<PAGE>


                                FOURTH AMENDMENT



                  FOURTH AMENDMENT (this "Amendment"), dated as of April 14,
1999, among Frontier Insurance Group, Inc. (the "Borrower"), the lending
institutions party to the Credit Agreement referred to below (each a "Bank" and,
collectively, the "Banks"), and Deutsche Bank AG, New York Branch and/or Cayman
Islands Branch, as Administrative Agent (the "Administrative Agent"). All
capitalized terms used herein and not otherwise defined herein shall have the
respective meanings provided such terms in the Credit Agreement.


                              W I T N E S S E T H :
                               - - - - - - - - - -


                  WHEREAS, the Borrower, the Banks and the Administrative Agent
are party to a Credit Agreement, dated as of June 3, 1997 (as amended, modified
and supplemented prior to the date hereof, the "Credit Agreement"); and

                  WHEREAS, the Borrower has requested that the Banks provide the
amendment provided for herein and the Banks have agreed to provide such
amendment on the terms and conditions set forth herein;

                  NOW, THEREFORE, it is agreed:

                  1. On the Amendment Effective Date (as hereinafter defined),
the Commitment of each Bank shall be modified to be the amount set forth
opposite the name of such Bank on Annex I hereto. In connection with the
foregoing, on the Amendment Effective Date, the Borrower shall, in coordination
with the Admininstrative Agent and the Banks, repay outstanding Revolving Loans
of certain Banks and incur additional Revolving Loans from other Banks, in each
case if necessary so that the Banks participate in each Borrowing of Revolving
Loans pro rata on the basis of their Commitments (after giving effect to this
Section 1). It is hereby agreed that the breakage costs incurred by the Banks in
connection with the repayment of Revolving Loans contemplated by this Section 1,
if any, shall be for the account of the Borrower. On the Amendment Effective
Date, Annex I to the Credit Agreement shall be deemed amended to read as set
forth in Annex I attached hereto to give effect to the foregoing.

                  2. Section 9 of the Credit Agreement is hereby amended as
follows:

                  (i) by deleting the table appearing in the definition of
"Applicable Eurodollar Rate Margin" in its entirety and inserting the following
new table in lieu thereof:

<TABLE>
<CAPTION>
               Applicable Rating Period                   Applicable Eurodollar Rate Margin
               ------------------------                   ---------------------------------
             <S>                                                      <C>
                  Category A Period                                    0.300%
                  Category B Period                                    0.350%
                  Category C Period                                    0.425%
                  Category D Period                                    0.500%"; and
</TABLE>




<PAGE>


                  (ii) by deleting the table appearing in the definition of
"Applicable Facility Fee Percentage" in its entirety and inserting the following
new table in lieu thereof:

<TABLE>
<CAPTION>
                 Applicable Rating Period                   Applicable Facility Fee Percentage
                 ------------------------                   ----------------------------------
               <S>                                                       <C>
                  Category A Period                                        0.100%
                  Category B Period                                        0.150%
                  Category C Period                                        0.200%
                  Category D Period                                        0.250%
</TABLE>

                  3. In order to induce the Banks to enter into this Amendment,
the Borrower hereby represents and warrants that (i) no Default or Event of
Default exists as of the Amendment Effective Date (as defined below) after
giving effect to this Amendment and (ii) on the Amendment Effective Date, both
before and after giving effect to this Amendment, all representations and
warranties contained in the Credit Agreement and in the other Credit Documents
are true and correct in all material respects, except (a) to the extent such
representations and warranties expressly relate to an earlier date, in which
case such representations and warranties are true and correct in all material
respects as of such earlier date, and (b) in the case of Section 5.08(e) of the
Credit Agreement, for the matters described in the press releases of the
Borrower dated October 6, 1997, February 2, 1998 and February 17, 1998.

                  4. This Amendment shall become effective on the date (the
"Amendment Effective Date") when:

                  (a) the Borrower, the Required Banks and each Bank whose
          Commitment is increasing as a result of this Amendment shall have
          signed a counterpart hereof (whether the same or different
          counterparts) and shall have delivered (including by way of facsimile
          transmission) the same to the Administrative Agent at its Notice
          Office;

                  (b) the Borrower shall have delivered to the Administrative
         Agent a new Note for each Bank whose Commitment is increasing as a
         result of this Amendment, reflecting its increased Commitment, which
         Note shall be issued in exchange for the Note currently held by such
         Bank; and

                  (c) the Borrower shall have delivered to the Agent a certified
         copy of resolutions duly adopted by the Borrower authorizing the
         increase in the Total Commitment contemplated by this Amendment.

                  5. This Amendment is limited as specified and shall not
constitute a modification, acceptance or waiver of any other provision of the
Credit Agreement or any other Credit Document.

                  6. This Amendment may be executed in any number of
counterparts and by the different parties hereto on separate counterparts, each
of which counterparts when executed and delivered shall be an original, but all
of which shall together constitute one and the same




                                      -2-



<PAGE>


instrument. A complete set of counterparts shall be lodged with the Borrower and
the Administrative Agent.

                  7. THIS AMENDMENT AND THE RIGHTS AND OBLIGATIONS OF THE
PARTIES HEREUNDER SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS
OF THE STATE OF NEW YORK.

                  8. The Borrower hereby covenants and agrees that, so long as
the Amendment Effective Date occurs, it shall pay each Bank which executes and
delivers to the Administrative Agent a counterpart hereof by the later to occur
of (x) the close of business on the Amendment Effective Date or (y) 5:00 p.m.
(New York time) on April 12, 1999, a cash fee in an amount equal to 10 basis
points (.10%) of an amount equal to the increase to the Commitment of such Bank
pursuant to this Amendment, in each case as same is in effect on the Amendment
Effective Date. All fees payable pursuant to this Section 8 shall be paid by the
Borrower to the Administrative Agent for distribution to the Banks not later
than the first Business Day following the Amendment Effective Date.

                                      * * *




                                      -3-



<PAGE>


                  IN WITNESS WHEREOF, each of the parties hereto has caused a
counterpart of this Amendment to be duly executed and delivered as of the date
hereof.

                                   FRONTIER INSURANCE GROUP, INC.


                                   By:________________________________
                                       Title:


                                   DEUTSCHE BANK AG, NEW YORK
                                     BRANCH AND/OR CAYMAN ISLANDS
                                     BRANCH,
                                       Individually and as Administrative Agent


                                   By:_________________________________
                                       Title:


                                   By:_________________________________
                                       Title:


                                   BANK OF AMERICA NT & SA


                                   By:________________________________
                                       Title:


                                   THE BANK OF NEW YORK


                                   By:________________________________
                                       Title:


                                    THE FIRST NATIONAL BANK OF
                                     CHICAGO


                                   By:________________________________
                                       Title:


                                      -4-



<PAGE>



                                  FIRST UNION NATIONAL BANK


                                  By:________________________________
                                     Title:


                                  UNION BANK OF CALIFORNIA

                                  By:________________________________
                                     Title:


                                      -5-



<PAGE>


                                                                         ANNEX I



                          LIST OF BANKS AND COMMITMENTS



<TABLE>
<CAPTION>
Bank                                                 Commitment                         Percentage
----                                                 ----------                         ----------
<S>                                                  <C>                                <C>
Deutsche Bank AG, New York Branch
   and/or Cayman Islands Branch                      $ 48,500,000                       27.714286%
Bank of America NT & SA                              $ 21,000,000                       12%
The Bank of  New York                                $ 21,000,000                       12%
The First National Bank of Chicago                   $ 28,000,000                       16%
First Union National Bank                            $ 28,000,000                       16%
Union Bank of California                             $ 28,500,000                       16.285714%

                  Total:                             $175,000,000                      100%
</TABLE>



                                  -6-