<PAGE>
                                                                   EXHIBIT 10.12

                           PURCHASE AND SALE AGREEMENT

      This Purchase and Sale Agreement ("Agreement"), dated as of May 2, 2002,
is among SS&C Technologies, Inc., a Delaware corporation (the "Company"),
General Atlantic Partners 15, L.P., a Delaware limited partnership ("GAP 15"),
and GAP Coinvestment Partners, L.P., a New York limited partnership ("GAPCO" and
together with GAP 15, the "Sellers").

                                   BACKGROUND

      Each of the Sellers desires to sell and the Company desires to purchase
the aggregate number of shares of Common Stock of the Company set forth opposite
the name of such Seller on Schedule 1.02 hereto (the "SECURITIES") on the terms
and conditions set forth in this Agreement.

      THEREFORE, the parties agree as follows:

                                    SECTION I
                         PURCHASE AND SALE OF SECURITIES

      1.01 SALE OF SECURITIES. Each Seller, severally and not jointly, agrees to
sell, assign, transfer and deliver to the Company on the Closing Date (as
defined below) the aggregate number of Securities set forth opposite the name of
such Seller on Schedule 1.02 hereto, and the Company agree to purchase such
Securities from such Seller on the Closing Date, pursuant to this Agreement.

      1.02 PURCHASE PRICE. In full consideration of the sale of the Securities
by the Sellers, the Company shall pay to each Seller on the Closing Date the
aggregate amount set forth opposite the name of such Seller on Schedule 1.02
hereto, at Eleven Dollars and Twenty-Five Cents ($11.25) per share, for an
aggregate purchase price of Six Million Ninety-Nine Thousand Seventy-Five
Dollars ($6,099,075.00) (the "Purchase Price"). The Purchase Price shall be paid
by the wire transfer of immediately available funds to each Seller's account as
designated by such Seller.

      1.03 CLOSING. The closing of the transactions contemplated by this
Agreement (the "CLOSING") will take place by exchange of closing documents by
telecopier or by other means mutually agreed upon by the parties on May 7, 2002
(the "CLOSING DATE"). At the Closing, each Seller will deliver to the Company a
stock certificate or stock certificates representing at least the number of
Securities being sold by such Seller, along with a stock power reasonably
acceptable to the Company, against payment to such Seller of its portion of the
Purchase Price as set forth on Schedule 1.02 hereto and in accordance with
Section 1.02 of this Agreement.




<PAGE>
                                   SECTION II
                  REPRESENTATIONS AND WARRANTIES OF THE SELLERS

      In order to induce the Company to purchase the Securities, each Seller
represents and warrants, severally and not jointly, to the Company as follows:

      2.01 EXISTENCE AND GOOD STANDING. Such Seller is a limited partnership
duly organized and validly existing under the laws of the jurisdiction of its
formation, and has full power and authority to sell the Securities being sold by
such Seller and to enter into and perform its obligations under this Agreement.

      2.02 AUTHORIZATION. The execution and delivery of this Agreement by such
Seller and the consummation by such Seller of the transactions contemplated by
this Agreement have been duly authorized by all necessary partnership action on
the part of such Seller. No consent, approval, license from, or exemption of,
and no registration, qualification, designation, declaration or filing with, any
court or governmental department, commission, board, bureau, agency or
instrumentality, or any other party, which has not been obtained as of this
date, is or will be necessary for the valid execution and delivery by such
Seller of this Agreement, or the consummation by such Seller of the transactions
contemplated by this Agreement.

      2.03 NO CONFLICT WITH OTHER INSTRUMENTS. Neither the execution and
delivery by such Seller of this Agreement, the consummation by such Seller of
the transactions contemplated by this Agreement, nor the compliance by such
Seller with the terms and conditions of this Agreement, will (a) violate any
provision of such Seller's organizational documents, as amended to date; (b)
violate or conflict with or result in a breach of any law, regulation, order,
writ, injunction or decree of any court, arbitrator or governmental
instrumentality to which such Seller is bound; (c) violate or be in conflict
with, or constitute a default (or an event which, with notice or lapse of time
or both, would constitute a default) under, or entitle any party to terminate
any or all of the provisions of, or cause the acceleration of or entitle any
party to accelerate the performance required by, or cause the acceleration of or
entitle any party to accelerate the maturity of any debt or obligation pursuant
to, any contract, agreement, arrangement, commitment or restriction of any kind
to which such Seller is a party or by which such Seller is bound; or (d) result
in the creation or imposition of any security interest, lien or other
encumbrance upon the Securities being sold by such Seller under any contract,
agreement, arrangement, commitment or restriction of any kind to which such
Seller is a party or by which such Seller is bound.

      2.04 VALIDITY AND BINDING EFFECT. This Agreement has been duly and validly
executed and delivered by such Seller; and this Agreement constitutes the legal,
valid and binding obligation of such Seller, enforceable against such Seller in
accordance with its terms, except as the enforceability of this Agreement may be
limited by bankruptcy, insolvency or other similar laws of general application
affecting the enforceability of creditors' rights generally, or by general
principles of equity.

      2.05 TITLE TO SECURITIES. Such Seller owns, and on the Closing Date such
Seller will own, all right, title and interest (legal and beneficial) in and to
the Securities being

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<PAGE>
sold by such Seller without restriction, other than restrictions imposed under
applicable securities laws and restrictions created by the Company. Upon such
Seller's delivery of certificates representing the Securities, duly endorsed for
transfer to the Company, and the Company's payment to such Seller of the
Purchase Price therefor, the Company will acquire such Securities free and clear
of all liens, charges and encumbrances, other than restrictions imposed under
applicable securities laws and restrictions created by the Company.

      2.06 LITIGATION. There is no (a) action, suit, claim, proceeding or
investigation pending or, to such Seller's knowledge, threatened against or
affecting, such Seller, at law or in equity, or before or by any federal, state,
municipal or other governmental department, commission, board, bureau, agency or
instrumentality, domestic or foreign, (b) arbitration proceeding relating to
such Seller, or (c) governmental inquiry pending, or to such Seller's knowledge
threatened, against or affecting such Seller, any of which, if adversely
determined, would invalidate or prevent the performance by such Seller of the
transactions contemplated by this Agreement.

      2.07 EXPERIENCE. Such Seller has sufficient knowledge and experience in
finance and business that it is capable of evaluating the risks and merits of
its sale of its Securities to the Company. The Company has answered to such
Seller's satisfaction all inquiries made by such Seller to the Company. Such
Seller acknowledges and agrees that, except for information previously disclosed
publicly by the Company, all information provided to such Seller by officials of
the Company is confidential. Such Seller agrees to maintain such disclosed
information in confidence unless such information is released publicly by the
Company.

      2.08 BROKERS. Such Seller shall be responsible for any fees and expenses
owed to any agent, broker or finder with which such Seller has made any
agreement or commitment in connection with the transactions contemplated by this
Agreement.

                                   SECTION III
                  REPRESENTATIONS AND WARRANTIES OF THE COMPANY

      In order to induce the Sellers to sell the Securities, the Company
represents and warrants to the Sellers as follows:

      3.01 EXISTENCE AND GOOD STANDING. The Company is a corporation duly
organized and validly existing under the laws of the State of Delaware, and has
full power and authority to acquire the Securities and to enter into and perform
its obligations under this Agreement.

      3.02 AUTHORIZATION. The execution and delivery of this Agreement by the
Company and the consummation by the Company of the transactions contemplated by
this Agreement have been duly authorized by all necessary corporate action on
the part of the Company. No consent, approval, license from, or exemption of,
and no registration, qualification, designation, declaration or filing with, any
court or governmental department, commission, board, bureau, agency or
instrumentality, or any other party, which has not been obtained as of this
date, is or will be necessary for the valid execution and delivery by the

                                      -3-
<PAGE>
Company of this Agreement, or the consummation by the Company of the
transactions contemplated by this Agreement.

      3.03 NO CONFLICT WITH OTHER INSTRUMENTS. Neither the execution and
delivery by the Company of this Agreement, the consummation by the Company of
the transactions contemplated by this Agreement, nor the compliance by the
Company with the terms and conditions by this Agreement, will (a) violate any
provision of the Company's Certificate of Incorporation, as amended to date, or
the Company's By-laws, as amended to date; (b) violate or conflict with or
result in a breach of any law, regulation, order, writ, injunction or decree of
any court, arbitrator or governmental instrumentality to which the Company is
bound; or (c) violate or be in conflict with, or constitute a default (or an
event which, with notice or lapse of time or both, would constitute a default)
under, or entitle any party to terminate any or all of the provisions of, or
cause the acceleration of or entitle any party to accelerate the performance
required by, or cause the acceleration of or entitle any party to accelerate the
maturity of any debt or obligation pursuant to, any contract, agreement,
arrangement, commitment or restriction of any kind to which the Company is a
party or by which the Company is bound.

      3.04 VALIDITY AND BINDING EFFECT. This Agreement has been duly and validly
executed and delivered by the Company, and this Agreement constitutes the legal,
valid and binding obligation of the Company, enforceable against the Company in
accordance with its terms, except as enforceability may be limited by
bankruptcy, insolvency or other similar laws of general application affecting
the enforceability of creditors' rights generally, or by general principles of
equity.

      3.05 LITIGATION. There is no (a) action, suit, claim, proceeding or
investigation pending or, to the Company's knowledge, threatened against or
affecting, the Company, at law or in equity, or before or by any federal, state,
municipal or other governmental department, commission, board, bureau, agency or
instrumentality, domestic or foreign, (b) arbitration proceeding relating to the
Company, or (c) governmental inquiry pending, or to the Company's knowledge
threatened, against or affecting the Company, any of which, if adversely
determined, would invalidate or prevent the performance by the Company of the
transactions contemplated by this Agreement.

      3.06 PURCHASE FOR INVESTMENT. The Company is acquiring the Securities for
its own account for investment purposes only and not with a view toward any
resale or distribution of the Securities.

                                  SECTION IIIA
                                   CONDITIONS

      3.01A CONDITIONS TO THE OBLIGATION OF THE COMPANY TO CLOSE. The obligation
of the Company to purchase the Securities, to pay the Purchase Price therefor at
the Closing and to perform its obligations hereunder shall be subject to the
satisfaction as determined by, or waiver by, the Company of the following
condition on or before the Closing Date: Unless already in the possession of the
Company or its counsel, the Sellers shall have delivered the

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<PAGE>
stock certificates representing the Securities and stock powers; and all of the
representations and warranties of the Sellers set forth in Section II shall be
true and correct on the Closing Date as though made on such date.

      3.02A CONDITIONS TO THE OBLIGATION OF THE SELLERS TO CLOSE. The obligation
of each Seller to sell the Securities being sold by such Seller and to perform
its obligations hereunder shall be subject to the satisfaction as determined by,
or waiver by, the Sellers of the following conditions on or before the Closing
Date: The Company shall have paid the aggregate Purchase Price for the
Securities; and all of the representations and warranties of the Company set
forth in Section III shall be true and correct on the Closing Date as though
made on such date.

                                   SECTION IV
                                  MISCELLANEOUS

      4.01 ENTIRE AGREEMENT; AMENDMENTS. This Agreement, together with the
schedule hereto, sets forth the entire agreement of the parties with respect to
the subject matter hereof and supersedes all prior agreements between them,
whether written or oral, with respect to its subject matter. Any amendment,
supplement or modification of or to any provision of this Agreement, any waiver
of any provision of this Agreement, and any consent to any departure by the
Company or the Sellers from the terms of any provision of this Agreement, shall
be effective (i) only if it is made or given in writing and signed by the
Company and the Sellers, and (ii) only in the specific instance and for the
specific purpose for which made or given. Neither the Company nor the Sellers
shall assign any of its rights or obligations under this Agreement without the
written consent of the other parties hereto.

      4.02 FEES AND EXPENSES. Each of the parties hereto shall pay its own fees
and expenses incurred in connection with this Agreement or otherwise.

      4.03 GOVERNING LAW. This Agreement and the rights and obligations of the
parties under it shall be governed by, and construed and enforced in accordance
with, the laws of the State of Delaware, without giving effect to the rules and
principles of conflicts of laws thereof.

      4.04 COUNTERPARTS; FACSIMILE EXECUTION. This Agreement may be executed in
any number of counterparts, each of which when so executed and delivered shall
be deemed an original, but all of which together shall constitute one and the
same instrument. For purposes of this Agreement, a document (or signature page
thereto) signed and transmitted by facsimile machine or telecopier is to be
treated as an original document.


                 [Remainder of page intentionally left blank.]



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<PAGE>
      IN WITNESS WHEREOF, the parties have executed this Agreement as of the
date first above written.

                   SS&C TECHNOLOGIES, INC.

                   By:    /s/ William C. Stone
                          --------------------
                          Name:  William C. Stone

                          Title:  President and Chief Executive Officer

                   GENERAL ATLANTIC PARTNERS 15, L.P.

                   By:      General Atlantic Partners, LLC, its General Partner

                   By:     /s/ Matthew Nimetz
                           ------------------
                          Name:  Matthew Nimetz
                          Title:  A Managing Member

                   GAP COINVESTMENT PARTNERS, L.P.

                   By:     /s/ Matthew Nimetz
                           ------------------
                        Name:  Matthew Nimetz
                        Title:  A General Partner



                                      -6-
<PAGE>
                                                                   Schedule 1.02

                          Securities and Purchase Price
<TABLE>
<CAPTION>

                Seller                                Securities                           Purchase Price
<S>                                                   <C>                                  <C>

GAP 15                                                  497,003                             $5,591,283.75

GAPCO                                                   45,137                               $507,791.25

Total                                                   542,140                             $6,099,075.00

</TABLE>



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