THE TRANSFER OF THIS AGREEMENT IS SUBJECT TO CERTAIN RESTRICTIONS CONTAINED
 HEREIN AND TO RESALE RESTRICTIONS UNDER THE SECURITIES ACT OF 1933, AS AMENDED


                             STOCK OPTION AGREEMENT


                  STOCK  OPTION  AGREEMENT,  dated as of February  15, 1999 (the
"Agreement"),  by and between NAC Re Corp., a Delaware  corporation  ("Issuer"),
and XL Capital Ltd, a limited liability company organized and incorporated under
the laws of the Cayman Islands ("Grantee").

                                    RECITALS

     A. The Merger Agreement.  Grantee,  Issuer and Dasher  Acquisition Corp., a
Delaware  corporation  ("Sub")  are  concurrently   herewith  entering  into  an
Agreement  and  Plan  of  Merger,  dated  as of the  date  hereof  (the  "Merger
Agreement"),  among Issuer,  Grantee and Sub, providing for, among other things,
the  merger  of Sub  with and into  Issuer,  with  Issuer  being  the  surviving
corporation.

     B.  Condition  to  Merger  Agreement.  As a  condition  and  inducement  to
Grantee's  and Sub's  execution  of the Merger  Agreement,  Grantee and Sub have
required that Issuer agree,  and Issuer has agreed,  to grant Grantee the Option
(as hereinafter defined).

     NOW,  THEREFORE,  in  consideration  of the  foregoing  and the  respective
representations,  warranties,  covenants and  agreements set forth herein and in
the Merger  Agreement,  and  intending to be legally  bound  hereby,  Issuer and
Grantee agree as follows:

     1. Defined Terms.  Capitalized  terms which are used but not defined herein
shall have the meanings ascribed to such terms in the Merger Agreement.

     2. Grant of Option.  Subject to the terms and  conditions set forth herein,
Issuer hereby grants to Grantee an irrevocable option (the "Option") to purchase
up to 1,860,215 shares (as adjusted as set forth herein, the "Option Shares") of
common stock, par value $0.10 per share, of Issuer ("Issuer Common Stock"), at a
purchase price per Option Share (as adjusted as set forth herein,  the "Purchase
Price") equal to $45.3125;  provided that in no event shall the number of Option
Shares  for which  this  Option is  exercisable  exceed  10.1% of the issued and
outstanding  shares of Issuer  Common  Stock.  Each  Option  Share  issued  upon
exercise of the Option shall be accompanied by the applicable  number of Company
Rights as provided in the Company Rights Agreement.

     3. Exercise of Option.

     (a) Holder may  exercise the Option,  in whole or in part,  at any time and
from time to time following the  occurrence of a Purchase Event (as  hereinafter
defined); provided that the Option shall terminate and be of no further force or
effect upon the earliest to occur of (A) the Effective  Time, (B) termination of
the  Merger  Agreement  in  accordance  with  the  terms  thereof  prior  to the
occurrence of a Purchase Event (as hereinafter  defined) or (C) the later of (1)
February 15, 2000 and (2) 6 months after a termination  of the Merger  Agreement
following the  occurrence of a Purchase  Event;  and provided,  further that any
purchase of shares upon  exercise of the Option  shall be subject to  compliance
with applicable law.  Notwithstanding the termination of the Option,  Grantee or
Holder,  as the case may be, shall be entitled to purchase  those Option  Shares
with respect to which it has exercised  the Option in accordance  with the terms
of this  Agreement  prior to the  termination  of the Option.  The term "Holder"
shall  mean the  holder  or  holders  of the  Option  from  time to time,  which
initially is Grantee.  The termination of the Option shall not affect any rights
hereunder which by their terms extend beyond the date of such termination.

     (b) As used herein, a "Purchase Event" means any of the following events:

          (i)  without  Grantee's  prior  written  consent,  Issuer  shall  have
     authorized,   recommended,  publicly  proposed  or  publicly  disclosed  an
     intention to authorize,  recommend or propose,  or entered into one or more
     agreements  with any  person  (other  than  Grantee  or any  subsidiary  of
     Grantee) to effect,  or effected,  in a single  transaction  or a series of
     related transactions, any Transaction Proposal; or

          (ii) any person  (other  than  Grantee or any  subsidiary  of Grantee)
     shall have acquired  beneficial  ownership (as such term is defined in Rule
     13d-3  promulgated  under  the  Exchange  Act) of or the  right to  acquire
     beneficial ownership of, or any "group" (as such term is defined in Section
     13(d)(3) of the Exchange  Act),  other than a group of which Grantee or any
     subsidiary   of  Grantee  is  a  member,   shall  have  been  formed  which
     beneficially owns or has the right to acquire  beneficial  ownership of 10%
     or more of the voting power of Issuer or any of its Subsidiaries; or

          (iii) any person  (other than  Grantee or any  subsidiary  of Grantee)
     shall have  commenced  (as such term is  defined  in Rule  14d-2  under the
     Exchange  Act),  or shall have  filed a  registration  statement  under the
     Securities  Act  with  respect  to, a tender  offer  or  exchange  offer to
     purchase any shares of Issuer Common Stock such that, upon  consummation of
     such  offer,  such  person  would  own or  control  10% or more of the then
     outstanding  shares of Issuer Common Stock (such an offer being referred to
     herein  as a "Tender  Offer"  or an  "Exchange  Offer,"  respectively);  or

          (iv) the Company Stockholder  Approval shall not have been received at
     a duly held meeting of stockholders or at any adjournment  thereof,  or the
     Stockholders  Meeting  shall not have been held or shall have been canceled
     prior to the  termination  of the Merger  Agreement,  in each case after it
     shall have been publicly  disclosed  that any person (other than Grantee or
     any  subsidiary of Grantee)  shall have (A) made, or disclosed an intention
     to make, a Transaction  Proposal,  or (B) filed an  application  or notice,
     whether in draft or final form, with a Governmental  Entity for approval or
     consent to make or consummate a Transaction Proposal; or

          (v) the Issuer or its Board of  Directors  shall  have (A)  withdrawn,
     modified or amended in any respect adverse to Grantee the recommendation of
     Issuer's  Board of  Directors  with  respect to the Merger  Agreement,  (B)
     failed as promptly as practicable after the Form S-4 is declared  effective
     to mail the Proxy Statement/  Prospectus to its  stockholders,  unless such
     failure  was  caused  by  the  actions  or  inactions  of  Grantee  or  its
     representatives,  or failed to include  in such Proxy  Statement/Prospectus
     the  Company  Board  Recommendation  or (C)  resolved  to  take  any of the
     foregoing actions; or

          (vi) the Merger  Agreement  shall have been  terminated  in accordance
     with its terms under any  circumstances in which the Termination Fee is or,
     upon the occurrence of the events specified  therein,  would become payable
     as provided in Section 7.3(b) or 7.3(c) of the Merger Agreement.

As used in this Agreement, "person" shall have the meaning specified in Sections
3(a)(9) and 13(d)(3) of the Exchange Act.

     (c) Issuer shall notify  Grantee  promptly in writing of the  occurrence of
any Purchase Event, it being understood that the giving of such notice by Issuer
shall not be a condition to the right of Holder to exercise the Option.

     (d) In the event  Holder  wishes to exercise  the Option,  it shall send to
Issuer a written  notice  (the date of which  being  herein  referred  to as the
"Notice  Date")  specifying  (i) the total number of Option Shares it intends to
purchase  pursuant to such  exercise  and (ii) a place and date not earlier than
three business days nor later than 60 business days from the Notice Date for the
closing (the "Closing") of such purchase (the "Closing Date");  provided that if
the Closing cannot be consummated by reason of any applicable Law or the need to
obtain any necessary approvals or consents of applicable  Governmental Entities,
the period of time that otherwise  would run pursuant to this sentence shall run
instead from the date on which such  restriction on consummation  has expired or
been terminated; and provided,  further, without limiting the foregoing, that if
prior  notification  or  application  to,  approval of or  authorization  by any
Governmental  Entity is required in connection with such purchase,  Issuer shall
use all reasonable  efforts to cooperate with the Holder in the prompt filing of
the  required  notice or  application  for  approval or  authorization,  and the
Closing shall occur immediately  following the date on which such approvals have
been obtained or any required  notification or waiting periods have expired. Any
exercise  of the  Option  shall be deemed to occur on the Notice  Date  relating
thereto.

     (e)  Notwithstanding  Section  3(d),  in no event shall any Closing Date be
more than 12 months after the related Notice Date, and if the Closing Date shall
not have  occurred  within 12 months  after the  related  Notice Date due to the
failure  to obtain  any such  required  approval,  the  exercise  of the  Option
effected  on the Notice Date shall be deemed to have  expired.  In the event (i)
Holder  receives  official  notice that an approval of any  Governmental  Entity
required for the purchase of Option Shares will not be issued or granted or (ii)
a Closing Date shall not have occurred within 12 months after the related Notice
Date due to the failure to obtain any such required  approval,  Grantee shall be
entitled to exercise the Option  (whether or not the Option would have otherwise
terminated)  in  connection  with the  resale  of Issuer  Common  Stock or other
securities  pursuant to a registration  statement as provided in Section 11. The
provisions  of this  Section  3 and  Section  4  shall  apply  with  appropriate
adjustments to any such exercise.

     4. Payment and Delivery of Certificates.

     (a) On each Closing Date,  Holder shall (i) pay to Issuer,  in  immediately
available  funds  by  wire  transfer  to a bank  account  designated  by  Issuer
(provided  that the  failure or refusal of Issuer to  designate  a bank  account
shall not preclude the Holder from  exercising  the Option),  an amount equal to
the Purchase Price  multiplied by the number of Option Shares to be purchased on
such Closing Date,  and (ii) present and surrender  this Agreement to the Issuer
at the address of the Issuer specified in Section 14(f).

     (b) At each  Closing,  simultaneously  with  the  delivery  of  immediately
available funds and surrender of this Agreement as provided in Section 4(a), (i)
Issuer shall deliver to Holder (A) a certificate  or  certificates  representing
the Option Shares to be purchased at such Closing,  which Option Shares shall be
free and clear of all Liens and subject to no preemptive  rights, and (B) if the
Option is exercised in part only, an executed new agreement  with the same terms
as this Agreement  evidencing the right to purchase the balance of the shares of
Issuer  Common Stock  purchasable  hereunder,  and (ii) Holder shall  deliver to
Issuer a letter  agreeing  that  Holder  shall  not  offer to sell or  otherwise
dispose of such Option Shares in violation of  applicable  federal and state law
or of the provisions of this Agreement.

     (c) In addition to any other  legend  that is required by  applicable  law,
certificates  for the Option Shares  delivered at each Closing shall be endorsed
with a restrictive legend which shall read substantially as follows:

     THE TRANSFER OF THE STOCK  REPRESENTED  BY THIS  CERTIFICATE  IS SUBJECT TO
     RESTRICTIONS  ARISING UNDER THE  SECURITIES  ACT OF 1933,  AS AMENDED,  AND
     PURSUANT TO THE TERMS OF A STOCK OPTION  AGREEMENT DATED AS OF FEBRUARY 15,
     1999.  A COPY OF SUCH  AGREEMENT  WILL BE  PROVIDED  TO THE  HOLDER  HEREOF
     WITHOUT  CHARGE UPON  RECEIPT BY THE  SECRETARY  OF THE ISSUER OF A WRITTEN
     REQUEST THEREFOR.

It is understood and agreed that (i) the portion of the above legend relating to
the  Securities  Act shall be removed by delivery of  substitute  certificate(s)
without such legend if such Option Shares have been  registered  pursuant to the
Securities  Act,  such  Option  Shares  have  been  sold in  reliance  on and in
accordance with Rule 144 under the Securities Act or Holder shall have delivered
to Issuer a copy of a letter from the staff of the SEC, or an opinion of counsel
in form and substance reasonably  satisfactory to Issuer and its counsel, to the
effect that such legend is not required for purposes of the Securities Act, (ii)
the  reference to  restrictions  pursuant to this  Agreement in the above legend
shall be removed by delivery of substitute certificate(s) without such reference
if the Option Shares evidenced by certificate(s)  containing such reference have
been sold or  transferred  in compliance  with the  provisions of this Agreement
under  circumstances  that do not require the  retention of such  reference  and
(iii) such  legend  shall be removed in its  entirety if the  conditions  in the
preceding clauses (i) and (ii) are both satisfied.

     (d) Upon the giving by Holder to Issuer of the  written  notice of exercise
of the Option  provided for under  Section  3(d),  the tender of the  applicable
Purchase Price in immediately  available  funds and the tender of this Agreement
to  Issuer,  Holder  shall be deemed to be the holder of record of the shares of
Issuer Common Stock issuable upon such exercise,  notwithstanding that the stock
transfer books of Issuer shall then be closed or that certificates  representing
such  shares of Issuer  Common  Stock shall not then be  actually  delivered  to
Holder. Issuer shall pay all expenses, and any and all federal,  foreign, state,
and local taxes and other  charges  that may be payable in  connection  with the
preparation, issuance and delivery of stock certificates under this Section 4(d)
in the name of Holder or its assignee, transferee, or designee.

     (e) Issuer agrees (i) that it shall at all times maintain,  free from Liens
and preemptive or similar rights, sufficient authorized but unissued or treasury
shares of Issuer Common Stock ("Available Authorized Shares") so that the Option
may be exercised without  additional  authorization of Issuer Common Stock after
giving effect to all other options,  warrants,  convertible securities and other
rights to purchase Issuer Common Stock then outstanding,  (ii) that it will not,
by charter amendment or through reorganization, recapitalization, consolidation,
merger,   dissolution,   liquidation,   spin-off,  sale  of  assets  or  similar
transaction,  or by any  other  voluntary  act,  avoid  or  seek  to  avoid  the
observance or performance of any of the covenants,  agreements,  stipulations or
conditions to be observed or performed  hereunder by Issuer,  (iii)  promptly to
take all action as may from time to time be required  (including  (A)  complying
with all premerger  notification,  reporting and waiting period requirements and
(B) in the event prior approval or  authorization of or notice or application to
any  Governmental  Entity is  necessary  before  the  Option  may be  exercised,
cooperating  fully with Holder in  preparing  such  applications  or notices and
providing  such  information to such  Governmental  Entity as it may require) in
order to permit Holder to exercise the Option and Issuer duly and effectively to
issue shares of the Issuer Common Stock  pursuant  hereto,  and (iv) promptly to
take all  action  provided  herein to  protect  the  rights  of  Holder  against
dilution. Notwithstanding the foregoing, it is understood that as of the date of
this Agreement,  Issuer does not have Available  Authorized Shares sufficient to
permit the exercise of the Option in full.  Issuer  covenants  and agrees to use
its best  efforts to cause its Board of Directors to  designate,  in  accordance
with its certificate of incorporation  and the DGCL, a series of preferred stock
of Issuer having terms such that each 1/100 of a share of such  preferred  stock
(a  "Preferred  Share")  shall have  voting,  dividend  and  liquidation  rights
equivalent to one share of Issuer  Common Stock.  In the event of an exercise of
the Option for a number of shares of Issuer Common Stock in excess of the number
of Available Authorized Shares (such excess, the "Excess Shares"), Grantee shall
be entitled to purchase a number of such Preferred Shares equal to the number of
Excess Shares at a price per 1/100th of a Preferred  Share equal to the Purchase
Price. Any such Preferred Shares so issued pursuant to the terms hereof shall be
"Option  Shares" and shares of "Issuer Common Stock" for all purposes under this
Agreement and all references herein to "Option Shares" and "Issuer Common Stock"
shall include the Preferred Shares.

     5.  Representations and Warranties of Issuer.  Issuer hereby represents and
warrants to Grantee (and Holder, if different than Grantee) as follows:

     (a)  Corporate  Authority.  Issuer has the  requisite  corporate  power and
authority  to  execute  and  deliver  this   Agreement  and  to  consummate  the
transactions  contemplated  hereby; the execution and delivery of this Agreement
and,  subject to  receiving  any  necessary  approvals  or  authorizations  from
Governmental Entities, the consummation of the transactions  contemplated hereby
have been duly and validly  authorized by the Board of Directors of Issuer,  and
no other corporate  proceedings on the part of Issuer are necessary to authorize
this Agreement or to consummate the transactions so contemplated; this Agreement
has been duly and validly  executed and  delivered by Issuer and  (assuming  due
authorization,  execution  and  delivery  by  Grantee)  constitutes  a valid and
binding obligation of Issuer,  enforceable against Issuer in accordance with its
terms, except that (i) such enforcement may be subject to applicable bankruptcy,
insolvency,  fraudulent  conveyance,  moratorium or other  similar laws,  now or
hereinafter  in effect,  affecting  creditors'  rights  generally,  and (ii) the
remedy of specific  performance  and  injunctive  and other  forms of  equitable
relief may be subject to equitable  defenses and to the  discretion of the court
before which any proceeding therefor may be brought.

     (b) Shares  Reserved  for  Issuance;  Capital  Stock.  Issuer has taken all
necessary  corporate action to authorize and reserve and permit it to issue, and
at all times from the date hereof  through the  termination of this Agreement in
accordance with its terms, will have reserved for issuance, upon the exercise of
the Option,  that number of shares of Issuer Common Stock  (including  Preferred
Shares)  equal to the maximum  number of shares of Issuer Common Stock and other
shares and  securities  which are at any time and from time to time  purchasable
upon exercise of the Option, and all such shares and other securities (including
Preferred  Shares),   upon  issuance  pursuant  to  the  Option,  will  be  duly
authorized, validly issued, fully paid and nonassessable,  and will be delivered
free and clear of all Liens (other than those created by this Agreement) and not
subject to any preemptive or other similar rights.

     (c)  No  Violations.  The  execution,  delivery  and  performance  of  this
Agreement  does not and will not, and the  consummation  by Issuer of any of the
transactions  contemplated hereby will not, constitute or result in (A) a breach
or  violation  of, or a default  under,  its  certificate  of  incorporation  or
by-laws, or the comparable governing instruments of any of its subsidiaries,  or
(B) a breach or violation of, or a default under, any Company Agreement (with or
without  the  giving of  notice,  the lapse of time or both) or under any Law or
governmental  or  non-governmental  permit or  license to which it or any of its
subsidiaries  is  subject,  that  would in any case  give any other  person  the
ability to prevent or enjoin  Issuer's  performance  under this Agreement in any
material respect.

     (d) Board  Action.  The Board of  Directors  of Issuer  has  approved  this
Agreement  and the  consummation  of the  transactions  contemplated  hereby  as
required under Section 203 of the DGCL and any other  applicable  state takeover
laws so that  any such  state  takeover  laws do not and will not  apply to this
Agreement or any of the transactions contemplated hereby (including the purchase
of shares of Issuer Common Stock pursuant to this Agreement).

     (e) Rights  Amendment.  The Company  Rights  Agreement  has been amended to
provide that neither  Grantee nor any Holder will become an  "Acquiring  Person"
and that no "Stock  Acquisition Date" or "Distribution  Date" (as such terms are
defined in the Company Rights Agreement) will occur as a result of the approval,
execution  or  delivery  of  this  Agreement  or  the  Merger  Agreement  or the
consummation of the transactions contemplated hereby and thereby,  including the
acquisition  of shares of Issuer  Common Stock by Grantee or Holder  pursuant to
this Agreement.

     6. Representations and Warranties of Grantee. Grantee hereby represents and
warrants to Issuer as follows:

     (a) Corporate Authority.  Grantee has full corporate power and authority to
enter into this Agreement and, subject to obtaining the approvals referred to in
this Agreement,  to consummate the transactions  contemplated by this Agreement;
the  execution  and  delivery  of this  Agreement  and the  consummation  of the
transactions  contemplated  hereby have been duly  authorized  by all  necessary
corporate  action  on the part of  Grantee;  and this  Agreement  has been  duly
executed and delivered by Grantee and (assuming due authorization, execution and
delivery by Issuer)  constitutes a valid and binding  obligation of the Grantee,
enforceable against the Grantee in accordance with its terms.

     (b) Purchase Not for  Distribution.  Any Option Shares or other  securities
acquired by Grantee or Holder upon exercise of the Option will not be taken with
a view to the  public  distribution  thereof  and  will  not be  transferred  or
otherwise  disposed  of  except  in a  transaction  registered  or  exempt  from
registration under the Securities Act.

     7. Adjustment upon Changes in Issuer Capitalization, Etc.

     (a) In the event of any change from time to time in Issuer Common Stock and
any  other  shares  or  securities  subject  to the  Option by reason of a stock
dividend,  subdivision,  spinoff, stock split, split-up, merger,  consolidation,
recapitalization, combination, exchange of shares, distribution on or in respect
of the  Issuer  Common  Stock that  would be  prohibited  under the terms of the
Merger  Agreement,  or  similar  transaction,  the type and  number of shares or
securities  subject to the Option,  and the Purchase  Price  therefor,  shall be
adjusted  appropriately,  and proper  provision  shall be made in the agreements
governing such transaction,  so that Holder shall receive,  upon exercise of the
Option, the economic benefits provided hereunder, including the number and class
of shares or other  securities  or property  that Holder would have  received in
respect of Issuer  Common  Stock if the Option  had been  exercised  immediately
prior  to such  event,  or the  record  date  therefor,  as  applicable.  If any
additional  shares  of  Issuer  Common  Stock are  issued  or  otherwise  become
outstanding  after the date of this  Agreement  (other than pursuant to an event
described in the first  sentence of this  Section  7(a) or upon  exercise of the
Option) the number of shares of Issuer  Common Stock subject to the Option shall
be adjusted so that, after such issuance, it, together with any shares of Issuer
Common Stock previously  issued pursuant  hereto,  equals 10.1% of the number of
shares of Issuer Common Stock then issued and outstanding, without giving effect
to any shares  subject to or issued  pursuant to the  Option.  In the event that
Issuer  issues or agrees to issue any shares of Issuer  Common Stock (other than
as  permitted  by the  Merger  Agreement)  at a price  per  share  less than the
Purchase Price (as theretofore adjusted pursuant to this Section 7) the Purchase
Price shall be reduced to equal such lesser price.  No provision of this Section
7 shall be deemed  to affect or  change,  or  constitute  authorization  for any
violation of, any of the covenants, agreements, representations or warranties in
the Merger Agreement.

     (b) Without limiting the parties'  relative rights,  remedies,  liabilities
and obligations under the Merger Agreement or this Agreement,  in the event that
Issuer shall enter into an agreement  (other than the Merger  Agreement)  (i) to
consolidate  with or merge into any  person,  other  than  Grantee or one of its
Subsidiaries,  and shall not be the continuing or surviving  corporation of such
consolidation or merger, (ii) to permit any person, other than Grantee or one of
its  Subsidiaries,  to merge into Issuer and Issuer shall be the  continuing  or
surviving corporation, but, in connection with such merger, the then outstanding
shares of Issuer  Common Stock shall be changed  into or  exchanged  for another
class or series of stock or other  securities  of Issuer or any other  person or
cash or any other  property or the  outstanding  shares of Issuer  Common  Stock
immediately prior to such merger shall,  after such merger,  represent less than
75% of the outstanding  shares and share equivalents having general voting power
of  the  merged  company,  or  (iii)  to  sell  or  otherwise  transfer  all  or
substantially  all of its  assets or the assets of its  subsidiaries  taken as a
whole,  in one transaction or a series of related  transactions,  to any person,
other than Grantee or one of its Subsidiaries,  then, and in each such case, the
agreement  governing such transaction  shall make proper  provisions so that the
Option shall,  upon the  consummation of any such transaction and upon the terms
and conditions set forth herein,  be converted into, or exchanged for, an option
(the  "Substitute  Option"),  at the  election  of  Holder,  of  either  (x) the
Acquiring Corporation (as hereinafter defined), (y) any person that controls the
Acquiring Corporation,  or (z) in the case of a merger described in clause (ii),
Issuer (such person being referred to as "Substitute Option Issuer").

     (c) The Substitute Option shall have the same terms as the Option, provided
that, if the terms of the Substitute  Option cannot,  for legal reasons,  be the
same as the Option,  such terms shall be as similar as possible  and in no event
less  advantageous to Holder,  and provided,  further that the Substitute Option
shall be  exercisable  immediately  upon  issuance  without the  occurrence of a
further  Purchase  Event.  Substitute  Option  Issuer  shall  also enter into an
agreement with Holder in  substantially  the same form as this Agreement,  which
shall be applicable to the Substitute Option.

     (d) The Substitute Option shall be exercisable for such number of shares of
Substitute  Common  Stock (as  hereinafter  defined) as is equal to the Assigned
Value (as  hereinafter  defined)  multiplied  by the  number of shares of Issuer
Common Stock for which the Option was  theretofore  exercisable,  divided by the
Average Price (as  hereinafter  defined).  The exercise  price of the Substitute
Option per share of  Substitute  Common Stock (the  "Substitute  Option  Price")
shall then be equal to the Purchase Price  multiplied by a fraction in which the
numerator  is the number of shares of Issuer  Common  Stock for which the Option
was  theretofore  exercisable  and the  denominator  is the  number of shares of
Substitute Common Stock for which the Substitute Option is exercisable.

     (e) The following terms have the meanings indicated:

          (i) "Acquiring Corporation" shall mean (x) the continuing or surviving
     corporation  of a  consolidation  or merger  with  Issuer  (if  other  than
     Issuer),  (y)  Issuer in a merger  in which  Issuer  is the  continuing  or
     surviving  person,  or (z) the  transferee of all or  substantially  all of
     Issuer's assets (or the assets of its subsidiaries taken as a whole).

          (ii)  "Assigned  Value"  shall  mean the  highest of (w) the price per
     share of Issuer  Common Stock at which a Tender Offer or an Exchange  Offer
     therefor has been made,  (x) the price per share of Issuer  Common Stock to
     be paid by any third party  pursuant to an agreement  with Issuer,  (y) the
     highest  closing  price for  shares  of  Issuer  Common  Stock  within  the
     six-month  period  immediately  preceding  the  date on which  the  merger,
     consolidation,  asset sale or other transaction in question is consummated,
     and (z) in the  event  of a sale of all or  substantially  all of  Issuer's
     assets (or of the assets of its subsidiaries as a whole) an amount equal to
     (I) the sum of the price paid in such sale for such  assets and the current
     market  value  of the  remaining  assets  of  Issuer,  as  determined  by a
     nationally recognized  investment banking firm selected by Holder,  divided
     by (II) the number of shares of Issuer  Common  Stock  outstanding  at such
     time. In calculating  the Assigned  Value, in the event that a Tender Offer
     or an Exchange  Offer is made for Issuer  Common  Stock or an  agreement is
     entered into for a merger or consolidation  involving  consideration  other
     than  cash,  the value of the  securities  or other  property  issuable  or
     deliverable  in exchange for Issuer  Common Stock shall be  determined by a
     nationally recognized investment banking firm selected by Holder.

          (iii) "Average  Price" shall mean the average closing price of a share
     of Substitute  Common Stock on the NYSE (or if such Substitute Common Stock
     is not  listed on the  NYSE,  the  average  closing  price on the  National
     Association of Securities  Dealers  Automated  Quotation  System or, if the
     shares of Substitute  Common Stock are not quoted thereon,  the highest bid
     price per share as quoted on the  principal  trading  market on which  such
     shares are traded as  reported  by a  recognized  source)  for the one year
     immediately preceding the date of consummation of the consolidation, merger
     or sale in question,  but in no event higher than the closing  price of the
     shares of Substitute Common Stock on the day preceding such  consolidation,
     merger or sale;  provided  that if Issuer is the  issuer of the  Substitute
     Option,  the Average  Price shall be  computed  with  respect to a share of
     common stock issued by Issuer,  by the person merging into Issuer or by any
     company which controls such person, as Holder may elect.

          (iv) "Substitute  Common Stock" shall mean the shares of capital stock
     (or similar equity  interest) with the greatest  voting power in respect of
     the  election  of  directors  (or  persons  similarly  responsible  for the
     direction of the business and affairs) of the Substitute Option Issuer.

     (f) In no event,  pursuant to any of the  foregoing  paragraphs,  shall the
Substitute  Option be  exercisable  for more than 10.1% of the  aggregate of the
shares  of  Substitute  Common  Stock  outstanding  prior  to  exercise  of  the
Substitute  Option. In the event that the Substitute Option would be exercisable
for more than 10.1% of the  aggregate of the shares of  Substitute  Common Stock
but for the  limitation in the first  sentence of this Section 7(f),  Substitute
Option Issuer shall make a cash payment to Holder equal to the excess of (i) the
value of the  Substitute  Option  without giving effect to the limitation in the
first sentence of this Section 7(f) over (ii) the value of the Substitute Option
after  giving  effect to the  limitation  in the first  sentence of this Section
7(f).  This  difference in value shall be determined by a  nationally-recognized
investment banking firm selected by Holder.

     (g) Issuer shall not enter into any  transaction  described in Section 7(b)
unless the  Acquiring  Corporation  and any person that  controls the  Acquiring
Corporation  assume in writing all the obligations of Issuer  hereunder and take
all other actions that may be necessary so that the provisions of this Section 7
are given full force and effect (including,  without limitation, any action that
may be  necessary so that the holders of the other shares of common stock issued
by Substitute Option Issuer are not entitled to exercise any rights by reason of
the issuance or exercise of the  Substitute  Option and the shares of Substitute
Common  Stock  are  otherwise  in no way  distinguishable  from or  have  lesser
economic value (other than any diminution in value  resulting from the fact that
the Substitute  Common Stock are restricted  securities,  as defined in Rule 144
under the Securities Act or any successor provision) than other shares of common
stock issued by Substitute Option Issuer).

     8. Repurchase at the Option of Holder.

     (a) At the  request  of  Holder at any time (i)  commencing  upon the first
occurrence  of a  Repurchase  Event (as  defined in Section  8(d)) and ending 18
months  immediately  thereafter  and (ii) for 30  business  days  following  the
occurrence  of either of the events set forth in clauses (i) and (ii) of Section
3(e) (but solely as to shares of Issuer  Common  Stock with respect to which the
required  approval was not received,  Issuer (or any successor) shall repurchase
from Holder (x) the Option and (y) all shares of Issuer  Common Stock  purchased
by Holder  pursuant  hereto with  respect to which  Holder  then has  beneficial
ownership. The date on which Holder exercises its rights under this Section 8 is
referred to as the  "Request  Date".  Such  repurchase  shall be at an aggregate
price (the "Section 8 Repurchase Consideration") equal to the sum of:

          (i) the  aggregate  Purchase  Price  paid by Holder  for any shares of
     Issuer Common Stock  acquired  pursuant to the Option with respect to which
     Holder then has beneficial ownership;

          (ii) the  excess,  if any,  of (x) the  Applicable  Price (as  defined
     below) for each share of Issuer  Common Stock over (y) the  Purchase  Price
     (subject to adjustment  pursuant to Section 7), multiplied by the number of
     shares of Issuer Common Stock with respect to which the Option has not been
     exercised; and

          (iii) the excess,  if any, of the  Applicable  Price over the Purchase
     Price  (subject to adjustment  pursuant to Section 7) paid (or, in the case
     of Option  Shares with respect to which the option has been  exercised  but
     the  Closing  Date has not  occurred,  payable) by Holder for each share of
     Issuer Common Stock with respect to which the Option has been exercised and
     with respect to which Holder then has beneficial  ownership,  multiplied by
     the number of such shares.

     (b) If Holder  exercises  its rights  under this  Section 8, Issuer  shall,
within 5 business  days after the Request  Date,  pay the  Section 8  Repurchase
Consideration to Holder in immediately  available  funds, and  contemporaneously
with  such  payment,  Holder  shall  surrender  to  Issuer  the  Option  and the
certificates  evidencing the shares of Issuer Common Stock purchased  thereunder
with respect to which  Holder then has  beneficial  ownership,  and Holder shall
warrant that it has sole record and beneficial  ownership of such shares and the
Option and that the same are then free and clear of all  Liens.  Notwithstanding
the  foregoing,  to the extent  that prior  notification  to or  approval of any
Governmental  Entity is  required in  connection  with the payment of all or any
portion of the Section 8 Repurchase Consideration, Holder shall have the ongoing
option to revoke its request for  repurchase  pursuant to Section 8, in whole or
in part, or to require that Issuer deliver from time to time that portion of the
Section 8 Repurchase Consideration that it is not then so prohibited from paying
and  promptly  file  the  required   notice  or  application  for  approval  and
expeditiously process the same (and each party shall cooperate with the other in
the  filing of any such  notice or  application  and the  obtaining  of any such
approval)  and the  period of time that  would  otherwise  run  pursuant  to the
preceding  sentence  for the payment of the portion of the Section 8  Repurchase
Consideration  shall run instead from the date on which, as the case may be, (i)
any required  notification  period has expired or been  terminated  or (ii) such
approval has been obtained and, in either event,  any requisite  waiting  period
shall  have  passed.  If any  Governmental  Entity  disapproves  of any  part of
Issuer's proposed  repurchase  pursuant to this Section 8, Issuer shall promptly
give notice of such fact to Holder.  If any  Governmental  Entity  prohibits the
repurchase (and Issuer hereby undertakes to use all reasonable efforts to obtain
all required approvals from Governmental Entities to accomplish such repurchase)
in part but not in whole,  then  Holder  shall  have the right (i) to revoke the
repurchase request or (ii) to the extent permitted by such Governmental  Entity,
determine whether the repurchase should apply to the Option and/or Option Shares
and to what  extent  to each,  and  Holder  shall  thereupon  have the  right to
exercise  the Option as to the number of Option  Shares for which the Option was
exercisable  at the Request Date less the sum of the number of shares covered by
the  Option in  respect  of which  payment  has been made  pursuant  to  Section
8(a)(ii) and the number of shares  covered by the portion of the Option (if any)
that has been repurchased;  whereupon,  in the case of clause (ii), Issuer shall
promptly  (x)  deliver to the Holder that  portion of the  Section 8  Repurchase
Consideration  Price  that  Issuer is not  prohibited  from  delivering  and (y)
deliver to the Holder, as appropriate, either (A) a new Agreement evidencing the
right of the Holder to  purchase  that number of shares of Issuer  Common  Stock
obtained  by  multiplying  the  number of  shares of Common  Stock for which the
surrendered  Agreement was  exercisable at the time of delivery of the notice of
repurchase  by a fraction,  the  numerator  of which is the Section 8 Repurchase
Consideration less the portion thereof  theretofore  delivered to the Holder and
the  denominator  of which is the Section 8 Repurchase  Consideration,  or (B) a
certificate  for the Option Shares it is then so prohibited  from  repurchasing;
provided,  that if the Option  shall have  terminated  prior to the date of such
notice or shall be scheduled to terminate at any time before the expiration of a
period  ending on the  thirtieth  business  day after  such date,  Holder  shall
nonetheless  have the right so to  exercise  the Option or  exercise  its rights
under Section 9 until the expiration of such period of 30 business days.  Holder
shall notify Issuer of its determination  under the preceding sentence within 10
business days of receipt of notice of disapproval of the repurchase.

     (c) For  purposes  of this  Agreement,  the  "Applicable  Price"  means the
highest of (i) the highest  price per share of Issuer  Common Stock paid for any
such share by the person or groups described in Section 8(d)(i),  (ii) the price
per share of Issuer  Common Stock  received by holders of Issuer Common Stock in
connection with any merger or other business combination  transaction  described
in Section 7(b)(i),  7(b)(ii) or 7(b)(iii),  and (iii) the highest closing sales
price per share of Issuer  Common Stock quoted on the NYSE (or if Issuer  Common
Stock is not listed on the NYSE,  the highest  closing price per share as quoted
on the Nasdaq  National  Market  System or, if the shares of Issuer Common Stock
are not  quoted  thereon,  the  highest  bid  price  per  share as quoted on the
principal  trading  market in which  such  shares are  traded as  reported  by a
recognized  source)  during the 40 business  days  preceding  the Request  Date;
provided,  however,  that in the  event of a sale of less  than all of  Issuer's
assets, the Applicable Price shall be the sum of the price paid in such sale for
such assets and the current  market value of the  remaining  assets of Issuer as
determined  by a  nationally  recognized  investment  banking  firm  selected by
Holder,  divided by the number of shares of the Issuer Common Stock  outstanding
at the time of such sale. If the  consideration to be offered,  paid or received
pursuant  to either of the  foregoing  clauses  (i) or (ii)  shall be other than
cash,  the value of such  consideration  shall be determined in good faith by an
independent  nationally  recognized  investment banking firm selected by Holder,
which determination shall be conclusive for all purposes of this Agreement.

     (d) As used  herein,  a  "Repurchase  Event"  shall occur if (i) any person
(other than Grantee or any subsidiary of Grantee) shall have acquired beneficial
ownership  of (as such  term is  defined  in Rule  13d-3  promulgated  under the
Exchange Act), or the right to acquire  beneficial  ownership of, or any "group"
(as such term is defined  under the  Exchange  Act) shall have been formed which
beneficially  owns or has the right to acquire  beneficial  ownership of, 35% or
more of the then  outstanding  shares of Issuer  Common  Stock,  (ii) any of the
transactions  described  in Section  7(b)(i),  7(b)(ii)  or  7(b)(iii)  has been
consummated or (iii) Issuer has entered into an agreement  pursuant to which any
of the transactions described in Section 7(b)(i), 7(b)(ii) or 7(b)(iii) could or
will be consummated.

     9. Repurchase of Substitute Option.

     (a) At the  request  of  Holder at any time (i)  commencing  upon the first
occurrence  of a Substitute  Repurchase  Event (as defined in Section  9(d)) and
ending 18 months immediately  thereafter and (ii) for 30 business days following
the  occurrence  of either of the events  set forth in  clauses  (i) and (ii) of
Section 3(e) (but solely as to shares of Substitute Common Stock with respect to
which the required approval was not received),  Substitute Option Issuer (or any
successor)  shall  repurchase  from  Holder (x) the Option and (y) all shares of
Substitute  Common  Stock  purchased by Holder  pursuant  hereto with respect to
which Holder then has beneficial  ownership.  The date on which Holder exercises
its rights under this Section 9 is referred to as the "Section 9 Request  Date".
Such  repurchase  shall be at an  aggregate  price (the  "Section  9  Repurchase
Consideration") equal to the sum of:

          (i) the  aggregate  Purchase  Price  paid by Holder  for any shares of
     Substitute  Common Stock acquired  pursuant to the  Substitute  Option with
     respect to which Holder then has beneficial ownership;

          (ii) the excess,  if any, of (x) the Substitute  Applicable  Price (as
     defined  below)  for each  share of  Substitute  Common  Stock over (y) the
     Purchase Price (subject to adjustment pursuant to Section 7), multiplied by
     the number of shares of  Substitute  Common Stock with respect to which the
     Substitute Option has not been exercised; and

          (iii) the excess, if any, of the Substitute  Applicable Price over the
     Purchase Price  (subject to adjustment  pursuant to Section 7) paid (or, in
     the case of Option  Shares (for purposes of this  Agreement,  Option Shares
     shall  include  shares of  Substitute  Common Stock and related  securities
     subject to the  Substitute  Option)  with  respect to which the  Substitute
     Option has been  exercised but the Closing Date has not occurred,  payable)
     by Holder for each share of  Substitute  Common Stock with respect to which
     the  Substitute  Option has been exercised and with respect to which Holder
     then has beneficial ownership, multiplied by the number of such shares.

     (b) If Holder exercises its rights under this Section 9, Substitute  Option
Issuer shall,  within 5 business days after the Section 9 Request Date,  pay the
Section 9 Repurchase Consideration to Holder in immediately available funds, and
contemporaneously with such payment, Holder shall surrender to Substitute Option
Issuer the  Substitute  Option  and the  certificates  evidencing  the shares of
Substitute  Common Stock purchased  thereunder with respect to which Holder then
has beneficial  ownership,  and Holder shall warrant that it has sole record and
beneficial  ownership of such shares and the Substitute Option and that the same
are then free and clear of all  Liens.  Notwithstanding  the  foregoing,  to the
extent that prior  notification  to or approval  of any  Governmental  Entity is
required in  connection  with the payment of all or any portion of the Section 9
Repurchase  Consideration,  Holder  shall have the ongoing  option to revoke its
request for repurchase pursuant to Section 9, in whole or in part, or to require
that  Substitute  Option  Issuer  deliver  from time to time that portion of the
Section 9 Repurchase Consideration that it is not then so prohibited from paying
and  promptly  file  the  required   notice  or  application  for  approval  and
expeditiously process the same (and each party shall cooperate with the other in
the  filing of any such  notice or  application  and the  obtaining  of any such
approval)  and the  period of time that  would  otherwise  run  pursuant  to the
preceding  sentence  for the payment of the portion of the Section 9  Repurchase
Consideration  shall run instead from the date on which, as the case may be, (i)
any required  notification  period has expired or been  terminated  or (ii) such
approval has been obtained and, in either event,  any requisite  waiting  period
shall  have  passed.  If any  Governmental  Entity  disapproves  of any  part of
Substitute  Option  Issuer's  proposed  repurchase  pursuant to this  Section 9,
Substitute Option Issuer shall promptly give notice of such fact to Holder (such
notice a "Notice of  Disapproval").  If any  Governmental  Entity  prohibits the
repurchase (and Substitute Option Issuer hereby undertakes to use all reasonable
efforts  to  obtain  all  required  approvals  from  Governmental   Entities  to
accomplish such repurchase) in part but not in whole, then Holder shall have the
right (i) to revoke the  repurchase  request or (ii) to the extent  permitted by
such Governmental  Entity,  determine whether the repurchase should apply to the
Substitute  Option and/or  Option Shares and to what extent to each,  and Holder
shall  thereupon  have the right to  exercise  the  Substitute  Option as to the
number of Option Shares for which the Substitute  Option was  exercisable at the
Section 9  Request  Date less the sum of the  number  of shares  covered  by the
Substitute  Option in respect of which payment has been made pursuant to Section
9(a)(ii)  and the  number of shares  covered by the  portion  of the  Substitute
Option  (if any)  that has been  repurchased;  whereupon,  in the case of clause
(ii),  Substitute  Option  Issuer shall  promptly (x) deliver to the Holder that
portion of the Section 9 Repurchase  Consideration  Price that Substitute Option
Issuer is not  prohibited  from  delivering  and (y) deliver to the  Holder,  as
appropriate, either (A) a new Stock Option Agreement evidencing the right of the
Holder to purchase that number of shares of Substitute  Common Stock obtained by
multiplying  the  number  of  shares of  Substitute  Common  Stock for which the
surrendered  Stock Option  Agreement was  exercisable at the time of delivery of
the notice of repurchase by a fraction,  the numerator of which is the Section 9
Repurchase  Consideration less the portion thereof theretofore  delivered to the
Holder and the denominator of which is the Section 9 Repurchase Consideration or
(B)  a  certificate  for  the  Option  Shares  it is  then  so  prohibited  from
repurchasing;  provided,  further,  that if the  Substitute  Option  shall  have
terminated  prior to the date of such notice or shall be  scheduled to terminate
at any time before the  expiration of a period ending on the thirtieth  business
day after such date, Grantee shall nonetheless have the right so to exercise the
Substitute Option or exercise its rights under Section 9 until the expiration of
such period of 30 business days. Holder shall notify Substitute Option Issuer of
its  determination  under the  preceding  sentence  within ten business  days of
receipt of Notice of Disapproval of the repurchase.

      (c) For purposes of this  Agreement,  the  "Substitute  Applicable  Price"
means the highest of (i) the highest price per share of Substitute  Common Stock
paid for any such share by the person or groups  described  in Section  9(d)(i),
(ii) the price per share of  Substitute  Common  Stock  received  by  holders of
Substitute  Common  Stock in  connection  with  any  merger  or  other  business
combination transaction described in Section 7(b)(i),  7(b)(ii) or 7(b)(iii), or
(iii) the highest  closing  sales  price per share of  Substitute  Common  Stock
quoted on the NYSE (or if the Substitute Common Stock is not listed on the NYSE,
the highest  closing  price per share as quoted the Nasdaq NMS or, if the shares
of Substitute Common Stock are not quoted thereon,  the highest bid price on the
principal trading market in which such shares are traded by a recognized source)
during the 40 business  days  preceding  the Section 9 Request  Date;  provided,
however,  that in the  event  of a sale of less  than all of  Substitute  Option
Issuer's assets,  the Substitute  Applicable Price shall be the sum of the price
paid in such sale for such assets and the current  market value of the remaining
assets of Substitute  Option  Issuer as  determined  by a nationally  recognized
investment  banking firm selected by Holder,  divided by the number of shares of
the  Substitute  Common  Stock  outstanding  at the  time of such  sale.  If the
consideration  to be  offered,  paid  or  received  pursuant  to  either  of the
foregoing  clauses  (i) or (ii) shall be other  than in cash,  the value of such
consideration  shall be  determined in good faith by an  independent  nationally
recognized investment banking firm selected by Holder, which determination shall
be conclusive for all purposes of this Agreement.

      (d) As used herein, a "Substitute Repurchase Event" shall occur if (i) any
person  (other than Grantee or any  subsidiary  of Grantee)  shall have acquired
beneficial ownership of (as such term is defined in Rule 13d-3 promulgated under
the  Exchange  Act),  or the right to acquire  beneficial  ownership  of, or any
"group" (as such term is defined  under the Exchange Act) shall have been formed
which beneficially owns or has the right to acquire beneficial ownership of, 35%
or more of the then outstanding  shares of Substitute  Common Stock, (ii) any of
the transactions  described in Section  7(b)(i),  7(b)(ii) or 7(b)(iii) has been
consummated  or (iii)  Substitute  Option  Issuer has entered  into an agreement
pursuant to which any of the transactions described in Section 7(b)(i), 7(b)(ii)
or 7(b)(iii) could or will be consummated.  If the  consideration  paid or to be
paid to holders of Substitute  Common Stock in the  transactions  referred to in
either of the foregoing  clauses (i) or (ii) shall be other than cash, the value
of such  consideration  shall be  determined  in good  faith  by an  independent
nationally   recognized  investment  banking  firm  selected  by  Holder,  which
determination shall be conclusive for all purposes of this Agreement.

     (e) All  references  to  "Issuer",  "Issuer  Common  Stock" and "Section 8"
contained  herein shall also be deemed to be  references to  "Substitute  Option
Issuer," "Substitute Common Stock" and "Section 9" respectively.

     10. Right of First Refusal. If, within one year after the Closing Date (but
not  thereafter),  Grantee proposes to sell all or any part of the Option Shares
in a transaction  not required to be registered  under the Securities Act (other
than in a  transfer  by  operation  of law  upon  consummation  of a  merger  or
consolidation,  in a tender or  exchange  offer or in a sale under Rule 144 or a
successor  provision  under  the  Securities  Act),  it shall  give  Issuer  the
opportunity, in the following manner, to purchase such Option Shares:

     (a)  Grantee  shall give  notice to Issuer in writing of its intent to sell
Option Shares (a "Disposition  Notice"),  specifying the number of Option Shares
to be sold, the price and the material terms of any agreement  relating thereto.
The Disposition Notice may be given at any time.

     (b) Issuer  shall have the right,  exercisable  by written  notice given to
Grantee  within 5  business  days  after  receipt of a  Disposition  Notice,  to
purchase  all,  but not less than all,  of the Option  Shares  specified  in the
Disposition  Notice at the price set  forth in the  Disposition  Notice.  If the
purchase price specified in the  Disposition  Notice includes any property other
than cash,  the  purchase  price to be paid by Issuer shall be an amount of cash
equal to the sum of (i) the cash  included in the  purchase  price plus (ii) the
fair market value of such other property at the date of the Disposition  Notice.
If such other property  consists of securities  with an existing  public trading
market,  the  average of the last sale  prices for such  securities  on the five
trading days ending five days prior to the date of the Disposition  Notice shall
be used as the  fair  market  value of such  property.  If such  other  property
consists of  something  other than cash or  securities  with an existing  public
trading  market and at the time of the  closing  referred  to in  paragraph  (c)
below,  agreement on the value of such other property has not been reached,  the
average of the closing prices for the Issuer's  common stock on the five trading
days ending five days prior to the date of the Disposition  Notice shall be used
as the per share  purchase  price;  provided,  however,  that promptly after the
closing,  Grantee and Issuer or its  designee,  as the case may be, shall settle
any additional  amounts to be paid or returned as a result of the  determination
of fair market  value of such other  property  made by a  nationally  recognized
investment  banking firm  selected by Issuer and  approved by Grantee  within 30
days of the  closing.  Such  determination  shall be final  and  binding  on all
parties hereto.

      (c) If Issuer exercises its right of first refusal hereunder,  the closing
of the  purchase of the Option  Shares with respect to which such right has been
exercised  shall take place within five  business  days after the notice of such
exercise;  provided,  however,  that at any  time  prior to the  closing  of the
purchase  of Option  Shares  hereunder,  Grantee may  determine  not to sell the
Option  Shares  and revoke  the  Disposition  Notice  and,  by so doing,  cancel
Issuer's right of first refusal with respect  thereto.  Issuer shall pay for the
Option Shares in immediately available funds.

     (d) If Issuer does not exercise its right of first refusal hereunder within
the  time  specified  for  such  exercise,  Grantee  shall  be free  for 90 days
following  the  expiration  of such time for  exercise  to sell or enter into an
agreement to sell the Option Shares specified in the Disposition  Notice, at the
price  specified in the  Disposition  Notice or any price in excess  thereof and
otherwise on substantially  the same terms set forth in the Disposition  Notice;
provided, that if such sale is not consummated within such 90-day period (unless
the approval or consent of a Governmental  Entity is required to consummate such
sale,  in which case the 90-day period shall not be deemed to have expired until
after such approval or consent shall have been granted),  then the provisions of
this Section 10 will again apply to the sale of such Option Shares.

     11. Registration Rights.

     (a) Demand Registration Rights.  Issuer shall, subject to the conditions of
Section  11(c)  below,  if requested  by any Holder,  including  Grantee and any
permitted  transferee  ("Selling  Stockholder"),  as  expeditiously  as possible
prepare, file and keep current a registration statement under the Securities Act
if such  registration  is  necessary  in  order  to  permit  the  sale or  other
disposition of any or all shares of Issuer Common Stock or other securities that
have been acquired by or are issuable to the Selling  Stockholder  upon exercise
of the  Option  in  accordance  with  the  intended  method  of  sale  or  other
disposition  stated  by the  Selling  Stockholder  in such  request,  including,
without limitation,  a "shelf"  registration  statement under Rule 415 under the
Securities Act or any successor provision, and Issuer shall use its best efforts
to qualify such shares or other  securities for sale under any applicable  state
securities laws.

      (b)  Piggyback  Registration  Rights.  If  Issuer  at any time  after  the
exercise of the Option  proposes to register  any shares of Issuer  Common Stock
under the Securities Act in connection with an  underwritten  public offering of
such Issuer  Common  Stock,  Issuer will  promptly  give  written  notice to the
Selling  Stockholders of its intention to do so and, upon the written request of
any Selling  Stockholder  given within 30 days after  receipt of any such notice
(which  request  shall  specify  the  number of shares  of Issuer  Common  Stock
intended  to be  included in such  underwritten  public  offering by the Selling
Stockholder),  Issuer will cause all such shares for which a Selling Stockholder
requests participation in such registration, to be so registered and included in
such underwritten public offering;  provided,  however, that Issuer may elect to
not cause such shares to be so registered  (i) if in the  reasonable  good faith
opinion of the underwriters for such offering,  the inclusion of all such shares
by the Selling Stockholder would materially interfere with the marketing of such
offering (in which case Issuer shall register as many shares as possible without
materially interfering with the marketing of the offering),  or (ii) in the case
of a registration solely to implement an employee benefit plan or a registration
filed on Form S-4 of the Securities  Act or any successor  Form. If some but not
all the shares of Issuer  Common  Stock with  respect to which Issuer shall have
received  requests  for  registration  pursuant to this  Section  11(b) shall be
excluded from such  registration,  Issuer shall make  appropriate  allocation of
shares to be  registered  among the  Selling  Stockholders  desiring to register
their shares pro rata in the proportion  that the number of shares  requested to
be  registered  by each such  Selling  Stockholder  bears to the total number of
shares requested to be registered by all such Selling Stockholders then desiring
to have Issuer Common Stock registered for sale.

     (c)  Conditions to Required  Registration.  Issuer shall use all reasonable
efforts to cause each registration  statement referred to in Section 11(a) above
to become effective and to obtain all consents or waivers of other parties which
are  required  therefor  and to  keep  such  registration  statement  effective;
provided,  however,  that  Issuer may delay any  registration  of Option  Shares
required  pursuant  to Section  11(a) above for a period not  exceeding  90 days
provided Issuer shall in good faith determine that any such  registration  would
adversely  affect an offering or  contemplated  offering of other  securities by
Issuer,  and Issuer  shall not be required to register  Option  Shares under the
Securities Act pursuant to Section 11(a) above:

          (i) prior to the earliest of (a)  termination of the Merger  Agreement
     pursuant  to  Article  VII  thereof,  (b)  failure  to obtain  the  Company
     Stockholder Approval, and (c) a Purchase Event;

          (ii) on more than two occasions during any calendar year;

          (iii)  within  90 days  after  the  effective  date of a  registration
     referred  to  in  Section  11(b)  above   pursuant  to  which  the  Selling
     Stockholder or Selling Stockholders concerned were afforded the opportunity
     to  register  such  shares  under the  Securities  Act and such shares were
     registered as requested;

          (iv)  unless  a  request   therefor  is  made  to  Issuer  by  Selling
     Stockholders  that  hold at least  25% or more of the  aggregate  number of
     Option Shares (including shares of Issuer Common Stock and other securities
     issuable upon exercise of the Option) then outstanding; and

          (v) after  such  date as all the  Option  Shares  may be resold in one
     transaction pursuant to Rule 144 of the Securities Act (or any successor or
     similar rule or act).

     In addition to the foregoing,  Issuer shall not be required to maintain the
effectiveness  of any  registration  statement  after the expiration of one year
from the effective  date of such  registration  statement.  Issuer shall use all
reasonable efforts to make any filings, and take all steps, under all applicable
state  securities  laws to the  extent  necessary  to  permit  the sale or other
disposition  of the Option Shares so registered in accordance  with the intended
method of distribution for such shares; provided, however, that Issuer shall not
be required to consent to general  jurisdiction or qualify to do business in any
state where it is not otherwise  required to so consent to such  jurisdiction or
to so qualify to do business. If requested by any such Holder in connection with
such  registration,  Issuer shall become a party to any  underwriting  agreement
relating to the sale of such shares, but only to the extent of obligating itself
in respect of  representations,  warranties,  indemnities  and other  agreements
customarily  included  in  secondary  offering  underwriting  agreements.   Upon
receiving  any request  under this Section 11 from any Holder,  Issuer agrees to
send a copy  thereof  to any other  person  known to Issuer  to be  entitled  to
registration  rights under this Section 11, in each case by promptly mailing the
same,  postage  prepaid,  to the  address of record of the  persons  entitled to
receive such copies.

     (d) Expenses.  Except where  applicable  state law prohibits such payments,
Issuer will pay all expenses (including, without limitation,  registration fees,
qualification  fees, blue sky fees and expenses (including the fees and expenses
of counsel), legal fees and expenses, including the reasonable fees and expenses
of one counsel to the holders whose Option Shares are being registered, printing
expenses and the costs of special audits or "cold comfort" letters,  expenses of
underwriters,  excluding  discounts  and  commissions  but  including  liability
insurance  if  Issuer  so  desires  or the  underwriters  so  require,  and  the
reasonable  fees and expenses of any  necessary  special  experts) in connection
with each  registration  pursuant to Section 11(a) or 11(b) above (including the
related  offerings  and  sales  by  holders  of  Option  Shares)  and all  other
qualifications,  notifications or exemptions  pursuant to Section 11(a) or 11(b)
above.

     (e)  Indemnification.  In connection  with any  registration  under Section
11(a) or 11(b) above Issuer hereby  indemnifies  the Selling  Stockholders,  and
each  underwriter  thereof,  including  each person,  if any, who controls  such
holder or underwriter  within the meaning of Section 15 of the  Securities  Act,
against all expenses,  losses,  claims,  damages and  liabilities  caused by any
untrue,  or alleged  untrue,  statement  of a  material  fact  contained  in any
registration  statement  or  prospectus  or  notification  or offering  circular
(including any amendments or supplements thereto) or any preliminary prospectus,
or caused by any omission, or alleged omission, to state therein a material fact
required to be stated  therein or necessary to make the  statements  therein not
misleading,  except  insofar  as  such  expenses,  losses,  claims,  damages  or
liabilities  of such  indemnified  party are caused by any untrue  statement  or
alleged untrue  statement  that was included by Issuer in any such  registration
statement or prospectus or  notification  or offering  circular  (including  any
amendments or  supplements  thereto) in reliance  upon and in  conformity  with,
information  furnished in writing to Issuer by such indemnified  party expressly
for use therein, and Issuer and each officer, director and controlling person of
Issuer  shall  be  indemnified  by each  such  Selling  Stockholder,  or by such
underwriter,  as the case may be, for all such expenses, losses, claims, damages
and liabilities  caused by any untrue,  or alleged untrue,  statement,  that was
included  by  Issuer  in  any  such  registration  statement  or  prospectus  or
notification  or offering  circular  (including  any  amendments or  supplements
thereto) in reliance  upon,  and in conformity  with,  information  furnished in
writing to Issuer by such Selling  Stockholder or such underwriter,  as the case
may be, expressly for such use.

     Promptly  upon receipt by a party  indemnified  under this Section 11(e) of
notice of the  commencement  of any action  against  such  indemnified  party in
respect  of  which  indemnity  or  reimbursement   may  be  sought  against  any
indemnifying party under this Section 11(e), such indemnified party shall notify
the indemnifying  party in writing of the  commencement of such action,  but the
failure  so to  notify  the  indemnifying  party  shall  not  relieve  it of any
liability  which it may  otherwise  have to any  indemnified  party  under  this
Section 11(e) unless the failure so to notify the  indemnified  party results in
substantial prejudice thereto. In case notice of commencement of any such action
shall be given to the  indemnifying  party as above provided,  the  indemnifying
party  shall be  entitled  to  participate  in and,  to the  extent it may wish,
jointly with any other  indemnifying  party  similarly  notified,  to assume the
defense  of such  action  at its own  expense,  with  counsel  chosen  by it and
satisfactory to such  indemnified  party.  The indemnified  party shall have the
right to employ  separate  counsel  in any such  action and  participate  in the
defense  thereof,  but the  fees  and  expenses  of  such  counsel  (other  than
reasonable costs of investigation) shall be paid by the indemnified party unless
(i) the indemnifying  party either agrees to pay the same, (ii) the indemnifying
party fails to assume the defense of such action with  counsel  satisfactory  to
the  indemnified  party,  or (iii) the  indemnified  party has been  advised  by
counsel that one or more legal  defenses  may be  available to the  indemnifying
party that may be contrary to the interest of the  indemnified  party,  in which
case the  indemnifying  party  shall be  entitled  to assume the defense of such
action notwithstanding its obligation to bear fees and expenses of such counsel.
No  indemnifying  party shall be liable for any settlement  entered into without
its consent, which consent may not be unreasonably withheld.

     If the indemnification provided for in this Section 11(e) is unavailable to
a party otherwise entitled to be indemnified in respect of any expenses, losses,
claims,  damages or liabilities referred to herein, then the indemnifying party,
in lieu of indemnifying such party otherwise  entitled to be indemnified,  shall
contribute  to the amount paid or payable by such party to be  indemnified  as a
result  of  such  expenses,  losses,  claims,  damages  or  liabilities  in such
proportion  as is  appropriate  to reflect  the  relative  benefits  received by
Issuer,  the Selling  Stockholders and the underwriters from the offering of the
securities and also the relative fault of Issuer,  the Selling  Stockholders and
the  underwriters  in connection with the statements or omissions which resulted
in such expenses,  losses, claims, damages or liabilities,  as well as any other
relevant  equitable  considerations.  The amount paid or payable by a party as a
result of the expenses,  losses,  claims,  damages and  liabilities  referred to
above shall be deemed to include any legal or other fees or expenses  reasonably
incurred by such party in connection with  investigating or defending any action
or claim;  provided,  however,  that in no case shall any Selling Stockholder be
responsible,  in the  aggregate,  for any  amount in excess of the net  offering
proceeds  attributable to its Option Shares included in the offering.  No person
guilty of fraudulent  misrepresentation  (within the meaning of Section 11(f) of
the Securities  Act) shall be entitled to  contribution  from any person who was
not guilty of such fraudulent misrepresentation. Any obligation by any holder to
indemnify shall be several and not joint with other holders.

     In  connection  with any  registration  pursuant to Section  11(a) or 11(b)
above, Issuer and each Selling Stockholder (other than Grantee) shall enter into
an agreement containing the indemnification provisions of this Section 11(e).

     (f)  Miscellaneous  Reporting.  Issuer  shall  comply  with  all  reporting
requirements and will do all such other things as may be necessary to permit the
expeditious  sale at any time of any Option  Shares by the Selling  Stockholders
thereof in accordance with and to the extent permitted by any rule or regulation
promulgated by the SEC from time to time,  including,  without limitation,  Rule
144.  Issuer  shall at its expense  provide the  Selling  Stockholders  with any
information  necessary  in  connection  with the  completion  and  filing of any
reports or forms  required to be filed by them under the  Securities  Act or the
Exchange Act, or required  pursuant to any state securities laws or the rules of
the NASD or any stock exchange.

     (g) Issue  Taxes.  Issuer will pay all stamp taxes in  connection  with the
issuance and the sale of the Option Shares and in  connection  with the exercise
of the  Option,  and  will  save  the  Selling  Stockholders  harmless,  without
limitation as to time,  against any and all liabilities with respect to all such
taxes.

     12. Quotation:  Listing.  If Issuer Common Stock or any other securities to
be acquired in  connection  with the exercise of the Option are then  authorized
for  quotation  or trading  or listing on the NYSE,  the Nasdaq NMS or any other
securities exchange or securities quotation system,  Issuer, upon the request of
Holder,  will  promptly  file an  application,  if required,  to  authorize  for
quotation  or trading or listing the shares of Issuer  Common Stock or any other
securities  (including  Preferred  Shares) to be acquired  upon  exercise of the
Option  on the  NYSE,  the  Nasdaq  NMS or such  other  securities  exchange  or
securities  quotation  system  and will use all  reasonable  efforts  to  obtain
approval, if required, of such quotation or listing as soon as practicable.

     13. Division of Option.  This Agreement (and the Option granted hereby) are
exchangeable,  without expense,  at the option of Holder,  upon presentation and
surrender  of this  Agreement  at the  principal  office  of  Issuer,  for other
Agreements providing for Options of different denominations entitling the holder
thereof to purchase in the  aggregate the same number of shares of Issuer Common
Stock purchasable  hereunder.  The terms "Agreement" and "Option" as used herein
include  any other Stock  Option  Agreement  and related  Options for which this
Agreement  (and the Option  granted  hereby) may be  exchanged.  Upon receipt by
Issuer of evidence reasonably satisfactory to it of the loss, theft, destruction
or mutilation of this Agreement, and (in the case of loss, theft or destruction)
of reasonably satisfactory indemnification,  and upon surrender and cancellation
of this Agreement, if mutilated, Issuer will execute and deliver a new Agreement
of like tenor and date.  Any such new  Agreement  executed and  delivered  shall
constitute an additional  contractual  obligation on the part of Issuer, whether
or not the Agreement so lost,  stolen,  destroyed or mutilated shall at any time
be enforceable by anyone.

     14. Limitation of Grantee Profit. (a)  Notwithstanding  any other provision
herein,  in no event shall  Grantee's  Total  Profit (as defined  below)  exceed
$38,000,000,  exclusive of any reimbursement of expenses pursuant to Section 7.3
of the Merger  Agreement  (the  "Maximum  Profit"),  and, if it otherwise  would
exceed such amount, Grantee, at its sole discretion, shall either (i) reduce the
number of shares subject to the Option (and any Substitute Option), (ii) deliver
to Issuer, or the Substitute Issuer, as the case may be, for cancellation shares
of Issuer Common Stock or Substitute  Common Stock, as the case may be (or other
securities into which such Option Shares are converted or exchanged),  (iii) pay
cash to  Issuer,  or the  Substitute  Issuer,  as the case  may be,  or (iv) any
combination of the foregoing,  so that Grantee's  actually realized Total Profit
shall not exceed the Maximum  Profit  after  taking into  account the  foregoing
actions.

     (b) For purposes of this  Agreement,  "Total  Profit"  shall mean:  (i) the
aggregate  amount of (A) the  excess  of (x) the net cash  amounts  received  by
Grantee  pursuant  to a sale of Option  Shares  (or  securities  into which such
shares are  converted or exchanged)  to any  unaffiliated  third party within 12
months  after the  exercise  of the  Option,  over (y) the  Grantee's  aggregate
purchase  price  for such  Option  Shares  (or other  securities),  plus (B) all
amounts received by Grantee on the transfer of the Option (including pursuant to
Section 8),  plus (C) all  equivalent  amounts  with  respect to the  Substitute
Option  (including  pursuant to Section  9),  plus (D) all  amounts  received by
Grantee   pursuant  to  Section  7.3  of  the  Merger   Agreement   (other  than
reimbursement in respect of Expenses), minus (ii) all amounts of cash previously
paid to Issuer  pursuant to this Section 14 plus the value of the Option  Shares
(or other securities)  previously delivered to Issuer for cancellation  pursuant
to this Section 14.

     (c) Notwithstanding any other provision of this Agreement,  nothing in this
Agreement shall affect the ability of Grantee to receive,  nor relieve  Issuer's
obligation  to pay,  any  payment  provided  for in  Section  7.3 of the  Merger
Agreement;  provided  that if and to the extent  the Total  Profit  received  by
Grantee  would  exceed the Maximum  Profit  following  receipt of such  payment,
Grantee  shall be obligated to comply with the terms of Section  14(a) within 30
days of the latest of (i) the date of receipt of such payment,  (ii) the date of
receipt of the net cash by  Grantee  pursuant  to the sale of Option  Shares (or
securities  into which such Option  Shares are  converted or  exchanged)  to any
unaffiliated  party  within 12 months  after the  exercise  of this  Option with
respect to such  Option  Shares,  (iii) the date of receipt of net cash from the
disposition of the Option or Substitute Option, as the case may be, and (iv) the
date of receipt of  equivalent  amounts  pursuant to the sale of the  Substitute
Option or shares of Substitute Common Stock (or other securities into which such
Substitute Common Stock is converted or exchanged).

     (d) For  purposes of paragraph  (a) of this  Section and clause  (b)(ii) of
this Section,  the value of any Option  Shares  delivered to Issuer shall be the
Assigned  Value of such  Option  Shares and the value of any  Substitute  Common
Stock delivered to Substitute Issuer shall be the Substitute Applicable Price of
such Substitute Common Stock.

     15. Miscellaneous.

     (a)  Expenses.  Except  as  otherwise  provided  herein  or in  the  Merger
Agreement,  each of the parties hereto shall bear and pay all costs and expenses
incurred by it or on its behalf in connection with the transactions contemplated
hereunder, including, without limitation, fees and expenses of its own financial
consultants, investment bankers, accountants and counsel.

     (b) Waiver and Amendment.  Any provision of this Agreement may be waived at
any time by the party that is entitled to the benefits of such  provision.  This
Agreement may not be modified,  amended, altered or supplemented except upon the
execution and delivery of a written  agreement  executed by the parties  hereto.
The  failure of any party to this  Agreement  to assert any of its rights  under
this  Agreement or otherwise  shall not  constitute a waiver of such rights.  No
single or partial exercise of any right,  remedy,  power or privilege  hereunder
shall  preclude  any other or further  exercise  thereof or the  exercise of any
other right, remedy,  power or privilege.  Any waiver shall be effective only in
the specific instance and for the specific purpose for which given and shall not
constitute a waiver to any  subsequent or other  exercise of any right,  remedy,
power or privilege hereunder.

     (c) Entire  Agreement:  No Third-Party  Beneficiaries;  Severability.  This
Agreement,  together  with the  Merger  Agreement  and the other  documents  and
instruments  referred  to herein and  therein,  between  Grantee  and Issuer (i)
constitutes  the  entire  agreement  and  supersedes  all prior  agreements  and
understandings,  both written and oral,  between the parties with respect to the
subject  matter  hereof and (ii) is not intended to confer upon any person other
than the parties hereto or their  respective  successors and assigns (other than
any  transferees  of the  Option  Shares  or any  permitted  transferee  of this
Agreement  pursuant  to Section  15(h)) any  rights,  remedies,  obligations  or
liabilities hereunder.  If any term, provision,  covenant or restriction of this
Agreement is held by a court of competent jurisdiction or Governmental Entity to
be invalid,  void or  unenforceable,  the  remainder  of the terms,  provisions,
covenants  and  restrictions  of this  Agreement  shall remain in full force and
effect  and shall in no way be  affected  impaired  or  invalidated.  If for any
reason such court or  Governmental  Entity  determines  that the Option does not
permit Holder to acquire,  or does not require  Issuer to  repurchase,  the full
number of shares of Issuer  Common  Stock as  provided  in  Section 2 (as may be
adjusted  herein),  it is the  express  intention  of Issuer to allow  Holder to
acquire or to require  Issuer to repurchase  such lesser number of shares as may
be permissible without any amendment or modification hereof.

     (d)  Governing  Law.  This  Agreement  shall be governed  and  construed in
accordance with the laws of the State of Delaware.

     (e) Descriptive Headings. The descriptive headings contained herein are for
convenience  of  reference  only and shall not affect in any way the  meaning or
interpretation of this Agreement.

     (f) Notices.  All notices and other  communications  hereunder  shall be in
writing and shall be deemed  given if  delivered  personally,  telecopied  (with
confirmation)  or  mailed  by  registered  or  certified  mail  (return  receipt
requested) to the parties at the addresses set forth in the Merger Agreement (or
at such other address for a party as shall be specified by like notice).

     (g) Counterparts.  This Agreement and any amendments hereto may be executed
in two  counterparts,  each of  which  shall  be  considered  one  and the  same
agreement and shall become effective when both counterparts have been signed, it
being understood that both parties need not sign the same counterpart.

     (h) Assignment.  Neither this Agreement nor any of the rights, interests or
obligations  hereunder  or under  the  Option  shall be  assigned  by any of the
parties  hereto  (whether by  operation of law or  otherwise)  without the prior
written consent of the other party, except that Holder may assign this Agreement
to a  wholly-owned  subsidiary  of Holder  and  Holder  may  assign  its  rights
hereunder in whole or in part after the occurrence of a Purchase Event.  Subject
to the preceding  sentence,  this Agreement shall be binding upon,  inure to the
benefit of and be enforceable by the parties and their respective successors and
assigns.

     (i) Further  Assurances.  In the event of any exercise of the Option by the
Holder,  Issuer and the Holder shall execute and deliver all other documents and
instruments and take all other action that may be reasonably  necessary in order
to consummate the transactions provided for by such exercise.

     (j) Specific Performance.  The parties hereto agree that this Agreement may
be enforced by either party through specific performance,  injunctive relief and
other equitable relief.  Both parties further agree to waive any requirement for
the securing or posting of any bond in connection with the obtaining of any such
equitable  relief  and that this  provision  is without  prejudice  to any other
rights  that the  parties  hereto  may  have for any  failure  to  perform  this
Agreement.

     (k) Rights Plan.  Until the Option has been exercised or terminated in full
and Grantee or Holder no longer holds any Option Shares, Issuer shall not amend,
modify or waive any provision of the Company Rights  Agreement or take any other
action which would cause Grantee or Holder to be an "Acquiring Person", or which
would cause a "Stock  Acquisition  Date" or  "Distribution  Date",  or any event
specified  in Section 11 or 13 of the Company  Rights  Agreement  or any similar
event with respect to the Company Rights to occur, by reason of the existence or
exercise  (in  whole or in part) of the  Option,  the  beneficial  ownership  by
Grantee or Holder or any of their respective "Affiliates" or "Associates" of any
of the Option Shares, or the consummation of the other transactions contemplated
hereby  (all  terms  in  quotes  are  used  as  defined  in the  Company  Rights
Agreement). This covenant shall also apply to any Substitute Option or shares of
Substitute  Common Stock issued in respect  thereof,  and to any securities into
which any Option Shares or Substitute Common Stock are converted or exchanged.

     (l) Consent to  Jurisdiction  and Service of Process.  Any suit,  action or
proceeding  seeking to enforce any provision of, or based on any matter  arising
out of or in connection with, this Agreement or the transactions contemplated by
this  Agreement  may be brought  against any of the parties in any federal court
located in the State of Delaware or any Delaware  state  court,  and each of the
parties hereto consents to the non-exclusive jurisdiction of such courts (and of
the  appropriate  appellate  courts  therefrom)  in any  such  suit,  action  or
proceeding  and waives any objection to venue laid therein.  Process in any such
suit, action or proceeding may be served on any party anywhere in the world and,
without limiting the generality of the foregoing,  each party hereto agrees that
service of process upon such party at the address  referred to in Section 8.4 of
the Merger Agreement, together with written notice of such service to such party
shall be deemed effective service of process upon such party.





     IN WITNESS  WHEREOF,  Issuer and  Grantee  have  caused  this Stock  Option
Agreement to be signed by their respective  officers  thereunto duly authorized,
all as of the day and year first written above.


                                             NAC RE CORP.

                                             By: /s/ Nicholas M. Brown, Jr.
                                                 -------------------------------
                                                 Name:  Nicholas M. Brown, Jr.
                                                 Title: President and Chief
                                                        Executive Officer


                                             XL CAPITAL LTD

                                             By: /s/ Brian M. O'Hara
                                                 -------------------------------
                                                 Name:  Brian M. O'Hara
                                                 Title: President and Chief
                                                        Executive Officer