1
    AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JANUARY 20, 1998


                                                           Registration No. 333-


                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-8

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933


                             ASPEN TECHNOLOGY, INC.
             (Exact Name of Registrant as Specified in Its Charter)

     MASSACHUSETTS                                 04-2739697
(State or Other Jurisdiction of                   (I.R.S. Employer
Incorporation or Organization)                     Identification No.)

                 TEN CANAL PARK, CAMBRIDGE, MASSACHUSETTS 02141
               (Address of Principal Executive Offices) (Zip Code)


            ASPEN TECHNOLOGY, INC. 1998 EMPLOYEE STOCK PURCHASE PLAN
                            (Full Title of the Plan)

                                LAWRENCE B. EVANS
                     Chairman of the Board of Directors and
                            Chief Executive Officer
                             ASPEN TECHNOLOGY, INC.
                                 Ten Canal Park
                         Cambridge, Massachusetts 02141
                     (Name and Address of Agent for Service)

                                 (617) 949-1000
          (Telephone Number, Including Area Code, of Agent for Service)

                                 With copies to:

       STEPHEN J. DOYLE, ESQ.                       MARK L. JOHNSON, ESQ.
 Vice President and General Counsel               FOLEY, HOAG & ELIOT LLP
       ASPEN TECHNOLOGY, INC.                      One Post Office Square
           Ten Canal Park                       Boston, Massachusetts 02109
   Cambridge, Massachusetts 02141                      (617) 832-1000
           (617) 949-1000



CALCULATION OF REGISTRATION FEE =================================================================================================================== Title of Amount Proposed Proposed Amount of Securities to be to be Maximum Offering Maximum Aggregate Registration Registered Registered Price Per Share(2)(3) Offering Price(2) Fee - ------------------------------------------------------------------------------------------------------------------- Common Stock, $.10 par value(1) 1,000,000 shares $30.25 $30,250,000 $7,586 ===================================================================================================================
(1) Each share of Common Stock will be accompanied by one Right to purchase Series A Participating Cumulative Preferred Stock of the Registrant. (2) Estimated solely for the purpose of determining the registration fee. (3) In accordance with Rules 457(c) and (h) under the Securities Act of 1933, the calculation is based on 85% of the average of the high and low sale prices reported in the consolidated reporting system of the Nasdaq National Market on January 12, 1998. 2 PART II INFORMATION REQUIRED IN THE REGISTRATION STATEMENT ITEM 3. INCORPORATION OF DOCUMENTS BY REFERENCE. The following documents heretofore filed by Aspen Technology, Inc. (the "Company") with the Securities and Exchange Commission (the "Commission") pursuant to the Securities Exchange Act of 1934, as amended (the "Exchange Act") are incorporated herein by reference: (1) the Company's Annual Report on Form 10-K for the fiscal year ended June 30, 1997, filed on September 29, 1997 pursuant to Section 12 of Exchange Act; (2) the Company's Quarterly Report on Form 10-Q for the quarterly period ended September 30, 1997, filed on November 14, 1997 pursuant to Section 13 of the Exchange Act; (3) the Company's Current Report on Form 8-K dated October 9, 1997, filed on October 10, 1997 pursuant to Section 13 of the Exchange Act; (4) the Company's definitive Proxy Statement dated October 29, 1997, filed on December 1, 1997 pursuant to Section 14 of the Exchange Act; (5) the description of the Company's Common Stock contained in the Registration Statement on Form 8-A filed on September 6, 1996 under Section 12 of the Exchange Act; and (6) the description of the Company's Rights to purchase Series A Participating Cumulative Preferred Stock contained in the Registration Statement on Form 8-A filed on October 10, 1997 under Section 12 of the Exchange Act. All reports and other documents filed by the Company pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act, on or after the date of this Registration Statement and prior to the filing of a post-effective amendment which indicates that all securities offered have been sold or which deregisters all securities then remaining unsold shall be deemed to be incorporated by reference in this Registration Statement and to be a part hereof from the date of the filing of such reports and documents. ITEM 4. DESCRIPTION OF SECURITIES. Not applicable. ITEM 5. INTERESTS OF NAMED EXPERTS AND COUNSEL. Not applicable. II-1 3 ITEM 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS. Section 67 of Chapter 156B of the Massachusetts General Laws provides a statutory framework covering indemnification of directors and officers against liabilities and expenses arising out of legal proceedings brought against them by reason of their status or service as directors or officers. In addition, Article VII of the Company's By-Laws provides for indemnification of directors, officers and employees of the Company. Section 67 and the Company's By-Laws generally provide that a director, officer or employee of the Company shall be indemnified by the Company for all expenses and liabilities of legal proceedings brought against him/her by reason of his/her status or service as a director, officer or employee unless the director, officer or employee is adjudged not to have acted in good faith in the reasonable belief that his/her action was in the best interest of the Company or, to the extent that such matter relates to service with respect to an employee benefit plan, in the best interests of the participants or beneficiaries of such plan The Company's Restated Articles of Organization also incorporate certain provisions permitted under the Massachusetts General Laws relating to the liability of directors. The provisions eliminate a director's liability for monetary damages for a breach of fiduciary duty, including gross negligence, except in circumstances involving certain wrongful acts, such as the breach of a director's duty of loyalty or acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law or authorization of distributions in violation of the Restated Articles of Organization or of loans to officers or directors of the Company or any transaction from which the director derived an improper personal benefit. These provisions do not eliminate a director's duty of care. Moreover, the provisions do not apply to claims against a director for violations of certain laws, including federal securities laws. ITEM 7. EXEMPTION FROM REGISTRATION CLAIMED. Not applicable. ITEM 8. EXHIBITS. The following exhibits are filed as part of this Registration Statement: 4.1 Restated Articles of Organization of the Company, as amended 4.2 By-Laws of the Company (incorporated by reference to Exhibit 3.3 to the Company's Registration Statement on Form S-1 of the Company, Registration No. 33-83916, filed with the Commission on September 13, 1994) 4.3 Specimen certificate representing Common Stock of the Company (incorporated by reference to Exhibit 4.1 to the Company's Registration Statement on Form S-1, Registration No. 33-83916, filed with the Commission on September 13, 1994) 4.4 Rights Agreement dated as of October 9, 1997, between the Company and American Stock Transfer and Trust Company, as Rights Agent (incorporated by reference to Exhibit 1 to the Company's Registration Statement on Form 8-A, File No. 0-24786, filed with the Commission on October 10, 1997) II-2 4 4.5 Specimen certificate representing Rights to purchase Series A Participating Cumulative Preferred Stock of the Company (included as exhibit B to the Rights Agreement referenced in Exhibit 4.4) 5.1 Opinion of Foley, Hoag & Eliot LLP 10.1 Aspen Technology, Inc. 1998 Employee Stock Purchase Plan 23.1 Consent of Arthur Andersen LLP 23.2 Consent of Foley, Hoag & Eliot LLP (included in Exhibit 5.1) 24.1 Power of Attorney (contained on the signature pages to this Registration Statement) ITEM 9. UNDERTAKINGS. 1. The undersigned Registrant hereby undertakes: (a) To file, during any period in which offers or sales are being made, a post-effective amendment to this Registration Statement: (i) To include any prospectus required by Section 10(a)(3) of the Securities Act of 1933; (ii) To reflect in the prospectus any facts or events arising after the effective date of the Registration Statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the Registration Statement; (iii) To include any material information with respect to the plan of distribution not previously disclosed in the Registration Statement or any material change to such information in the Registration Statement; provided, however, that paragraphs (i) and (ii) above do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in periodic reports filed by the Registrant pursuant to Section 13 or Section 15(d) of the Exchange Act that are incorporated by reference herein. (b) That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered herein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. (c) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering. 2. The undersigned Registrant hereby undertakes that, for purposes of determining any liability under the Securities Act of 1933, each filing of the Registrant's annual report pursuant to Section 13(a) or II-3 5 Section 15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan's annual report pursuant to Section 15(d) of the Exchange Act) that is incorporated by reference in this Registration Statement shall be deemed to be a new registration statement relating to the securities offered herein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. 3. Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the Registrant pursuant to the foregoing provisions, or otherwise, the Registrant has been advised that in the opinion of the Commission such indemnification is against public policy as expressed in the Securities Act of 1933 and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the Registrant of expenses incurred or paid by a director, officer or controlling person of the Registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the Registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Act and will be governed by the final adjudication of such issue. II-4 6 SIGNATURE Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Cambridge, Massachusetts, on this fifteenth day of January, 1998. ASPEN TECHNOLOGY, INC. By: /s/ Lawrence B. Evans ---------------------------------------- Lawrence B. Evans Chairman of the Board of Directors and Chief Executive Officer POWER OF ATTORNEY KNOW ALL MEN BY THESE PRESENTS that each individual whose signature appears below constitutes and appoints Lawrence B. Evans, Mary A. Palermo and Stephen J. Doyle, and each of them, true and lawful attorneys-in-fact and agents with full power of substitution, for and in name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this Registration Statement, and to file the same, with all exhibits thereto, and all documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing which they, or any of them, may deem necessary or advisable to be done in connection with this Registration Statement, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents or any of them, or any substitute or substitutes for him, any or all of them, may lawfully do or cause to be done by virtue hereof. Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed by the following persons, in the capacities indicated, as of this fifteenth day of January, 1998. SIGNATURE TITLE /s/ LAWRENCE B. EVANS Chairman of the Board of Directors and Chief - ---------------------------- Executive Officer (Principal Executive Officer) LAWRENCE B. EVANS /s/ MARY A. PALERMO Executive Vice President (Principal Accounting - ---------------------------- Officer and Principal Financial Officer) MARY A. PALERMO /s/ JOSEPH F. BOSTON Director - ---------------------------- JOSEPH F. BOSTON II-5 7 SIGNATURE TITLE /s/ GRESHAM T. BREBACH, JR. Director - ------------------------------ GRESHAM T. BREBACH, JR. /s/ DOUGLAS R. BROWN Director - ------------------------------ DOUGLAS R. BROWN /s/ JOAN C. MCARDLE Director - ------------------------------ JOAN C. MCARDLE /s/ ALISON ROSS Director - ------------------------------ ALISON ROSS II-6 8 EXHIBIT INDEX Exhibit No. Description 4.1 Restated Articles of Organization of Aspen Technology, Inc., as amended 4.2 By-Laws of Aspen Technology, Inc. (incorporated by reference to Exhibit 3.3 to Aspen Technology, Inc.'s Registration Statement on Form S-1, Registration No. 33-83916, filed with the Securities and Exchange Commission on September 13, 1994) 4.3 Specimen certificate representing Common Stock of Aspen Technology, Inc. (incorporated by reference to Exhibit 4.1 to Aspen Technology, Inc.'s Registration Statement on Form S-1, Registration No. 33-83916, filed with the Securities and Exchange Commission on September 13, 1994) 4.4 Rights Agreement dated as of October 9, 1997, between Aspen Technology, Inc. and American Stock Transfer and Trust Company, as Rights Agent (incorporated by reference to Exhibit 1 to Aspen Technology, Inc.'s Registration Statement on Form 8-A, File No. 0-24786, filed with the Securities and Exchange Commission on October 10, 1997) 4.5 Specimen certificate representing Rights to purchase Series A Participating Cumulative Preferred Stock of Aspen Technology, Inc. (included as exhibit B to the Rights Agreement referenced in Exhibit 4.4) 5.1 Opinion of Foley, Hoag & Eliot LLP 10.1 Aspen Technology, Inc. 1998 Employee Stock Purchase Plan 23.1 Consent of Arthur Andersen LLP 23.2 Consent of Foley, Hoag & Eliot LLP (included in Exhibit 5.1) 24.1 Power of Attorney (contained on the signature pages to this Registration Statement)
   1
                                                                     Exhibit 4.1
                                                          FEDERAL IDENTIFICATION
                                                                  NO. 04-2739697

                        THE COMMONWEALTH OF MASSACHUSETTS

                             MICHAEL JOSEPH CONNOLLY
                               SECRETARY OF STATE
                    ONE ASHBURTON PLACE, BOSTON, MASS. 02108

                        RESTATED ARTICLES OF ORGANIZATION

                     General Laws, Chapter 156B, Section 74

     This certificate must be submitted to the Secretary of the Commonwealth
within sixty days after the date of the vote of stockholders adopting the
restated articles of organization. The fee for filing this certificate is
prescribed by General Laws, Chapter 156B, Section 114. Make check payable to the
Commonwealth of Massachusetts.

     We, Joseph F. Boston and Richard M. Harter                  , President and
                                                                        Clerk of

                             Aspen Technology, Inc.
- --------------------------------------------------------------------------------
                              (Name of Corporation)

located at Ten Canal Park, Cambridge, MA 02141 do hereby certificate that the
following restatement of the articles of organization of the corporation was
duly adopted at a meeting held on October 5, 1994, by vote of (See Continuation
Page 1) being at least two-thirds of each class of stock outstanding and
entitled to vote and of each class or series of stock adversely affected
thereby:

     1.   The name by which the corporation shall be known as: Aspen Technology,
          Inc.

     2.   The purposes for which the corporation is formed are as follows: To
          design and market computer software programs, and in general to carry
          on any business permitted to corporations under Chapter 156B of the
          General Laws as now in effect or as hereafter amended, or any
          successor provision to such Chapter.

   2


     3.   The total number of shares and the par value, if any, of each class of
          stock which the corporation is authorized to issue is as follows:

WITHOUT PAR VALUE WITH PAR VALUE ----------------- -------------- CLASS OF STOCK NUMBER OF SHARES NUMBER OF SHARES PAR VALUE - -------------- ---------------- ---------------- --------- Preferred 10,000,000 $0.10 Common 15,000,000 $0.10
*4. If more than one class is authorized, a description of each of the different classes of stock with, if any, the preferences, voting powers, qualifications, special or relative rights or privileges as to each class thereof and any series now established: The Corporation shall have authority to issue 25,000,000 shares of capital stock of which 15,000,000 shares shall be common stock in the amount as set forth below and 10,000,000 shares shall be preferred stock in the amount as set forth below:
Classification No. of shares Par Value -------------- ------------- --------- Common Stock 15,000,000 $0.10 Preferred Stock 10,000,000 $0.10
(See Continuation Page 2) *5. The restrictions, if any, imposed by the articles of organization upon the transfer of shares of stock of any class are as follows: None *6. Other lawful provisions, if any, for the conduct and regulation of the business and affairs of the corporation, for its voluntary dissolution, or for limiting, defining, or regulating the powers of the corporation, or of its directors or stockholders, or of any class of stockholders: Meetings of the stockholders may be held anywhere within the United States. The directors may make, amend, or repeal the By-Laws, in whole or in part, except with respect to any provision thereof which by law or the By-laws requires action by the stockholders. The Corporation may be a partner in any business enterprise which it would have power to conduct by itself. (See Continuation Page 3) 3 CONTINUATION PAGE 1 Restated Articles of Organization Aspen Technology, Inc. 2,616,130 shares of Common Stock out of 2,830,197 shares outstanding, 5,000 shares of Class A Convertible Preferred Stock out of 5,000 shares outstanding, 101,986 shares of Class B Convertible Preferred Stock out of 101,986 shares outstanding, and 250,000 shares of Series C-1 Preferred Stock out of 250,000 shares outstanding. 4 CONTINUATION PAGE 2 Restated Articles of Organization Aspen Technology, Inc. The shares of preferred stock may be issued from time to time in one or more classes or series. The Board of Directors is hereby authorized to establish and designate the different class or series, and to fix and determine preferences, voting powers, qualifications, and special or relative rights or privileges thereof and such designations as shall be stated in a vote or votes providing for the issue of such class or series adopted by the Board of Directors, which preferences, voting powers, qualifications, and special or relative rights or privileges need not be uniform among class or series. Any of the preferences, voting powers, qualification and special or relative rights or privileges of any such class or series of stock may be made dependent upon facts ascertainable outside the vote or votes providing for the issue or such stock adopted by the Board of Directors, provided that the manner in which such facts shall operate upon the preferences, voting powers, qualifications, and special or relative rights or privileges of such class or series of stock is clearly and expressly set forth in the vote or votes providing for the issue of such class or series adopted by the Board of Directors. Prior to the issuance of any shares of the class or series having terms so determined by the Board of Directors other than a reissue of shares as shares of the same class and series, the Corporation shall submit to the Secretary of State a certificate signed by the president or a Vice president and by the Clerk or an Assistant Clerk setting forth the text of the vote or votes of the Board of Directors determining the terms of the class or series or the number of votes and a certificate that such vote or votes were duly adopted by the Board of Directors. 5 CONTINUATION PAGE 3 Restated Articles of Organization Aspen Technology, Inc. No director shall be personally liable to the corporation or to any of its stockholders for monetary damages for any breach of fiduciary duty by such director as a director notwithstanding any provision of law imposing such liability; provided, however, that, to the extent required from time to time by applicable law, this provision shall not eliminate the liability of a director, to the extent such liability is provided by applicable law, (a) for any breach of the director's duty of loyalty to the corporation or its stockholders, (b) for acts or omissions not in good faith which involve intentional misconduct or a knowing violation of law, (c) under Section 61 or Section 62 of the Business Corporation Law of the Commonwealth of Massachusetts, or (d) for any transaction from which the director derived an improper personal benefit. No amendment to or repeal of this paragraph shall apply to or have any effect on the liability or alleged liability of any director for or with respect to any acts or omissions of such director occurring prior to the effective date of such amendment or repeal. The number of directors shall be determined in accordance with the By-laws. The directors shall be divided into three classes by the Board, as nearly equal in number as may be, the term of office of those of the first class to expire at the first annual meeting of stockholders after their election, the term of office of those of the second class to expire at the second annual meeting of stockholders after their election, and the term of office of those of the third class to expire at the third annual meeting of stockholders after their election, all directors to serve until their successor are elected and qualified. At each annual election held thereafter, the directors to succeed those whose terms expire shall be elected for a term of office to expire at the third annual meeting of stockholders after their election and after their successors are elected and qualified. 6 *We further certify that the foregoing restated articles of organization effect no amendments to the articles of organization of the corporation as heretofore amended, except amendments to the following articles 3, 4 and 6 ---------------- Briefly describe amendments in space below: A. ARTICLE III IS AMENDED TO INCREASE THE NUMBER OF AUTHORIZED SHARES OF COMMON STOCK OF THE COMPANY AND TO INCREASE THE NUMBER OF AUTHORIZED SHARES OF PREFERRED STOCK OF THE COMPANY. B. ARTICLE IV IS AMENDED TO ELIMINATE THE CLASS A, CLASS B AND SERIES C-1 PREFERRED STOCK OF THE COMPANY. C. ARTICLE VI IS AMENDED TO PROVIDE FOR THE EXCULPATION OF DIRECTORS. IN WITNESS WHEREOF AND UNDER THE PENALTIES OF PERJURY, we have hereto signed our names this 1st day of November in the year 1994. /s/ Joseph F. Boston President /s/ Richard M. Harter Clerk 7 THE COMMONWEALTH OF MASSACHUSETTS RESTATED ARTICLES OF ORGANIZATION (General Laws, Chapter 156B, Section 74) I hereby approve the within restated articles of organization and, the filing fee in the amount of $14,245.00 having been paid, said articles are deemed to have been filed with me this 1st day of November, 1994. /s/ Michael Joseph Connolly MICHAEL JOSEPH CONNOLLY Secretary of State TO BE FILLED IN BY CORPORATION PHOTOCOPY OF RESTATED ARTICLES OF ORGANIZATION TO BE SENT TO: Richard M. Harter, Esq. Bingham, Dana & Gould 150 Federal Street Boston, MA 02110 Telephone (617) 951-8415 8 FEDERAL IDENTIFICATION NO. 04-2739697 THE COMMONWEALTH OF MASSACHUSETTS William Francis Galvin Secretary of the Commonwealth One Ashburton Place, Boston, Massachusetts 02108-1512 ARTICLES OF AMENDMENT (General Laws, Chapter 156B, Section 72) We, Joseph F. Boston, , President and Stephen J. Doyle , Assistant Clerk, of Aspen Technology, Inc. - -------------------------------------------------------------------------------- (Exact name of corporation) located at: Ten Canal Park, Cambridge, MA 02141 - -------------------------------------------------------------------------------- (Street address of corporation in Massachusetts) certify that these Articles of Amendment affecting articles numbered: Article 3 and Article 4 - -------------------------------------------------------------------------------- (Number those articles 1, 2, 3, 4, 5, and/or 6 being amended) of the Articles of Organization were duly adopted at a meeting held on December 16, 1996, by vote of: 5,241,622 shares of Common of 9,729,730 shares outstanding, being at least a majority of each type, class or series outstanding and entitled to vote thereon. That Section 3 of the Corporation's Articles of Organization is hereby amended to read in its entirety as follows: 3. The total number of shares and the par value, if any, of each class of capital stock which the corporation (see continuation page 1) 9 To change the number of shares and the par value (if any) of any type, class or series of stock which the corporation is authorized to issue, fill in the following: The total presently authorized is:
- ------------------------------------- ------------------------------------------------- WITHOUT PAR VALUE STOCKS WITH PAR VALUE STOCKS - ------------------- ----------------- ---------------- ----------------- -------------- TYPE NUMBER OF SHARES TYPE NUMBER OF SHARES PAR VALUE - ------------------- ----------------- ---------------- ----------------- -------------- Common: Common: 15,000,000 .10 - ------------------- ----------------- ---------------- ----------------- -------------- - ------------------- ----------------- ---------------- ----------------- -------------- Preferred: Preferred: 10,000,000 .10 - ------------------- ----------------- ---------------- ----------------- -------------- - ------------------- ----------------- ---------------- ----------------- --------------
Change the total authorized to:
- ------------------------------------- ------------------------------------------------- WITHOUT PAR VALUE STOCKS WITH PAR VALUE STOCKS - ------------------- ----------------- ---------------- ----------------- -------------- TYPE NUMBER OF SHARES TYPE NUMBER OF SHARES PAR VALUE - ------------------- ----------------- ---------------- ----------------- -------------- Common: Common: 40,000,000 .10 - ------------------- ----------------- ---------------- ----------------- -------------- - ------------------- ----------------- ---------------- ----------------- -------------- Preferred: Preferred: 10,000,000 .10 - ------------------- ----------------- ---------------- ----------------- -------------- - ------------------- ----------------- ---------------- ----------------- --------------
10 CONTINUATION PAGE 1 is authorized to issue as follows:
WITH PAR VALUE WITHOUT PAR VALUE CLASS OF STOCK NUMBER OF SHARES NUMBER OF SHARES PAR VALUE Preferred 10,000,000 $0.10 Common 40,000,000 $0.10
That Section 4 of the Corporation's Articles of Organization is hereby amended to read in its entirety as follows: 4. If more than one class is authorized, a description of each of the different classes of stock, with, if any, the preferences, voting powers, qualifications, special or relative rights or privileges as to each class thereof and any series now established: The Corporation shall have authority to issue 50,000,000 shares of capital stock of which 40,000,000 shares shall be Common Stock in the amount as set forth below and 10,000,000 shares shall be preferred stock in the amount set forth below:
CLASSIFICATION NO. OF SHARES PAR VALUE Common Stock 40,000,000 $0.10 Preferred Stock 10,000,000 $0.10
The shares of preferred stock may be issued from time to time in one or more classes or series. The Board of Directors is hereby authorized to establish and designate the different class or series, and to fix and determine preferences, voting powers, qualifications, and special or relative rights or privileges thereof and such (see continuation page 2) The foregoing amendment(s) will become effective when these Articles of Amendment are filed in accordance with General Laws, Chapter 156B, Section 6 unless these articles specify, in accordance with the vote adopting the amendment, a later effective date not more than thirty days after such filing in which event the amendment will become effective on such later date. Later effective date: SIGNED UNDER THE PENALTIES OF PERJURY, this 6th day of January, 1997. /s/ Joseph F. Boston, President /s/ Stephen J. Doyle, Assistant Clerk 11 CONTINUATION PAGE 2 designations as shall be stated in a vote or votes providing for the issue of such class or series adopted by the Board of Directors, which preferences, voting powers, qualifications, and special or relative rights or privileges need not be uniform among class or series. Any of the preferences, voting powers, qualifications, and special or relative rights or privileges of any such class or series of stock may be made dependent upon facts ascertainable outside the vote or votes providing for the issue of such stock adopted by the Board of Directors, provided that the manner in which such facts shall operate upon the preferences, voting powers, qualifications, and special or relative rights or privileges of such class or series of stock is clearly and expressly set forth in the vote or votes providing for the issue of such class or series adopted by the Board of Directors. Prior to the issuance of any shares of the class or series having terms so determined by the Board of Directors other than a reissue of shares as shares of the same class and series, the Corporation shall submit to the Secretary of State a certificate signed by the President or a Vice President and by the Clerk or an Assistant Clerk setting forth the text of the vote or votes of the Board of Directors determining the terms of the class or series or the number of votes and a certificate that such vote or votes were duly adopted by the Board of Directors. 12 THE COMMONWEALTH OF MASSACHUSETTS ARTICLES OF AMENDMENT (General Laws, Chapter 156B, Section 72) I hereby approve the within Articles of Amendment, and the filing fee in the amount of $25,100 having been paid, said article is deemed to have been filed with me this 6th day of January, 1997. Effective date: /s/ William Francis Galvin WILLIAM FRANCIS GALVIN Secretary of the Commonwealth TO BE FILLED IN BY CORPORATION Photocopy of document to be sent to: Aspen Technology, Inc. Ten Canal Park Cambridge, MA 02141 Attn: Karen Hrynyszyn 13 FEDERAL IDENTIFICATION NO. 04-2739697 THE COMMONWEALTH OF MASSACHUSETTS William Francis Galvin Secretary of the Commonwealth ONE ASHBURTON PLACE, BOSTON, MASS. 02108 CERTIFICATE OF VOTE OF DIRECTORS ESTABLISHING A SERIES OF A CLASS OF STOCK General Laws, Chapter 156B, Section 26 We, Joseph F. Boston, , President, and Stephen J. Doyle , Clerk of Aspen Technology, Inc. - -------------------------------------------------------------------------------- (Name of Corporation) located at Ten Canal Park, Cambridge, MA 02141 do hereby certify that at a meeting of the directors of the corporation held on October 9, 1997, the following vote establishing and designating a series of a class of stock and determining the relative rights and preferences thereof was duly adopted: See Continuation Sheet 2A attached hereto. 14 CONTINUATION SHEET 2A ASPEN TECHNOLOGY, INC. VOTED: That the Corporation designate and establish 400,000 shares of its authorized but unissued Preferred Stock as its Series A Participating Cumulative Preferred Stock, par value $.10 per share (the "Series A Preferred Stock"); that the rights, preferences, privileges, limitations and restrictions that shall be applicable to the shares of Series A Preferred Stock, set forth in their entirety in EXHIBIT B attached hereto, be, and they hereby are, approved; and that the President or any Vice President and the Clerk or any Assistant Clerk of the Corporation be, and they hereby are, authorized to execute a Certificate of Vote of Directors Establishing a Series of a Class of Stock (the "Certificate of Vote of Directors") setting forth such rights, preferences, privileges, limitations and restrictions of the Series A Preferred Stock in the name of the Corporation, and to file the Certificate of Vote of Directors with the Secretary of State of The Commonwealth of Massachusetts and such other governmental authorities as may be required by law. 15 EXHIBIT B TERMS OF SERIES A PARTICIPATING CUMULATIVE PREFERRED STOCK OF ASPEN TECHNOLOGY, INC. SECTION 1. DESIGNATION AND NUMBER OF SHARES. The shares of such series shall be designated as "Series A Participating Cumulative Preferred Stock" (the "Series A Preferred Stock"), par value $.10 per share. The number of shares initially constituting the Series A Preferred Stock shall be 400,000; PROVIDED, HOWEVER, that, if more than a total of 400,000 shares of Series A Preferred Stock shall be issuable upon the exercise of Rights (the "Rights") issued pursuant to the Rights Agreement dated as of October 9, 1997, between the Corporation and American Stock Transfer and Trust Company, a limited power banking trust company licensed by the New York State Banking Authority, as Rights Agent (the "Rights Agreement"), the Board of Directors of the Corporation, pursuant to Section 26 of the Business Corporation Law of The Commonwealth of Massachusetts, shall direct by vote or votes that a certificate be properly executed, acknowledged, filed and recorded, in accordance with the provisions of Section 26 thereof, providing for the total number of shares of Series A Preferred Stock authorized to be issued to be increased (to the extent that the Articles of Organization then permits) to the largest number of whole shares (rounded up to the nearest whole number) issuable upon exercise of such Rights. SECTION 2. DIVIDENDS OR DISTRIBUTIONS. (a) Subject to the prior and superior rights of the holders of shares of any other series of Preferred Stock or other class of capital stock of the Corporation ranking prior and superior to the shares of Series A Preferred Stock with respect to dividends, the holders of shares of the Series A Preferred Stock shall be entitled to receive, when, as and if declared by the Board of Directors, out of the assets of the Corporation legally available therefor, (1) quarterly dividends payable in cash on the last day of each fiscal quarter in each year, or such other dates as the Board of Directors of the Corporation shall approve (each such date being referred to herein as a "Quarterly Dividend Payment Date"), commencing on the first Quarterly Dividend Payment Date after the first issuance of a share or a fraction of a share of Series A Preferred Stock, in the amount of $1.00 per whole share (rounded to the nearest cent) less the amount of all cash dividends declared on the Series A Preferred Stock pursuant to the following clause (2) since the immediately preceding Quarterly Dividend Payment Date or, with respect to the first Quarterly Dividend Payment Date, since the first issuance of any share or fraction of a share of Series A Preferred Stock (the total of which shall not, in any event, be less than zero) and (2) dividends payable in cash on the payment date for each cash dividend declared on the Common Stock in an amount per whole share (rounded to the nearest cent) equal to the Formula Number (as hereinafter defined) then in effect times the cash dividends then to be paid on each share of Common Stock. In addition, if the Corporation shall pay any dividend or make any distribution on the Common Stock payable in assets, securities or other forms of noncash consideration (other than dividends or distributions solely in shares of Common Stock), then, in each such case, the Corporation shall simultaneously pay or make on each outstanding whole 16 share of Series A Preferred Stock a dividend or distribution in like kind equal to the Formula Number then in effect times such dividend or distribution on each share of the Common Stock. As used herein, the "Formula Number" shall be 100; PROVIDED, HOWEVER, that if at any time after October 9, 1997, the Corporation shall (i) declare or pay any dividend on the Common Stock payable in shares of Common Stock or make any distribution on the Common Stock in shares of Common Stock, (ii) subdivide (by a stock split or otherwise) the outstanding shares of Common Stock into a larger number of shares of Common Stock or (iii) combine (by a reverse stock split or otherwise) the outstanding shares of Common Stock into a smaller number of shares of Common Stock, then in each such event the Formula Number shall be adjusted to a number determined by multiplying the Formula Number in effect immediately prior to such event by a fraction, the numerator of which is the number of shares of Common Stock that are outstanding immediately after such event and the denominator of which is the number of shares of Common Stock that are outstanding immediately prior to such event (and rounding the result to the nearest whole number); and PROVIDED FURTHER, that, if at any time after October 9, 1997, the Corporation shall issue any shares of its capital stock in a merger, reclassification, or change of the outstanding shares of Common Stock, then in each such event the Formula Number shall be appropriately adjusted to reflect such merger, reclassification or change so that each share of Series A Preferred Stock continues to be the economic equivalent of a Formula Number of shares of Common Stock prior to such merger, reclassification or change. (b) The Corporation shall declare a dividend or distribution on the Series A Preferred Stock as provided in Section 2(a) immediately prior to or at the same time it declares a dividend or distribution on the Common Stock(other than a dividend or distribution solely in shares of Common Stock); PROVIDED, HOWEVER, that, in the event no dividend or distribution (other than a dividend or distribution in shares of Common Stock) shall have been declared on the Common Stock during the period between any Quarterly Dividend Payment Date and the next subsequent Quarterly Dividend Payment Date, a dividend of $1.00 per share on the Series A Preferred Stock shall nevertheless be payable on such subsequent Quarterly Dividend Payment Date. The Board of Directors may fix a record date for the determination of holders of shares of Series A Preferred Stock entitled to receive a dividend or distribution declared thereon, which record date shall be the same as the record date for any corresponding dividend or distribution on the Common Stock. (c) Dividends shall begin to accrue and be cumulative on outstanding shares of Series A Preferred Stock from and after the Quarterly Dividend Payment Date next preceding the date of original issue of such shares of Series A Preferred Stock; PROVIDED, HOWEVER, that dividends on such shares which are originally issued after the record date for the determination of holders of shares of Series A Preferred Stock entitled to receive a quarterly dividend and on or prior to the next succeeding Quarterly Dividend Payment Date shall begin to accrue and be cumulative from and after such Quarterly Dividend Payment Date. Notwithstanding the foregoing, dividends on shares of Series A Preferred Stock which are originally issued prior to the record date for the determination of holders of shares of Series A Preferred Stock entitled to receive a quarterly dividend on the first Quarterly Dividend Payment Date shall be calculated as if cumulative from and after the last day of the fiscal quarter next preceding the date of original issuance of such shares. Accrued but unpaid dividends shall not bear interest. Dividends paid on the shares of Series A Preferred Stock in an amount less than the total amount of such dividends at the time 17 accrued and payable on such shares shall be allocated pro rata on a share-by-share basis among all such shares at the time outstanding. (d) So long as any shares of the Series A Preferred Stock are outstanding, no dividends or other distributions shall be declared, paid or distributed, or set aside for payment or distribution, on the Common Stock unless, in each case, the dividend required by this Section 2 to be declared on the Series A Preferred Stock shall have been declared. (e) The holders of the shares of Series A Preferred Stock shall not be entitled to receive any dividends or other distributions except as provided herein. SECTION 3. VOTING RIGHTS. The holders of shares of Series A Preferred Stock shall have the following voting rights: (a) Each holder of Series A Preferred Stock shall be entitled to a number of votes equal to the Formula Number then in effect, for each share of Series A Preferred Stock held of record on each matter on which holders of the Common Stock or stockholders generally are entitled to vote, multiplied by the maximum number of votes per share which any holder of the Common Stock or stockholders generally then have with respect to such matter (assuming any holding period or other requirement to vote a greater number of shares is satisfied). (b) Except as otherwise provided herein or by applicable law, the holders of shares of Series A Preferred Stock and the holders of shares of Common Stock shall vote together as one class for the election of directors of the Corporation and on all other matters submitted to a vote of stockholders of the Corporation. (c) If, at the time of any annual meeting of stockholders for the election of directors, the equivalent of six quarterly dividends (whether or not consecutive) payable on any share or shares of Series A Preferred Stock are in default, the number of directors constituting the Board of Directors of the Corporation shall be increased by two. In addition to voting together with the holders of Common Stock for the election of other directors of the Corporation, the holders of record of the Series A Preferred Stock, voting separately as a class to the exclusion of the holders of Common Stock, shall be entitled at said meeting of stockholders (and at each subsequent annual meeting of stockholders), unless all dividends in arrears have been paid or declared and set apart for payment prior thereto, to vote for the election of two directors of the Corporation, the holders of any Series A Preferred Stock being entitled to cast a number of votes per share of Series A Preferred Stock equal to the Formula Number. Until the default in payments of all dividends which permitted the election of said directors shall cease to exist, any director who shall have been so elected pursuant to the next preceding sentence may be removed at any time, either with or without cause, only by the affirmative vote of the holders of the shares of Series A Preferred Stock at the time entitled to cast a majority of the votes entitled to be cast for the election of any such director at a special meeting of such holders called for that purpose, and any vacancy thereby created may be filled by the vote of such holders. If and when such default shall cease to exist, the holders of the Series A Preferred Stock shall be divested of the foregoing special voting rights, subject to revesting in the event of each and every subsequent like default in 18 payments of dividends. Upon the termination of the foregoing special voting rights, the terms of office of all persons who may have been elected directors pursuant to said special voting rights shall forthwith terminate, and the number of directors constituting the Board of Directors shall be reduced by two. The voting rights granted by this Section 3(c) shall be in addition to any other voting rights granted to the holders of the Series A Preferred Stock in this Section 3. (d) Except as provided herein, in Section 11 or by applicable law, holders of Series A Preferred Stock shall have no special voting rights and their consent shall not be required (except to the extent they are entitled to vote with holders of Common Stock as set forth herein) for authorizing or taking any corporate action. SECTION 4. CERTAIN RESTRICTIONS. (a) Whenever quarterly dividends or other dividends or distributions payable on the Series A Preferred Stock as provided in Section 2 are in arrears, thereafter and until all accrued and unpaid dividends and distributions, whether or not declared, on shares of Series A Preferred Stock outstanding shall have been paid in full, the Corporation shall not (i) declare or pay dividends on, make any other distributions on, or redeem or purchase or otherwise acquire for consideration any shares of stock ranking junior (either as to dividends or upon liquidation, dissolution or winding up) to the Series A Preferred Stock; (ii) declare or pay dividends on or make any other distributions on any shares of stock ranking on a parity (either as to dividends or upon liquidation, dissolution or winding up) with the Series A Preferred Stock, except dividends paid ratably on the Series A Preferred Stock and all such parity stock on which dividends are payable or in arrears in proportion to the total amounts to which the holders of all such shares are then entitled; (iii) redeem or purchase or otherwise acquire for consideration shares of any stock ranking on a parity (either as to dividends or upon liquidation, dissolution or winding up) with the Series A Preferred Stock; PROVIDED that the Corporation may at any time redeem, purchase or otherwise acquire shares of any such parity stock in exchange for shares of any stock of the Corporation ranking junior (either as to dividends or upon dissolution, liquidation or winding up) to the Series A Preferred Stock; or (iv) purchase or otherwise acquire for consideration any shares of Series A Preferred Stock, or any shares of stock ranking on a parity with the Series A Preferred Stock, except in accordance with a purchase offer made in writing or by publication (as determined by the Board of Directors) to all holders of such shares upon such terms as the Board of Directors, after consideration of the respective annual dividend rates and other relative rights and preferences of the respective series and classes, shall determine in good faith will result in fair and equitable treatment among the respective series or classes. (b) The Corporation shall not permit any subsidiary of the Corporation to purchase or otherwise acquire for consideration any shares of stock of the Corporation unless the Corporation 19 could, under paragraph (a) of this Section 4, purchase or otherwise acquire such shares at such time and in such manner. SECTION 5. LIQUIDATION RIGHTS. Upon the liquidation, dissolution or winding up of the Corporation, whether voluntary or involuntary, no distribution shall be made (1) to the holders of shares of stock ranking junior (either as to dividends or upon liquidation, dissolution or winding up) to the Series A Preferred Stock unless, prior thereto, the holders of shares of Series A Preferred Stock shall have received an amount equal to the accrued and unpaid dividends and distributions thereon, whether or not declared, to the date of such payment, plus an amount equal to the greater of (x) $10.00 per whole share or (y) an aggregate amount per share equal to the Formula Number then in effect times the aggregate amount to be distributed per share to holders of Common Stock or (2) to the holders of stock ranking on a parity (either as to dividends or upon liquidation, dissolution or winding up) with the Series A Preferred Stock, except distributions made ratably on the Series A Preferred Stock and all other such parity stock in proportion to the total amounts to which the holders of all such shares are entitled upon such liquidation, dissolution or winding up. SECTION 6. CONSOLIDATION, MERGER, ETC.. In case the Corporation shall enter into any consolidation, merger, combination or other transaction in which the shares of Common Stock are exchanged for or changed into other stock or securities, cash or any other property, then in any such case the then outstanding shares of Series A Preferred Stock shall at the same time be similarly exchanged or changed into an amount per share equal to the Formula Number then in effect times the aggregate amount of stock, securities, cash or any other property (payable in kind), as the case may be, into which or for which each share of Common Stock is exchanged or changed. In the event both this Section 6 and Section 2 appear to apply to a transaction, this Section 6 will control. SECTION 7. NO REDEMPTION; NO SINKING FUND. (a) The shares of Series A Preferred Stock shall not be subject to redemption by the Corporation or at the option of any holder of Series A Preferred Stock; PROVIDED, HOWEVER, that the Corporation may purchase or otherwise acquire outstanding shares of Series A Preferred Stock in the open market or by offer to any holder or holders of shares of Series A Preferred Stock. (b) The shares of Series A Preferred Stock shall not be subject to or entitled to the operation of a retirement or sinking fund. SECTION 8. RANKING. The Series A Preferred Stock shall rank junior to all other series of Preferred Stock of the Corporation, unless the Board of Directors shall specifically determine otherwise in fixing the powers, preferences and relative, participating, optional and other special rights of the shares of such series and the qualifications, limitations and restrictions thereof. SECTION 9. FRACTIONAL SHARES. The Series A Preferred Stock shall be issuable upon exercise of the Rights issued pursuant to the Rights Agreement in whole shares or in any fraction of a share that is one one-hundredth (1/100th) of a share or any integral multiple of such fraction which shall entitle the holder, in proportion to such holder's fractional shares, to receive dividends, 20 exercise voting rights, participate in distributions and to have the benefit of all other rights of holders of Series A Preferred Stock. In lieu of fractional shares, the Corporation, prior to the first issuance of a share or a fraction of a share of Series A Preferred Stock, may elect (1) to make a cash payment as provided in the Rights Agreement for fractions of a share other than one one-hundredth (1/100th) of a share or any integral multiple thereof or (2) to issue depository receipts evidencing such authorized fraction of a share of Series A Preferred Stock pursuant to an appropriate agreement between the Corporation and a depository selected by the Corporation; PROVIDED that such agreement shall provide that the holders of such depository receipts shall have all the rights, privileges and preferences to which they are entitled as holders of the Series A Preferred Stock. SECTION 10. REACQUIRED SHARES. Any shares of Series A Preferred Stock purchased or otherwise acquired by the Corporation in any manner whatsoever shall be retired and canceled promptly after the acquisition thereof. All such shares shall upon their cancellation become authorized but unissued shares of Preferred Stock, without designation as to series until such shares are once more designated as part of a particular series by the Board of Directors pursuant to the provisions of Section 2 of Article IV of the Articles of Incorporation. SECTION 11. AMENDMENT. None of the powers, preferences and relative, participating, optional and other special rights of the Series A Preferred Stock as provided herein or in the Certificate of Incorporation shall be amended in any manner which would alter or change the powers, preferences, rights or privileges of the holders of Series A Preferred Stock so as to affect them adversely without the affirmative vote of the holders of at least 66-2/3% of the outstanding shares of Series A Preferred Stock, voting as a separate class; PROVIDED, HOWEVER, that no such amendment approved by the holders of at least 66-2/3% of the outstanding shares of Series A Preferred Stock shall be deemed to apply to the powers, preferences, rights or privileges of any holder of shares of Series A Preferred Stock originally issued upon exercise of the Rights after the time of such approval without the approval of such holder. * * * * * 21 IN WITNESS WHEREOF AND UNDER THE PENALTIES OF PERJURY, we have hereto signed our names this 9th day of October in the year 1997. /s/ Joseph F. Boston , President /s/ Stephen J. Doyle , Clerk 22 THE COMMONWEALTH OF MASSACHUSETTS Certificate of Vote of Directors Establishing A Series of a Class of Stock (General Laws, Chapter 156B, Section 26) I hereby approve the within certificate and, the filing fee in the amount of $100.00 having been paid, said certificate is hereby filed this 10th day of October, 1997. /s/ William Francis Galvin WILLIAM FRANCIS GALVIN Secretary of the Commonwealth Corporations Division One Ashburton Place, Boston, MA 02108-1512 TO BE FILLED IN BY CORPORATION PHOTO COPY OF CERTIFICATE TO BE SENT TO: Stephen J. Doyle, Esq. General Counsel Aspen Technology, Inc. Ten Canal Park Cambridge, Massachusetts 02141 Telephone (617) 557-0100
   1
                                                                     EXHIBIT 5.1


                             FOLEY, HOAG & ELIOT LLP
                             One Post Office Square
                        Boston, Massachusetts 02109-2170
                            Telephone: (617) 832-1000
                            Facsimile: (617) 832-7000
                                  Telex 940693
                               http://www.fhe.com






                                          January 20, 1998



ASPEN TECHNOLOGY, INC.
Ten Canal Park
Cambridge, Massachusetts  02141

Ladies and Gentlemen:

      We have acted as counsel for Aspen Technology, Inc., a Massachusetts
corporation (the "Company"), in connection with the preparation and filing with
the Securities and Exchange Commission under the Securities Act of 1933, as
amended, of a Registration Statement on Form S-8 (the "Registration Statement")
relating to the offering by the Company of up to 1,000,000 shares (the "Shares")
of the Company's Common Stock, $0.10 par value, issuable pursuant to the Aspen
Technology, Inc. 1998 Employee Stock Purchase Plan (the "Plan").

     In arriving at the opinions expressed below, we have examined and relied
on the following documents:

     (i)    the Registration Statement;

     (ii)   the Plan;

     (iii)  the Restated Articles of Organization of the Company, as amended
            as of the date hereof;

     (iv)   the By-Laws of the Company, as amended as of the date hereof; and

     (v)    the minutes of a meeting of the Board of Directors of the Company
            held on October 9, 1997.

In addition, we have examined and relied on the originals or copies certified or
otherwise identified to our satisfaction of all such other records, documents
and instruments of the Company and such other persons, and we have made such
investigations of law, as we have deemed appropriate as a basis for the opinions
expressed below. We have assumed the genuineness of all signatures and the
authenticity of all documents submitted to us as originals and the conformity to
the original documents of all documents submitted to us as certified or
photostatic copies.
   2
ASPEN TECHNOLOGY, INC.
January 20, 1998
Page Two



      We express no opinion other than as to the laws of the Commonwealth of
Massachusetts.

      Based upon the foregoing, we are of the opinion that:

      1.  The Company has the corporate power necessary for the issuance of 
the Shares under the Plan, as contemplated by the Registration Statement.

      2.  The Shares have been duly authorized and, when issued against payment
of the agreed consideration therefor in accordance with the respective exercise
prices therefor as described in the Plan, will be validly issued, fully paid and
non-assessable.

      We consent to the filing of this opinion as Exhibit 5.1 to the
Registration Statement.


                                        Very truly yours,


                                        FOLEY, HOAG & ELIOT LLP




                                        By /s/ Mark L. Johnson
                                           --------------------------------
                                           A Partner
   1
                                                                    EXHIBIT 10.1



                             ASPEN TECHNOLOGY, INC.

                        1998 EMPLOYEE STOCK PURCHASE PLAN

        1.     Definitions. As used in this 1998 Employee Stock Purchase Plan of
Aspen Technology, Inc., the following terms shall have the meanings respectively
assigned to them below:

        1.1    Beneficiary means the person designated as beneficiary on the
                 Optionee's Membership Agreement or, if no such beneficiary is
                 named, the person to whom the Option is transferred by will or
                 under the applicable laws of descent and distribution.

        1.2    Code means the Internal Revenue Code of 1986, as amended.

        1.3    Committee means the Compensation Committee of the Board of
                 Directors of the Company.

        1.4    Company means Aspen Technology, Inc.

        1.5    Compensation means annual compensation, including commissions,
                 overtime and bonuses for the most recently completed calendar
                 year.

        1.6    Control Group mean the Company and the Related Corporations.

        1.7    Eligible Employee means a person who is eligible under the
                 provisions of Section 7 to receive an Option as of a particular
                 Grant Date.

        1.8    Exercise Date means a date not more than 27 months after a Grant
                 Date, as determined by the Committee, on which Options must, if
                 ever, be executed.

        1.9    Grant Date means a date specified by the Committee on which
                 Options are to be granted to Eligible Employees.

        1.10   Market Value means, as of a particular date, the value as
                 determined by the Committee in accordance with applicable
                 provisions of the Code and Treasury Department rulings and
                 regulations thereunder or, if applicable, the closing price of
                 the Stock on the NASDAQ National Market System, as reported in
                 The Wall Street Journal.
   2
                                      -2-


   1.11   Membership Agreement means an agreement whereby an Optionee
            authorizes the Company to withhold payroll deductions from his or
            her Compensation.

   1.12   Option means an option to purchase shares of Stock granted under
            the Plan.

   1.13   Optionee means an Eligible Employee to whom an Option is granted.

   1.14   Plan means this 1998 Employee Stock Purchase Plan of the Company.

   1.15   Related Corporation means any corporation which is a parent
            corporation of the Company, as defined in Section 424(e) of the
            Code, and any corporation controlled by that parent corporation
            or the Company.

   1.16   Stock means common stock, $0.10 par value, of the Company.

   2.     Purpose of the Plan. The Plan is intended to encourage ownership of
Stock by employees of the Company and to provide additional incentive for the
employees to promote the success of the business of the Company. It is intended
that the Plan shall be an "employee stock purchase plan" within the meaning of
Section 423 of the Code.

   3.     Term of the Plan. The Plan shall become effective on January 1,
1998. No option shall be granted under the Plan after September 30, 2007.

   4.      Administration of the Plan. The Plan shall be administered by the
Committee, which shall determine from time to time whether to grant Options
under the Plan, shall specify which dates shall be Grant Dates and Exercise
Dates, shall determine the Market Value of the Stock, and shall fix the maximum
percentage of each Optionee's Compensation which may be withheld for the purpose
of purchasing shares of Stock; provided that the maximum percentage shall not
exceed ten percent. The Committee shall have authority to interpret the Plan, to
prescribe, amend and rescind rules and regulations relating to the Plan, to
determine the terms of Options granted under the Plan, and to make all other
determinations necessary or advisable for the administration of the Plan.

   5.     Termination and Amendment of Plan. The Committee may terminate or
amend the Plan at any time; provided however, that the Committee may not,
without approval by the holders of a majority of the shares of Stock, increase
the maximum number of shares of Stock purchasable under the Plan,
   3
                                      -3-


change the description of employees or classes of employees eligible to receive
Options, change the manner of determining the exercise price of Options, or
extend the period during which Options may be granted or exercised. No
termination of or amendment to the Plan may adversely affect the rights of an
Optionee with respect to any Option held by the Optionee as of the date of such
termination or amendment.

         6.    Shares of Stock Subject to the Plan. No more than an aggregate of
1,000,000 shares of Stock may be issued or delivered pursuant to the exercise of
Options granted under the Plan, subject to adjustment to reflect events
described in Section 9.8. Shares to be delivered upon the exercise of Options
may be either shares of Stock which are authorized but unissued or shares of
Stock held by the Company in its treasury. If an Option expires or terminates
for any reason without having been exercised in full, the unpurchased shares
subject to the Option shall become available for other Options granted under the
Plan. The Company shall, at all times during which Options are outstanding,
reserve and keep available shares of Stock, sufficient to satisfy such Options,
and shall pay all fees and expenses incurred by the Company in connection there
with. In the event of any capital change in the outstanding Stock as
contemplated by Section 9.8, the number of shares of Stock reserved and kept
available by the Company shall be appropriately adjusted.

         7.    Persons Eligible to Receive Options. Each employee of each 
specified member of the Controlled Group shall be granted an Option on a Grant
Date on which the employee meets all of the following requirements:

         7.1   The employee has been employed by the Controlled Group for at 
                  least one month and is customarily so employed for at least
                  twenty hours per week and for more than five months per
                  calendar year.

         7.2   The employee will not, after grant of the Option, own stock
                  possessing five percent or more of the total combined voting
                  power or value of all classes of stock of the Company or of
                  any Related Corporation. For purposes of this paragraph (b),
                  the rules of Section 424(d) of the Code shall apply in
                  determining the stock ownership of the employee, and stock
                  which the employee may purchase under outstanding options
                  shall be treated as stock owned by the employee.

         7.3   Upon grant of the Option, the employee's rights to purchase stock
                  under all employee stock purchase plans (as defined in Section
                  423(b) of the Code) of the Company and its Related
                  Corporations will not accrue at a rate which exceeds $25,000
                  of fair market value of the stock (determined as of the Grant
                  Date) for each calendar year
   4
                                      -4-


                  in which such option is outstanding at any time. The accrual
                  of rights to purchase stock shall be determined in accordance
                  with Section 423(b)(8) of the Code.

         8.    Dates for Granting Options. Options shall be granted on each date
designated by the Committee as a Grant Date.

        9.     Terms and Conditions of Options.

        9.1    General. All Options granted on a particular Grant Date shall
                  comply with the terms and conditions set forth in Section 9.3
                  through 9.12, and each Option shall be identical except as to
                  the number of shares of Stock purchasable under the Option,
                  which shall be determined in accordance with Section 9.2.

        9.2    Number of Shares. The maximum number of shares of Stock which an
                  Optionee shall be permitted to purchase shall be an amount
                  equal to five percent of the Optionee's Compensation as of the
                  Grant Date divided by 85 percent of the Market Value of the
                  Stock as of the Grant Date.

        9.3    Purchase Price. The purchase price of shares of Stock shall be 85
                  percent of the lesser of (a) the Market Value of the shares as
                  of the Grant Date, or (b) the Market Value of the shares as of
                  the Exercise Date, or such greater percentage as may be set by
                  the Committee from time to time.

        9.4    Restrictions on Transfer. Options may not be transferred
                  otherwise than by will or under the laws of descent and
                  distribution. An Option may not be exercised by anyone other
                  than the Optionee during the lifetime of the Optionee. Shares
                  of Stock may be sold or otherwise transferred by the Optionee
                  without restriction subject to the provisions of Section 9.11.

        9.5    Expiration. Each Option shall expire at the close of business on
                  the Exercise Date or on such earlier date as may result from
                  the operation of Section 9.6.

        9.6    Termination of Employment of Optionee. If an Optionee ceases for
                  any reason (other than death or retirement) to be continuously
                  employed by the Company or a Related Corporation, whether due
                  to voluntary severance, involuntary severance, transfer, or
                  disaffiliation of the employer corporation with the Company,
                  his or her Option shall immediately expire, and the Optionee's
                  accumulated payroll deduction shall be returned by the Company
                  without interest. For
   5
                                      -5-


                  purposes of this Section 9.6, an Optionee shall be deemed to
                  be employed throughout any leave of absence for military
                  service, illness or other bona fide purpose which does not
                  exceed the longer of ninety days of the period during which
                  the Optionee's reemployment rights are guaranteed by statute
                  or by contract. If the Optionee does not return to active
                  employment prior to the termination of such period, his or her
                  employment shall be deemed to have ended on the ninety-first
                  day of such leave of absence.

        9.7    Retirement or Death of Optionee. If an Optionee retires or dies,
                  the employee or, in the case of death, his or her Beneficiary
                  shall be entitled to withdraw the Optionee's accumulated
                  payroll deductions without interest or to purchase shares on
                  the Exercise Date to the extent that the Optionee would be so
                  entitled had he or she continued to be employed by the
                  Controlled Group. The number of shares purchasable shall be
                  limited by the amount of the Optionee's accumulated payroll
                  deductions as of the date of his or her retirement or death.
                  Accumulated payroll deductions shall be applied by the Company
                  toward the purchase of shares only if the Optionee or
                  Beneficiary submits to the Company a Stock Purchase Agreement
                  pursuant to Section 9.10. Accumulated payroll deductions not
                  withdrawn or applied to the purchase of shares shall be
                  delivered by the Company to the Optionee or Beneficiary
                  without interest within a reasonable time after the Exercise
                  Date.

        9.8    Capital Changes Affecting the Stock. In the event that, between
                  the Grant Date and the Exercise Date of an Option, a stock
                  dividend is paid or becomes payable in respect of the Stock or
                  there occurs a split up or contraction in the number of shares
                  of Stock, the number of shares for which the Option may
                  thereafter be exercised and the price to be paid for each such
                  share shall be proportionately adjusted. In the event that,
                  after the Grant Date, there occurs a reclassification or
                  change of outstanding shares of the Stock or a consolidation
                  or merger of the Company with or into another corporation or a
                  sale or conveyance, substantially as a whole, of the property
                  of the Company, the Optionee shall be entitled on the Exercise
                  Date to receive shares of stock or other securities equivalent
                  in kind and value to the shares of Stock he or she would have
                  held if he or she had exercised the Option in full immediately
                  prior to such reclassification, change, consolidation, merger,
                  sale or conveyance and had continued to hold such shares
                  (together with all other shares and securities thereafter
                  issued in respect thereof) until the Exercise Date. In the
                  event that, after the Grant Date, there occurs a dissolution
                  or liquidation of the Company, except pursuant to a
                  transaction to which Section 424(a) of the Code applies, each
                  Option
   6
                                      -6-

                to purchase Stock of the Company to be dissolved or liquidated
                shall terminate, but the Optionee holding such Option shall
                have the right to exercise his or her Option prior to such
                dissolution or liquidation.

      9.9    Payroll Deductions. An Optionee may purchase shares under his or
                her Option by completing and returning to the Company a
                Membership Agreement indicating the amount of his or her
                Compensation, not to exceed ten percent, which is to be
                withheld each pay period. A Membership Agreement may continue
                from the period following one Grant Date to the periods
                following subsequent Grant Dates until revoked by the
                Optionee. The Optionee may withdraw any or all of his or her
                accumulated payroll deductions on the Exercise Date or such
                earlier date as is permitted by the Membership Agreement by
                submitting a written request therefor to the Company no later
                than two weeks prior to the date on which the withdrawal will
                be effective.

      9.10   Exercise of Options. On the Exercise Date the Optionee may
                purchase the number of shares purchasable by his or her
                accumulated payroll deduction, provided that:

                (a)    The number of shares of Stock purchasable shall not 
                       exceed the number of shares the Optionee is entitled
                       to purchase pursuant to Section 9.2.

                (b)    If the number of shares purchasable includes a fraction,
                       that number shall be adjusted to the next smaller
                       whole number and the purchase price shall be adjusted
                       accordingly.

                If the Optionee fails to elect to purchase shares on the
                Exercise Date, accumulated payroll deductions will be returned
                promptly after the Exercise Date without interest.

      9.11   Delivery of Stock. Within a reasonable time after the Exercise
                Date, the Company shall deliver or cause to be delivered to
                the Optionee a certificate or certificates for the number of
                shares purchased by the Optionee. At the time of any exercise
                of any Option, the Company may, if it shall deem it necessary
                or desirable for any reason connected with any law or
                applicable regulation of the Securities and Exchange
                Commission or state securities laws, require the Optionee or a
                transfer of the Optionee's rights to represent in writing to
                the Company that it is such person's then intention to acquire
                the Stock for investment, and not with a view to the
                distribution thereof. The Company shall have the right to
                place a legend on all certificates
   7
                                      -7-

                  that the shares represented by such certificates may not be
                  transferred unless a Registration Statement with respect to
                  these shares is effective under the Securities Act of 1933, as
                  amended, or unless the Company shall receive an opinion of
                  counsel satisfactory to it that transfer will not violate said
                  act or regulations thereunder. If any law or applicable
                  regulation of the Securities and Exchange Commission or other
                  body having jurisdiction in the premises shall require that
                  the Company or the Optionee take any action in connection with
                  the shares being purchased under the Option, delivery of the
                  certificate or certificates for such shares shall be postponed
                  until the necessary action shall have been completed. The
                  Optionee shall have no rights as a shareholder in respect of
                  shares for which he or she has not received a certificate.

        9.12   Return of Accumulated Payroll Deductions. In the event that the
                  Optionee or the Beneficiary is entitled to the return of
                  accumulated payroll deductions, whether by reason of voluntary
                  withdrawal, termination of employment, retirement, death, or
                  otherwise such amount shall be returned without interest
                  within a reasonable time after the Exercise Date or such
                  earlier date as is permitted by the Membership Agreement.
                  Payroll deductions shall be returned by the Company to the
                  Optionee or the Beneficiary, as the case may be. An Optionee's
                  Membership Agreement may specify that amounts exceeding the
                  purchase price will be carried forward to the next option
                  period under the Plan.

        9.13   Notification of Disposition. Each Membership Agreement shall
                  require a person purchasing shares of stock pursuant to the
                  exercise of an Option to notify the Company of any disposition
                  of shares so purchased prior to the expiration of two years
                  from the Grant Date or prior to the expiration of one year
                  from the Exercise Date and, to the extent applicable law
                  imposes upon the Company withholding tax requirements, to
                  remit to the Company cash sufficient to satisfy those
                  requirements.

   1
                                                                    EXHIBIT 23.1



                    CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS

      As independent public accountants, we hereby consent to (i) the
incorporation by reference in this registration statement of our report dated
August 13, 1997 (except with respect to the matters discussed in footnote 3(g)
as to which the date is August 28, 1997) included in Aspen Technology, Inc.'s
Annual Report on Form 10-K for the fiscal year ended June 30, 1997 and (ii) all
references to our Firm included in this registration statement.





                                        /s/ ARTHUR ANDERSEN LLP

Boston, Massachusetts
January 15, 1998