Document:

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                                                                    EXHIBIT 4.10

                             STREAM MACHINE COMPANY

                     STOCK OPTION AGREEMENT - EARLY EXERCISE

I. NOTICE OF STOCK OPTION GRANT

         Simplex Solutions, Inc.

         -------------------------

         -------------------------

         Simplex Solutions, Inc. has been granted a Nonstatutory Stock Option to
purchase Common Stock of the Company, subject to the terms and conditions of
this Agreement, as follows:

         Date of Grant                               November 30, 2001
                                                     ---------------------------

         Vesting Commencement Date                   November 30, 2001
                                                     ---------------------------

         Exercise Price per Share                    $0.25
                                                     ---------------------------

         Total Number of Shares Granted              50,000
                                                     ---------------------------

         Total Exercise Price                        $12,500
                                                     ---------------------------

         Term/Expiration Date:                       November 30, 2011
                                                     ---------------------------

         Vesting Schedule:

         This Option shall vest and may be exercised (in accordance with Section
3), in whole or in part, in accordance with the following schedule:

         100% of the shares subject to the Option are fully vested as of the
Vesting Commencement Date.

         Termination Period

         This Option may be exercised, to the extent it is then vested, within
twelve (12) months after Optionee ceases to be a Service Provider in accordance
with Section 8 of this Agreement. In no event shall this Option be exercised
later than the Term/Expiration Date provided above.

II. AGREEMENT

         1. Definitions. As used herein, the following definitions shall apply:

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                  (a) "Agreement" means this stock option agreement between the
Company and Optionee evidencing the terms and conditions of this Option.

                  (b) "Applicable Laws" means the requirements relating to the
administration of stock options under U.S. state corporate laws, U.S. federal
and state securities laws, the Code, any stock exchange or quotation system on
which the Common Stock is listed or quoted and the applicable laws of any
foreign country or jurisdiction that may apply to this Option.

                  (c) "Board" means the Board of Directors of the Company or any
committee of the Board that has been designated by the Board to administer this
Agreement.

                  (d) "Cause" means (i) the Optionee's failure to adequately
perform the duties associated with the Agreement for the Company (or its
successor) as determined in good faith by the Company's board of directors; (ii)
the Optionee's engaging in conduct that the Optionee reasonably should know or
that the Optionee intends to be seriously injurious to the Company, its
affiliates or its shareholders; (iii) a material and willful violation of a
federal or state law or regulation applicable to the business of the Company;
(iv) the conviction of a felony under the laws of the United States or any
State, or the misappropriation of material property belonging to the Company or
its affiliates committed by an officer of the Optionee or employee of the
Optionee who is providing services to the Company; or (v) the Optionee's
knowingly and intentionally breaching in any material respect the terms of the
service agreement between itself and the Company and any extensions of such
agreement or any subsequent agreement in which a continuation of services is
provided.

                  (e) "Change of Control" shall mean (i) a merger or
consolidation of the Company with or into any other corporation or entity or
person or any other corporate reorganization in which the shareholders of the
Company immediately prior to such transaction(s) own or control, immediately
after consummation of such transaction(s), less than fifty percent (50%) of the
voting power of the surviving entity (but excluding any transaction or series of
transactions effected solely for the purpose of reincorporating the Company into
another jurisdiction), (ii) any transaction (or series of related transactions
involving a person or entity, or group of affiliated persons or entities) in
which in excess of fifty percent (50%) of the outstanding voting power of the
Company is transferred, or (iii) a sale lease or other disposition of all or
substantially all the assets of the Company.

                  (f) "Code" means the Internal Revenue Code of 1986, as
amended.

                  (g) "Common Stock" means the common stock of the Company.

                  (h) "Company" means Stream Machine Company, a California
corporation.

                  (i) "Consultant" means any person or entity, including an
advisor, engaged by the Company or a Parent or Subsidiary to render services to
such entity.

                  (j) "Director" means a member of the Board.

                  (k) "Exchange Act" means the Securities Exchange Act of 1934,
as amended.

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                  (l) "Fair Market Value" means, as of any date, the value of
Common Stock determined as follows:

                           (i) If the Common Stock is listed on any established
stock exchange or a national market system, including without limitation The
Nasdaq National Market or The Nasdaq SmallCap Market of The Nasdaq Stock Market,
its Fair Market Value shall be the closing sales price for such stock (or the
closing bid, if no sales were reported) as quoted on such exchange or system for
the last market trading day prior to the time of determination, as reported in
The Wall Street Journal or such other source as the Administrator deems
reliable;

                           (ii) If the Common Stock is regularly quoted by a
recognized securities dealer but selling prices are not reported, its Fair
Market Value shall be the mean between the high bid and low asked prices for the
Common Stock on the last market trading day prior to the day of determination;
or

                           (iii) In the absence of an established market for the
Common Stock, the Fair Market Value thereof shall be determined in good faith by
the Board.

                  (m) "Nonstatutory Stock Option" means an Option not intended
to qualify as an incentive stock option within the meaning of Section 422 of the
Code and the regulations promulgated thereunder.

                  (n) "Notice of Grant" means the written notice, in Part I of
this Agreement, evidencing certain the terms and conditions of this Option. The
Notice of Grant is part of the Agreement.

                  (o) "Option" means this stock option.

                  (p) "Optioned Stock" means the Common Stock subject to this
Option.

                  (q) "Optionee" means the person named in the Notice of Grant
or such entity's successor.

                  (r) "Parent" means a "parent corporation," whether now or
hereafter existing, as defined in Section 424(e) of the Code.

                  (s) "Service Provider" means a Consultant of the Company.

                  (t) "Share" means a share of the Common Stock, as adjusted in
accordance with Section 9 of this Agreement.

                  (u) "Subsidiary" means a "subsidiary corporation", whether now
or hereafter existing, as defined in Section 424(f) of the Code.

         2. Grant of Option. The Board hereby grants to the Optionee named in
the Notice of Grant, attached as Part I of this Agreement, the Option to
purchase the number of Shares, as set forth in the Notice of Grant, at the
exercise price per share set forth in the Notice of Grant (the "Exercise
Price"), subject to the terms and conditions of this Agreement.

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         3. Exercise of Option.

                  (a) Right to Exercise.

                           (i) Subject to subsections 3(a)(ii) and 3(a)(iii)
below, this Option shall be exercisable cumulatively according to the Vesting
Schedule set forth in the Notice of Grant. Alternatively, at the election of the
Optionee, this Option may be exercised in whole or in part at any time as to
Shares that have not yet vested. For purposes of this Agreement, Shares subject
to the Option shall vest based on Optionee continuing to be a Service Provider
of the Company. Vested Shares shall not be subject to the Company's repurchase
right (as set forth in the Restricted Stock Purchase Agreement, attached hereto
as Exhibit C-1).

                           (ii) As a condition to exercising this Option for
unvested Shares, the Optionee shall execute the Restricted Stock Purchase
Agreement.

                           (iii) This Option may not be exercised for a fraction
of a Share.

                  (b) Method of Exercise. This Option is exercisable by delivery
of an exercise notice, in the form attached as Exhibit A (the "Exercise
Notice"), which shall state the election to exercise the Option, the number of
Shares in respect of which the Option is being exercised (the "Exercised
Shares"), and such other representations and agreements as may be required by
the Company. The Exercise Notice shall be completed by the Optionee and
delivered to Secretary of the Company. The Exercise Notice shall be accompanied
by payment of the aggregate Exercise Price as to all Exercised Shares. This
Option shall be deemed to be exercised upon receipt by the Company of such fully
executed Exercise Notice accompanied by such aggregate Exercise Price.

                  (c) Legal Compliance. No Shares shall be issued pursuant to
the exercise of this Option unless such issuance and exercise complies with
Applicable Laws. Assuming such compliance, for income tax purposes the Exercised
Shares shall be considered transferred to the Optionee on the date the Option is
exercised with respect to such Exercised Shares.

                  (d) Buyout Provisions. The Board may at any time offer to buy
out for a payment in cash or Shares an Option previously granted based on such
terms and conditions as the Board shall establish and communicate to the
Optionee at the time that such offer is made.

         4. Optionee's Representations. In the event the Shares have not been
registered under the Securities Act of 1933, as amended, at the time this Option
is exercised, the Optionee shall, if required by the Company, concurrently with
the exercise of all or any portion of this Option, deliver to the Company its
Investment Representation Statement in the form attached hereto as Exhibit B.

         5. Method of Payment. Payment of the aggregate Exercise Price shall be
by cash or check, at the election of the Optionee.

         6. Non-Transferability of Option. This Option may not be transferred in
any manner otherwise than by will or by the laws of descent or distribution and
may be exercised during the lifetime of Optionee only by the Optionee. The terms
of this Agreement shall be binding upon the executors, administrators, heirs,
successors and assigns of the Optionee.

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         7. Term of Option. This Option may be exercised only within the term
set out in the Notice of Grant, and may be exercised during such term only in
accordance with the terms of this Agreement.

         8. Termination of Relationship as a Service Provider. If the Optionee
ceases to be a Service Provider, this Option may be exercised for a period of
twelve (12) months after the date of such termination (but in no event later
than the expiration date of this Option as set forth in the Notice of Grant) to
the extent that the Option is vested on the date of such termination. To the
extent that the Optionee does not exercise this Option within the time specified
herein, the Option shall terminate.

         9. Adjustments Upon Changes in Capitalization, Dissolution, Merger or
Asset Sale.

                  (a) Changes in Capitalization. Subject to any required action
by the stockholders of the Company, the number of shares of Common Stock covered
by this Option, as well as the price per share of Common Stock covered by this
Option, shall be proportionately adjusted for any increase or decrease in the
number of issued shares of Common Stock resulting from a stock split, reverse
stock split, stock dividend, combination or reclassification of the Common
Stock, or any other increase or decrease in the number of issued shares of
Common Stock effected without receipt of consideration by the Company; provided,
however, that conversion of any convertible securities of the Company shall not
be deemed to have been "effected without receipt of consideration." Such
adjustment shall be made by the Board, whose determination in that respect shall
be final, binding and conclusive. Except as expressly provided herein, no
issuance by the Company of shares of stock of any class, or securities
convertible into shares of stock of any class, shall affect, and no adjustment
by reason thereof shall be made with respect to, the number or price of the
Shares subject to this Option.

                  (b) Dissolution or Liquidation. In the event of the proposed
dissolution or liquidation of the Company, the Board shall notify Optionee as
soon as practicable prior to the effective date of such proposed transaction.
The Board in its discretion may provide for the Optionee to have the right to
exercise its Option until fifteen (15) days prior to such transaction as to all
of the Optioned Stock covered thereby, including Shares as to which the Option
would not otherwise be exercisable. The Board may permit the Option to be
exercised contingent upon this transaction. To the extent it has not been
previously exercised, the Option will terminate immediately prior to the
consummation of such proposed action.

                  (c) Merger or Asset Sale. In the event of a merger of the
Company with or into another corporation, or the sale of substantially all of
the assets of the Company, the Option shall be assumed or an equivalent option
substituted by the successor corporation or a Parent or Subsidiary of the
successor corporation. In the event that the successor corporation or a Parent
or Subsidiary of the successor corporation refuses to assume or substitute for
the Option, the Optionee shall have the right to exercise the Option as to all
of the Optioned Stock, including Shares as to which it would not otherwise be
exercisable. If the Option becomes exercisable in lieu of assumption or
substitution in the event of a merger or sale of assets, the Board shall notify
the Optionee in writing or electronically that the Option shall be fully
exercisable for a period of fifteen (15) days from the date of such notice. The
Option shall terminate upon the expiration of such period. For the purposes of
this paragraph, the Option shall be considered assumed if, following the merger
or sale of assets, the

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option confers the right to purchase or receive, for each Share of Optioned
Stock subject to the Option immediately prior to the merger or sale of assets,
the consideration (whether stock, cash, or other securities or property)
received in the merger or sale of assets by holders of Common Stock for each
Share held on the effective date of the transaction (and if holders were offered
a choice of consideration, the type of consideration chosen by the holders of a
majority of the outstanding Shares); provided, however, that if such
consideration received in the merger or sale of assets is not solely common
stock of the successor corporation or its Parent, the Board may, with the
consent of the successor corporation, provide for the consideration to be
received upon the exercise of the Option, for each Share of Optioned Stock
subject to the Option, to be solely common stock of the successor corporation or
its Parent equal in fair market value to the per share consideration received by
holders of Common Stock in the merger or sale of assets.

         10. Lock-Up Period. Optionee hereby agrees that, in connection with the
initial public offering of the Company's capital stock under the Securities Act,
Optionee shall not any Shares or other securities of the Company held by or on
behalf of the Purchaser or beneficially owned by the Optionee in accordance with
the rules and regulations of the Securities and Exchange Commission for a period
of 180-day period (the "Market Standoff Period") following the date of the final
prospectus relating to the Company's initial public offering. This restriction
shall be binding on any transferee of the Shares subjected to this Option. The
Company may impose stop-transfer instructions with respect to securities subject
to the foregoing restrictions until the end of such Market Standoff Period.

         11. Notices. Any notice to be given to the Company hereunder shall be
in writing and shall be addressed to the Company at its then current principal
executive office or to such other address as the Company may hereafter designate
to the Optionee by notice as provided in this Section. Any notice to be given to
the Optionee hereunder shall be addressed to the Optionee at the address set
forth beneath its signature hereto, or at such other address as the Optionee may
hereafter designate to the Company by notice as provided herein. A notice shall
be deemed to have been duly given when personally delivered or mailed by
registered or certified mail to the party entitled to receive it.

         12. Entire Agreement; Governing Law. This Agreement constitutes the
entire agreement of the parties with respect to the subject matter hereof and
supersedes in its entirety all prior undertakings and agreements of the Company
and Optionee with respect to the subject matter hereof, and may not be modified
adversely to the Optionee's interest except by means of a writing signed by the
Company and Optionee. This agreement is governed by the internal substantive
laws, but not the choice of law rules, of California.

         13. Section 83(b) Election for Unvested Shares Purchased Pursuant to
Options. With respect to the exercise of this Option for unvested Shares, an
election may be filed by the Optionee with the Internal Revenue Service, within
30 days of the purchase of the Shares, electing pursuant to Section 83(b) of the
Code to be taxed currently on any difference between the purchase price of the
Shares and their Fair Market Value on the date of purchase. This will result in
a recognition of taxable income to the Optionee on the date of exercise,
measured by the excess, if any, of the Fair Market Value of the Shares, at the
time the Option is exercised over the purchase price for the Shares. Absent such
an election, taxable income will be measured and recognized by Optionee at the
time or times on which the Company's repurchase option lapses. Optionee is
strongly

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encouraged to seek the advice of its own tax consultants in connection with the
purchase of the Shares and the advisability of filing of the Election under
Section 83(b) of the Code. A form of Election under Section 83(b) is attached
hereto as Exhibit C-4 for reference.

         14. NO GUARANTEE OF CONTINUED SERVICE. OPTIONEE ACKNOWLEDGES AND AGREES
THAT THE VESTING OF SHARES PURSUANT TO THE VESTING SCHEDULE HEREOF IS EARNED
ONLY BY CONTINUING AS A SERVICE PROVIDER AT THE WILL OF THE COMPANY (AND NOT
THROUGH THE ACT OF BEING HIRED, BEING GRANTED AN OPTION OR PURCHASING SHARES
HEREUNDER). OPTIONEE FURTHER ACKNOWLEDGES AND AGREES THAT THIS AGREEMENT, THE
TRANSACTIONS CONTEMPLATED HEREUNDER AND THE VESTING SCHEDULE SET FORTH HEREIN DO
NOT CONSTITUTE AN EXPRESS OR IMPLIED PROMISE OF CONTINUED ENGAGEMENT AS A
SERVICE PROVIDER FOR THE VESTING PERIOD, FOR ANY PERIOD, OR AT ALL, AND SHALL
NOT INTERFERE WITH OPTIONEE'S RIGHT OR THE COMPANY'S RIGHT TO TERMINATE
OPTIONEE'S RELATIONSHIP AS A SERVICE PROVIDER AT ANY TIME, WITH OR WITHOUT
CAUSE.

         By signature of the Optionee and the signature of the Company's
representative below, Optionee and the Company agree that this Option is granted
under and governed by the terms and conditions of this Agreement. Optionee has
reviewed this Agreement in its entirety, has had an opportunity to obtain the
advice of counsel prior to executing this Agreement and fully understands all
provisions of this Agreement. Optionee hereby agrees to accept as binding,
conclusive and final all decisions or interpretations of the Board upon any
questions relating to this Agreement. Optionee further agrees to notify the
Company upon any change in the residence address indicated below.

OPTIONEE                                    STREAM MACHINE COMPANY

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Signature                                   By

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Print Name                                  Title

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Title

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Residence Address

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                                    EXHIBIT A

                             STREAM MACHINE COMPANY

                                 EXERCISE NOTICE

Stream Machine Company
46831 Lakeview Blvd.
Fremont, CA 94538
Attention: Stock Plan Administrator

         1. Exercise of Option. Effective as of today, ________________, _____,
the undersigned ("Purchaser") hereby elects to purchase ______________ shares
(the "Shares") of the Common Stock of Stream Machine Company (the "Company")
under and pursuant to the Stock Option Agreement dated November 30, 2001 (the
"Option Agreement"). The purchase price for the Shares shall be $____ , as
required by the Option Agreement.

         2. Delivery of Payment. Purchaser herewith delivers to the Company the
full purchase price for the Shares.

         3. Representations of Purchaser. Purchaser acknowledges that Purchaser
has received, read and understood the Option Agreement and agrees to abide by
and be bound by its terms and conditions.

         4. Rights as Shareholder. Until the issuance (as evidenced by the
appropriate entry on the books of the Company or of a duly authorized transfer
agent of the Company) of the Shares, no right to vote or receive dividends or
any other rights as a stockholder shall exist with respect to the Optioned
Stock, notwithstanding the exercise of the Option. The Shares so acquired shall
be issued to the Optionee as soon as practicable after exercise of the Option.
No adjustment will be made for a dividend or other right for which the record
date is prior to the date of issuance, except as provided in Section 9 of the
Option Agreement.

         5. Tax Consultation. Purchaser understands that Purchaser may suffer
adverse tax consequences as a result of Purchaser's purchase or disposition of
the Shares. Purchaser represents that Purchaser has consulted with any tax
consultants Purchaser deems advisable in connection with the purchase or
disposition of the Shares and that Purchaser is not relying on the Company for
any tax advice.

         6. Restrictive Legends and Stop-Transfer Orders.

                  (a) Legends. Optionee understands and agrees that the Company
shall cause the legends set forth below or legends substantially equivalent
thereto, to be placed upon any certificate(s) evidencing ownership of the Shares
together with any other legends that may be required by the Company or by state
or federal securities laws:

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                  THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED
                  UNDER THE SECURITIES ACT OF 1933 (THE "ACT") AND MAY NOT BE
                  OFFERED, SOLD OR OTHERWISE TRANSFERRED, PLEDGED OR
                  HYPOTHECATED UNLESS AND UNTIL REGISTERED UNDER THE ACT OR, IN
                  THE OPINION OF COMPANY COUNSEL SATISFACTORY TO THE ISSUER OF
                  THESE SECURITIES, SUCH OFFER, SALE OR TRANSFER, PLEDGE OR
                  HYPOTHECATION IS IN COMPLIANCE THEREWITH.

                  THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO
                  CERTAIN RESTRICTIONS ON TRANSFER, INCLUDING A 180-DAY MARKET
                  STANDOFF PROVISION, AS SET FORTH IN THE EXERCISE NOTICE AND
                  THE STAND-ALONE OPTION AGREEMENT BETWEEN THE ISSUER AND THE
                  ORIGINAL HOLDER OF THESE SHARES, COPIES OF WHICH MAY BE
                  OBTAINED AT THE PRINCIPAL OFFICE OF THE ISSUER. SUCH TRANSFER
                  RESTRICTIONS ARE BINDING ON TRANSFEREES OF THESE SHARES.

                  (b) Stop-Transfer Notices. Optionee agrees that, in order to
ensure compliance with the restrictions referred to herein, the Company may
issue appropriate "stop transfer" instructions to its transfer agent, if any,
and that, if the Company transfers its own securities, it may make appropriate
notations to the same effect in its own records.

                  (c) Refusal to Transfer. The Company shall not be required (i)
to transfer on its books any Shares that have been sold or otherwise transferred
in violation of any of the provisions of this Exercise Notice or (ii) to treat
as owner of such Shares or to accord the right to vote or pay dividends to any
purchaser or other transferee to whom such Shares shall have been so
transferred.

         7. Successors and Assigns. The Company may assign any of its rights
under this Exercise Notice to single or multiple assignees, and this Exercise
Notice shall inure to the benefit of the successors and assigns of the Company.
Subject to the restrictions on transfer herein set forth, this Exercise Notice
shall be binding upon Optionee and its administrators, successors and assigns.

         8. Arbitration. Any dispute or controversy arising out of, relating to,
or concerning any interpretation, construction, performance or breach of this
agreement, shall be settled by arbitration to be held in Alameda County,
California, in accordance with the rules then in effect of the American
Arbitration Association. The arbitrator may grant injunctions or other relief in
such dispute or controversy. The decision of the arbitrator shall be final,
conclusive and binding on the parties to the arbitration. Judgment may be
entered on the arbitrator's decision in any court having jurisdiction.

         9. Entire Agreement; Governing Law. The Option Agreement is
incorporated herein by reference. This Agreement, and all exhibits expressly
referenced herein constitute the entire agreement of the parties with respect to
the subject matter hereof and supersede in their entirety all prior undertakings
and agreements of the Company and Purchaser with respect to the subject matter
hereof, and may not be modified adversely to the Purchaser's interest except by
means of a writing signed by the Company and Purchaser. This agreement is
governed by the internal substantive laws, but not the choice of law rules, of
California.

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Submitted by:                               Accepted by:

OPTIONEE                                    STREAM MACHINE COMPANY

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Signature

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Print Name

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Address

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                                            Date Received:
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                                    EXHIBIT B

                       INVESTMENT REPRESENTATION STATEMENT

SHAREHOLDER:      Simplex Solutions, Inc.

COMPANY:          Stream Machine Company

SECURITY:         Common Stock

AMOUNT:

DATE:

         In connection with that certain option grant dated November 30, 2001 of
the above-listed Securities, the undersigned represents on behalf of Shareholder
represents to Stream Machine Company (the "Company") the following:

                  (a) Shareholder is aware of the Company's business affairs and
financial condition and has acquired sufficient information about the Company to
reach an informed and knowledgeable decision to acquire the Securities.
Shareholder has had an opportunity to discuss the Company's business, management
and financial affairs with the Company's management and has had the opportunity
to ask questions of the officers of the Company, which questions were answered
to Shareholder's satisfaction. Shareholder understands that such discussions, as
well as any written information issued by the Company, were intended to describe
certain aspects of the Company's business and prospects but were not a thorough
or exhaustive description.

                  (b) Shareholder is experienced and knowledgeable in financial
and business matters and therefore Shareholder is capable of evaluating the
merits and risks of the investment.

                  (c) Shareholder is acquiring the Securities solely for
Shareholder's own account for investment purposes only and not with a view to,
or for resale in connection with, any "distribution" thereof as that term is
used for purposes of the Securities Act.

                  (d) Shareholder realizes that investment in the Securities
involves a high degree of risk. Shareholder is able to bear the risk of the
investment, to hold the Securities for an indefinite period of time and to
suffer a complete loss of the investment.

                  (e) Shareholder acknowledges and understands that the
Securities constitute "restricted securities" under the Securities Act and have
not been registered under the Securities Act in reliance upon a specific
exemption therefrom, which exemption depends upon, among other things, the bona
fide nature of Shareholder's investment intent as expressed herein. In this
connection, Shareholder understands that, in the view of the Securities and
Exchange Commission, the statutory basis for such exemption may be unavailable
if Shareholder's representation was predicated solely upon a present intention
to hold the Securities for the minimum capital gains

<PAGE>

period specified under tax statutes, for a deferred sale, for or until an
increase or decrease in the market price of the Securities, or for a period of
one year or any other fixed period in the future.

                  (f) Shareholder understands that the Securities must be held
indefinitely unless subsequently registered under the Securities Act or unless
an exemption from registration is otherwise available. Moreover, Shareholder
understands that the Company is under no obligation to register the Securities
except as may be provided by express written agreement. In addition, Shareholder
understands that the certificate(s) evidencing the Securities will be imprinted
with a legend which prohibits the transfer of the Securities unless they are
registered or such registration is not required in the opinion of counsel
satisfactory to the Company.

                  (g) Shareholder is aware of the provisions of Rule 144,
promulgated under the Securities Act, which in substance permits limited public
resale of "restricted securities" acquired in a transaction not involving a
public offering subject to the satisfaction of certain conditions, including:
(i) the availability of certain public information about the Company, (ii) the
resale occurring not less than one year after the party has purchased and "fully
paid" for the securities to be sold, (iii) the sale being made through a broker
in an unsolicited "broker's transaction" or in transactions directly with a
market maker (as such term is defined under the Securities Exchange Act of
1934), (iv) the amount of securities being sold during any three month period
not exceeding the specified limitations stated in the Rule and (v) the timely
filing of a Form 144, if applicable.

                  (h) Shareholder further understands that at the time
Shareholder wishes to sell the Securities, there may be no public market upon
which to make such a sale, and that, even if such a public market then exists,
the Company may not be satisfying the current public information requirements of
Rule 144, and that, in such event, Shareholder would be precluded from selling
the Securities under Rule 144 even if the one-year minimum holding period were
satisfied.

                  (i) Shareholder further understands that, notwithstanding the
fact that Rule 144 is not exclusive, the staff of the SEC has expressed its
opinion that persons proposing to sell private placement securities other than
in a registered offering and otherwise that pursuant to Rule 144 will have a
substantial burden of proof in establishing that an exemption from registration
is available for such offers or sales, and that such persons and their
respective brokers who participate in such transactions do so at their own risk.

                  (j) The address set forth below is Shareholder's true and
correct principal address, and Shareholder has no present intention of becoming
a resident of any other state or jurisdiction. Shareholder hereby instructs the
Company to issue the certificate(s) representing the Securities in the name of
Shareholder as set forth below, and confirms to the Company that it will be the
beneficial owner of such shares.

                  (k) Shareholder agrees, in connection with the initial public
offering of the Company's securities, (i) not to sell, make short sales of,
loan, grant any options for the purchase of, or otherwise dispose of any
securities of the Company held by me (other than those securities included in
the registration) without the prior written consent of the Company or the
underwriters managing such initial underwritten public offering of the Company's
securities for one hundred eighty (180) days from the effective date of such
registration and (ii) further agrees to execute any

<PAGE>

agreement reflecting (i) above as may be requested by the underwriters at the
time of the public offering.

Date:
     -------------------

SIMPLEX SOLUTIONS, INC.

By:
   -------------------------------

Name:
     -----------------------------

Title:
      ----------------------------

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(address)

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                                   EXHIBIT C-1

                             STREAM MACHINE COMPANY

                       RESTRICTED STOCK PURCHASE AGREEMENT

         THIS AGREEMENT is made between Simplex Solutions, Inc. (the
"Purchaser") and Stream Machine Company (the "Company") as of
__________________, ____.

                                    RECITALS

         (1) As required by the Option Agreement, as a condition to Purchaser's
election to exercise the Option with respect to unvested shares, Purchaser must
execute this Restricted Stock Purchase Agreement, which sets forth the rights
and obligations of the parties with respect to Shares acquired upon exercise of
the Option.

         (2) Pursuant to the exercise of the stock option granted to Purchaser
under the Stock Option Agreement (the "Option Agreement") dated November 30,
2001 by and between the Company and Purchaser, which Option Agreement is hereby
incorporated by reference, Purchaser has elected to purchase _________ of those
shares which have not become vested under the vesting schedule set forth in the
Option Agreement ("Unvested Shares"). The Unvested Shares and the shares subject
to the Option Agreement, which have become vested are sometimes collectively
referred to herein as the "Shares."

         1. Repurchase Option.

                  (a) If Purchaser's status as a Service Provider is terminated
for any reason, the Company shall have the right and option to purchase from
Purchaser, or Purchaser's personal representative, as the case may be, all of
the Purchaser's Unvested Shares as of the date of such termination at the price
paid by the Purchaser for such Shares (the "Repurchase Option").

                  (b) Upon the occurrence of a termination, the Company may
exercise its Repurchase Option by delivering personally or by registered mail,
to Purchaser (or its transferee or legal representative, as the case may be),
within ninety (90) days of the termination, a notice in writing indicating the
Company's intention to exercise the Repurchase Option and setting forth a date
for closing not later than thirty (30) days from the mailing of such notice. The
closing shall take place at the Company's office. At the closing, the holder of
the certificates for the Unvested Shares being transferred shall deliver the
stock certificate or certificates evidencing the Unvested Shares, and the
Company shall deliver the purchase price therefor.

                  (c) At its option, the Company may elect to make payment for
the Unvested Shares to a bank selected by the Company. The Company shall avail
itself of this option by a notice in writing to Purchaser stating the name and
address of the bank, date of closing, and waiving the closing at the Company's
office.

<PAGE>

                  (d) If the Company does not elect to exercise the Repurchase
Option conferred above by giving the requisite notice within ninety (90) days
following the termination, the Repurchase Option shall terminate.

                  (e) The Repurchase Option shall terminate in accordance with
the Vesting Schedule in Optionee's Option Agreement.

         2. Transferability of the Shares; Escrow.

                  (a) Purchaser hereby authorizes and directs the Secretary of
the Company, or such other person designated by the Company, to transfer the
Unvested Shares as to which the Repurchase Option has been exercised from
Purchaser to the Company.

                  (b) To insure the availability for delivery of Purchaser's
Unvested Shares upon repurchase by the Company pursuant to the Repurchase Option
under Section 1, Purchaser hereby appoints the Vice President, Finance, or any
other person designated by the Company as escrow agent, as its attorney-in-fact
to sell, assign and transfer unto the Company, such Unvested Shares, if any,
repurchased by the Company pursuant to the Repurchase Option and shall, upon
execution of this Agreement, deliver and deposit with the Vice President,
Finance of the Company, or such other person designated by the Company, the
share certificates representing the Unvested Shares, together with the stock
assignment duly endorsed in blank, attached hereto as Exhibit C-2. The Unvested
Shares and stock assignment shall be held by the Vice President, Finance in
escrow, pursuant to the Joint Escrow Instructions of the Company and Purchaser
attached as Exhibit C-3 hereto, until the Company exercises its purchase right
as provided in Section 1, until such Unvested Shares are vested, or until such
time as this Agreement no longer is in effect. Upon vesting of the Unvested
Shares, the escrow agent shall promptly deliver to the Purchaser the certificate
or certificates representing such Shares in the escrow agent's possession
belonging to the Purchaser, and the escrow agent shall be discharged of all
further obligations hereunder; provided, however, that the escrow agent shall
nevertheless retain such certificate or certificates as escrow agent if so
required pursuant to other restrictions imposed pursuant to this Agreement.

                  (c) The Company, or its designee, shall not be liable for any
act it may do or omit to do with respect to holding the Shares in escrow and
while acting in good faith and in the exercise of its judgment.

                  (d) Transfer or sale of the Shares is subject to restrictions
on transfer imposed by any applicable state and federal securities laws. Any
transferee shall hold such Shares subject to all the provisions hereof and the
Exercise Notice executed by the Purchaser with respect to any Unvested Shares
purchased by Purchaser and shall acknowledge the same by signing a copy of this
Agreement.

         3. Ownership, Voting Rights, Duties. This Agreement shall not affect in
any way the ownership, voting rights or other rights or duties of Purchaser,
except as specifically provided herein.

         4. Legends. The share certificate evidencing the Shares issued
hereunder shall be endorsed with the following legend (in addition to any legend
required under applicable state securities laws):

<PAGE>

                  THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO
                  CERTAIN RESTRICTIONS UPON TRANSFER AND RIGHTS OF REPURCHASE AS
                  SET FORTH IN AN AGREEMENT BETWEEN THE COMPANY AND THE
                  STOCKHOLDER, A COPY OF WHICH IS ON FILE WITH THE SECRETARY OF
                  THE COMPANY.

         5. Adjustment for Stock Split. All references to the number of Shares
and the purchase price of the Shares in this Agreement shall be appropriately
adjusted to reflect any stock split, stock dividend or other change in the
Shares, which may be made by the Company after the date of this Agreement.

         6. Notices. Notices required hereunder shall be given in person or by
registered mail to the address of Purchaser shown on the records of the Company,
and to the Company at their respective principal executive offices.

         7. Survival of Terms. This Agreement shall apply to and bind Purchaser
and the Company and their respective permitted assignees and transferees, heirs,
legatees, executors, administrators and legal successors.

         8. Section 83(b) Election. Purchaser hereby acknowledges that it has
been informed that, with respect to the exercise of an option for Unvested
Shares, an election may be filed by the Purchaser with the Internal Revenue
Service, within 30 days of the purchase of the Shares, electing pursuant to
Section 83(b) of the Code to be taxed currently on any difference between the
purchase price of the Shares and their Fair Market Value on the date of
purchase. This will result in a recognition of taxable income to the Purchaser
on the date of exercise, measured by the excess, if any, of the fair market
value of the Shares, at the time the option is exercised over the purchase price
for the Shares. Absent such an election, taxable income will be measured and
recognized by Purchaser at the time or times on which the Company's Repurchase
Option lapses. Purchaser is strongly encouraged to seek the advice of its own
tax consultants in connection with the purchase of the Shares and the
advisability of filing of the Election under Section 83(b) of the Code. A form
of Election under Section 83(b) is attached hereto as Exhibit C-4 for reference.

                  PURCHASER ACKNOWLEDGES THAT IT IS PURCHASER'S SOLE
RESPONSIBILITY AND NOT THE COMPANY'S TO FILE TIMELY THE ELECTION UNDER SECTION
83(b), EVEN IF PURCHASER REQUESTS THE COMPANY OR ITS REPRESENTATIVE TO MAKE THIS
FILING ON PURCHASER'S BEHALF.

         9. Representations. Purchaser has reviewed with its own tax advisors
the federal, state, local and foreign tax consequences of this investment and
the transactions contemplated by this Agreement. Purchaser is relying solely on
such advisors and not on any statements or representations of the Company or any
of its agents. Purchaser understands that it (and not the Company) shall be
responsible for its own tax liability that may arise as a result of this
investment or the transactions contemplated by this Agreement.

         10. Governing Law. This Agreement shall be governed by the internal
substantive laws, but not the choice of law rules, of California.

<PAGE>

                  Purchaser represents that it has read this Agreement and is
familiar with its terms and provisions. Purchaser hereby agrees to accept as
binding, conclusive and final all decisions or interpretations of the Board upon
any questions arising under this Agreement.

         IN WITNESS WHEREOF, this Agreement is deemed made as of the date first
set forth above.

                                            STREAM MACHINE COMPANY

                                            ----------------------------------
                                            By

                                            ----------------------------------
                                            Title

                                            PURCHASER

                                            ----------------------------------
                                            Signature

                                            ----------------------------------
                                            Printed Name

                                            ----------------------------------
                                            Title

                                            ----------------------------------
                                            Taxpayer Identification No.

                                            Address:

                                            ----------------------------------

                                            ----------------------------------

<PAGE>

                                   EXHIBIT C-2

                      ASSIGNMENT SEPARATE FROM CERTIFICATE

         FOR VALUE RECEIVED Simplex Solutions, Inc., hereby sells, assigns and
transfers unto Stream Machine Company (__________) shares of the Common Stock of
Stream Machine Company standing in my name of the books of said corporation
represented by Certificate No. _____ herewith and do hereby irrevocably
constitute and appoint _____________________________ to transfer the said stock
on the books of the within named corporation with full power of substitution in
the premises.

         This Stock Assignment may be used only in accordance with the
Restricted Stock Purchase Agreement between Stream Machine Company and the
undersigned dated ______________, ____.

Dated:                ,
      ----------------  ----

                                       Signature:
                                                 -------------------------------

                                       Print Name:
                                                  ------------------------------

                                       Title:
                                             -----------------------------------

INSTRUCTIONS: Please do not fill in any blanks other than the signature line.
The purpose of this assignment is to enable the Company to exercise its
"repurchase option," as set forth in the Agreement, without requiring additional
signatures on the part of the Purchaser.

<PAGE>

                                   EXHIBIT C-3

                            JOINT ESCROW INSTRUCTIONS

            ,
------------  ----

Stream Machine Company
46831 Lakeview Blvd.
Fremont, CA 94538

Attention: Stock Plan Administrator

Dear             :
     ------------

         As Escrow Agent for both Stream Machine Company (the "Company"), and
the undersigned purchaser of stock of the Company (the "Purchaser"), you are
hereby authorized and directed to hold the documents delivered to you pursuant
to the terms of that certain Restricted Stock Purchase Agreement ("Agreement")
between the Company and the undersigned, in accordance with the following
instructions:

         1. In the event the Company and/or any assignee of the Company
(referred to collectively for convenience herein as the "Company") exercises the
Company's repurchase option set forth in the Agreement, the Company shall give
to Purchaser and you a written notice specifying the number of shares of stock
to be purchased, the purchase price, and the time for a closing hereunder at the
principal office of the Company. Purchaser and the Company hereby irrevocably
authorize and direct you to close the transaction contemplated by such notice in
accordance with the terms of said notice.

         2. At the closing, you are directed (a) to date the stock assignments
necessary for the transfer in question, (b) to fill in the number of shares
being transferred, and (c) to deliver same, together with the certificate
evidencing the shares of stock to be transferred, to the Company or its
assignee, against the simultaneous delivery to you of the purchase price (by
cash, a check, or some combination thereof) for the number of shares of stock
being purchased pursuant to the exercise of the Company's repurchase option.

         3. Purchaser irrevocably authorizes the Company to deposit with you any
certificates evidencing shares of stock to be held by you hereunder and any
additions and substitutions to said shares as defined in the Agreement.
Purchaser does hereby irrevocably constitute and appoint you as Purchaser's
attorney-in-fact and agent for the term of this escrow to execute with respect
to such securities all documents necessary or appropriate to make such
securities negotiable and to complete any transaction herein contemplated,
including but not limited to the filing with any applicable state blue sky
authority of any required applications for consent to, or notice of transfer of,
the securities. Subject to the provisions of this paragraph 3, Purchaser shall
exercise all rights and privileges of a stockholder of the Company while the
stock is held by you.

<PAGE>

         4. Upon written request of the Purchaser, but no more than once per
calendar year, unless the Company's repurchase option has been exercised, you
will deliver to Purchaser a certificate or certificates representing so many
shares of stock as are not then subject to the Company's repurchase option.
Within 120 days after cessation of Purchaser's continuous services to the
Company, or any parent or subsidiary of the Company, you will deliver to
Purchaser a certificate or certificates representing the aggregate number of
shares held or issued pursuant to the Agreement and not purchased by the Company
or its assignees pursuant to exercise of the Company's repurchase option.

         5. If at the time of termination of this escrow you should have in your
possession any documents, securities, or other property belonging to Purchaser,
you shall deliver all of the same to Purchaser and shall be discharged of all
further obligations hereunder.

         6. Your duties hereunder may be altered, amended, modified or revoked
only by a writing signed by all of the parties hereto.

         7. You shall be obligated only for the performance of such duties as
are specifically set forth herein and may rely and shall be protected in relying
or refraining from acting on any instrument reasonably believed by you to be
genuine and to have been signed or presented by the proper party or parties. You
shall not be personally liable for any act you may do or omit to do hereunder as
Escrow Agent or as attorney-in-fact for Purchaser while acting in good faith,
and any act done or omitted by you pursuant to the advice of your own attorneys
shall be conclusive evidence of such good faith.

         8. You are hereby expressly authorized to disregard any and all
warnings given by any of the parties hereto or by any other person or
corporation, excepting only orders or process of courts of law and are hereby
expressly authorized to comply with and obey orders, judgments or decrees of any
court. In case you obey or comply with any such order, judgment or decree, you
shall not be liable to any of the parties hereto or to any other person, firm or
corporation by reason of such compliance, notwithstanding any such order,
judgment or decree being subsequently reversed, modified, annulled, set aside,
vacated or found to have been entered without jurisdiction.

         9. You shall not be liable in any respect on account of the identity,
authorities or rights of the parties executing or delivering or purporting to
execute or deliver the Agreement or any documents or papers deposited or called
for hereunder.

         10. You shall not be liable for the outlawing of any rights under the
Statute of Limitations with respect to these Joint Escrow Instructions or any
documents deposited with you.

         11. You shall be entitled to employ such legal counsel and other
experts as you may deem necessary properly to advise you in connection with your
obligations hereunder, may rely upon the advice of such counsel, and may pay
such counsel reasonable compensation therefor.

         12. Your responsibilities as Escrow Agent hereunder shall terminate if
you shall cease to be an officer or agent of the Company or if you shall resign
by written notice to each party. In the event of any such termination, the
Company shall appoint a successor Escrow Agent.

<PAGE>

         13. If you reasonably require other or further instruments in
connection with these Joint Escrow Instructions or obligations in respect
hereto, the necessary parties hereto shall join in furnishing such instruments.

         14. It is understood and agreed that should any dispute arise with
respect to the delivery and/or ownership or right of possession of the
securities held by you hereunder, you are authorized and directed to retain in
your possession without liability to anyone all or any part of said securities
until such disputes shall have been settled either by mutual written agreement
of the parties concerned or by a final order, decree or judgment of a court of
competent jurisdiction after the time for appeal has expired and no appeal has
been perfected, but you shall be under no duty whatsoever to institute or defend
any such proceedings.

         15. Any notice required or permitted hereunder shall be given in
writing and shall be deemed effectively given upon personal delivery or upon
deposit in the United States Post Office, by registered or certified mail with
postage and fees prepaid, addressed to each of the other parties thereunto
entitled at the following addresses or at such other addresses as a party may
designate by ten days' advance written notice to each of the other parties
hereto.

                  COMPANY:          Stream Machine Company
                                    46831 Lakeview Blvd.
                                    Fremont, CA 94538
                                    Attention: Stock Plan Administrator

                  PURCHASER:
                                    -----------------------------------

                                    -----------------------------------

                                    -----------------------------------

                  ESCROW AGENT:     Stream Machine Company
                                    46831 Lakeview Blvd.
                                    Fremont, CA 94538
                                    Attention: Stock Plan Administrator

         16. By signing these Joint Escrow Instructions, you become a party
hereto only for the purpose of said Joint Escrow Instructions; you do not become
a party to the Agreement.

         17. This instrument shall be binding upon and inure to the benefit of
the parties hereto, and their respective successors and permitted assigns.

<PAGE>

         18. These Joint Escrow Instructions shall be governed by the internal
substantive laws, but not the choice of law rules, of California.

                                            STREAM MACHINE COMPANY

                                            ----------------------------------
                                            By

                                            ----------------------------------
                                            Title

                                            PURCHASER

                                            ----------------------------------
                                            Signature

                                            ----------------------------------
                                            Typed or Printed Name

                                            ----------------------------------
                                            Title

                                            ESCROW AGENT

                                            ----------------------------------
                                            Stock Plan Administrator

<PAGE>

                                   EXHIBIT C-4

                          ELECTION UNDER SECTION 83(b)
                      OF THE INTERNAL REVENUE CODE OF 1986

         The undersigned taxpayer hereby elects, pursuant to Sections 55 and
83(b) of the Internal Revenue Code of 1986, as amended, to include in taxpayer's
gross income or alternative minimum taxable income, as the case may be, for the
current taxable year the amount of any compensation taxable to taxpayer in
connection with taxpayer's receipt of the property described below:

1. The name, address, taxpayer identification number and taxable year of the
undersigned are as follows:

         NAME:                      TAXPAYER:

         ADDRESS:

         IDENTIFICATION NO.:        TAXPAYER:

         TAXABLE YEAR:

2. The property with respect to which the election is made is described as
follows: _____________ shares (the "Shares") of the Common Stock of Stream
Machine Company (the "Company").

3. The date on which the property was transferred is: __________________, ____.

4. The property is subject to the following restrictions:

         The Shares may not be transferred and are subject to forfeiture under
         the terms of an agreement between the taxpayer and the Company. These
         restrictions lapse upon the satisfaction of certain conditions
         contained in such agreement.

5. The fair market value at the time of transfer, determined without regard to
any restriction other than a restriction which by its terms will never lapse, of
such property is: $______________________.

6. The amount (if any) paid for such property is: $______________________.

         The undersigned has submitted a copy of this statement to the person
for whom the services were performed in connection with the undersigned's
receipt of the above-described property. The transferee of such property is the
person performing the services in connection with the transfer of said property.

         The undersigned understands that the foregoing election may not be
revoked except with the consent of the Commissioner.

Dated:                         ,
       ------------------------  -----      ------------------------------------
                                            Taxpayer<PAGE>
                                                                     EXHIBIT 4.2

                             ASPEN TECHNOLOGY, INC.

                           CERTIFICATE OF DESIGNATIONS
                                       OF
                             SERIES B-1 CONVERTIBLE
                                 PREFERRED STOCK
                                       AND
                             SERIES B-2 CONVERTIBLE
                                 PREFERRED STOCK

                (Pursuant to Section 151 of the Delaware General
                                Corporation Law)

            Aspen Technology, Inc., a Delaware corporation (the "Corporation"),
in accordance with the provisions of Section 103 of the Delaware General
Corporation Law (the "DGCL") does hereby certify that, in accordance with
Section 141(c) of the DGCL, the following resolution was duly adopted by the
Board of Directors of the Corporation as of February 4, 2002:

            RESOLVED, that two series of Preferred Stock, Series B-1 Convertible
Preferred Stock, par value $0.10 per share and Series B-2 Convertible Preferred
Stock, par value $0.10 per share, of the Corporation are hereby created and the
designation, number of shares, powers, preferences, rights, qualifications,
limitations and restrictions thereof (in addition to any provisions set forth in
the Certificate of Incorporation of the Corporation which are applicable to the
Preferred Stock of all classes and series) are as follows:

                     SERIES B-1 CONVERTIBLE PREFERRED STOCK
                                       AND
                     SERIES B-2 CONVERTIBLE PREFERRED STOCK

      1. Designation, Amount, Par Value and Stated Value. The following two (2)
series of preferred stock shall be designated as (i) the Corporation's Series
B-1 Convertible Preferred Stock (the "SERIES B-1 PREFERRED STOCK"), and the
number of shares so designated shall be 30,000 and (ii) the Corporation's Series
B-2 Convertible Preferred Stock (the "SERIES B-2 PREFERRED STOCK"), and the
number of shares so designated shall be 20,000. The Series B-1 Preferred Stock
and Series B-2 Preferred Stock are sometimes collectively referred to as the
"SERIES B PREFERRED STOCK." Each share of Series B Preferred Stock shall have a
par value of $0.10 per share and a stated value equal to $1,000 plus any amount
added to the Stated Value
<PAGE>
pursuant to Section 3(c) hereof or Section 2(c) of the Registration Rights
Agreement (the "STATED VALUE").

      2.          Definitions.  In addition to the terms defined elsewhere in
this Certificate of Designations, (a) the terms set forth in Exhibit A hereto
have the meanings indicated therein, and (b) the following terms have the
meanings indicated:

            "CONVERSION PRICE" means the Initial Conversion Price as of the
      applicable Original Issue Date, as adjusted pursuant to Section 15 below.

            "EQUITY CONDITIONS" means, with respect to a specified issuance of
      Common Stock, that each of the following conditions is satisfied: (i) the
      number of authorized but unissued and otherwise unreserved shares of
      Common Stock is sufficient for such issuance; (ii) such shares of Common
      Stock are registered for resale by the Holders and may be sold by the
      Holders pursuant to an effective Underlying Shares Registration Statement,
      all such shares may be sold without volume restrictions pursuant to Rule
      144(k) under the Securities Act or all Underlying Shares owned by each
      Holder may be sold without volume restrictions pursuant to Rule 144 under
      the Securities Act; (iii) the Common Stock is listed or quoted (and is not
      suspended from trading) on an Eligible Market and such shares of Common
      Stock are approved for listing upon issuance; (iv) such issuance would be
      permitted in full without violating Section 16 hereof or the rules or
      regulations of any Trading Market; (v) no Bankruptcy Event has occurred;
      (vi) the Corporation is not in default with respect to any material
      obligation hereunder or under any other Transaction Document; and (vii)
      none of the following events have occurred and are continuing (A) an event
      constituting a Triggering Event or (B) an event that with the passage of
      time and without being cured would constitute a Triggering Event other
      than a pending, proposed or intended Change of Control.

            "HOLDER" means any holder of Series B Preferred Stock.

            "INITIAL CONVERSION PRICE" means (i) in the case of Series B-1
      Preferred Stock, $19.9703, and (ii) in the case of Series B-2 Preferred
      Stock, the greater of (x) the lesser of (a) 117.5% of the average of the
      daily Volume Weighted Average Prices over the twenty (20) consecutive
      Trading Day period ending on February 27, 2002 (including such date) or
      (b) 112.5% of the average of the daily Volume Weighted Average Prices over
      the three (3) consecutive Trading Day period ending on February 27, 2002
      (including such date), or (y) $15.00 (as adjusted for any stock splits,
      stock dividends, stock combinations or

                                       2
<PAGE>
      similar events occurring after the Original Issue Date of the Series B-1
      Preferred Stock and prior to the Original Issue Date of the Series B-2
      Preferred Stock).

            "INITIAL PURCHASE PRICE" means (i) in the case of Series B-1
      Preferred Stock, $17.75, and (ii) in the case of Series B-2 Preferred
      Stock, the greater of (x) the lesser of (a) the average of the daily
      Volume Weighted Average Prices over the twenty (20) consecutive Trading
      Day period ending on February 27, 2002 (including such date) or (b) the
      average of the daily Volume Weighted Average Prices over the three (3)
      consecutive Trading Day period ending on February 27, 2002 (including such
      date), or (y) $15.00 (as adjusted for any stock splits, stock dividends,
      stock combinations or similar events occurring after the Original Issue
      Date of the Series B-1 Preferred Stock and prior to the Original Issue
      Date of the Series B-2 Preferred Stock).

            "JUNIOR SECURITIES" means the Common Stock and all other equity or
      equity equivalent securities of the Corporation.

            "ORIGINAL ISSUE DATE" means the date of the first issuance of any
      shares of the Series B-1 Preferred Stock or Series B-2 Preferred Stock, as
      applicable, regardless of the number of transfers of any particular shares
      of such Series B Preferred Stock and regardless of the number of
      certificates that may be issued to evidence such Series B Preferred Stock.

            "PURCHASE AGREEMENT" means the Securities Purchase Agreement, dated
      February 6, 2002, among the Corporation and the original purchasers of the
      Series B Preferred Stock.

      3.          Dividends.

            (a) Holders shall be entitled to receive, out of funds legally
available therefor, and the Corporation shall pay, cumulative dividends on the
Series B Preferred Stock at the rate per share (as a percentage of the Stated
Value per share) of 4% per annum, payable quarterly in arrears commencing on
June 30, 2002 and thereafter on each March 31, June 30, September 30 and
December 31, except if such date is not a Trading Day, in which case such
dividend shall be payable on the next succeeding Trading Day (each, a "DIVIDEND
PAYMENT DATE"). Dividends on the Series B Preferred Stock shall be calculated on
the basis of a 365-day year, shall accrue daily commencing on the Original Issue
Date for the applicable series of Series B Preferred Stock, and shall be deemed
to accrue from such date whether or not earned or declared and whether or not
there are profits, surplus or other funds of the Corporation legally available
for the payment of dividends.

            (b) Subject to the conditions and limitations set forth below, the
Corporation may pay required dividends (i) in cash or (ii) in Common Stock. The
Corporation must deliver written notice (the "DIVIDEND NOTICE") to the Holders
indicating the manner in which it intends to pay dividends at least ten Trading
Days prior to each Dividend Payment Date, but the Corporation may indicate in
any such notice that the election contained therein shall continue for
subsequent Dividend Payment Dates until revised. Failure to timely provide such
written notice shall be deemed an election by the Corporation to pay the
dividend in Common Stock, unless payment of dividends in such manner is not
permitted at the time of a dividend, in which case such dividend shall be
payable in cash. All dividends payable in respect of the Series B Preferred
Stock on any Dividend Payment Date must be paid in the same manner.

            (c) Notwithstanding the foregoing, the Corporation may not pay
dividends by issuing Common Stock unless, at such time, the Equity Conditions
are satisfied with respect to such Common Stock dividend shares and all of the
Underlying Shares then issuable upon conversion in full of all outstanding
Series B Preferred Stock. If the Corporation is required to pay dividends in
cash on any Dividend Payment Date and does not timely make such payment, any
Holder may (but shall not be required to) treat such cash amount as if it had
been added to

                                       3
<PAGE>
the Stated Value as of such Dividend Payment Date. If the Corporation may not
legally pay dividends on any Dividend Payment Date, such amount shall be added
to the Stated Value as of such Dividend Payment Date.

            (d) So long as any Series B Preferred Stock is outstanding, (i)
neither the Corporation nor any Subsidiary shall, directly or indirectly,
redeem, purchase or otherwise acquire any Junior Securities or set aside any
monies for such a redemption, purchase or other acquisition in excess of
$10,000,000 per calendar year, provided that the Corporation shall be entitled
to carry forward any amount not used in any calendar year to subsequent calendar
years, and (ii) the Corporation shall not pay or declare any dividend or make
any distribution on any Junior Securities, except pro rata stock dividends on
the Common Stock payable in additional shares of Common Stock and dividends due
and paid in the ordinary course on preferred stock of the Corporation, in each
case only at such times as the Corporation is in compliance with its payment and
other obligations hereunder.

            (e) In the event that the Corporation elects to pay dividends in
shares of Common Stock, the number of shares of Common Stock to be issued to
each Holder as such dividend shall be (i) determined by dividing the total
dividend then payable to such Holder by the Dividend Market Price (as defined
below) as of the applicable Dividend Payment Date, and rounding up to the
nearest whole share, and (ii) paid to such Holder in accordance with Section
3(f) below. The term "DIVIDEND MARKET PRICE" shall mean the average of the
Volume Weighted Average Prices of Common Stock for the five (5) consecutive
Trading Days prior to the applicable Dividend Payment Date (not including such
date).

            (f) In the event that any dividends are paid in Common Stock the
Corporation shall, on or before the third (3rd) Trading Day following the
payment date of such dividend, (i) issue and deliver to such Holder a
certificate, registered in the name of the Holder or its designee, for the
number of shares of Common Stock to which the Holder shall be entitled or (ii)
if and when the applicable shares of Common Stock may be held in a balance
account with The Depository Trust Corporation through its Deposit Withdrawal
Agent Commission System and after the Holder has notified the Corporation that
this clause (ii) shall apply, credit the number of shares of Common Stock to
which the Holder shall be entitled to the Holder's or its designee's balance
account with The Depository Trust Corporation through its Deposit Withdrawal
Agent Commission System.

      4. Registration of Series B Preferred Stock. The Corporation shall
register shares of the Series B Preferred Stock, upon records to be maintained
by the Corporation for that purpose (the "SERIES B PREFERRED STOCK REGISTER"),
in the name of the record Holders thereof from time to time. The Corporation may
deem and treat the registered Holder of shares of Series B Preferred Stock as
the absolute owner thereof for the purpose of any conversion hereof or any
distribution to such Holder, and for all other purposes, absent actual notice to
the contrary.

      5. Registration of Transfers. The Corporation shall register the transfer
of any shares of Series B Preferred Stock in the Series B Preferred Stock
Register, upon surrender of certificates evidencing such Shares to the
Corporation at its address specified herein. Upon any such registration or
transfer, a new certificate evidencing the shares of Series B Preferred Stock

                                       4
<PAGE>
so transferred shall be issued to the transferee and a new certificate
evidencing the remaining portion of the shares not so transferred, if any, shall
be issued to the transferring Holder.

      6.          Liquidation.

            (a) In the event of any liquidation, dissolution or winding up of
the Corporation, either voluntary or involuntary (a "LIQUIDATION EVENT"), the
Holders of Series B Preferred Stock shall be entitled to receive, prior and in
preference to any distribution of any of the assets or surplus funds of the
Corporation to the holders of Junior Securities by reason of their ownership
thereof, an amount per share in cash equal to the Stated Value for each share of
Series B Preferred Stock then held by them (as adjusted for any stock splits,
stock dividends, stock combinations and similar transactions with respect to the
Series B Preferred Stock), plus all accrued but unpaid dividends on such Series
B Preferred Stock as of the date of such event (the "SERIES B STOCK LIQUIDATION
Preference"). If, upon the occurrence of a Liquidation Event, the assets and
funds thus distributed among the holders of the Series B Preferred Stock shall
be insufficient to permit the payment to such Holders of the full Series B Stock
Liquidation Preference, then the entire assets and funds of the Corporation
legally available for distribution shall be distributed ratably among the
Holders of the Series B Preferred Stock in proportion to the aggregate Series B
Stock Liquidation Preference that would otherwise be payable to each of such
Holders.

            (b) In the event of a Liquidation Event, following completion of the
distributions required by the first sentence of paragraph (a) of this Section 6,
if assets or surplus funds remain in the Corporation, the holders of the Common
Stock shall share ratably in all remaining assets of the Corporation, based on
the number of shares of Common Stock then outstanding.

            (c) The Corporation shall mail written notice of any Liquidation
Event to each record Holder not less than 20 Trading Days prior to the payment
date or effective date thereof.

      7.          Conversion.

            (a) Conversion at Option of Holder. At the option of any Holder, any
Series B Preferred Stock held by such Holder may be converted into Common Stock
based on the applicable Conversion Price then in effect for such series of
Series B Preferred Stock. A Holder may convert Series B Preferred Stock into
Common Stock pursuant to this paragraph at any time and from time to time after
the applicable Original Issue Date, by delivering to the Corporation a
Conversion Notice, in the form attached hereto as Exhibit B, appropriately
completed and duly signed, and the date any such Conversion Notice is delivered
to the Corporation (as determined in accordance with the notice provisions
hereof) is a "Conversion Date."

            (b) Conversion at Option of Corporation. If, at any time after the
Effective Date, the Closing Price on each of twenty (20) consecutive Trading
Days (a "QUALIFYING PERIOD") exceeds 135% of the applicable Conversion Price for
a series of Series B Preferred Stock (each, a "THRESHOLD PRICE"), the
Corporation may require the Holders to convert the

                                       5
<PAGE>
shares of such series into Common Stock based on the applicable Conversion
Price. The Corporation may require a conversion pursuant to this paragraph by
delivering irrevocable written notice of such election to the Holders, and the
fifth Trading Day after the date any such notice is delivered to the Holders (as
determined in accordance with the notice provisions hereof) will be the
"CONVERSION DATE" for such required conversion. Notwithstanding the foregoing,
(i) if the Corporation has publicly announced a pending, proposed or intended
Change of Control and the Qualifying Period includes any Trading Days on or
after the date of such public announcement, then to the extent that a Holder has
not had the ability to sell all or a portion of the Underlying Shares pursuant
to Rule 144 under the Securities Act or an effective Underlying Share
Registration Statement for at least 20 Trading Days after the date of the public
announcement of such Change of Control, the Conversion Date with respect to
those shares of Series B Preferred Stock that are convertible into the portion
of the Underlying Shares that are not so saleable shall be deferred until the
date on which such Underlying Shares shall have been so saleable for a period of
20 Trading Days from the date of such public announcement (and if no such period
of 20 Trading Days occurs prior to the Change of Control with respect to any
such Underlying Shares then the notice of conversion applicable to those shares
of Series B Preferred Stock convertible into such Underlying Shares shall be
void) and (ii) the Corporation may not require any conversion under this
paragraph (and any notice thereof will be void), unless from the beginning of
such period of 20 consecutive Trading Days through the Conversion Date, (A) the
Equity Conditions are satisfied with respect to all of the Underlying Shares
then issuable upon conversion in full of all outstanding Series B Preferred
Stock, and (B) the Closing Price equals or exceeds the applicable Threshold
Price.

      8.          Mechanics of Conversion.

            (a) The number of Underlying Shares issuable upon any conversion of
shares of either series of Series B Preferred Stock hereunder shall equal (i)
the Stated Value of such share of Series B Preferred Stock to be converted,
divided by the applicable Conversion Price on the Conversion Date, plus (ii) the
amount of any accrued but unpaid dividends on such share of Series B Preferred
Stock through the Conversion Date, divided by the applicable Conversion Price on
the Conversion Date.

            (b) Upon conversion of any Series B Preferred Stock, the Corporation
shall promptly (but in no event later than three Trading Days after the
Conversion Date) issue or cause to be issued and cause to be delivered to or
upon the written order of the Holder and in such name or names as the Holder may
designate a certificate for the Underlying Shares issuable upon such conversion,
free of restrictive legends unless such Underlying Shares are not then freely
transferable without volume restrictions pursuant to Rule 144(k) under the
Securities Act. The Holder, or any Person so designated by the Holder to receive
Underlying Shares, shall be deemed to have become holder of record of such
Underlying Shares as of the Conversion Date. If and when such Underlying Shares
may be freely transferred pursuant to Rule 144 under the Securities Act or
pursuant to an effective Underlying Shares Registration Statement, the
Corporation shall use its best efforts to deliver Underlying Shares hereunder
electronically through the Depository Trust Corporation or another established
clearing corporation performing similar functions, and shall issue such
Underlying Shares in the same manner as dividend payment shares are issued
pursuant to Section 3(f) above.

                                       6
<PAGE>
            (c) A Holder shall not be required to deliver the original
certificate(s) evidencing the Series B Preferred Stock being converted in order
to effect a conversion of such Series B Preferred Stock. Execution and delivery
of the Conversion Notice shall have the same effect as cancellation of the
original certificate(s) and issuance of a new certificate evidencing the
remaining shares of Series B Preferred Stock. Upon surrender of a certificate
following one or more partial conversions, the Corporation shall promptly
deliver to the Holder a new certificate representing the remaining shares of
Series B Preferred Stock.

            (d) The Corporation's obligations to issue and deliver Underlying
Shares upon conversion of Series B Preferred Stock in accordance with the terms
hereof are absolute and unconditional, irrespective of any action or inaction by
any Holder to enforce the same, any waiver or consent with respect to any
provision hereof, the recovery of any judgment against any Person or any action
to enforce the same, or any setoff, counterclaim, recoupment, limitation or
termination, or any breach or alleged breach by any Holder or any other Person
of any obligation to the Corporation or any violation or alleged violation of
law by any Holder or any other Person, and irrespective of any other
circumstance which might otherwise limit such obligation of the Corporation to
any Holder in connection with the issuance of such Underlying Shares.

      9.          Redemption Rights.

            (a)         Holders Redemption Rights.

                        (i) Subject to the provisions of Section 9(a)(iii)
            below, if, at any time on or after the eighteen (18) month
            anniversary of the applicable Original Issue Date of a Series B
            Preferred Stock, the average of the Closing Prices for twenty (20)
            consecutive Trading Days immediately preceding such eighteen (18)
            month anniversary or any date thereafter is below the applicable
            Conversion Price of such series of Series B Preferred Stock, the
            Holder of such Series B Preferred Stock, upon 15 Trading Days
            advance notice (the "REDEMPTION NOTICE") to the Corporation, shall
            have the right to request the Corporation to redeem that number of
            shares of Series B Preferred Stock held by such Holders as is set
            forth in the Redemption Notice at a per share price (the "REDEMPTION
            PRICE") equal to the Stated Value of such shares of Series B
            Preferred Stock to be redeemed plus all accrued but unpaid dividends
            thereon to the date of payment.

                        (ii) Notwithstanding anything to the contrary in Section
            9(a)(i), the Holders of the Series B Preferred Stock (x) may not
            deliver a Redemption Notice with respect to a particular series of
            Series B Preferred Stock until after the date that is eighteen (18)
            months after the Original Issue Date of such series of Series B
            Preferred Stock, (y) may not deliver a Redemption Notice covering in
            aggregate more than $15,000,000 of Stated Value, with respect to the
            Series B-1 Preferred Stock, and $10,000,000 of Stated Value, with
            respect to the Series B-2 Preferred Stock, until after the date that
            is twenty - four (24) months after the Original Issue Date of such
            series of Series B Preferred Stock, and (z) may deliver a Redemption
            Notice with respect to a particular series of Series B Preferred

                                       7
<PAGE>
            Stock after the date that is twenty-four (24) months after the
            Original Issue Date of such series of Series B Preferred Stock,
            irrespective of whether the average of the Closing Prices for the
            twenty (20) consecutive Trading Days is below the applicable
            Conversion Price of such series of Series B Preferred Stock and
            without limit as to Stated Value.

                        (iii) Within three (3) Trading Days of receipt of a
            Redemption Notice, the Corporation will deliver written notice to
            each Holder of the applicable series of Series B Preferred Stock
            (the "CORPORATION NOTICE"), confirming pursuant to the Redemption
            Notice the aggregate amount of such Series B Preferred Stock being
            redeemed, the Redemption Date and the applicable Redemption Prices.
            Notwithstanding the aggregate shares set forth in the Redemption
            Notice, each Holder of such series of Series B Preferred Stock shall
            have the right to elect to have all or any number of shares of the
            applicable series of Series B Preferred Stock held by such Holder
            redeemed on the Redemption Date at the applicable Redemption Price
            by notifying the Corporation within five (5) Trading Days of receipt
            of the Corporation Notice of its election to do so, and specifying
            the number of shares as to which such election is made. In the event
            that the aggregate number of shares of Series B Preferred Stock to
            be redeemed on such Redemption Date exceeds the aggregate
            limitations set forth in Section 9(a)(ii), the number of shares to
            be redeemed from each Holder shall be reduced pro rata based upon
            the aggregate number of shares of the applicable series of Series B
            Preferred Stock held by each Holder requesting redemption.

                        (iv) The Redemption Notice will specify the effective
            date of the redemption, which must be a Trading Day at least 15
            Trading Days after the date such notice is delivered (the
            "REDEMPTION DATE"), and the entire Redemption Price may be paid at
            the Corporation's option in cash or in Common Stock. The Corporation
            must deliver written notice to the Holders indicating the manner in
            which it intends to pay the Redemption Price at least three (3)
            Trading Days after receipt of the Redemption Notice. Failure to
            timely provide such written notice shall be deemed an election by
            the Corporation to make the payment in Common Stock. Notwithstanding
            the foregoing, the Corporation may not pay the Redemption Price by
            issuing Common Stock unless, at such time, the Equity Conditions are
            satisfied with respect to such Common Stock.

                        (v) Upon receipt of payment of the Redemption Price,
            each Holder will deliver the original certificate(s) evidencing the
            Series B Preferred Stock so redeemed to the Corporation, unless such
            Holder is awaiting receipt of a new certificate evidencing such
            shares from the Corporation pursuant to another provision hereof. At
            any time on or prior to the Corporation Redemption Date, the Holders
            may convert any or all of the shares of Series B Preferred Stock,
            and the Corporation shall honor any such conversions in accordance
            with the terms hereof.

                        (vi) In the event that the Corporation elects to pay the
            Redemption Price in shares of Common

                                       8
<PAGE>
            Stock, the number of shares of Common Stock to be issued to each
            Holder as payment of the Redemption Price shall be determined by
            dividing the total Redemption Price then payable to such Holder by
            the Redemption Market Price (as defined below) as of the applicable
            Redemption Date, and rounding up to the nearest whole share. Such
            shares shall be issued to such Holder in the same manner as dividend
            payment shares are issued pursuant to Section 3(f) above. The term
            "REDEMPTION MARKET PRICE" shall mean the average of the Volume
            Weighted Average Prices of Common Stock for the ten (10) consecutive
            Trading Days prior to the applicable Redemption Date (not including
            such date).

            (b) Mandatory Redemption. On the seven year anniversary of the
Original Issue Date of the Series B-1 Preferred Stock (the "MANDATORY REDEMPTION
DATE"), the Corporation shall redeem all of the then outstanding Series B
Preferred Stock at a price equal to 100% of the Stated Value of such shares of
Series B Preferred Stock plus all accrued but unpaid dividends thereon to the
date of payment in cash or Common Stock (or a combination thereof) at the
election of the Corporation. The Corporation must deliver written notice to the
Holders indicating the manner in which it intends to pay the Redemption Price at
least twenty (20) Trading Days prior to the Mandatory Redemption Date. Failure
to timely provide such written notice shall be deemed an election by the
Corporation to make the payment in Common Stock. Notwithstanding the foregoing,
the Corporation may not pay the Redemption Price by issuing Common Stock except
to the extent the Equity Conditions are satisfied with respect to such Common
Stock. Upon receipt of payment of the Redemption Price, each Holder will deliver
the original certificate(s) evidencing the Series B Preferred Stock so redeemed
to the Corporation, unless such Holder is awaiting receipt of a new certificate
evidencing such shares from the Corporation pursuant to another provision
hereof. At any time on or prior to the Mandatory Redemption Date, the Holders
may convert any or all of the shares of Series B Preferred Stock, and the
Corporation shall honor any such conversions in accordance with the terms
hereof.

      10. Triggering Events. At any time or times following the occurrence of a
Triggering Event (other than a Change of Control), each Holder shall have the
option to elect, by notice to the Corporation (an "EVENT NOTICE"), to require
the Corporation to repurchase all or any portion of (i) the Series B Preferred
Stock then held by such Holder, at a price per share equal to the greater of (A)
115% of the Stated Value plus all accrued but unpaid dividends thereon through
the date of payment, or (B) the Event Equity Value of the Underlying Shares
issuable upon conversion of such Series B Preferred Stock (including such
accrued but unpaid dividends thereon), and (ii) any Underlying Shares issued to
such Holder upon conversion of Series B Preferred Stock, at a price per share
equal to the Event Equity Value of such Underlying Shares. The aggregate amount
payable pursuant to the preceding sentence is referred to as the "EVENT PRICE."
The Corporation shall pay the aggregate Event Price to each Holder no later than
the third Trading Day following the date of delivery of the Event Notice, and
upon receipt thereof such Holder shall deliver original certificates evidencing
the shares of Series B Preferred Stock and Underlying Shares so repurchased to
the Corporation (to the extent such certificates have been delivered to the
Holder).

      11. Voting Rights. Except as otherwise provided herein or as required by
applicable law, the Holders of the Series B Preferred Stock shall be entitled to
vote on all matters on which holders of Common Stock are entitled to vote,
including, without limitation, the election of

                                       9
<PAGE>
directors. For such purposes, each Holder shall be entitled to a number of votes
in respect of the shares of Series B Preferred Stock owned by it equal to the
number of shares of Common Stock into which such shares of Series B Preferred
Stock are convertible as of the record date for the determination of
stockholders entitled to vote on such matter, or if no record date is
established, at the date such vote is taken or any written consent of
stockholders is solicited. Except as otherwise provided herein, in any relevant
agreement or as required by applicable law, the holders of the Series B
Preferred Stock and Common Stock, respectively, shall vote together as a single
class on all matters submitted to a vote or consent of stockholders; provided
that so long as any shares of Series B Preferred Stock are outstanding, the
Corporation shall not, without the affirmative vote of the Holders of a majority
of the shares of Series B Preferred Stock then outstanding, (a) alter or change
adversely the powers, preferences or rights given to the Series B Preferred
Stock or alter or amend this Certificate of Designations (whether by merger,
reorganization, consolidation or otherwise), (b) authorize or create any class
of stock ranking as to dividends or distribution of assets upon a Liquidation
Event or Change of Control senior to the Series B Preferred Stock, (c) amend its
certificate of incorporation or bylaws so as to affect adversely any rights of
the Holders (whether by merger, reorganization, consolidation or otherwise), (d)
increase the authorized number of shares of Series B Preferred Stock, or (e)
enter into any agreement with respect to the foregoing.

      12. Charges, Taxes and Expenses. Issuance of certificates for shares of
Series B Preferred Stock and for Underlying Shares issued on conversion of (or
otherwise in respect of) the Series B Preferred Stock shall be made without
charge to the Holders for any issue or transfer tax, withholding tax, transfer
agent fee or other incidental tax or expense in respect of the issuance of such
certificates, all of which taxes and expenses shall be paid by the Corporation;
provided, however, that the Corporation shall not be required to pay any tax
that may be payable in respect of any transfer involved in the registration of
any certificates for Common Stock or Series B Preferred Stock in a name other
than that of the Holder. The Holder shall be responsible for all other tax
liability that may arise as a result of holding or transferring the Series B
Preferred Stock or receiving Underlying Shares in respect of the Series B
Preferred Stock.

      13. Replacement Certificates. If any certificate evidencing Series B
Preferred Stock or Underlying Shares is mutilated, lost, stolen or destroyed,
the Corporation shall issue or cause to be issued in exchange and substitution
for and upon cancellation hereof, or in lieu of and substitution for such
certificate, a new certificate, but only upon receipt of evidence reasonably
satisfactory to the Corporation of such loss, theft or destruction and customary
and reasonable indemnity, if requested. Applicants for a new certificate under
such circumstances shall also comply with such other reasonable regulations and
procedures and pay such other reasonable third-party costs as the Corporation
may prescribe.

      14. Reservation of Underlying Shares. The Corporation covenants that it
shall at all times reserve and keep available out of the aggregate of its
authorized but unissued and otherwise unreserved Common Stock, solely for the
purpose of enabling it to issue the Underlying Shares as required hereunder (i)
a sufficient number of authorized but unissued and otherwise unreserved shares
of Common Stock available to issue Underlying Shares upon any conversion of
Shares or, if the number of shares so reserved is insufficient to make available
a sufficient number of authorized but unissued and otherwise unreserved shares
of Common Stock

                                       10
<PAGE>
for such issuance within 60 days after the occurrence of such deficiency, and
(ii) at least 5,825,000 authorized but unissued and otherwise unreserved shares
of Common Stock (as adjusted for any stock splits, stock combinations or similar
events) less any shares of Common Stock issued upon conversion of the Shares, as
dividends on the Shares, upon exercise of the Warrants or upon a redemption of
the Shares. The Corporation covenants that all Underlying Shares so issuable and
deliverable shall, upon issuance in accordance with the terms hereof, be duly
and validly authorized, issued and fully paid and nonassessable.

      15.         Certain Adjustments.  The Conversion Price is subject to
adjustment from time to time as set forth in this Section 15.

            (a) Stock Dividends and Splits. If the Corporation, at any time
while Series B Preferred Stock is outstanding, (i) pays a stock dividend on its
Common Stock or otherwise makes a distribution on any class of capital stock
that is payable in shares of Common Stock (other than regular dividends on the
Series B Preferred Stock), (ii) subdivides outstanding shares of Common Stock
into a larger number of shares, or (iii) combines outstanding shares of Common
Stock into a smaller number of shares, then in each such case the applicable
Conversion Price for each series of Series B Preferred Stock shall be multiplied
by a fraction of which the numerator shall be the number of shares of Common
Stock outstanding immediately before such event and of which the denominator
shall be the number of shares of Common Stock outstanding immediately after such
event. Any adjustment made pursuant to clause (i) of this paragraph shall become
effective immediately after the record date for the determination of
stockholders entitled to receive such dividend or distribution, and any
adjustment pursuant to clause (ii) or (iii) of this paragraph shall become
effective immediately after the effective date of such subdivision or
combination.

            (b) Pro Rata Distributions. If the Corporation, at any time while
Series B Preferred Stock is outstanding, distributes to all holders of Common
Stock (i) evidences of its indebtedness, (ii) any security (other than a
distribution of Common Stock covered by the preceding paragraph), (iii) rights
or warrants to subscribe for or purchase any security, or (iv) any other asset
other than cash paid as a dividend (in each case, "DISTRIBUTED PROPERTY"), then,
at the request of any Holder delivered before the 90th day after the record date
fixed for determination of stockholders entitled to receive such distribution,
the Corporation will deliver to such Holder, within five Trading Days after such
request (or, if later, on the effective date of such distribution), the
Distributed Property that such Holder would have been entitled to receive in
respect of the Underlying Shares for which such Holder's Series B Preferred
Stock could have been converted immediately prior to such record date. If such
Distributed Property is not delivered to a Holder pursuant to the preceding
sentence, then upon any conversion of Series B Preferred Stock that occurs after
such record date, such Holder shall be entitled to receive, in addition to the
Underlying Shares otherwise issuable upon such conversion, the Distributed
Property that such Holder would have been entitled to receive in respect of such
number of Underlying Shares had the Holder been the record holder of such
Underlying Shares immediately prior to such record date.

            (c) Change of Control Transactions. If, at any time while Series B
Preferred Stock is outstanding, the Corporation proposes to enter into a
transaction that would constitute a Change of Control, the Corporation shall
mail written notice of the proposed Change of Control

                                       11
<PAGE>
transaction to each record Holder not less than 20 Trading Days prior to the
effective date thereof. Each Holder shall have the right to receive on the date
of the consummation of such Change of Control, at its option, either (i) for
each Underlying Share that would have been issuable upon such conversion of the
shares of Series B Preferred Stock upon the effective time of such Change of
Control, the same kind and amount of securities, cash or property as it would
have been entitled to receive upon the occurrence of such Change of Control if
it had been, immediately prior to such Change of Control, the holder of one
share of Common Stock or (ii) for each share of Series B Preferred Stock, cash
in an amount equal to 115% of the Stated Value plus all accrued but unpaid
dividends thereon through the date of payment. If holders of Common Stock are
given any choice as to the securities, cash or property to be received in a
Change of Control transaction, then each Holder shall be given the same choice
as to the consideration it receives pursuant to clause (i) above. Each Holder
shall make the election of which consideration it has elected to receive at
least three (3) Trading Days prior to the effective date of a Change of Control.
Failure of any Holder to timely provide written notice of its election shall be
deemed an election by such Holder to receive the consideration specified in
clause (ii) above.

            (d)         Subsequent Equity Sales.

                        (i) If, at any time while any shares of either series of
            Series B Preferred Stock are outstanding, the Corporation or any
            Subsidiary issues additional shares of Common Stock or rights,
            warrants, options or other securities or debt convertible,
            exercisable or exchangeable for shares of Common Stock or otherwise
            entitling any Person to acquire shares of Common Stock
            (collectively, "COMMON STOCK EQUIVALENTS") at an effective net price
            to the Corporation per share of Common Stock (the "EFFECTIVE PRICE")
            less than the lesser of (A) the Initial Purchase Price for a series
            of Series B Preferred Stock or (B) then-applicable Conversion Price
            for a series of Series B Preferred Stock, then the applicable
            Conversion Price for such series of Series B Preferred Stock shall
            be reduced to equal the Effective Price. For purposes of this
            paragraph, in connection with any issuance of any Common Stock
            Equivalents, (A) the maximum number of shares of Common Stock
            potentially issuable at any time upon conversion, exercise or
            exchange of such Common Stock Equivalents (the "DEEMED NUMBER")
            shall be deemed to be outstanding upon issuance of such Common Stock
            Equivalents, (B) the Effective Price applicable to such Common Stock
            shall equal the minimum dollar value of consideration payable to the
            Corporation to purchase such Common Stock Equivalents and to
            convert, exercise or exchange them into Common Stock (net of any
            discounts, fees, commissions and other expenses), divided by the
            Deemed Number, (C) no further adjustment shall be made to the
            Conversion Price upon the actual issuance of Common Stock upon
            conversion, exercise or exchange of such Common Stock Equivalents,
            and (D) upon the expiration or termination of any Common Stock
            Equivalent that does not result in the issuance of any Common Stock
            or additional Common Stock Equivalent, any adjustment that has been
            made under this paragraph (d) in respect of the issuance of such
            Common Stock Equivalent shall be readjusted as if such Common Stock
            Equivalent had not been issued (but shall in no event affect
            previously converted stock).

                                       12
<PAGE>
                        (ii) If, at any time while Series B Preferred Stock is
            outstanding, the Corporation or any Subsidiary issues Common Stock
            Equivalents with an Effective Price or a number of underlying shares
            that floats or resets or otherwise varies or is subject to
            adjustment based (directly or indirectly) on market prices of the
            Common Stock (a "FLOATING PRICE SECURITY"), then for purposes of
            applying the preceding paragraph in connection with any subsequent
            conversion, the Effective Price will be determined separately on
            each Conversion Date and will be deemed to equal the lowest
            Effective Price at which any holder of such Floating Price Security
            is entitled to acquire Common Stock on such Conversion Date
            (regardless of whether any such holder actually acquires any shares
            on such date).

                        (iii) Notwithstanding the foregoing, no adjustment will
            be made under this paragraph (d) in respect of the issuance of
            Excluded Stock.

            (e) Calculations. All calculations under this Section 15 shall be
made to the nearest cent or the nearest 1/100th of a share, as applicable. The
number of shares of Common Stock outstanding at any given time shall not include
shares owned or held by or for the account of the Corporation, and the
disposition of any such shares shall be considered an issue or sale of Common
Stock.

            (f) Notice of Adjustments. Upon the occurrence of each adjustment
pursuant to this Section 15, the Corporation at its expense will promptly
compute such adjustment in accordance with the terms hereof and prepare a
certificate describing in reasonable detail such adjustment and the transactions
giving rise thereto, including all facts upon which such adjustment is based.
Upon written request, the Corporation will promptly deliver a copy of each such
certificate to each Holder and to the Corporation's Transfer Agent.

            (g) Notice of Corporate Events. If the Corporation (i) declares a
dividend or any other distribution of cash, securities or other property in
respect of its Common Stock, including without limitation any granting of rights
or warrants to subscribe for or purchase any capital stock of the Corporation or
any Subsidiary, (ii) authorizes or approves, enters into any agreement
contemplating or solicits stockholder approval for any Fundamental Transaction
or (iii) authorizes the voluntary dissolution, liquidation or winding up of the
affairs of the Corporation, then the Corporation shall deliver to each Holder a
notice describing the material terms and conditions of such transaction, at
least 20 calendar days prior to the applicable record or effective date on which
a Person would need to hold Common Stock in order to participate in or vote with
respect to such transaction, and the Corporation will take all steps reasonably
necessary in order to insure that each Holder is given the practical opportunity
to convert its Series B Preferred Stock prior to such time so as to participate
in or vote with respect to such transaction; provided, however, that the failure
to deliver such notice or any defect therein shall not affect the validity of
the corporate action required to be described in such notice.

      16.         Limitation on Conversion.

            (a) Notwithstanding anything to the contrary contained herein, the
number of shares of Common Stock that may be acquired by any Holder upon any
conversion of Series B

                                       13
<PAGE>
Preferred Stock (or otherwise in respect of the Series B Preferred Stock) shall
be limited to the extent necessary to insure that, following such conversion (or
other issuance), the total number of shares of Common Stock then beneficially
owned by such Holder and its Affiliates and any other Persons whose beneficial
ownership of Common Stock would be aggregated with the Holder's for purposes of
Section 13(d) of the Exchange Act, does not exceed 4.999% (the "MAXIMUM
PERCENTAGE") of the total number of issued and outstanding shares of Common
Stock (including for such purpose the shares of Common Stock issuable upon such
conversion). For such purposes, beneficial ownership shall be determined in
accordance with Section 13(d) of the Exchange Act and the rules and regulations
promulgated thereunder. Each delivery of a Conversion Notice by a Holder will
constitute a representation by such Holder that it has evaluated the limitation
set forth in this paragraph and determined that issuance of the full number of
Underlying Shares requested in such Conversion Notice is permitted under this
paragraph. By written notice to the Corporation, any Holder may waive the
provisions of this Section or increase or decrease the Maximum Percentage to any
other percentage specified in such notice, but (i) any such waiver or increase
will not be effective until the 61st day after such notice is delivered to the
Corporation, and (ii) any such waiver or increase or decrease will apply only to
such Holder and not to any other Holder and (iii) any such waiver or increase
shall not be effective to the extent such waiver or increase would cause the
Corporation to violate the Nasdaq Stockholder Approval Rule.

            (b) For purposes of this Section 16, in determining the number of
outstanding shares of Common Stock, a Holder may rely on the number of
outstanding shares of Common Stock as reflected in (1) the Corporation's most
recent Form 10-Q, Form 10-K or other public filing with the Commission, as the
case may be, (2) a more recent public announcement by the Corporation, or (3)
any other notice by the Corporation or its transfer agent setting forth the
number of shares of Common Stock outstanding. Upon the written request of any
Holder, the Corporation shall promptly, but in no even later than one (1)
Trading Day following the receipt of such notice, confirm in writing to any such
Holder the number of shares of Common Stock then outstanding.

      17. Fractional Shares. The Corporation shall not be required to issue or
cause to be issued fractional Underlying Shares on conversion of Series B
Preferred Stock. If any fraction of an Underlying Share would, except for the
provisions of this Section, be issuable upon conversion of Series B Preferred
Stock, the number of Underlying Shares to be issued will be rounded up to the
nearest whole share.

      18. Notices. Any and all notices or other communications or deliveries
hereunder (including without limitation any Conversion Notice) shall be in
writing and shall be deemed given and effective on the earliest of (i) the date
of transmission, if such notice or communication is delivered via facsimile at
the facsimile number specified in this Section prior to 5:30 p.m. (New York City
time) on a Trading Day, (ii) the next Trading Day after the date of
transmission, if such notice or communication is delivered via facsimile at the
facsimile number specified in this Section on a day that is not a Trading Day or
later than 5:30 p.m. (New York City time) on any Trading Day, (iii) the Trading
Day following the date of mailing, if sent by nationally recognized overnight
courier service, or (iv) upon actual receipt by the party to whom such notice is
required to be given. The addresses for such communications shall be: (i) if to
the Corporation, to 10 Canal Park, Cambridge, Massachusetts 02141, facsimile:
(617) 949-1722,

                                       14
<PAGE>
attention: Chief Executive Officer and General Counsel, or (ii) if to a Holder,
to the address or facsimile number appearing on the Corporation's stockholder
records or such other address or facsimile number as such Holder may provide to
the Corporation in accordance with this Section.

      19.         Miscellaneous.

            (a) The headings herein are for convenience only, do not constitute
a part of this Certificate of Designations and shall not be deemed to limit or
affect any of the provisions hereof.

            (b) Any of the rights of the Holders of Series B Preferred Stock set
forth herein may be waived by the affirmative vote of the holders of a majority
of the shares of Series B Preferred Stock then outstanding. No waiver of any
default with respect to any provision, condition or requirement of this
Certificate of Designations shall be deemed to be a continuing waiver in the
future or a waiver of any subsequent default or a waiver of any other provision,
condition or requirement hereof, nor shall any delay or omission of either party
to exercise any right hereunder in any manner impair the exercise of any such
right.

      IN WITNESS WHEREOF, Aspen Technology, Inc. has caused this Certificate of
Designations to be duly executed as of this 6th day of February, 2002.

                                    ASPEN TECHNOLOGY, INC.

                                         By: /s/ Lisa W. Zappala
                                             --------------------
                                             Name:  Lisa W. Zappala
                                             Title: Senior Vice President,
                                                    Finance and Chief Financial
                                                    Officer

                                       15
<PAGE>
                                                                       EXHIBIT A

                             ADDITIONAL DEFINITIONS

      "AFFILIATE" means any Person that, directly or indirectly through one or
more intermediaries, controls or is controlled by or is under common control
with a Person, as such terms are used in and construed under Rule 144. With
respect to a Purchaser, any investment fund or managed account that is managed
on a discretionary basis by the same investment manager as such Purchaser will
be deemed to be an Affiliate of such Purchaser.

      "BANKRUPTCY EVENT" means any of the following events: (a) the Corporation
or any Material Subsidiary commences a case or other proceeding under any
bankruptcy, reorganization, arrangement, adjustment of debt, relief of debtors,
dissolution, insolvency or liquidation or similar law of any jurisdiction
relating to the Corporation or any Material Subsidiary thereof; (b) there is
commenced against the Corporation or any Material Subsidiary any such case or
proceeding that is not dismissed within 60 days after commencement; (c) the
Corporation or any Material Subsidiary is adjudicated insolvent or bankrupt or
any order of relief or other order approving any such case or proceeding is
entered; (d) the Corporation or any Material Subsidiary suffers any appointment
of any custodian or the like for it or any substantial part of its property that
is not discharged or stayed within 60 days; (e) the Corporation or any Material
Subsidiary makes a general assignment for the benefit of creditors; (f) the
Corporation or any Material Subsidiary fails to pay, or states in writing that
it is unable to pay or is unable to pay, its debts generally as they become due;
or (g) the Corporation or any Subsidiary, by any act or failure to act,
expressly indicates its consent to, approval of or acquiescence in any of the
foregoing or takes any corporate or other action that effects any of the
foregoing.

      "CHANGE OF CONTROL" means the occurrence of any of the following in one or
a series of related transactions: (i) an acquisition after the date hereof by an
individual or legal entity or "group" (as described in Rule 13d-5(b)(1) under
the Exchange Act) of a majority of the voting rights or equity interests in the
Corporation; (ii) a replacement of more than one-half of the members of the
Corporation's Board of Directors that is not approved by those individuals who
are members of the Board of Directors on the date hereof (or other directors
previously approved by such individuals); (iii) a merger or consolidation of the
Corporation or a sale of all or substantially all of the assets of the
Corporation in one or a series of related transactions, unless following such
transaction or series of transactions, the holders of the Corporation's
securities prior to the first such transaction continue to hold, directly or
indirectly, at least a majority of the voting rights and equity interests in the
surviving entity or acquirer of such assets; (iv) a recapitalization,
reorganization or other transaction involving the Corporation that constitutes
or results in a transfer of a majority of the voting rights or equity interests
in the Corporation to Persons other than holders of the Corporation's voting
equity securities prior to such transaction; or (v) consummation of a "Rule
13e-3 transaction" as defined in Rule 13e-3 under the Exchange Act with respect
to the Corporation other than a Rule 13e-3 transaction in which no Purchaser's
interest in the Corporation has been adversely changed or diluted in any
material manner.

                                       16
<PAGE>
      "CLOSING PRICE" means, for any date, the price determined by the first of
the following clauses that applies: (a) if the Common Stock is then listed or
quoted on an Eligible Market or any other national securities exchange, the last
closing price per share of the Common Stock for such date (or the nearest
preceding date) on the primary Eligible Market or exchange on which the Common
Stock is then listed or quoted; (b) if prices for the Common Stock are then
quoted on the OTC Bulletin Board, the average of the highest closing bid price
and the lowest closing ask price per share of the Common Stock for such date (or
the nearest preceding date) so quoted; (c) if prices for the Common Stock are
then reported in the "Pink Sheets" published by the National Quotation Bureau
Incorporated (or a similar organization or agency succeeding to its functions of
reporting prices), the most recent bid price per share of the Common Stock so
reported; or (d) in all other cases, the fair market value of a share of Common
Stock as determined by an independent appraiser selected in good faith by a
majority-in-interest of the Purchasers and the Corporation.

      "COMMISSION" means the Securities and Exchange Commission.

      "COMMON STOCK" means the common stock of the Corporation, par value $0.10
per share.

      "EFFECTIVE DATE" means the date that an Underlying Shares Registration
Statement is declared effective by the Commission.

      "ELIGIBLE MARKET" means the New York Stock Exchange, the American Stock
Exchange, the Nasdaq National Market or the Nasdaq SmallCap Market.

      "EVENT EQUITY VALUE" means 115% of the average of the Closing Prices for
the five Trading Days preceding the date of delivery of the notice requiring
payment of the Event Equity Value, provided that if the Corporation does not
make such required payment (together with any other payments, expenses and
liquidated damages then due and payable under the Transaction Documents) when
due or, in the event the Corporation disputes in good faith the occurrence of
the Triggering Event pursuant to which such notice relates, does not instead
deposit such required payment (together with such other payments, expenses and
liquidated damages then due) in escrow with an independent third-party escrow
agent within five Trading Days of the date such required payment is due, then
the Event Equity Value shall be 115% of the greater of (a) the average of the
Closing Prices for the five Trading Days preceding the date of delivery of the
notice requiring payment of the Event Equity Value and (b) the average of the
Closing Prices for the five Trading Days preceding the date on which such
required payment (together with such other payments, expenses and liquidated
damages) is paid in full.

      "EXCHANGE ACT" means the Securities Exchange Act of 1934, as amended.

      "EXCLUDED STOCK" means any shares of Common Stock issued or issuable (A)
upon exercise, conversion or exchange of any Common Stock Equivalents described
in Schedule 3.1(g) to the Purchase Agreement (provided that such exercise or
conversion occurs in accordance with the terms thereof, without amendment or
modification, and that the applicable exercise or conversion price or ratio is
described in such schedule); (B) to officers, directors, employees or
consultants of the Corporation pursuant to a stock option plan, employee stock

                                       17
<PAGE>
purchase plan or other equity incentive plan approved by the Board of Directors
of the Corporation; (C) pursuant to as part of a bona fide firm commitment
underwritten public offering with a nationally recognized underwriter (including
any "at the market offering," as defined in Rule 415(a)(4) under the Securities
Act, only if such offering does not constitute an "equity line" and generates
aggregate gross proceeds of at least $50 million); (D) in connection with any
transaction with a strategic investor, vendor, lessor, customer, supplier,
marketing partner, developer or integrator or any similar arrangement, in each
case the primary purpose of which is not to raise equity capital; (E) in
connection with a transaction involving a merger or acquisition of an entity,
business or assets (not principally for the purpose of obtaining cash); or (F)
in connection with any other transaction for consideration other than cash up to
108,166 shares of Common Stock in the aggregate (as adjusted for stock splits,
stock combinations and similar events).

      "MATERIAL SUBSIDIARY" means any significant subsidiary, as defined in Rule
1-02(w) of Regulation S-X promulgated by the Commission, of the Corporation.

      "PERSON" means an individual or corporation, partnership, trust,
incorporated or unincorporated association, joint venture, limited liability
Corporation, joint stock Corporation, government (or an agency or subdivision
thereof) or other entity of any kind.

      "PURCHASER" has the meaning set forth in the Purchase Agreement.

      "REGISTRATION RIGHTS AGREEMENT" means the Registration Rights Agreement,
dated as of February 6, 2002 among the Corporation and the Purchasers.

      "REQUIRED EFFECTIVENESS DATE" means the date on which an Underlying Shares
Registration Statement is required to become effective pursuant to the
Registration Rights Agreement.

      "RULE 144" means Rule 144 promulgated by the Commission pursuant to the
Securities Act, as such Rule may be amended from time to time, or any similar
rule or regulation hereafter adopted by the Commission having substantially the
same effect as such Rule.

      "SECURITIES" means the Shares, the Warrants and the Underlying Shares.

      "SECURITIES ACT" means the Securities Act of 1933, as amended.

      "SHARES" means, collectively, the shares of Series B-1 Preferred Stock and
Series B-2 Preferred Stock.

      "SUBSIDIARY" means any subsidiary, as defined in Rule 1-02(x) of
Regulation S-X promulgated by the Commission, of the Corporation.

      "TRADING DAY" means (a) any day on which the Common Stock is traded on its
primary Trading Market, or (b) if the Common Stock is not then listed or quoted
on any national securities exchange, market or trading or quotation facility,
then a day on which trading occurs on the New York Stock Exchange (or any
successor thereto).

                                       18
<PAGE>
      "TRADING MARKET" means the Nasdaq National Market or any other Eligible
Market on which the Common Stock is then listed or quoted.

      "TRANSACTION DOCUMENTS" means the Purchase Agreement, the Registration
Rights Agreement, this Certificate of Designations and the Warrants.

      "TRIGGERING EVENT" means any of the following events: (a) immediately
prior to any Bankruptcy Event; (b) the Common Stock is not listed or quoted, or
is suspended from trading, on an Eligible Market for a period of five
consecutive Trading Days or ten aggregate Trading Days in any 365 day period;
(c) the Corporation fails for any reason to deliver a certificate evidencing any
Securities to a Purchaser within ten Trading Days after delivery of such
certificate is required pursuant to any Transaction Document or the exercise or
conversion rights of the Holders pursuant to the Transaction Documents are
otherwise suspended for any reason; (d) the Corporation fails to have available
both (i) a sufficient number of authorized but unissued and otherwise unreserved
shares of Common Stock available to issue Underlying Shares upon any exercise of
the Warrants or any conversion of Shares and does not make available a
sufficient number of authorized but unissued and otherwise unreserved shares of
Common Stock for such issuance within 60 days after the occurrence of such
deficiency and (ii) at least 5,825,000 authorized but unissued and otherwise
unreserved shares of Common Stock (as adjusted for any stock splits, stock
combinations or similar events), less reductions reasonably agreed to by the
Purchasers to reflect shares of Common Stock issued upon conversion of the
Shares (and, therefore, reduced aggregate dividend payments), as dividends on
the Shares, upon exercise of the Warrants or upon a redemption of the Shares;
(e) at any time after the Required Effectiveness Date, any Common Stock issuable
pursuant to the Transaction Documents is not listed on an Eligible Market; (f)
any other Event (as defined in the Registration Rights Agreement) occurs and
remains uncured for 60 days; (g) the Corporation fails to make any cash payment
required under the Transaction Documents and such failure is not cured within
five days after notice of such default is first given to the Corporation by a
Purchaser; (h) the Corporation defaults in the timely performance of any other
obligation under the Transaction Documents and such default continues uncured
for a period of 20 days after the date on which notice of such default is first
given to the Corporation by a Purchaser (it being understood that no prior
notice need be given in the case of a default that cannot reasonably be cured
within 20 days), or (i) any Change of Control event.

      "UNDERLYING SHARES" means the shares of Common Stock issuable upon
conversion of, or in redemption of, the Shares, as payment of dividends on the
Shares and upon exercise of the Warrants, and any securities issued in exchange
for, or upon conversion or in respect of, such shares.

      "UNDERLYING SHARES REGISTRATION STATEMENT" means a registration statement
meeting the requirements set forth in the Registration Rights Agreement and
covering the resale of the Underlying Shares by the Purchasers.

      "VOLUME WEIGHTED AVERAGE PRICE" means, with respect to a Trading Day, the
average of the daily volume weighted average trading price (the total dollar
amount traded on each day divided by trading volume for such day) of the Common
Stock for the regular Trading Day

                                       19
<PAGE>
session as reported at 4:15 (New York time) as reported by Bloomberg, LP
function key HP by using W to calculate the daily weighted average.

      "WARRANTS" means the Common Stock purchase warrants issued pursuant to the
Purchase Agreement.

                                       20
<PAGE>
                                                                       EXHIBIT B

                            FORM OF CONVERSION NOTICE

(To be executed by the registered Holder
in order to convert shares of Series B Preferred Stock)

The undersigned hereby elects to convert the number of shares of Series B
Convertible Preferred Stock indicated below into shares of common stock, par
value $0.10 per share (the "COMMON STOCK"), of Aspen Technology, Inc., a
Delaware corporation (the "CORPORATION"), according to the conditions hereof, as
of the date written below.

                      __________________________________________________________
                      Date to Effect Conversion

                      __________________________________________________________
                      Number and series of shares of Series B Preferred
                      Stock owned prior to Conversion

                      __________________________________________________________
                      Number and series of shares of Series B Preferred
                      Stock to be Converted

                      __________________________________________________________
                      Stated Value of shares of Series B Preferred Stock to be
                      Converted (including _______________ of dividends added
                      under Section 2(b) of the Registration Rights Agreement)

                      __________________________________________________________
                      Number of shares of Common Stock to be Issued

                      __________________________________________________________
                      Applicable Conversion Price

                      __________________________________________________________
                      Number and series of shares of Series B Preferred
                      Stock subsequent to Conversion

                      Name of Holder
                      By:_______________________________________________________

                      Name:_____________________________________________________

                      Title:____________________________________________________

                                       21

<PAGE>

                            CERTIFICATE OF CORRECTION
                     FILED TO CORRECT A CERTAIN ERROR IN THE
                         CERTIFICATE OF DESIGNATIONS OF
                   SERIES B-1 CONVERTIBLE PREFERRED STOCK AND
                    SERIES B-2 CONVERTIBLE PREFERRED STOCK OF
                             ASPEN TECHNOLOGY, INC.

     Aspen Technology Inc., a corporation organized and existing under the by
virtue of the General Corporation Law of the State of Delaware DOES HEREBY
CERTIFY:

     1.  The name of the corporation is Aspen Technology, Inc.

     2.  That a Certificate of Designations of Series B-1 Convertible Preferred
Stock and Series B-2 Convertible Preferred Stock was filed with the Secretary of
State of the State of Delaware on February 6, 2002, and that said Certificate
requires correction as permitted by Section 103 of the General Corporation Law
of the State of Delaware.

     3.  The inaccuracy or defect of said Certificate to be corrected is set
forth in Section 2 of the Certificate as follows:

     ""INITIAL PURCHASE PRICE" means (i) in the case of Series B-1 Preferred
Stock, $1,000, and (ii) in the case of Series B-2 Preferred Stock, the greater
of (x) the lesser of (a) the average of the daily Volume Weighted Average Prices
over the twenty (20) consecutive Trading Day period ending on February 27, 2002
(including such date) or (b) the average of the daily Volume Weighted Average
Prices over the three (3) consecutive Trading Day period ending on February 27,
2002 (including such date), or (y) $15.00 (as adjusted for any stock splits,
stock dividends, stock combinations or similar events occurring after the
Original Issue Date of the Series B-1 Preferred Stock and prior to the Original
Issue Date of the Series B-2 Preferred Stock)."

     4.  The corrected portion of Section 2 should read as follows:

     ""INITIAL PURCHASE PRICE" means (i) in the case of Series B-1 Preferred
Stock, $17.75, and (ii) in the case of Series B-2 Preferred Stock, the greater
of (x) the lesser of (a) the average of the daily Volume Weighted Average Prices
over the twenty (20) consecutive Trading Day period ending on February 27, 2002
(including such date) or (b) the average of the daily Volume Weighted Average
Prices over the three (3) consecutive Trading Day period ending on February 27,
2002 (including such date), or (y) $15.00 (as adjusted for any stock splits,
stock dividends, stock combinations or similar events occurring after the
Original Issue Date of the Series B-1 Preferred Stock and prior to the Original
Issue Date of the Series B-2 Preferred Stock)."

     IN WITNESS WHEREOF, Aspen Technology, Inc. has caused this Certificate to
be signed by its Chief Financial Officer this 12th day of February, 2002.

                                    ASPEN TECHNOLOGY, INC.

                                    By: /s/ Lisa W. Zappala
                                       ------------------------------------
                                       Lisa W. Zappala
                                       Chief Financial Officer

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