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FOR ADDITIONAL INFORMATION CONTACT: DEBBIE CIPRESSI -- PHONE (215) 564-6600,
EXT. 3452

                                               E-MAIL DEBBIE.CIPRESSI@CMACMI.COM

FOR IMMEDIATE RELEASE


                           CMAC INVESTMENT CORPORATION

                         ADOPTS SHAREHOLDER RIGHTS PLAN


        PHILADELPHIA, PA., APRIL 20, 1998 -- CMAC Investment Corporation (NYSE:
CMT) (the "Company") announced today that its Board of Directors has declared a
dividend on its shares of Common Stock (the "Common Stock") of preferred share
purchase rights (the "Rights") as part of a Shareholder Rights Plan (the
"Plan").

        The Plan is designed to help insure that all stockholders of the Company
receive fair value for their Common Shares in the event of any proposed takeover
of the Company and to guard against the use of partial tender offers or other
coercive tactics to gain control of the Company without offering fair value to
the Company's stockholders.

        Under the terms of the Plan, the Rights will be distributed as a
dividend at the rate of one Right for each Common Share held as of the close of
business on May 5, 1998. Stockholders will not actually receive certificates for
the Rights at this time, but the Rights, all of which expire on May 5, 2008,
will become part of each Common Share.

        Each Right will entitle the holder to buy 1/1000 of a share of Series A
Junior Participating Preferred Shares of the Company (the "Preferred Shares") at
an exercise price of $300. Each Preferred Share fraction is designed to be
equivalent in voting and dividend rights to one Common Share. The Rights will be
exercisable for Preferred Shares and will trade separately from the Common
Shares (at which time stockholders will receive certificates for the Rights)
only if a person or group acquires beneficial ownership of 12% or more of the
Company's Common Shares or commences a tender or exchange offer that would
result in such a person or group owning 12% or more of the Common Shares.

        If any person acquires 12% or more of Common Shares -- other than
through a tender or exchange offer for all Common Shares that provides a fair
price and other terms for such shares -- or if a 12%-or-more stockholder
engages in certain "self-dealing" transactions or engages in a merger or other
business combination in which the Company survives and its Common Shares remain
outstanding, the other stockholders will be able to exercise the Rights and buy
Common Shares of the Company having twice the value of the exercise price of the
Rights. Additionally,



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if the Company is involved in certain other mergers where its shares are
exchanged or certain major sales of its assets occur, stockholders will be able
to purchase the other party's common shares in an amount equal to twice the
value of the exercise price of the Rights. Upon the occurrence of any of these
events, the Rights will no longer be exercisable into Preferred Shares.

        The Company will be entitled to redeem the Rights at $.001 per Right at
any time until the tenth day following public announcement that a person has
acquired a 12% ownership position in Common Shares of the Company. The Company
in its discretion may extend the period during which it can redeem the Rights.

        CMAC Investment Corporation (NYSE: CMT), headquartered in Philadelphia,
is the parent company of Commonwealth Mortgage Assurance Company (CMAC), which
provides private mortgage insurance and risk management services to mortgage
lending institutions through offices in key cities nationwide. Private mortgage
insurance protects lenders from default-related losses on residential first
mortgage loans made to home buyers who make down payments of less than 20
percent of a home's purchase price, and facilitates the sale of mortgage loans
in the secondary mortgage market.



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