1


     AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON APRIL 16, 2001


                                                      REGISTRATION NO. 333-45504
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                            ------------------------


                                AMENDMENT NO. 7


                                    FORM S-1
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
                            ------------------------

                            SIMPLEX SOLUTIONS, INC.
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)
                            ------------------------


                                                            
            DELAWARE                           7371                          56-1918734
(STATE OR OTHER JURISDICTION OF    (PRIMARY STANDARD INDUSTRIAL           (I.R.S. EMPLOYER
 INCORPORATION OR ORGANIZATION)    CLASSIFICATION CODE NUMBER)         IDENTIFICATION NUMBER)


                               521 ALMANOR AVENUE
                          SUNNYVALE, CALIFORNIA 94085
                                 (408) 617-6100
  (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE, OF
                   REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)
                            ------------------------

                              PENELOPE A. HERSCHER
                      CHAIRMAN AND CHIEF EXECUTIVE OFFICER
                            SIMPLEX SOLUTIONS, INC.
                               521 ALMANOR AVENUE
                          SUNNYVALE, CALIFORNIA 94085
                                 (408) 617-6100
 (NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE,
                             OF AGENT FOR SERVICE)
                            ------------------------

                                   COPIES TO:


                                              
             LARRY W. SONSINI, ESQ.                          JUSTIN L. BASTIAN, ESQ.
              ROBERT SANCHEZ, ESQ.                              AMIE PETERS, ESQ.
        WILSON SONSINI GOODRICH & ROSATI                     MONICA HEEMIN CHA, ESQ.
            PROFESSIONAL CORPORATION                         MORRISON & FOERSTER LLP
               650 PAGE MILL ROAD                               755 PAGE MILL ROAD
              PALO ALTO, CA 94304                              PALO ALTO, CA 94304
                 (650) 493-9300                                   (650) 813-5600


        APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC:

As soon as practicable after the effective date of this Registration Statement.

    If any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, check the following box.  [ ]

    If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering.  [ ] __________

    If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering.  [ ] __________

    If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box.  [ ]

    THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL
FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(a) OF
THE SECURITIES ACT OF 1933 OR UNTIL THE REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION ACTING PURSUANT TO SAID SECTION 8(a)
MAY DETERMINE.
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   2

                                    PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 13. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION

     The following table sets forth the costs and expenses, other than
underwriting discounts and commissions, payable by the Registrant in connection
with the sale of Common Stock being registered. All amounts are estimates except
the SEC registration fee and the NASD filing fee.



                                                                AMOUNT
                                                              TO BE PAID
                                                              ----------
                                                           
SEC Registration Fee........................................  $   13,200
NASD Fee....................................................       5,500
Nasdaq National Market Listing Fee..........................       5,000
Printing and Engraving......................................     200,000
Legal Fees and Expenses.....................................     600,000
Accounting Fees and Expenses................................   1,100,000
Blue Sky Fees and Expenses..................................       5,000
Transfer Agent Fees.........................................      15,000
Miscellaneous...............................................      56,300
                                                              ----------
  Total.....................................................  $2,000,000
                                                              ==========


ITEM 14. INDEMNIFICATION OF DIRECTORS AND OFFICERS

     As permitted by Section 145 of the Delaware General Corporation Law, the
Registrant's certificate of incorporation includes a provision that eliminates
the personal liability of its directors for monetary damages for breach or
alleged breach of their duty of care to the Company or its stockholders. In
addition, as permitted by Section 145 of the Delaware General Corporation Law,
the certificate of incorporation of the Registrant provides, inter alia, that
each person who is made a party or is threatened to be made a party to or
otherwise involved in any action, suit or proceeding, whether civil, criminal,
administrative or investigative (hereinafter a "proceeding"), by reason of the
fact that he or she is or was a director or officer of the Company or, while a
director or officer of the Company, is or was serving at the request of the
Company as a director, officer, employee or agent of another corporation or of a
partnership, joint venture, trust or other enterprise, including service with
respect to an employee benefit plan (hereinafter an "indemnitee"), whether the
basis of such proceeding is alleged action in an official capacity as a director
or officer or in any other capacity while serving as a director or officer, is
authorized to be indemnified and held harmless by the Company to the fullest
extent authorized by the Delaware General Corporation Law, as the same exists or
may hereafter be amended, against all expense, liability and loss (including
attorneys' fees, judgments, fines, ERISA excise taxes or penalties and amounts
paid in settlement) reasonably incurred or suffered by such indemnitee in
connection therewith and such indemnification shall continue as to an
indemnitee's heirs, executors and administrators; provided, however, that,
except with respect to the proceedings brought by an indemnitee to enforce
rights to indemnification (subject to certain restrictions and as more fully
described in the Registrant's certificate of incorporation), the Company shall
indemnify any such indemnitee in connection with a proceeding (or part thereof)
initiated by such indemnitee only if such proceeding (or part thereof) was
authorized by the Board of Directors of the Company. The right to
indemnification conferred in the Registrant's certificate of incorporation
includes the right to be paid by the Company the expenses incurred in connection
with any such proceeding in advance of its final disposition; provided, however,
that, if and to the extent that the Delaware General Corporation Law requires,
such an advancement of expenses incurred by an indemnitee in his or her capacity
in which service was or is rendered by such indemnitee, including, without
limitation, service with respect to an employee benefit plan, shall be made only
upon delivery to the Company of an undertaking by or on behalf of such
indemnitee, to repay all amounts so advanced if it shall ultimately be
determined by final judicial decision from which there is no further right to
appeal that

                                       II-1
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such indemnitee is not entitled to be indemnified for such expenses under the
Company's certificate of incorporation or otherwise.

     The Registrant's policy is to enter into indemnification agreements with
each of its directors and executive officers that provide the maximum indemnity
allowed to directors and executive officers by Section 145 of the Delaware
General Corporation Law and the Bylaws, as well as certain additional procedural
protections. In addition, such indemnity agreements provide that directors and
executive officers will be indemnified to the fullest possible extent not
prohibited by law against all expenses (including attorney's fees) and
settlement amounts paid or incurred by them in any action or proceeding,
including any derivative action by or in the right of the Registrant, on account
of their services as directors or executive officers of the Registrant or as
directors or officers of any other company or enterprise when they are serving
in such capacities at the request of the Registrant. Pursuant to the indemnity
agreements, the Company will not be obligated to indemnify or advance expenses
to an indemnified party with respect to proceedings or claims initiated by the
indemnified party and not by way of defense, except with respect to proceedings
specifically authorized by the Board of Directors or brought to enforce a right
to indemnification under such indemnity agreement, the Company's certificate of
incorporation, Bylaws or any statute or law, or as otherwise required under
Section 145 of the Delaware General Corporation Law. Also under the indemnity
agreements, the Company is not obligated to indemnify the indemnified party for
(i) any expenses incurred by the indemnified party with respect to any
proceeding instituted by the indemnified party to enforce or interpret the
agreement, if a court of competent jurisdiction determines that each of the
material assertions made by the indemnified party in such proceeding was not
made in good faith or was frivolous, (ii) acts, omissions or transactions on the
part of the indemnified party from which such party may not be relieved of
liability under applicable law or (iii) expenses and the payment of profits
arising from the purchase and sale by the indemnified party of securities in
violation of Section 16(b) of the Exchange Act, or any similar or successor
statute.

     The indemnification provisions in the certificate of incorporation and the
indemnification agreements entered into between the Registrant and its directors
and executive officers, may be sufficiently broad to permit indemnification of
the Registrant's officers and directors for liabilities arising under the
Securities Act.

     Reference is made to the following documents filed as exhibits to this
Registration Statement regarding relevant indemnification provisions described
above and elsewhere herein:



EXHIBIT
NUMBER                               DOCUMENT
- -------                              --------
        
 1.1       Form of Underwriting Agreement
 3.1       Amended and Restated Certificate of Incorporation of the
           Registrant
           Form of Amended and Restated Certificate of Incorporation of
           the Registrant
10.1       Form of Indemnification Agreement entered into by the
           Registrant with each of its directors and executive officers
 3.3       Bylaws of the Registrant


ITEM 15. RECENT SALES OF UNREGISTERED SECURITIES

     Within the last three years, we have issued the following unregistered
securities:

          (a) On April 6, May 6 and June 6, 1998, we sold an aggregate of
     3,253,336 shares of our Series E Preferred Stock to a group of six (6)
     private investors for an aggregate purchase price of $12,200,010 which was
     paid in cash. We believe the sale of the shares were exempt from
     registration by virtue of Section 4(2) of the Securities Act and Rule 506
     of Regulation D promulgated thereunder. The purchasers (i) represented to
     us that they were accredited investors within the definition of Rule 501 of
     Regulation D, (ii) represented to us that they understood that the
     securities were restricted and must be held for an indefinite period of
     time, (iii) represented to us that they were acquiring the shares for
     investment for their own account and not with a view to the distribution
     thereof and (iv) were afforded the opportunity to ask questions of our
     management.

                                       II-2
   4

          (b) On February 12, 1998, we sold 250,000 shares of our common stock
     to Aki Fujimura, our President, Chief Operating Officer and Director, at a
     purchase price of $2.04 per share. Mr. Fujimura paid for his shares with a
     promissory note in the amount of $509,250 and $750 in cash. On March 30,
     1999, we sold 47,222 shares of our common stock to Mr. Fujimura at a
     purchase price of $6.00 per share. We believe the sale was exempt from
     registration by virtue of Section 4(2) of the Securities Act and Rule 506
     of Regulation D promulgated thereunder. The purchaser: (I) represented to
     us that he understood that the securities were restricted and must be held
     for an indefinite period of time, (II) represented to us that he was
     acquiring the shares for investment for their own account and not with a
     view to distribution thereof and (III) were afforded the opportunities to
     ask questions of management.

          (c) On January 19, 1999, we sold 64,375 shares of our common stock to
     Steven L. Teig, our Chief Technical Officer, at a purchase price of $3.75
     per share. Mr. Teig paid for his shares with a promissory note in the
     amount of $241,406. We believe the sale was exempt from registration by
     virtue of Section 4(2) of the Securities Act and Rule 506 of Regulation D
     promulgated thereunder. The purchaser: (I) represented to us that he
     understood that the securities were restricted and must be held for an
     indefinite period of time, (II) represented to us that he was acquiring the
     shares for investment for their own account and not with a view to
     distribution thereof and (III) were afforded the opportunities to ask
     questions of management.

          (d) On March 30, 1999, we sold 33,333 shares of our common stock to
     Luis P. Buhler, our Chief Financial Officer, at a purchase price of $6.00
     per share. Mr. Buhler paid for his shares with a promissory note in the
     amount of $200,000. We believe the sale was exempt from registration by
     virtue of Section 4(2) of the Securities Act and Rule 506 of Regulation D
     promulgated thereunder. The purchaser: (I) represented to us that he
     understood that the securities were restricted and must be held for an
     indefinite period of time, (II) represented to us that he was acquiring the
     shares for investment for their own account and not with a view to
     distribution thereof and (III) were afforded the opportunities to ask
     questions of management.

          (e) From September 1999 through March 31, 2001, we sold an aggregate
     of 268,543 shares of our common stock for an aggregate consideration of
     $855,029 pursuant to the exercise of options granted to certain of our
     employees, directors and consultants under our 1995 Stock Plan. We believe
     the sales were exempt from registration by virtue of Rule 701 promulgated
     under Section 3(b) of the Securities Act because they were each
     transactions pursuant to a compensatory benefit plan or a written contract
     relating to compensation.

          (f) From September 1999 through March 31, 2001, we sold an aggregate
     of 39,575 shares of our common stock for an aggregate consideration of
     $158,254 pursuant to the exercise of options granted to certain of our
     directors and officers under our 1995 Stock Plan. We believe the sales were
     exempt from registration by virtue of Section 4(2) of the Securities Act
     and Rule 506 of Regulation D promulgated thereunder. The purchasers were
     accredited investors within the meaning of Rule 501 of Regulation D.

          (g) From September 1999 through March 31, 2001, we sold an aggregate
     of 14,156 shares of our common stock for an aggregate consideration of
     $127,655 pursuant to the exercise of options exempt from registration by
     virtue of Regulation S.

          (h) On June 29, 1999, we granted a warrant to purchase aggregate of
     66,667 shares of our Series E Preferred Stock to TBCC Funding Trust II. We
     believe the sales were exempt from registration by virtue of Section 4(2)
     of the Securities Act and Rule 506 of Regulation D promulgated thereunder.
     The purchasers were accredited investors within the meaning of Rule 501 of
     Regulation D.

          (i) On March 31, 2000, we issued an aggregate of 928,983 shares of our
     common stock in conjunction with the acquisition of all of the outstanding
     capital stock of Snaketech S.A. We believe the sales were exempt from
     registration by virtue of Section 4(2) of the Securities Act, Rule 506 of

                                       II-3
   5

     Regulation D promulgated thereunder and Regulation S. Sales to former
     Snaketech stockholders who are resident in the United States were made in
     reliance on Rule 506 of Regulation D. All such United States residents were
     accredited investors within the meaning of Rule 501 of Regulation D. Sales
     to former Snaketech stockholders who are resident outside the United States
     were made in reliance on Regulation S. Each such non-United States resident
     has agreed in writing to resale restrictions that prohibit resale of our
     securities other than in compliance with the provisions of Regulation S.

          (j) On October 4, 2000, we issued an aggregate of 2,551,434 shares of
     our common stock in connection with our acquisition of all of the
     outstanding capital stock of Altius Solutions, Inc. We believe the sales
     were exempt from registration by virtue of Section 4(2) of the Securities
     Act, Rule 506 of Regulation D promulgated thereunder and Regulation S.
     Sales to former Altius stockholders who are resident in the United States
     were made in reliance on Rule 506 of Regulation D. Of these former Altius
     stockholders, fewer than 35 in the aggregate were not accredited investors
     within the meaning of Rule 501 of Regulation D and all former Altius
     stockholders were provided appropriate information pursuant to an
     information statement as required by Rule 502(b) of Regulation D. Sales to
     former Altius stockholders who are resident outside the United States were
     made in reliance on Regulation S. Each such non-United States resident has
     agreed in writing to resale restrictions that prohibit resale of our
     securities other than in compliance with the provisions of Regulation S.

          (k) On October 4, 2000, in connection with our acquisition of Altius,
     we assumed a warrant to Silicon Valley Bank to purchase a total of 2,091
     shares of common stock at an exercise price per share of $1.91 per share.
     We believe the sales were exempt from registration by virtue of Section
     4(2) of the Securities Act. The purchaser was an accredited investor within
     the meaning of Rule 501 of Regulation D.

     None of the foregoing transactions involved any underwriters, underwriting
discounts or commissions, or any public offering, and we believe that each
transaction was exempt from the registration requirements of the Securities Act
by virtue of Section 4(2) thereof, Regulation D promulgated thereunder or Rule
701 pursuant to compensatory benefit plans and contracts relating to
compensation as provided under such Rule 701. The recipients in such
transactions represented their intention to acquire the securities for
investment only and not with a view to or for sale in connection with any
distribution thereof, and appropriate legends were affixed to the share
certificates and instruments issued in such transactions. All recipients had
adequate access to information about the Company.

     In particular, the securities described in the Preferred Stock financings
and warrant issuances are owned in their entirety by individuals or large
institutional investors who (A) represented to us that they were "accredited
investors" within the definition of Rule 501 of Regulation D, familiar with
investing in private companies, (B) represented to us that they understood that
the securities they were purchasing were restricted and the risk of possible
loss associated with their investment, (C) represented to us that they were
familiar with our history and business, (D) received our recent financial
information and (E) were afforded the opportunity to ask questions of our
management. Each of the investors had expressed previous interest to our
officers and directors in making an investment in us when an opportunity was
available, and such investors were contacted only on a one-on-one basis without
any general solicitation or advertising of the investment opportunity.
Accordingly, we believe that the each of the foregoing transactions was exempt
from the registration requirements of the Securities Act by virtue of Section
4(2) thereof.

                                       II-4
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ITEM 16. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES

     (a) EXHIBITS




EXHIBIT                        EXHIBIT DESCRIPTION
- -------                        -------------------
        
 1.1**     Form of Underwriting Agreement
 2.1**     Form of Share Purchase Agreement by and among Simplex and
           Snaketech S.A. dated as of March 13, 2000
 2.2**     Agreement and Plan of Reorganization by and among Simplex,
           Altius Solutions and certain additional parties dated as of
           October 4, 2000
 3.1**     Amended and Restated Certificate of Incorporation of the
           Registrant
 3.2**     Form of Amended and Restated Certificate of Incorporation of
           the Registrant
 3.3**     Bylaws of the Registrant
 3.4**     Form of Amended and Restated Bylaws of the Registrant
 3.5**     Certificate of Amendment of the Certificate of Incorporation
           of the Registrant
 3.6**     Form of Certificate of Amendment of the Registrant
 4.1*      Form of Registrant's Common Stock Certificate
 5.1**     Form of Opinion of Wilson Sonsini Goodrich & Rosati,
           Professional Corporation, regarding legality of the
           securities being issued
10.1**     Form of Indemnification Agreement entered into by and
           between the Registrant and each of its directors and
           executive officers
10.2**     Form of Management Continuity Agreement entered into by and
           between the Registrant and certain of its officers
10.3**     1995 Stock Plan
10.4**     2001 Incentive Stock Plan
10.5**     2001 Employee Stock Purchase Plan
10.6**     Series E Preferred Stock Agreement of the Registrant dated
           April 6, 1998
10.7**     Fourth Amended and Restated Rights Agreement of the
           Registrant dated April 6, 1998
10.8**     Registration Rights Agreement dated March 31, 2000 by and
           between the Registrant and Shareholders of Snaketech S.A.
10.9**     Restricted Stock Purchase Agreement, Promissory Note and
           Stock Pledge Agreement of Aki Fujimura dated February 12,
           1998
10.10**    Form of Promissory Note of the Registrant
10.11**    Lease agreement by and between the Registrant and 525
           Almanor LLC dated March 1997
10.12**    Consent of Collett International Inc.
10.13**    First Consent of Gartner Group
10.14**    Second Consent of Gartner Group
10.15**    Consent of Integrated Circuit Engineering Corporation
10.16**    Restricted Stock Purchase Agreement, Promissory Note and
           Stock Pledge Agreement of Aki Fujimura dated March 30, 1999
10.17**    Restricted Stock Purchase Agreement, Promissory Note and
           Stock Pledge Agreement of Steven Teig dated January 19, 1999
10.18**    Restricted Stock Purchase Agreement, Promissory Note and
           Stock Pledge Agreement of Luis Buhler dated March 30, 1999
10.19+**   Software License Agreement between the Registrant and
           Computational Applications and System Integration, Inc.
           dated July 15, 1998
10.20+**   Software License Agreement between the Registrant and
           Digital Semiconductor (a business unit of Digital Equipment
           Corporation which has been acquired by Compaq Computer
           Corporation) dated September 21, 1995
10.21+     Cross License Agreement between the Registrant and Chris
           Terman dated July 24, 1995
10.22**    Offer Letter between the Registrant and James Behrens dated
           February 28, 2000
10.23**    Employment Agreement between the Registrant and Aurangzeb
           Khan dated September 8, 2000
10.24**    Management Continuity exhibit between the Registrant and
           Luis Buhler dated January 20, 1999



                                       II-5
   7




EXHIBIT                        EXHIBIT DESCRIPTION
- -------                        -------------------
        
 10.25**   Consent of Sony Computer Entertainment, Inc.
 23.1**    Consent of Wilson Sonsini Goodrich & Rosati, Professional
           Corporation (included in Exhibit 5.1)
 23.2**    Consent of PricewaterhouseCoopers LLP, Independent
           Accountants
 23.3**    Consent of Befec-Price Waterhouse, Independent Accountants
 23.4**    Consent of Deloitte & Touche LLP, Independent Auditors
 24.1      Power of Attorney (see page II-10)



- ---------------
 * To be filed by amendment.
** Previously filed.
 + Confidential Treatment requested.

     (b) FINANCIAL STATEMENT SCHEDULES

        Schedule II -- Valuation and Qualifying Accounts.

                                       II-6
   8

       REPORT OF INDEPENDENT ACCOUNTANTS ON FINANCIAL STATEMENT SCHEDULE

To the Board of Directors and Stockholders of Simplex Solutions, Inc.

     In connection with our audits of the consolidated financial statements of
Simplex Solutions, Inc. as of September 30, 1999 and 2000, and for each of the
three years in the period ended September 30, 2000, which consolidated financial
statements are included in the Prospectus, we have also audited the financial
statement schedule listed in Item 16(b) herein. In our opinion, this financial
statement schedule, when considered in relation to the basic financial
statements taken as a whole, presents fairly, in all material respects, the
information required to be included therein.

PricewaterhouseCoopers LLP

San Jose, California
October 23, 2000

                                       II-7
   9

                            SIMPLEX SOLUTIONS, INC.
                       VALUATION AND QUALIFYING ACCOUNTS
                                 (IN THOUSANDS)



                                                 BALANCE AT                                  BALANCE AT
                                                 BEGINNING      ADDITIONS                       END
                                                  OF YEAR      (DEDUCTIONS)    WRITE-OFFS     OF YEAR
                                                 ----------    ------------    ----------    ----------
                                                                                 
Allowance for doubtful accounts:
  Year ended September 30, 1998................    $    0         $   10          $--         $    10
  Year ended September 30, 1999................        10            161           --             171
  Year ended September 30, 2000................       171             14           --             185
Valuation allowance for deferred tax assets:
  Year ended September 30, 1998................    $2,530         $2,844          $--         $ 5,374
  Year ended September 30, 1999................     5,374          4,514           --           9,888
  Year ended September 30, 2000................     9,888            426           --          10,314


                                       II-8
   10

ITEM 17. UNDERTAKINGS

     The undersigned hereby undertakes to provide to the underwriters at the
closing specified in the underwriting agreement, certificates in such
denominations and registered in such names as required by the Underwriters to
permit prompt delivery to each purchaser.

     Insofar as indemnification for liabilities arising under the Securities Act
may be permitted to directors, officers and controlling persons of the
Registrant pursuant to the provisions referenced in Item 14 of this Registration
Statement or otherwise, the Registrant has been advised that in the opinion of
the Securities and Exchange Commission such indemnification is against public
policy as expressed in the Act, and is, therefore, unenforceable. In the event
that a claim for indemnification against such liabilities (other than the
payment by the Registrant of expenses incurred or paid by a director, officer,
or controlling person of the Registrant in the successful defense of any action,
suit or proceeding) is asserted by such director, officer or controlling person
in connection with the securities being registered hereunder, the Registrant
will, unless in the opinion of its counsel the matter has been settled by
controlling precedent, submit to a court of appropriate jurisdiction the
question whether such indemnification by it is against public policy as
expressed in the Securities Act and will be governed by the final adjudication
of such issue.

     The undersigned Registrant hereby undertakes that:

          (1) For purposes of determining any liability under the Securities
     Act, the information omitted from the form of Prospectus filed as part of
     this Registration Statement in reliance upon Rule 430A and contained in a
     form of Prospectus filed by the Registrant pursuant to Rule 424(b)(1) or
     (4) or 497(h) under the Act shall be deemed to be part of this Registration
     Statement as of the time it was declared effective.

          (2) For the purpose of determining any liability under the Securities
     Act, each post-effective amendment that contains a form of Prospectus shall
     be deemed to be a new Registration Statement relating to the securities
     offered therein, and the offering of such securities at that time shall be
     deemed to be the initial bona fide offering thereof.

                                       II-9
   11

                                   SIGNATURES


     Pursuant to the requirements of the Securities Act, the Registrant has duly
caused this Amendment No. 7 to Registration Statement on Form S-1 to be signed
on its behalf by the undersigned, thereunto duly authorized, in the City of
Sunnyvale, State of California, on the sixteenth day of April, 2001.


                                          SIMPLEX SOLUTIONS, INC.

                                          By:   /s/ PENELOPE A. HERSCHER
                                            ------------------------------------
                                                   Penelope A. Herscher,
                                            Chief Executive Officer and Chairman
                                                 of the Board of Directors


     PURSUANT TO THE REQUIREMENTS OF THE SECURITIES ACT OF 1933, AS AMENDED THIS
AMENDMENT NO. 7 TO REGISTRATION STATEMENT ON FORM S-1 HAS BEEN SIGNED BY THE
FOLLOWING PERSONS IN THE CAPACITIES AND ON THE DATES INDICATED.





                      SIGNATURE                                     TITLE                     DATE
                      ---------                                     -----                     ----
                                                                                   
              /s/ PENELOPE A. HERSCHER                   Chief Executive Officer and     April 16, 2001
- -----------------------------------------------------      Chairman of the Board of
                Penelope A. Herscher                         Directors (Principal
                                                              Executive Officer)

                          *                               President, Chief Operating     April 16, 2001
- -----------------------------------------------------        Officer and Director
                    Aki Fujimura

                 /s/ LUIS P. BUHLER                        Chief Financial Officer       April 16, 2001
- -----------------------------------------------------      (Principal Financial and
                   Luis P. Buhler                            Accounting Officer)

                          *                                        Director              April 16, 2001
- -----------------------------------------------------
                 Joseph B. Costello

                          *                                        Director              April 16, 2001
- -----------------------------------------------------
                Harvey C. Jones, Jr.

                          *                                        Director              April 16, 2001
- -----------------------------------------------------
                F. Gibson Myers, Jr.

                          *                                        Director              April 16, 2001
- -----------------------------------------------------
                  A. Richard Newton

                          *                                        Director              April 16, 2001
- -----------------------------------------------------
                  Larry W. Sonsini

               *By: /s/ LUIS P. BUHLER
- -----------------------------------------------------
                   Luis P. Buhler
                  Attorney-in-Fact



                                      II-10
   12

                                 EXHIBIT INDEX




EXHIBIT                        EXHIBIT DESCRIPTION
- -------                        -------------------
        
 1.1**     Form of Underwriting Agreement
 2.1**     Form of Share Purchase Agreement by and among Simplex and
           SnakeTech S.A. dated as of March 13, 2000
 2.2**     Agreement and Plan of Reorganization by and among Simplex,
           Altius Solutions and certain additional parties dated as of
           October 4, 2000
 3.1**     Amended and Restated Certificate of Incorporation of the
           Registrant
 3.2**     Form of Amended and Restated Certificate of Incorporation of
           the Registrant
 3.3**     Bylaws of the Registrant
 3.4**     Form of Amended and Restated Bylaws of the Registrant
 3.5**     Certificate of Amendment of the Certificate of Incorporation
           of the Registrant
 3.6**     Form of Certificate of Amendment of the Registrant
 4.1*      Form of Registrant's Common Stock Certificate
 5.1**     Form of Opinion of Wilson Sonsini Goodrich & Rosati,
           Professional Corporation, regarding legality of the
           securities being issued
10.1**     Form of Indemnification Agreement entered into by and
           between the Registrant and each of its directors and
           executive officers
10.2**     Form of Management Continuity Agreement entered into by and
           between the Registrant and certain of its officers
10.3**     1995 Stock Plan
10.4**     2001 Incentive Stock Plan
10.5**     2001 Employee Stock Purchase Plan
10.6**     Series E Preferred Stock Agreement of the Registrant dated
           April 6, 1998
10.7**     Fourth Amended and Restated Rights Agreement of the
           Registrant dated April 6, 1998
10.8**     Registration Rights Agreement dated March 31, 2000 by and
           between the Registrant and Shareholders of SnakeTech S.A.
10.9**     Restricted Stock Purchase Agreement, Promissory Note and
           Stock Pledge Agreement of Aki Fujimura dated February 12,
           1998
10.10**    Form of Promissory Note of the Registrant
10.11**    Lease agreement by and between the Registrant and 525
           Almanor LLC dated March 1997
10.12**    Consent of Collett International Inc.
10.13**    First Consent of Gartner Group
10.14**    Second Consent of Gartner Group
10.15**    Consent of Integrated Circuit Engineering Corporation
10.16**    Restricted Stock Purchase Agreement, Promissory Note and
           Stock Pledge Agreement of Aki Fujimura dated March 30, 1999
10.17**    Restricted Stock Purchase Agreement, Promissory Note and
           Stock Pledge Agreement of Steven Teig dated January 19, 1999
10.18**    Restricted Stock Purchase Agreement, Promissory Note and
           Stock Pledge Agreement of Luis Buhler dated March 30, 1999
10.19+**   Software License Agreement between the Registrant and
           Computational Applications and System Integration, Inc.
           dated July 15, 1998
10.20+**   Software License Agreement between the Registrant and
           Digital Semiconductor (a business unit of Digital Equipment
           Corporation which has been acquired by Compaq Computer
           Corporation) dated September 21, 1995
10.21+     Cross License Agreement between the Registrant and Chris
           Terman dated July 24, 1995
10.22**    Offer Letter between the Registrant and James Behrens dated
           February 28, 2000
10.23**    Employment Agreement between the Registrant and Aurangzeb
           Kahn dated September 8, 2000


   13




EXHIBIT                        EXHIBIT DESCRIPTION
- -------                        -------------------
        
10.24**    Management Continuity exhibit between the Registrant and
           Luis Buhler dated January 20, 1999
10.25**    Consent of Sony Computer Entertainment, Inc.
23.1**     Consent of Wilson Sonsini Goodrich & Rosati, Professional
           Corporation (included in Exhibit 5.1)
23.2**     Consent of PricewaterhouseCoopers LLP
23.3**     Consent of Befec-Price Waterhouse, Independent Accountants
23.4**     Consent of Deloitte & Touche LLP, Independent Auditors
24.1       Power of Attorney (see page II-10)



- ---------------
 * To be filed by amendment.

** Previously filed.

 + Confidential Treatment requested.