)
208-3333 OR AT BMOORE@ AMBAC.COM.

                                       4


                INFORMATION ABOUT AMBAC COMMON STOCK OWNERSHIP

WHICH STOCKHOLDERS OWN AT LEAST 5% OF AMBAC?

    The following table shows all persons we know to be direct or indirect
owners of at least 5% of Ambac common stock as of December 31, 2000. Persons
who are direct or indirect owners of Ambac common stock are sometimes referred
to in this Proxy Statement as "BENEFICIAL OWNERS" or as persons who
"BENEFICIALLY OWN" Ambac common stock. Our information is based on reports
filed with the Securities and Exchange Commission by each of the firms listed
in the table below. If you wish, you may obtain these reports from the SEC.




                                      NUMBER OF
                                     SHARES OWNED PERCENT OF
NAME AND ADDRESS OF BENEFICIAL OWNER BENEFICIALLY   CLASS

- ------------------------------------------------------------
                                            

FMR CORP.                              12,631,764      12.0%
   82 Devonshire Street
   Boston, Massachusetts 02109

J.P. MORGAN CHASE & CO.                 9,132,506       8.6%
   270 Park Avenue
   New York, New York 10017

GOLDMAN SACHS ASSET MANAGEMENT          5,946,050       5.6%
   32 Old Slip
   New York, NY 10005



                                       5


HOW MUCH STOCK IS OWNED BY DIRECTORS AND EXECUTIVE OFFICERS?

    The following table shows the Ambac common stock owned directly or
indirectly by Ambac's directors and executive officers as of February 15, 2001.
Except for Mr. Lassiter, no director or executive officer beneficially owns 1%
or more of the shares of Ambac common stock. All directors and executive
officers as a group beneficially own 3.0% of the shares of Ambac common stock.
We have adjusted all shares, options, restricted stock units ("RSUS") and
phantom stock units to reflect Ambac's three-for-two stock split in December
2000.




                                               SHARES
                                            BENEFICIALLY                             TOTAL HOLDINGS
                                                OWNED      PERCENT  UNVESTED         (INCLUDING RSUs
NAME OF BENEFICIAL OWNER                   (1)(2)(3)(4)(5) OF CLASS RSUs(6)  PSUs(7)    AND PSUs)

- ----------------------------------------------------------------------------------------------------
                                                                      

OUTSIDE DIRECTORS
  Michael A. Callen.......................          26,487      --     4,628   7,576          38,691
  Renso L. Caporali.......................          15,369      --     3,020   5,442          23,831
  Jill M. Considine.......................             626      --     3,020     552           4,198
  Richard Dulude..........................          17,229      --     4,628   8,318          30,175
  W. Grant Gregory........................          38,053      --     4,628  10,061          52,742
  C. Roderick O'Neil......................          33,087      --     4,628   4,011          41,726

EXECUTIVE OFFICERS
  Phillip B. Lassiter.....................       1,543,976     1.5%   16,640      --       1,560,616
  Robert J. Genader.......................         701,477      --    10,775      --         712,252
  Frank J. Bivona.........................         438,327      --     5,517      --         443,844
  David L. Boyle..........................         228,036      --     5,967      --         234,003
  Kevin J. Doyle..........................          74,253      --     4,364      --          78,617
  All executive officers and directors as
   a group (12 persons)...................       3,162,056     3.0%   70,072  35,960       3,268,088

- ----------------------------------------------------------------------------------------------------


 (1) To our knowledge, except for Messrs. Lassiter and Genader, who share
     voting and investment power with their spouses, each of the directors and
     executive officers has sole voting and investment power over his shares.

 (2) The number of shares shown for Mr. Lassiter includes 12,000 shares owned
     by his spouse. Mr. Lassiter disclaims beneficial ownership of these
     shares.

     The number of shares shown for Mr. Gregory includes 4,999 shares held in
     the Gregory 1997 Children's Trust, of which his daughter is a beneficiary.
     Mr. Gregory disclaims beneficial ownership of these shares.

 (3) The number of shares shown for each director and executive officer
     includes shares that may be acquired upon exercise of stock options that
     were exercisable as of February 15, 2001 or that will become exercisable
     within 60 days after February 15, 2001. These shares are shown in the
     following table



OUTSIDE DIRECTORS NUMBER OF SHARES EXECUTIVE OFFICERS NUMBER OF SHARES
- ----------------- ---------------- ------------------ ----------------
                                             
Mr. Callen.......            9,000 Mr. Lassiter......          427,596
Dr. Caporali.....            6,000 Mr. Genader.......          487,500
Ms. Considine....              626 Mr. Bivona........          329,229
Mr. Dulude.......            9,000 Mr. Boyle.........          222,500
Mr. Gregory......            9,000 Mr. Doyle.........           68,875
Mr. O'Neil.......            9,000


 (4) The number of shares shown for each executive officer also includes the
     number of shares of Ambac common stock owned indirectly as of February 15,
     2001 by these executive officers in our Savings Incentive Plan ("SIP ").
     Our information on these shares is based on reports from the SIP Trustee.

                                       6


 (5) The number of shares shown for Messrs. Lassiter, Genader, Bivona, Boyle
     and Doyle include vested restricted stock units ("RSUs") that we awarded
     under our equity plans. These RSUs are shown in the following table:



EXECUTIVE OFFICERS NUMBER OF VESTED RSUs
- ------------------ ---------------------
                
Mr. Lassiter......               829,039
Mr. Genader.......               170,455
Mr. Bivona........                93,638
Mr. Boyle.........                     0
Mr. Doyle.........                     0


 (6) This column shows the 4,500 RSUs that were granted to each of Messrs.
     Callen, Dulude, Gregory, and O'Neil at the 1998 Annual Meeting under the
     1997 Non-Employee Directors Equity Plan and accrued dividends and the
     3,000 RSUs that were granted to Mr. Caporali and Ms. Considine at the 2000
     Annual Meeting under the 1997 Non-Employee Directors Equity Plan and
     accrued dividends. These RSUs generally will vest on the date of the
     Annual Meeting held in the fifth calendar year following the date of
     grant. At that time, each of these directors will receive one share of
     Ambac common stock in settlement of each RSU. For more information on
     these RSUs, see below at page 9 under "How We Compensate Directors."

     This column also shows RSUs for Messrs. Lassiter, Genader, Bivona, Boyle
     and Doyle that were awarded as part of each executive officer's 1999 bonus
     and 2000 bonus pursuant to the Ambac Deferred Compensation Sub-Plan of the
     1997 Equity Plan (the "SUB-PLAN") and accrued dividends. See page 25 for
     more detailed descriptions of these awards made pursuant to the Sub-Plan.

 (7) Under Ambac's Deferred Compensation Plan, directors may defer their cash
     compensation. If a director has elected to defer cash compensation into
     Phantom Stock Units ("PSUs"), these PSUs are shown in this column. For
     more information on the Deferred Compensation Plan, see below at page 10.

DID AMBAC INSIDERS COMPLY WITH SECTION 16(a) BENEFICIAL OWNERSHIP REPORTING IN
2000?

    Section 16(a) of the Securities Exchange Act of 1934 requires that our
insiders--our directors, executive officers, and greater-than-10%
stockholders--file reports with the SEC and the New York Stock Exchange on
their initial beneficial ownership of Ambac common stock and any subsequent
changes. They must also provide us with copies of the reports.

    We reviewed copies of all reports furnished to us and obtained written
representations that no other reports were required. Based on this, we believe
that all of our insiders complied with their filing requirements for 2000.

                                       7


                          INFORMATION ABOUT DIRECTORS

THE BOARD OF DIRECTORS

    The Board of Directors oversees the business of Ambac and monitors the
performance of management. In accordance with corporate governance principles,
the Board does not involve itself in day-to-day operations. The directors keep
themselves informed by discussing matters with the Chairman, other key
executives and our principal external advisers (legal counsel, outside
auditors, investment bankers and other consultants) by reading the reports and
other materials that we send them regularly and by participating in Board and
committee meetings.

    Ambac's Board usually meets five times per year in regularly scheduled
meetings, but will meet more often if necessary. The Board met five times
during 2000. All directors attended at least 75% of the Board meetings and
meetings of the Committees of which they were members.

    Each of our directors also serves as a director of our principal operating
subsidiary, Ambac Assurance Corporation, a leading triple-A rated financial
guarantee insurance company.

THE COMMITTEES OF THE BOARD

    The Board has three standing committees: the Audit Committee, the
Compensation and Organization Committee and the Nominating Committee. None of
the directors who serve as members of these committees is, or has ever been, an
employee of Ambac or our subsidiaries.


THE AUDIT               The Audit Committee recommends the selection of the
COMMITTEE               independent auditors to the Board, approves the scope
                        of the annual audit by the independent auditors and our
                        internal auditors, reviews audit findings and
                        accounting policies and oversees compliance with
                        Ambac's Code of Business Conduct. The Committee also
                        meets privately, outside the presence of Ambac
                        management, with both the independent auditors and the
                        internal auditors. Under the rules of the New York
                        Stock Exhange, all of the members of the Audit
                        Committee are independent. The Committee's Report is
                        printed below at page 11.

                        In January 2000, the Audit Committee approved and
                        adopted an Audit Committee Charter, which is attached
                        to this Proxy Statement as Appendix A.

                        The Committee met three times during 2000.

                        Messrs. Callen, Dulude, Gregory and O'Neil and Dr.
                        Caporali and Ms. Considine currently serve as members
                        of the Committee. Mr. O'Neil serves as Chairman of the
                        Committee.


THE COMPENSATION        The Compensation and Organization Committee establishes
AND ORGANIZATION        and approves all elements of compensation for the
COMMITTEE               executive officers. Each year, as the SEC requires, the
                        Committee reports to you on executive compensation. The
                        Committee's Report on Executive Compensation for 2000
                        is printed below, starting at page 22.

                                       8


                        The Committee administers Ambac's 1997 equity plan and
                        has sole authority for awards under the plan. The
                        Committee evaluates existing and proposed employee
                        benefit plans and may approve of plan changes. The
                        Committee also administers the 1997 Executive Incentive
                        Plan and Ambac's Deferred Compensation Plan for Outside
                        Directors and Ambac's Senior Officer Deferred
                        Compensation Sub-Plan of the 1997 Equity Plan.

                        The Committee met three times during 2000.

                        Messrs. Callen, Dulude, Gregory and O'Neil and Dr.
                        Caporali and Ms. Considine currently serve as members
                        of the Committee. Mr. Dulude serves as Chairman of the
                        Committee.


THE NOMINATING          The Nominating Committee is responsible for identifying
COMMITTEE               and recommending qualified candidates to the Board for
                        election as directors. In addition, our By-laws provide
                        a procedure for you to recommend candidates for
                        director at an annual meeting. For more information,
                        see below at page 31 under "Information About
                        Stockholder Proposals."

                        The Committee met once during 2000.

                        Messrs. Callen, Dulude, O'Neil and Gregory currently
                        serve as members of the Committee. Mr. Gregory serves
                        as Chairman of the Committee.

HOW WE COMPENSATE DIRECTORS


ANNUAL                  We compensate directors who are not employees of Ambac
CASH FEE                or our subsidiaries with an annual cash fee of $20,000
                        per year.


ANNUAL STOCK            We also grant each non-employee director 3,750 stock
OPTION AWARD            options on the date of each annual meeting. (The Board
                        adjusted the number of stock options awarded from 2,500
                        to 3,750 to reflect Ambac's three-for-two stock split
                        in December 2000.) These options have an exercise price
                        equal to the average of the high and low trading price
                        of our stock on the New York Stock Exchange on the date
                        of grant. The options generally will vest on the first
                        anniversary of the date of the grant and expire on the
                        date of the annual meeting held in the seventh calendar
                        year following the date of the grant.


AWARD OF                Ambac grants each non-employee director 3,000
RESTRICTED STOCK        restricted stock units ("RSUs") at the annual meeting
UNITS EVERY             at which the director is first elected to the Board.
FIVE YEARS              (The Board adjusted the number of RSUs awarded from
                        2,000 to 3,000 to reflect Ambac's three-for-two stock
                        split in December 2000.)

                        .   These RSUs generally will vest on the date of the
                            annual meeting held in the fifth year following the
                            date of grant and will be settled by the delivery
                            of one share of Ambac common stock for each RSU.

                                       9


                        .   If the director remains on the Board after the
                            first award of RSUs vests, Ambac will grant the
                            director a second award of 3,000 RSUs, subject to
                            similar vesting conditions and restrictions on
                            transfer.


MEETING FEES            We also pay each non-employee director a meeting fee
                        of:

                        .   $1,000 for attendance at each meeting of
                            stockholders and each Board meeting; and

                        .   $1,000 for attendance at each committee meeting.


FEE FOR CHAIRING        We pay an annual fee of $1,500 to each non-employee
A COMMITTEE               director who chairs a committee.



EXPENSES AND            Ambac reimburses all directors for travel and other
BENEFITS                related expenses incurred in attending stockholder,
                        Board and committee meetings.

                        We provide non-employee directors with life and health
                        insurance benefits. We also allow them to participate
                        in our Matching Gift Program up to $20,000. Under this
                        Program, Ambac will match gifts by directors to
                        qualified organizations.


THE DEFERRED            Under our Deferred Compensation Plan for Outside
COMPENSATION            Directors, non-employee directors may elect to defer
PLAN                    all or part of their director compensation that is paid
                        in cash.

                        .   At the director's election, we credit deferrals to
                            a bookkeeping account that we maintain on the
                            director's behalf either as a cash credit (which we
                            credit with interest quarterly), or as phantom
                            stock units ("PSU") based on the market value of
                            Ambac common stock (on which we pay quarterly
                            dividend equivalents in additional PSUs) or as
                            performance units measured by the performance of
                            those mutual funds the director selects out of a
                            limited group of funds.

                        .   We do not fund the Deferred Compensation Plan. We
                            settle accounts only in cash.


SERVICE ON THE          Although Ambac Assurance does not pay its non-employee
AMBAC ASSURANCE         directors an annual fee for serving on its Board of
BOARD                   Directors, it does pay them meeting fees (in the same
                        amounts as we do for the Ambac Board) and reimburses
                        all directors for expenses.


DIRECTORS WHO           We do not compensate our employees or employees of our
ARE AMBAC               subsidiaries for service as a director. We do, however,
EMPLOYEES               reimburse them for travel and other related expenses.

                                      10


                          THE AUDIT COMMITTEE REPORT

    The Audit Committee of Ambac is responsible for providing independent,
objective oversight of Ambac's accounting functions and internal controls. The
Audit Committee recommends the selection of the independent auditors to the
Board. The Audit Committee is currently composed of six independent directors,
each of whom is independent as defined under the rules of the New York Stock
Exchange. The Audit Committee operates under a written charter adopted by the
Board of Directors, attached to this Proxy Statement as Appendix A.

    Management is responsible for Ambac's internal controls and financial
reporting process. The independent accountants are responsible for performing
an independent audit of Ambac's consolidated financial statements in accordance
with auditing standards generally accepted in the United States of America and
to issue a report thereon. The Audit Committee's responsibility is to monitor
and oversee these processes. However, none of the members of the Committee is
professionally engaged in the practice of accounting or auditing nor are all of
our members experts in those fields. The Committee relies without independent
verification on the information provided to it and on the representations made
by management and the independent auditors.

    In connection with these responsibilities, we met with management and KPMG
LLP to review and discuss the December 31, 2000 financial statements. We also
discussed with the independent accountants the matters required by Statement on
Auditing Standards No. 61 (Communication with Audit Committees). The
Corporation's independent accountants also provided us the written disclosures
required by Independence Standards Board Standard No. 1 (Independence
Discussions with Audit Committees), and we discussed with KPMG its
independence.

    Based upon the review and discussions referred to above, we recommended to
the Board of Directors, and the Board of Directors has approved, that Ambac's
audited financial statements be included in Ambac's Annual Report on SEC Form
10-K for the fiscal year December 31, 2000. We also recommended the selection
of KPMG LLP as Ambac's independent auditors for 2001 and, based on that
recommendation, the Board has selected KPMG LLP as Ambac's independent auditors
for 2001.

PRINCIPAL ACCOUNTING FIRM FEES

    Fees paid to KPMG for the fiscal year ended December 31, 2000 were: Audit:
$789,500; Financial Information Systems Design and Implementation Fees: $0 and
All Other Fees: $682,193. Of the $682,193 All Other Fees, $148,200 were fees
paid to KPMG for consents provided by KPMG in connection with the registration
of securities of our clients which were guaranteed by Ambac Assurance. These
fees were reimbursed to Ambac by the clients.

                                          THE AUDIT COMMITTEE

                                          C. Roderick O'Neil, Chairman
                                          Michael A. Callen
                                          Renso L. Caporali
                                          Jill M. Considine
March 22, 2001                            Richard Dulude
                                          W. Grant Gregory


                                      11


                   INFORMATION ABOUT THE EXECUTIVE OFFICERS

THE EXECUTIVE OFFICERS

    These are the biographies of Ambac's current executive officers, except for
Mr. Lassiter, the Chief Executive Officer, and Mr. Genader, the President and
Chief Operating Officer, whose biographies are included below at pages 28 and
29 under "Proposal 1: Elect Seven Directors."


FRANK J. BIVONA         VICE CHAIRMAN AND CHIEF FINANCIAL OFFICER--FINANCE AND
Age 45                  INVESTMENT GROUP.

                        In January 2001, Mr. Bivona was promoted to Vice
                        Chairman and Chief Financial Officer--Finance and
                        Investment Group of Ambac and Ambac Assurance. In
                        February 2000, he was named as Head of the Finance and
                        Investment Group, in addition to his position as
                        Ambac's Chief Financial Officer. Mr. Bivona also has
                        executive responsibility for managing Ambac's
                        investment portfolio, asset and liability management
                        services, corporate marketing, investor and public
                        relations and corporate administration. Mr. Bivona
                        served as Executive Vice President and Chief Financial
                        Officer of Ambac and Ambac Assurance from January 1998
                        to January 2001. Mr. Bivona served as Senior Vice
                        President and Chief Financial Officer of Ambac from
                        1993 to January 1998 and Ambac Assurance from 1987 to
                        January 1998. Mr. Bivona also served as Treasurer of
                        Ambac from 1993 to July 1998 and Ambac Assurance from
                        1987 to July 1998. Mr. Bivona also serves as a trustee
                        of Cadre Institutional Investors Trust. Mr. Bivona
                        joined Ambac Assurance from Citibank in 1986.


DAVID L. BOYLE          VICE CHAIRMAN--PORTFOLIO RISK MANAGEMENT GROUP.
Age 54                  In February 2000, Mr. Boyle was named Vice Chairman of
                        Ambac's Portfolio Risk Management Group. The Portfolio
                        Risk Management Group oversees our specialized finance
                        and public finance portfolios, market risk management,
                        reinsurance, technology and internal audit. Mr. Boyle
                        previously served as Vice Chairman of the Municipal
                        Financial Services Group from January 1998 to February
                        2000. Mr. Boyle joined Ambac and Ambac Assurance in
                        March 1997 as Senior Vice President of the Financial
                        Management Services Division. He became an Executive
                        Vice President in July 1997. Mr. Boyle joined Ambac
                        from Citibank, where, as a managing director, he held
                        various management positions in corporate banking over
                        a 22-year career.

GREGG L. BIENSTOCK      MANAGING DIRECTOR, HUMAN RESOURCES AND EMPLOYMENT
Age 36                  COUNSEL.
                        Mr. Bienstock has been Managing Director, Human
                        Resources and Employment Counsel since January 1999.
                        Mr. Bienstock served as First Vice President, Director
                        of Human Resources and Employment Counsel of Ambac and
                        Ambac Assurance from February 1997 to January 1999. Mr.
                        Bienstock joined Ambac from the Bristol Myers-Squibb
                        Corporation, where he served as a Director of Human
                        Resources from February 1996 to February 1997. From
                        September 1993 to February 1996, Mr. Bienstock was an
                        associate with the New York law firm of Proskauer Rose
                        LLP. Prior to joining Proskauer, from April 1992 to
                        September 1993, Mr. Bienstock was an Assistant General
                        Counsel for the Mayor's Office of Labor Relations for
                        the City of New York.


                                      12



KEVIN J. DOYLE   e      MANAGING DIRECTOR AND GENERAL COUNSEL.
Age 44                  Mr. Doyle was named Managing Director and General
                        Counsel of Ambac and Ambac Assurance in January 2000.
                        Mr. Doyle is Ambac's chief legal officer. From January
                        1996 to January 2000, Mr. Doyle served as the Managing
                        Director and General Counsel of the Specialized Finance
                        Division of Ambac Assurance. Mr. Doyle served as First
                        Vice President and General Counsel of the Specialized
                        Finance Division of Ambac Assurance from July 1995 to
                        January 1996. Mr. Doyle joined Ambac Assurance as a
                        Vice President and Assistant General Counsel from the
                        New York law firm LeBoeuf, Lamb, Greene & MacRae in
                        1991.

                                      13


HOW WE COMPENSATE EXECUTIVE OFFICERS

    The tables on pages 14 through 16 show salaries, bonuses and other
compensation paid during the last three years, options granted in 2000, options
exercised in 2000 and option values as of year-end 2000 for the Chief Executive
Officer and our next four most highly compensated executive officers. We have
adjusted all share and option amounts to reflect Ambac's three-for-two stock
split.

                          SUMMARY COMPENSATION TABLE



                                                                    LONG-TERM
                                        ANNUAL COMPENSATION    COMPENSATION AWARDS
                                        ------------------- -------------------------
                                                            RESTRICTED   SECURITIES    ALL OTHER
                                                               STOCK     UNDERLYING   COMPENSATION
   NAME AND PRINCIPAL POSITION     YEAR SALARY($)  BONUS($) UNITS($)(1) OPTIONS($)(2)    ($)(3)
- ---------------------------------------------------------------------------------------------------
                                                                    
PHILLIP B. LASSITER                2000   $620,000 $930,000    $413,335       287,232      $78,509
 Chairman and                      1999    560,000  750,000     333,350       250,063       52,340
 Chief Executive Officer           1998    560,000  840,000           0       187,811       50,200

ROBERT J. GENADER                  2000    345,000  600,000     266,658       140,242       31,049
 President and Chief               1999    310,000  487,500     216,650        63,888       28,973
 Operating Officer                 1998    310,000  525,000           0        81,098       27,900

FRANK J. BIVONA                    2000    270,000  318,750     141,687        86,731       24,301
 Vice Chairman and                 1999    245,000  240,000     106,650        47,150       22,615
 Chief Financial Officer--Finance  1998    245,000  260,000           0        42,820       22,050
 and Investment Group

DAVID L. BOYLE                     2000    330,000  318,750     141,687        90,000       29,699
 Vice Chairman--Portfolio          1999    300,000  281,250     125,030        20,000       28,040
 Risk Management Group             1998    300,000  300,000           0       100,000       18,300

KEVIN J. DOYLE                     2000    174,000  232,500     103,346        21,750       15,660
 Managing Director                 1999    164,000  206,250      91,667        15,000       15,327
 and General Counsel               1998    164,000  210,000           0        15,000       14,520



- --------------------------------------------------------------------------------
 (1) Pursuant to the Ambac Deferred Compensation Sub-Plan of the 1997 Equity
     Plan (the "SUB-PLAN"), the Compensation and Organization Committee paid
     25% of each executive officer's bonus for 1999 and 2000 in restricted
     stock units ("RSUS"). Amounts shown in this column are based on the market
     value of the underlying Common Stock on the date of grant and do not
     reflect the discount attributed to such value by the Committee to take
     account of vesting requirements, restrictions on transfer and other
     limitations. See page 25 for more detailed descriptions of these awards
     made pursuant to the Sub-Plan. As dividends are paid on the common stock,
     dividend equivalents are accrued on the RSUs as additional RSUs and vest
     according to the same schedule.

     The total number of RSUs held by the named executive officers as of
     December 31, 2000, and the total value of these RSUs (based on the $58.31
     per share closing price of Ambac common stock on the New York Stock
     Exchange on Friday, December 31, 2000), were as follows: Mr.
     Lassiter--767,719 RSUs ($44,765,695); Mr. Genader--175,565 RSUs
     ($10,237,195); Mr. Bivona--96,112 RSUs ($5,604,291); Mr. Boyle--4,062 RSUs
     ($236,855); and Mr. Doyle--2,980 RSUs ($173,764).

 (2) The number of securities underlying options for 1998, 1999 and 2000
     includes restoration options awarded upon the exercise of stock options in
     accordance with Ambac's Restoration Option Program. For the specific
     breakdown of option and restoration option grants made in 2000, please
     refer below to the table on page 15 under "Option Grants in 2000." For a
     more detailed description of our Restoration Option Program, please see
     footnote 3 under the "Option Grants in 2000" table on page 15.

                                      14



(3)  The column called "ALL OTHER COMPENSATION" includes the amounts that Ambac
     contributed or credited on behalf of the named officers in 2000 to (a) our
     Savings Incentive Plan (the "SIP"), and (b) our Non-Qualified SIP. We
     credit amounts that we are precluded from contributing to the SIP because
     of limitations under the Internal Revenue Code to accounts that we maintain
     under Ambac's Non-Qualified SIP.

                                                            CREDITS TO THE
                                          CONTRIBUTIONS     NON-QUALIFIED
                                            TO THE SIP           SIP
                                          -------------    --------------
Mr. Lassiter.........................        $15,000           $40,802
Mr. Genader..........................         13,700            17,349
Mr. Bivona...........................         14,700             9,601
Mr. Boyle............................         14,403            15,296
Mr. Doyle............................         13,700             1,960


                             OPTION GRANTS IN 2000



                                                INDIVIDUAL GRANTS
                    --------------------------------------------------------------------------
                    NUMBER OF SECURITIES UNDERLYING PERCENT OF TOTAL
                          OPTIONS GRANTED (#)       OPTIONS GRANTED                             GRANT DATE
                                      RESTORATION   TO EMPLOYEES IN  EXERCISE PRICE EXPIRATION PRESENT VALUE
       NAME           OPTIONS(1)      OPTIONS(2)          2000         ($/SH)(3)       DATE       ($)(4)
- ------------------------------------------------------------------------------------------------------------
                                                                             
Phillip B. Lassiter         225,000                           12.53%         $31.02    1/24/07    $2,592,000
                                             62,232            3.46           53.48    1/28/04       891,162
Robert J. Genader           120,000                                           31.02    1/24/07     1,382,400
                                             20,241            6.68           46.56    3/03/03       210,304
                                                               1.13
Frank J. Bivona              75,000                            4.18           31.02    1/24/07       864,000
                                             11,730            0.65           46.56    3/03/03       121,875
David L. Boyle               90,000                            5.01           31.02    1/24/07     1,036,800
Kevin J. Doyle               21,750                            1.21           31.02    1/24/07       250,560

- ------------------------------------------------------------------------------------------------------------


(1) Options awarded to the named executive officers by the Compensation and
    Organization Committee were long-term incentive awards granted on January
    24, 2000. Each executive officer's options will vest in two equal
    installments when the market price of Ambac common stock meets or exceeds
    $43.33 and $56.66 for twenty consecutive trading days or no later than the
    sixth anniversary of the grant date. Vesting is accelerated upon
    retirement, death or permanent disability. Generally, all of the executive
    officers' options will expire seven years from the date of grant or,
    earlier, if employment terminates. We have adjusted all options awarded to
    reflect Ambac's three-for-two stock split in December 2000.


(2) Restoration options were awarded upon the exercise of stock options in
    accordance with Ambac's Restoration Option Program. A restoration option is
    awarded automatically when the underlying option is exercised by tendering
    shares of common stock to pay the exercise price. Each restoration option
    will vest one year from the date of grant and has the same exercise,
    transfer and expiration provisions as its underlying option. We have
    adjusted all options awarded to reflect Ambac's three-for-two stock split
    in December 2000.
(3) The exercise price per share is the fair market value of the common stock
    on the date of grant. We determine this by calculating the average of the
    high and low price of Ambac common stock on the New York Stock Exchange on
    the date of grant. We have adjusted all share prices to reflect Ambac's
    three-for-two stock split in December 2000.

(4) We calculated these values by using the Black-Scholes stock option pricing
    model as follows:

   FOR THE JANUARY OPTION GRANTS. The model, as we applied, uses the grant date
   of January 24, 2000. The fair market value on that date was $31.02 per share
   as we discussed above. The model also assumes: (a) a risk-free rate of
   return of

                                      15


   6.6% (which was the yield on a U.S. Treasury Strip zero coupon bond with a
   maturity that approximates the term of the option), (b) stock price
   volatility of 30.1% (calculated using month-end closing prices of Ambac
   common stock on the New York Stock Exchange for the period beginning with
   January 31, 1997 and ending as of the end of the month preceding the grant
   date); (c) a constant dividend yield of .95% based on the quarterly cash
   dividend rate at the time of grant on Ambac common stock; and (d) an
   exercise date, on average, of 5.5 years after grant.

   FOR THE RESTORATION OPTION GRANTS. We use the following assumptions in
   applying the model for each Restoration Option Grant: (a) a risk-free rate
   of return equal to the yield on grant date of a U.S. Treasury Strip zero
   coupon bond with a maturity that approximates the term of the option; (b)
   stock price volatility of Ambac common stock calculated using month-end
   closing prices of Ambac common stock on the New York Stock Exchange for the
   three year period prior to the grant date; (c) a constant dividend yield
   based on the quarterly cash dividend rate at the time of grant on Ambac
   common stock; and (d) exercise of the restoration option at the end of its
   term.

   WE DID NOT ADJUST THE MODEL FOR NON-TRANSFERABILITY, RISK OF FORFEITURE, OR
   VESTING RESTRICTIONS. THE ACTUAL VALUE (IF ANY) AN EXECUTIVE OFFICER
   RECEIVES FROM A STOCK OPTION WILL DEPEND UPON THE AMOUNT BY WHICH THE MARKET
   PRICE OF AMBAC COMMON STOCK EXCEEDS THE EXERCISE PRICE OF THE OPTION ON THE
   DATE OF EXERCISE. THE HYPOTHETICAL VALUES ARE PRESENTED PURSUANT TO SEC
   RULES AND THERE CAN BE NO ASSURANCE THAT THE AMOUNT STATED AS "GRANT DATE
   PRESENT VALUE" WILL ACTUALLY BE REALIZED.

      AGGREGATED OPTION EXERCISES DURING 2000 AND YEAR-END OPTION VALUES


                                          NUMBER OF SECURITIES
                                                  UNDERLYING UNEXERCISED       VALUE OF UNEXERCISED
                                                      OPTIONS HELD AT      IN-THE-MONEY OPTIONS HELD AT
                    NUMBER OF SHARES                 DECEMBER 31, 2000     DECEMBER 31, 2000 ($)(1)(2)
                      ACQUIRED ON       VALUE    ------------------------- ----------------------------
       NAME             EXERCISE     REALIZED($) EXERCISABLE UNEXERCISABLE  EXERCISABLE  UNEXERCISABLE
- -------------------------------------------------------------------------------------------------------
                                                                       
Phillip B. Lassiter          238,028  $6,224,755     427,596       234,732   $ 9,930,705     $4,659,250
Robert J. Genader            123,146   3,494,240     487,500       110,241    16,975,472      2,519,425
Frank J. Bivona               81,725   2,438,854     329,229        69,230    11,654,404      1,590,671
David L. Boyle                     0           0     222,500        92,500     6,460,428      2,490,338
Kevin J. Doyle                     0           0      68,875        15,875     2,274,100        404,152

- -------------------------------------------------------------------------------------------------------


(1) We have adjusted all shares to reflect Ambac's three-for-two stock split in
    December 2000.

(2) This valuation represents the difference between $58.31, the closing price
    of Ambac common stock on the New York Stock Exchange on Friday, December
    31, 2000, and the exercise price of the stock options. "In-the-money" stock
    options are options for which the exercise price is less than the market
    price of the underlying stock on a particular date.

THE PENSION PLAN

    Ambac's Pension Plan is a defined benefit pension plan intended to be
tax-qualified under Section 401(a) of the Internal Revenue Code.

   .   In general, officers and employees of Ambac and its subsidiaries become
       participants in the Pension Plan after one year of service. All
       executive officers participate in the Pension Plan. Non-employee
       directors of Ambac and our subsidiaries are not eligible to participate
       in the Pension Plan.

                                      16


   .   Benefits under the Pension Plan vest after five years. Upon normal
       retirement at age 65, a retired employee receives an annual pension from
       the Pension Plan, subject to a statutory limit. The Pension Plan also
       contains provisions for early retirement and survivor benefits.

    The table below illustrates the annual pension benefits payable to
executive officers under the Pension Plan. The table also reflects the excess
and supplemental benefit plans that we have established to provide retirement
benefits over Internal Revenue Code limitations. We calculated the benefits
before offsetting (a) an employee's primary Social Security benefit and (b)
benefits payable under the retirement plan of Citibank, N.A., Ambac's former
parent company (the "CITIBANK PLAN"). Benefits shown in the table reflect a
straight life form of annuity benefit. If payment is made in the form of a
joint and survivor annuity, the annual amounts of benefit could be
substantially below those illustrated.




                                          TOTAL YEARS OF SERVICE AT RETIREMENT
                               ------------------------------------------------------------
   AVERAGE        YEARS OF
   COVERED       SERVICE AT
 COMPENSATION  TRANSITION DATE      10       15       20        25         30         35
                                                           
- -------------------------------------------------------------------------------------------
    $150,000       30                NA       NA       NA         NA $   90,000 $   97,500
                   15                NA $ 45,000 $ 52,500 $   60,000     67,500     75,000
                    0          $ 15,000   22,500   30,000     37,500     45,000     52,500
- -------------------------------------------------------------------------------------------
     200,000       30                NA       NA       NA         NA    120,000    130,000
                   15                NA   60,000   70,000     80,000     90,000    100,000
                    0            20,000   30,000   40,000     50,000     60,000     70,000
- -------------------------------------------------------------------------------------------
     500,000       30                NA       NA       NA         NA    300,000    325,000
                   15                NA  150,000  175,000    200,000    225,000    250,000
                    0            50,000   75,000  100,000    125,000    150,000    175,000
- -------------------------------------------------------------------------------------------
   1,000,000       30                NA       NA       NA         NA    600,000    650,000
                   15                NA  300,000  350,000    400,000    450,000    500,000
                    0           100,000  150,000  200,000    250,000    300,000    350,000
- -------------------------------------------------------------------------------------------
   1,500,000       30                NA       NA       NA         NA    900,000    975,000
                   15                NA  450,000  525,000    600,000    675,000    750,000
                    0           150,000  225,000  300,000    375,000    450,000    525,000
- -------------------------------------------------------------------------------------------
   2,000,000       30                NA       NA       NA         NA  1,200,000  1,300,000
                   15                NA  600,000  700,000    800,000    900,000  1,000,000
                    0           200,000  300,000  400,000    500,000    600,000    700,000
- -------------------------------------------------------------------------------------------
   2,500,000       30                NA       NA       NA         NA  1,500,000  1,625,000
                   15                NA  750,000  875,000  1,000,000  1,125,000  1,250,000
                    0           250,000  375,000  500,000    625,000    600,000    875,000



SERVICE FROM 1992       For service on or after January 1, 1992, the annual
                        retirement benefit is equal to 1% (without an offset
                        for any Social Security benefits) of an employee's
                        Average Compensation (as described in the next
                        sentence) multiplied by the employee's years of
                        credited service. "Average Compensation" is defined,
                        generally, as average annual base salary (which, in the
                        case of executive officers identified in the Summary
                        Compensation Table on page 14, is the amount shown
                        under the column called "SALARY") for the five highest
                        consecutive paid years of the ten years of employment
                        preceding retirement.

                                      17



SERVICE BEFORE          For service prior to January 1, 1992, the annual
1992                    retirement benefit is equal to 2% (with an offset for
                        Social Security benefits) of an employee's Average
                        Compensation (determined as if the employee retired on
                        December 31, 1991) multiplied by years of credited
                        service up to thirty years.

YEARS OF SERVICE        In view of the change in the formula for determining
                        benefits under the Pension Plan that became effective
                        as of January 1, 1992 (the "TRANSITION DATE"), we
                        prepared the above table to show the benefits payable
                        depending on how many years of service the executive
                        officer would have:


                        .   prior to the Transition Date, and

                        .   at Retirement.

                        In order to simplify the chart, we show only 0, 15 and
                        30 years of service at Transition, since those values
                        cover the range for our executive officers.

                        The years of credited service under the Pension Plan
                        (including credit for years of past service under the
                        Citibank Plan) as of December 31, 2000 for executive
                        officers named in the Summary Compensation Table were
                        as follows: Mr. Lassiter--31 years, Mr. Genader--26
                        years, Mr. Bivona--23 years, Mr. Boyle--4 years, and
                        Mr. Doyle--9 years.

                        The benefits payable under the Pension Plan to
                        employees who receive credit for years of past service
                        under the Citibank Plan will be reduced by the amount
                        of any benefits payable under the Citibank Plan.

EMPLOYMENT AGREEMENT WITH THE CHIEF EXECUTIVE OFFICER


IN GENERAL              Ambac's employment agreement with Mr. Lassiter provides
                        that he shall serve as the Chairman and Chief Executive
                        Officer and as a director.


                        .   The agreement has a two year term, which is
                            extended on a daily basis, until Ambac or Mr.
                            Lassiter terminates it.

                        .   Mr. Lassiter is to receive a base salary at a rate
                            not less than his current rate.

                        .   He is to participate in bonus arrangements under
                            which he is eligible to earn an annual bonus based
                            on Ambac's achieving certain performance goals to
                            be established by the Board.


SUPPLEMENTAL            Mr. Lassiter has a supplemental pension benefit that
PENSION BENEFIT         will be based on the benefit formula of the Pension
                        Plan that was in effect until the end of 1991. The
                        formula, however, will take into account his bonus
                        compensation (including that portion of his bonus paid
                        in RSUs) and will be determined without giving effect
                        to provisions of the Internal Revenue Code that limit


                                      18


                        the amount of compensation that may be taken into
                        account in calculating benefits and the amount of
                        annual benefits that may be paid. Mr. Lassiter's
                        supplemental pension benefit will be reduced, however,
                        to take account of enhancements in Ambac's
                        contributions to the Savings Incentive Plan ("SIP")
                        that we introduced in 1992.


PAYMENTS AND            If Mr. Lassiter's employment is terminated other than
BENEFITS                for "Cause" (as we define it below), or if he resigns
                        for "Good Reason" (as we define it below), Mr. Lassiter
                        will:

- -- AFTER TERMINATION    .   receive, for the remainder of the term (which
   OR RESIGNATION           typically would be for two years), compensation
                            at an annualized rate equal to the sum of his base
                            annual salary and target bonus at the time of
                            termination;

                        .   be fully vested in all awards under the 1991 Stock
                            Incentive Plan and the 1997 Equity Plan;

                        .   receive a lump-sum payment equal to the amount that
                            we would have contributed to his account under the
                            SIP and any nonqualified plan we maintained during
                            the two years following termination;

                        .   be credited with an additional two years of service
                            under the Pension Plan; and

                        .   continue to participate in all Ambac medical and
                            other welfare plans for a limited time following
                            termination.


- -- AFTER CHANGE IN      All stock options and other awards under the 1997
   CONTROL              Equity Plan that are made to Mr. Lassiter after
                        January 1, 1998 will vest in full upon the occurrence of
                        a "Change in Control" (as we define it below), whether
                        or not his employment is subsequently terminated.

                        In addition, if Mr. Lassiter's employment terminates
                        following a Change in Control, his severance amount
                        would be calculated and paid in the same manner as we
                        describe below under "Management Retention Agreements
                        with Executive Officers."

                        Mr. Lassiter would also be entitled to the "gross up"
                        payment described in that section.


OTHER RESTRICTIONS      Mr. Lassiter will be subject to certain restrictions
                        prohibiting him from engaging in competition with Ambac
                        or any of our subsidiaries (except that these
                        restrictions will not apply following a Change in
                        Control) and from divulging any confidential or
                        proprietary information he obtained while he was our
                        employee.


                                      19


MANAGEMENT RETENTION AGREEMENTS WITH EXECUTIVE OFFICERS


IN GENERAL              We have entered into management retention agreements
                        with each of our executive officers (other than Mr.
                        Lassiter) to provide for payments and certain benefits
                        if they are terminated following a "Change in Control"
                        (as we define it below).

PAYMENTS AND            If there is a Change in Control and, within three years
BENEFITS AFTER          of the Change in Control, the executive's employment is
CHANGE IN CONTROL       terminated by Ambac or its successor other than for
                        "Cause" (as we define it below), or if the executive
                        resigns for "Good Reason" (as we define it below), the
                        executive will


                        .   receive cash payments equal to two times the sum of
                            (a) the executive's highest annual base salary and
                            (b) the product of the executive's highest bonus
                            percentage (as a percentage of base salary) times
                            his highest base salary;

                        .   be fully vested in all stock options and other
                            awards under the 1991 Stock Incentive Plan and the
                            1997 Equity Plan;

                        .   receive a lump-sum payment equal to the amount that
                            we would have contributed to the executive's
                            account under the SIP and any nonqualified plan we
                            maintained during the two years following
                            termination;

                        .   be credited with an additional two years of service
                            under the Pension Plan; and

                        .   continue to participate in Ambac's medical and
                            other welfare benefits programs for a limited time
                            following termination.

                        All stock options and other awards under the 1997
                        Equity Plan that are made to executive officers after
                        January 1, 1998 will vest in full upon the occurrence
                        of a Change in Control, whether or not the executive's
                        employment is subsequently terminated.

                        The agreements also provide for a "gross up" payment in
                        an amount that is intended to make the executive whole,
                        on an after-tax basis, for any excise tax (but not any
                        other tax) imposed on the payments described above.

DEFINITIONS

    The following definitions are used in the Management Retention Agreements
and the Employment Agreement with the Chief Executive Officer described above:


"CHANGE IN              A "Change in Control" generally occurs if
CONTROL"
                        .   an individual, entity or group acquires beneficial
                            ownership of 20% or more of the outstanding common
                            stock. Acquisitions by Ambac and


                                      20


                            its affiliates or any employee benefit plan that
                            they sponsor and certain acquisitions by persons
                            who owned at least 15% of the outstanding shares of
                            common stock on January 31, 1996 are not considered
                            a change in control;

                        .   the individuals who, as of January 29, 1997,
                            constitute the Board, and subsequently elected
                            members of the Board whose election is approved or
                            recommended by at least a majority of these members
                            or their successors whose election was so approved
                            or recommended, cease for any reason to constitute
                            at least a majority of the Board; or

                        .   our stockholders approve a merger or similar
                            business combination, or a sale of all or
                            substantially all of Ambac's assets, unless the
                            Ambac stockholders immediately prior to the
                            completion of the transaction will continue to own
                            at least 70% of outstanding shares and voting power
                            of the corporation that results from the
                            transaction.


"CAUSE"                 "Cause" for an executive's termination generally
                        includes:


                        .   the willful commission of acts that are dishonest
                            and demonstrably and materially injurious to Ambac;

                        .   the conviction of certain felonies; or

                        .   a material breach of any of the executive's
                            agreements concerning confidentiality and
                            proprietary information.

                        An executive's termination will not be considered to
                        have been for Cause unless at least three-quarters of
                        the members of the Board adopt a resolution finding
                        that the executive has engaged in conduct that
                        constitutes Cause as defined in the agreement.


"GOOD REASON"           An executive will generally have "Good Reason" to
                        terminate his employment if:


                        .   there is substantial adverse change in the
                            executive's duties or responsibilities;

                        .   the office of the executive is relocated more than
                            25 miles from the location where the executive
                            worked immediately prior to the Change in Control;
                            or

                        .   Ambac fails to honor its obligations under the
                            agreement.

                        During a 30-day period following the first anniversary
                        of a Change in Control, a resignation by the executive
                        for any reason will be considered a termination for
                        Good Reason.

                                      21


                   REPORT ON EXECUTIVE COMPENSATION FOR 2000
                BY THE COMPENSATION AND ORGANIZATION COMMITTEE

    The Compensation and Organization Committee of the Board administers
Ambac's executive compensation program. The members of the Committee are
independent non-employee, non-affiliated directors. The Committee has furnished
the following report on executive compensation for 2000:

WHAT IS OUR EXECUTIVE COMPENSATION PHILOSOPHY?

    The Committee has designed Ambac's executive compensation program to
support what we believe to be an appropriate relationship between executive pay
and the creation of stockholder value. To emphasize this relationship, we link
a significant portion of executive compensation to the market performance of
Ambac common stock. The objectives of our program are:

   .   To support a pay-for-performance policy that differentiates bonus
       amounts among all executives based on both their individual performance
       and the performance of Ambac;

   .   To align the interests of executives with the long-term interests of
       stockholders through stock option and restricted stock unit awards whose
       value over time depends upon the market value of Ambac's common stock;

   .   To provide compensation comparable to that offered by other leading
       companies in our industry, enabling Ambac to compete for and retain
       talented executives who are critical to our long-term success; and

   .   To motivate key executives to achieve strategic business initiatives and
       to reward them for their achievement.

WHAT IS OUR POSITION ON MAXIMIZING THE DEDUCTIBILITY OF EXECUTIVE COMPENSATION?

    In 1997, our stockholders approved the 1997 Executive Incentive Plan
("EIP") and the 1997 Equity Plan. We designed these plans to allow Ambac to
receive a tax deduction for incentive compensation payments to our Chief
Executive Officer and our other four most highly paid executive officers.
Without these qualifying performance-based plans, Ambac could not deduct
incentive compensation payments to the extent the amounts paid to any of these
executive officers in any year exceeded $1 million.

    The Committee intends to pursue a strategy of maximizing the deductibility
of the compensation we pay to our executives. However, we intend to retain the
flexibility to take actions that we consider to be in the best interests of
Ambac and our stockholders and which may be based on considerations in addition
to tax deductibility.

                                      22


WHAT ARE THE ELEMENTS OF EXECUTIVE COMPENSATION?

    We compensate our executives through base salary, bonus (paid in a
combination of cash and restricted stock units) and long-term incentive awards
in the form of stock options. We target total compensation for our executive
officers so that at least 60% (and in the case of the Chairman, 75%) consists
of bonus and long term incentive awards. In this way, a significant portion of
the value ultimately realized by the executives will depend upon Ambac's
performance and can be considered "at risk."

    Our executives participate in a retirement plan, health plan, savings
incentive plan and other voluntary benefit plans that we make available to all
Ambac employees generally. We also provide our executives, and all Ambac
employees who are eligible, with nonqualified savings incentive and pension
plans. We also provide our executives with a voluntary deferred compensation
arrangement, which is similar to those typically offered to executives by the
corporations with which we compete for talent.

    Ambac has also entered into management retention agreements with our
executive officers to provide for certain payments and other benefits if they
are terminated following a change in control of Ambac. These agreements, and
the employment agreement with Ambac's Chief Executive Officer, which includes
comparable change in control provisions, are discussed elsewhere in the Proxy
Statement.

HOW DID WE DETERMINE BASE SALARIES FOR 2000?

IN GENERAL              We annually review the base salaries of our executives
                        to determine if adjustments are appropriate to ensure
                        that their salaries are competitive and that they
                        reflect the executive's increased responsibilities as
                        Ambac grows.

                        For executives other than the Chief Executive Officer,
                        we also consider the recommendations of Mr. Lassiter,
                        Ambac's Chairman and Chief Executive Officer.

COMPARATIVE DATA        In conducting our review for 2000, we considered
                        comparative data prepared by both Ambac's senior human
                        resources officer and by Johnson Associates, Inc., the
                        Committee's outside consultant for executive
                        compensation.

                        The comparison group we chose for compensation purposes
                        (the "COMPARISON GROUP") consisted mainly of our
                        competitors in the financial guarantee insurance
                        industry. The index we chose for our performance graph
                        was the Investor's Business Daily Insurance
                        Property/Casualty/Title Index. This was the publicly
                        available index that we found best corresponded to our
                        business and included the greatest number of companies
                        in the Comparison Group. The performance graph follows
                        this Report in the Proxy Statement.

                        We obtained data for the Comparison Group from a number
                        of sources, including proxy statements, public
                        information available from regulatory agencies and
                        surveys by consulting firms. We used this comparative
                        data as a benchmark in reaching our own determination
                        of what were appropriate salary levels for our
                        executives.


                                      23



BASE SALARIES OF        The data for the Comparison Group supported an
THE EXECUTIVES          increase in base salaries for 2000 and the
                        Committee accepted Mr. Lassiter's recommendation to
                        increase base salaries for all of the named
                        executives. We note that the base salaries of our
                        executives (excluding the Chief Executive Officer)
                        are generally at or below the median for salaries
                        of executives in the Comparison Group. The base
                        salary for each of the named executive officers is
                        reported in the "Summary Compensation Table"
                        elsewhere in the Proxy Statement.

BASE SALARY OF THE      The Committee increased the base salary of Mr.
CHIEF EXECUTIVE         Lassiter for 2000 by approximately 10% from
OFFICER                 $560,000 to $620,000. We note that Mr. Lassiter's
                        base salary in 2000 was in the median for salaries
                        of chief executive officers in the Comparison
                        Group.

HOW DID WE DETERMINE BONUSES FOR 2000?


2000 OVERALL            In January 2001, the Committee evaluated Ambac's
PERFORMANCE             performance during 2000 under each of the nine
                        categories set out in the EIP: return on equity;
                        core/operating earnings growth; total return to
                        stockholders; expense management; risk management;
                        market share; industry leadership/image building;
                        new products/initiatives; and organizational
                        development/corporate culture. We did not weight
                        the categories but instead arrived at an overall
                        "grade" for corporate performance. We determined
                        Ambac's overall performance to be extremely strong
                        based especially on its excellent performance in
                        the categories of return on equity, core/operating
                        earnings growth, total return to shareholders;
                        expense management, market share and organizational
                        development/corporate culture.

BONUSES FOR THE         The Committee awarded bonus compensation for 2000
EXECUTIVES              to each executive based on the executive's scope of
                        responsibility, individual performance and specific
                        contribution to Ambac's overall performance. We
                        again considered the Chief Executive Officer's
                        recommendations and also took into account the
                        comparative data. The bonus for each of the named
                        executive officers is reported in the "Summary
                        Compensation Table" elsewhere in the Proxy
                        Statement.

                        Under the Ambac Senior Officer Deferred Compensation
                        Sub-Plan of the 1997 Equity Plan, 25% of each executive
                        officer's bonus is paid in RSUs unless the executive
                        officer has satisfied the stock ownership target under
                        the Ambac Stock Ownership Program. An executive who has
                        met the ownership target may elect to receive 25% of
                        his or her bonus in the form of RSUs. Each executive
                        officer is receiving 25% of his bonus in the form of
                        RSUs. Bonus amounts are reported in the Summary
                        Compensation Table elsewhere in this Proxy Statement.



                                      24


                        The value we ascribed to the RSUs awarded under the
                        Sub-Plan for 2000 was based on a 25% discount from the
                        market value of Ambac's common stock on the date of
                        grant. The Committee decided to discount these RSUs in
                        order to account for vesting requirements and
                        restrictions on transfer of the RSUs. Accordingly, the
                        value we ascribed to the RSUs differs from the amounts
                        reported in the Summary Compensation Table under the
                        column headed "Annual Compensation--Restricted Stock
                        Units", as those amounts, in accordance with SEC
                        requirements, are based on the market price of the
                        Common Stock on the date of grant.


BONUS FOR THE           At our meeting in January 2000, the Committee
CHIEF EXECUTIVE         selected Mr. Lassiter as the only executive to
OFFICER                 participate in the EIP. We then established a
                        formula under the EIP for determining Mr.
                        Lassiter's bonus for the performance year. The
                        formula emphasized return on equity and core
                        earnings growth.


                        In January 2001, we applied the formula and awarded Mr.
                        Lassiter a bonus of $1,240,000. Although we had the
                        authority to award a bonus of less than the amount
                        determined by the formula, in view of Ambac's very
                        strong performance in 2000 under Mr. Lassiter's
                        leadership, we decided to award Mr. Lassiter the
                        maximum amount under the formula. Pursuant to the
                        Sub-Plan, Mr. Lassiter elected to receive 25% of his
                        bonus in the form of RSUs having the terms described
                        above.

                        For 2001, we selected Messrs. Lassiter and Genader as
                        the only executive officers to participate in the EIP.

WHAT WERE THE LONG-TERM INCENTIVE AWARDS IN 2000?

2000 GRANTS             In 2000, we provided long-term incentive awards for
                        executives by granting stock options. These awards
                        provide compensation to executives only if
                        shareholder value increases. We believe these
                        awards focus executives on the Company's long-term
                        success. In determining the number of stock options
                        awarded, we reviewed surveys of similar awards
                        given by companies within the Comparison Group and
                        the executive's past performance. We also
                        considered the number of stock options previously
                        granted to executives.

                        This year, we decided to award, for the first time,
                        performance-based stock options. These options vest
                        only if the share price of Ambac's common stock meets
                        certain targets. For 2000, each of the options granted
                        to the executives will vest in two equal installments
                        when the market price of Ambac common stock meets or
                        exceeds $43.33 and



                                      25


                        $56.66 for twenty consecutive trading days or no later
                        than the sixth anniversary of the grant date. (Please
                        note that we have adjusted the share price to reflect
                        Ambac's three-for-two stock split in December 2000.) As
                        we have done since 1997, we again limited the term of
                        the stock options to seven years. The number of stock
                        options awarded to each of the executives (including
                        Mr. Lassiter) was in the top quarter of recent awards
                        given by companies within the Comparison Group. The
                        number of stock options awarded to each of the named
                        executive officers is reported in the "Option Grants in
                        2000" table elsewhere in the Proxy Statement.


STOCK OWNERSHIP         The Committee continues to apply our stock ownership
GUIDELINES              guidelines to all managing directors and executive
                        officers. The guidelines set an appropriate level of
                        ownership of Ambac stock (based on the market value of
                        Ambac common stock) as a multiple of the officer's
                        total cash compensation (base salary plus cash bonus).
                        The multiple ranges from a high of seven times total
                        cash compensation (in the case of Mr. Lassiter) to a
                        low of one and one-half times total cash compensation
                        for managing directors. Messrs. Lassiter, Genader and
                        Bivona have all met their stock ownership guidelines.


                        The Committee believes these guidelines have the
                        positive effect of further aligning the interests of
                        the executives with all stockholders.

                                     THE COMPENSATION AND ORGANIZATION COMMITTEE

                                          Richard Dulude, Chairman
                                          Michael A. Callen
                                          Renso L. Caporali
                                          Jill M. Considine
                                          W. Grant Gregory
                                          C. Roderick O'Neil

March 22, 2001



                                      26


                               PERFORMANCE GRAPH

    The graph below compares the five-year total return to stockholders (stock
price appreciation plus reinvested dividends) for Ambac common stock with the
comparable return of two indexes: the Standard & Poor's 500 Stock Index and the
Investor's Business Daily Insurance--Property/Casualty/Title Index.

    The graph assumes that you invested $100 in Ambac common stock and in each
of the indexes on December 31, 1995, and that all dividends were reinvested.
Points on the graph represent the performance as of the last business day of
each of the years indicated.


                                     [CHART]


                            12/31/95    12/31/96   12/31/97   12/31/98    12/31/99   12/31/00
                                                                   

Ambac Financial Group, Inc.  $100.0      $143.2     $200.3     $263.9      $230.6     $389.6

S&P 500 Index                 100.0       123.0      164.0      210.9       255.2      232.0

IBD-INS.
Property/Casualty/
Title Index                   100.0       105.0      129.2      103.3        78.5      110.2



    If you had invested $100 in Ambac common stock on the date of our Initial
Public Offering (July 18, 1991), your investment would have grown to
approximately $925.58 by the end of 2000. This compares with a $100 investment
growing to approximately $420.76 in the S&P 500 Index and to approximately
$196.26 in the IBD Insurance Index.

    For this computation, we assumed that all dividends were reinvested, just
as we did for the five-year total return comparison above.

                                      27


               DISCUSSION OF PROPOSALS RECOMMENDED BY THE BOARD

PROPOSAL 1: ELECT SEVEN DIRECTORS

    The Board has nominated seven directors for election at the Annual Meeting.
Each nominee is currently serving as one of our directors. Mr. Genader was
appointed as a director in January 2001. If you re-elect them, they will hold
office until the next annual meeting or until their successors have been
elected.

    As we noted above, each nominee also serves as a director of Ambac
Assurance.

    We know of no reason why any nominee may be unable to serve as a director.
If any nominee is unable to serve, your proxy may vote for another nominee
proposed by the Board, or the Board may reduce the number of directors to be
elected. If any director resigns, dies or is otherwise unable to serve out his
term, or the Board increases the number of directors, the Board may fill the
vacancy until the next annual meeting.

                                   NOMINEES


PHILLIP B.              CHAIRMAN OF THE BOARD AND CHIEF EXECUTIVE OFFICER OF
LASSITER                AMBAC AND AMBAC ASSURANCE since April 1991. Mr.
Age 57                  Lassiter also served as President of Ambac and Ambac
Director since 1991     Assurance from August 1992 to January 2001. Mr.
                        Lassiter joined Ambac in 1991 from Citibank, where he
                        was a member of the Policy Committee and Finance
                        Committee and served as Deputy Sector Head for
                        Citibank's North American investment and corporate
                        banking activities. Mr. Lassiter also serves as a
                        director of Diebold Inc. and Worldinsure Limited.

MICHAEL A. CALLEN       PRESIDENT, AVALON ARGUS ASSOCIATES, LLC (financial
Age 60                  consulting) since April 1996. Mr. Callen was Special
Director since 1991     Advisor to the National Commercial Bank located in
                        Jeddah in the Kingdom of Saudi Arabia from April 1993
                        through April 1996. He was an independent consultant
                        from January 1992 until June 1993, and an Adjunct
                        Professor at Columbia University Business School during
                        1992. He was a director of Citicorp and Citibank and a
                        Sector Executive for Citicorp from 1987 until January
                        1992. Mr. Callen also serves as a director of Intervest
                        Corporation of New York and Intervest Bancshares
                        Corporation.

RENSO L. CAPORALI       RETIRED CHAIRMAN AND CHIEF EXECUTIVE OFFICER OF GRUMMAN
Age 68                  CORPORATION (defense and aerospace). Dr. Caporali was
Director since 1995     Senior Vice President of Raytheon Company (electronics,
                        aircraft, engineering and construction) from April 1995
                        until he retired in May 1998. Previously, Dr. Caporali
                        had retired in June 1994 as Chairman and Chief
                        Executive Officer of Grumman Corporation. He was
                        Chairman and Chief Executive Officer of Grumman
                        Corporation from July 1990 until June 1994. Dr.
                        Caporali also serves as a director of Bank of Akron.


                                      28



JILL M. CONSIDINE       CHAIRMAN AND CHIEF EXECUTIVE OFFICER OF THE DEPOSITORY
Age 56                  TRUST & CLEARING CORPORATION since November 1999 and
Director since 2000     Chairman and Chief Executive Officer of The Depository
                        Trust Company (securities depository and clearing
                        house) since January 1999. Prior to joining The
                        Depository Trust Company, Ms. Considine served as the
                        President of the New York Clearing House Association,
                        L.L.C. from 1993 to 1999. Ms. Considine served as a
                        Managing Director, Chief Administrative Officer and as
                        a member of the Board of Directors of American Express
                        Bank Ltd., from 1991 to 1993. Prior to that, Ms.
                        Considine served as the New York State Superintendent
                        of Banks from 1985 to 1991. Ms. Considine also serves
                        as a director of the Atlantic Mutual Insurance
                        Companies and The Interpublic Group of Companies, Inc.

RICHARD DULUDE          RETIRED VICE CHAIRMAN OF CORNING INCORPORATED
Age 68                  (diversified manufacturing). Mr. Dulude was Vice
Director since 1992     Chairman of Corning Incorporated from November 1990
                        until he retired in April 1993. Mr. Dulude was Group
                        President of Corning Incorporated from 1983 until 1990.
                        Mr. Dulude also serves as a director of Landec
                        Corporation.

ROBERT J. GENADER       PRESIDENT AND CHIEF OPERATING OFFICER OF AMBAC AND
Age 54                  AMBAC. In January 2001, Mr. Genader was named as the
Director since January  President and Chief Operating Officer of Ambac and
2001                    Ambac Assurance. From February 2000 to January 2001,
                        Mr. Genader served as Vice Chairman of Ambac's
                        Financial Insurance Business Group. From January 1998
                        to February 2000, Mr. Genader served as Vice Chairman
                        of the Specialized Finance Division when the
                        Specialized Finance Division and the Public Finance
                        Division were combined to create the Financial
                        Insurance Business Group. Mr. Genader has been a
                        director of Ambac Assurance since 1992. Mr. Genader
                        served as an Executive Vice President of Ambac from
                        1991 to January 1998 and Ambac Assurance from 1986 to
                        January 1998. He joined Ambac Assurance from Citibank
                        in 1986. Mr. Genader also served as Chairman of the
                        Association of Financial Guaranty Insurors from January
                        1994 to January 1996.

W. GRANT GREGORY        CHAIRMAN OF GREGORY & HOENEMEYER, INC. (merchant
Age 60                  banking) since 1988. Mr. Gregory retired in 1987 as
Director since 1991     Chairman of the Board of Touche Ross & Co., now
                        Deloitte and Touche. Mr. Gregory also serves as a
                        director of DoubleClick Inc., an Internet advertising
                        company. In addition, Mr. Gregory serves as a director
                        of three private companies: yClip.com, an e-commerce
                        enabled incentives company; zUniversity.com, an online
                        network for higher education; and Class.com, an
                        Internet leader in accredited distance learning.


The Board recommends that you vote "FOR" the election of all seven nominees for
                                   director.

                                      29


PROPOSAL 2: RATIFY SELECTION OF KPMG LLP AS INDEPENDENT AUDITORS FOR 2001

    We are asking you to ratify the Board's selection of KPMG LLP, certified
public accountants, as independent auditors for 2001. The Audit Committee
recommended the selection of KPMG to the Board. KPMG has served as the
independent auditors of Ambac Assurance since 1985 and of Ambac since our
incorporation in 1991.

    A representative of KPMG will attend the Annual Meeting to answer your
questions.

    We are submitting this proposal to you because the Board believes that such
action follows sound corporate practice. If you do not ratify the selection of
independent auditors, the Board will consider it a direction to consider
selecting other auditors for next year. However, even if you ratify the
selection, the Board may still appoint new independent auditors at any time
during the year if it believes that such a change would be in the best
interests of Ambac and our stockholders.


The Board recommends that you vote "FOR" ratification of the selection of KPMG
                     LLP as independent auditors for 2001.

                                      30


                    INFORMATION ABOUT STOCKHOLDER PROPOSALS

    Under our By-laws, if you wish to nominate a director or bring other
business before the stockholders:

   .   You must notify the Corporate Secretary in writing not less than 60 days
       nor more than 90 days before the annual meeting.

   .   If we give you less than 70 days' notice of the meeting date, however,
       you may notify us within 10 days after the notice was mailed or publicly
       disclosed.

   .   Your notice must contain the specific information required in our
       By-laws.

    Please note that these By-laws requirements relate only to matters you wish
to bring before your fellow stockholders at an annual meeting. They do not
apply to proposals that you wish to have included in our proxy statement.

    If you wish to submit proposals to be included in our 2001 proxy statement,
we must receive them on or before Thursday, November 29, 2001. Please address
your proposals to: ANNE G. GILL, CORPORATE SECRETARY, AMBAC FINANCIAL GROUP,
INC., ONE STATE STREET PLAZA, NEW YORK, NEW YORK 10004.

    If you would like a copy of our By-laws, we will send you one without
charge. Please write to the Corporate Secretary of Ambac.

                              By order of the Board of Directors,

                                        /s/ Anne G.Gill
                                          Anne G. Gill
                         First Vice President, Corporate Secretary and
                                   Assistant General Counsel

March 28, 2001

                                      31


                                                                      APPENDIX A

                          AMBAC FINANCIAL GROUP, INC.

           CHARTER OF THE AUDIT COMMITTEE OF THE BOARD OF DIRECTORS

PURPOSE

The purpose of the Ambac Financial Group, Inc. Audit Committee (the
"COMMITTEE") is to understand, assess, and monitor the corporate control
environment of Ambac Financial Group, Inc. (the "COMPANY"). The Committee will
assist the Board of Directors in fulfilling its oversight responsibilities by
reviewing the financial information that is provided to stockholders and
others, the systems of internal controls established by management and the
Board of Directors, and the audit process of the Company.

The Committee will meet at least three times per year. The Committee will
comply with the requirements of the Securities and Exchange Commission (the
"SEC") and the New York Stock Exchange (the "NYSE") regarding corporate audit
committees.

MEMBERSHIP REQUIREMENTS

The Committee will be comprised of at least three independent directors who are
financially literate or who become financially literate within a reasonable
period of time. These directors will not have any relationship to the Company
that will interfere with their exercise of independent judgment from management
and the Company as members of the Committee. At least one member of the
Committee will have accounting or related financial management expertise.

PRIMARY DUTIES

In accordance with the SEC requirements, the Committee will provide a report in
the Company's proxy statement which states whether the Committee:

   .   reviewed and discussed the audited financial statements with management;

   .   discussed with the independent auditors the matters required by
       Statement on Auditing Standards No. 61 (which requires the outside
       auditors to communicate to the Committee matters related to the conduct
       of the audit);

   .   received the written disclosures and the letter from the auditors
       regarding the auditors' independence and discussed the auditors'
       independence as required by Independent Standards Board Standard No. 1
       with the auditors; and

                                      A-1


   .   recommended to the Board of Directors that the financial statements be
       included in the Company's annual report on Form 10-K (or 10-KSB) for the
       last fiscal year for filing with the SEC based upon its discussions with
       the auditors regarding the auditors' independence.

In accordance with the NYSE requirements, the Committee will:

   .   review and reassess the adequacy of the audit committee charter on an
       annual basis;

   .   select, evaluate, and replace the outside auditor, who is ultimately
       accountable to the Committee and the Board of Directors of the Company
       (or nominate the outside auditor for stockholder approval in any proxy
       statement);

   .   ensure that the outside auditor submits a formal written statement to
       the Committee on a periodic basis that delineates all relationships
       between the outside auditor and the Company;

   .   actively discuss with the outside auditor any relationships between the
       outside auditor and the Company or any other relationships that may
       impact the objectivity and independence of the outside auditor; and

   .   recommend that the Board of Directors takes appropriate action in
       response to the report of the outside auditor to satisfy itself of the
       independence of the outside auditor.

In general, the Committee will:

   .   review the scope of the annual audit of the Company's financial
       statements, the fees for the audit and for non-audit services, and the
       findings and recommendations of the outside auditors;

   .   review the Company's accounting practices, internal auditing controls,
       and business ethics practices, as appropriate, including the monitoring
       and enforcement of the Company's Code of Business Conduct;

   .   review the Company's internal audit function, including the scope of the
       audits and the findings of the internal auditors;

   .   review elements of the Company's financial statements on a periodic
       basis; and

   .   meet with the internal auditors and other personnel of the Company, as
       appropriate.

In carrying out its responsibilities, the Committee will comply with the SEC
and the NYSE audit committee requirements. However, the policies and procedures
of the Committee will remain flexible, and the Committee may assume other
responsibilities as it deems necessary to ensure that the corporate accounting
and reporting practices are appropriate given the circumstances of the Company.
The evaluation of the Company's financial statements by the Committee is not of
the same quality as the audits performed by the outside auditors, nor does the
Committee's evaluation supersede or alter the traditional responsibilities of
the Company's management for preparing, or the outside auditors for auditing,
the Company's financial statements.

                                      A-2


                                 [LOGO] Ambac
                  ONE STATE STREET PLAZA, NEW YORK, NY 10004


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                                              VOTE BY INTERNET

                                ---------------------------------------------
                                Have your proxy card available when you access
                                the website HTTP://WWW.VOTEFAST.COM. You will be
                                prompted to enter your Control Number and then
                                you can follow the simple prompts that will be
                                presented to you to record your vote.

                                ---------------------------------------------
                                                VOTE BY MAIL

                                ---------------------------------------------
                                 Please mark, sign and date your proxy card and
                                 return it in the POSTAGE-PAID ENVELOPE provided
                                 or return it to: Corporate Election Services,
                                 PO Box 1150, Pittsburgh, PA 15230.

                                ---------------------------------------------

- ------------------------  ------------------------   ----------------------
   VOTE BY TELEPHONE          VOTE BY INTERNET             VOTE BY MAIL
 Call Toll-Free using a    Access the website and       Return your proxy
 touch-tone telephone:        cast your vote:          in the postage-paid
     1-800-250-9081       http://www.votefast.com       envelope provided.
- ------------------------  ------------------------   ----------------------


                       VOTE 24 HOURS A DAY, 7 DAYS A WEEK!

     YOUR TELEPHONE OR INTERNET VOTE MUST BE RECEIVED BY 11:59 P.M. EASTERN
          DAYLIGHT TIME ON APRIL 30, 2001 TO BE COUNTED IN THE FINAL TABULATION.

             ======================================================
               YOUR CONTROL NUMBER IS:
             ======================================================

          Please fold and detach card at perforation before mailing.

AMBAC FINANCIAL GROUP, INC.                                            PROXY
- --------------------------------------------------------------------------------
THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS FOR THE ANNUAL
MEETING OF STOCKHOLDERS ON MAY 1, 2001.

The undersigned hereby appoints Phillip B. Lassiter, Frank J. Bivona and Anne G.
Gill, and each of them, proxies, with power of substitution, to vote all shares
of Common Stock of Ambac Financial Group, Inc. which the undersigned is entitled
to vote at the Annual Meeting of Stockholders to be held on Tuesday, May 1, 2001
at 11:30 a.m., local time, at Ambac's executive offices, One State Street Plaza,
New York, New York, and at any adjournments of the Annual Meeting. The proxies
have the authority to vote as directed on the reverse side of this card with the
same effect as though the undersigned were present in person and voting. The
proxies are further authorized in their discretion to vote upon such other
business as may properly come before the Annual Meeting and any adjournments of
the Annual Meeting. The undersigned revokes all proxies previously given to vote
at the Annual Meeting.

                                        --------------------------------------
                                        Signature(s)

                                        --------------------------------------
                                        Signature(s)


                                        IMPORTANT: Please sign EXACTLY as your
                                        name(s) appears on the left. Joint
                                        owners should each sign. If you are
                                        signing as an executor, administrator,
                                        trustee, guardian, attorney or corporate
                                         officer, please give your full title.

                                        Date:                          , 2001
                                             --------------------------



                             YOUR VOTE IS IMPORTANT!

If you do not vote by telephone or Internet, please sign and date this proxy
card and return it promptly in the enclosed postage-paid envelope, or otherwise
to Corporate Election Services, PO Box 1150, Pittsburgh, PA 15230, so that your
shares may be represented at the Meeting. If you vote by telephone or internet,
it is not necessary to return this proxy card.

           Please fold and detach card at perforation before mailing.

AMBAC FINANCIAL GROUP, INC.                                             PROXY
- ------------------------------------------------------------------------------

PLEASE INDICATE BELOW HOW YOU WISH YOUR SHARES TO BE VOTED. UNLESS YOU INDICATE
OTHERWISE, YOUR PROXY WILL VOTE "FOR" ALL OF THE PROPOSALS ON THIS CARD. WE
CANNOT VOTE YOUR SHARES UNLESS YOU SIGN, DATE AND RETURN THIS CARD.

THE BOARD OF DIRECTORS RECOMMEND THAT YOU VOTE "FOR" ALL PROPOSALS.

1. Elect Seven Directors

                                                                           
   Nominees: (01) Phillip B. Lassiter  (02) Michael A. Callen  (03) Renso L. Caporali  (04)  Jill M. Considine
             (05) Richard Dulude       (06) Robert J. Genader  (07) W. Grant Gregory



      [ ] FOR all nominees listed above.       [ ] WITHHOLD AUTHORITY
          (Except as listed to the contrary        to vote for all nominees
           below.)                                 listed above.

         To withhold authority to vote for any individual nominee, write that
nominee's name or number below.

- --------------------------------------------------------------------------------

2. Ratify Selection of KPMG LLP as Independent Auditors for 2001.

     [ ] FOR      [ ] AGAINST      [ ] ABSTAIN

                     TO BE SIGNED AND DATED ON REVERSE SIDE