EXHIBIT 10.9.1

Modification Agreement

             This Modification Agreement dated July 25, 2001 by and between
Avant! Corporation, a Delaware corporation with principal offices located at
46871 Bayside Parkway, Fremont, California 94538 (the "Corporation"), and Mr.
Gerald C. Hsu (the "Executive").

             WHEREAS, the Executive has been Chairman of the Board, President
and Chief Executive Officer of the Corporation since 1994 and, in such
capacities, has been instrumental in making the Corporation a leader in the
electronic design automation (the "EDA") industry, growing the Corporation from
a business with approximately  $1.6 million of revenues and a net loss of
approximately $5.0 million in 1993 to approximately $358.1 million of revenues
and $52.9 million of net income in 2000, and with a substantial increase in
profit margins during such period, all of which has contributed to the creation
of substantial stockholder value;

             WHEREAS, Executive currently is party to an Amended and Restated
Employment Agreement dated as of August 24, 2000 (the "Employment Agreement")
(capitalized terms used herein, which are not expressly defined herein, shall
have the meaning given to them in the Employment Agreement);

             WHEREAS, Executive has recently suffered a heart attack and his
physicians have recommended that Executive significantly reduce his work
responsibilities in order to improve his prospects for a full recovery and avoid
further risks to his health;

             WHEREAS, based on these recommendations, Executive has advised the
Corporation's Board of Directors that he wishes to become less actively involved
in the day-to-day operations of the Corporation and to focus his efforts more on
the strategic direction of the Corporation and, in connection therewith, has
advised the Board that he wishes to relinquish his positions as President and
Chief Executive Officer of the Corporation;

             WHEREAS, the Board acknowledged that, largely through the efforts
of the Executive, the Corporation has developed a pool of talented executives
who are capable of fulfilling many of the responsibilities he has performed for
the Corporation;

             WHEREAS, Executive has agreed, at the Board's request, to remain as
Chairman of the Board and assume the position of Chief Strategist of the
Corporation, and the Board believes that it will benefit greatly from his
continued participation in these roles;

             WHEREAS, in connection with the change in Executive's position with
the Corporation and in recognition of Executive's willingness to acknowledge
that such change in position will not be deemed a Voluntary Retirement, as
defined in the Employment Agreement, that would otherwise trigger certain
immediate payments and benefits to Executive, the Executive and the Corporation
have agreed to modify in certain respects the terms and conditions on which the
Executive will continue to be employed by the Corporation from that currently in
the Employment Agreement, and the purpose of this Agreement is to memorialize
such modifications.

             NOW, THEREFORE, in consideration of the foregoing premises and
other good and valuable consideration, the receipt of which is hereby
acknowledged, the parties hereto agree as follows:

             1.          Changes in Position and Responsibilities.

             (a)         Effective as of July 25, 2001, (the "Effective Date")
Executive will no longer serve as President and Chief Executive Officer of the
Corporation.  He will continue to serve as Chairman of the Board and will assume
the position of Chief Strategist and will remain as an employee of the
Corporation.  In those capacities, he will be primarily responsible for (i)
conducting strategic research and establishing the strategic direction and
objectives of the Corporation, (ii) the assessment and management of investments
and other financial and corporate transactions, (iii) the continued training of
selected senior executives and motivation of employees, (iv) assisting in the
maintenance of relationships with certain significant customers, financial
contacts, investors and community organizations, (v) assist in the design and
implementation, with other members of the Board of Directors and senior
executives, of corporate governance procedures, policies and processes, (vi)
charity and donation programs (including but not limited to Avant! Foundation
and Green Spot Foundation) and (vii) reinforcing the Corporation's culture,
attitude, behavior, and style.

             (b)        The Corporation acknowledges and agrees that the
Executive will be entitled to devote only such portion of his business time and
effort as he, in his sole discretion (which discretion shall be exercised in
good faith), deems necessary to perform his duties as Chairman of the Board and
Chief Strategist, and that the Executive will have the full freedom and right to
pursue any business activity (profit or non-profit) other than business
activities in the EDA industry for any person or entity other than the
Corporation (or any person or entity designated by the Corporation).

             2.          Modification of Compensation.

             (a)         For the period from the Effective Date through December
31, 2001, the Executive will continue to receive his Minimum Salary (currently
payable at the rate of $1,600,000 per year).

             (b)        For the year ended December 31, 2001, the Executive will
receive (i) a guaranteed bonus of $1,500,000, which amount has been determined
based on (A) the Corporation having revenue and operating income (which are the
measures used for determining Executive's bonus in 2001) for the first six
months of 2001 that will equal or exceed the respective budgeted amounts for
that period, and (B) the amount of the full bonus for 2001 that Executive would
have earned (i.e., $3,000,000) had Executive remained as Chief Executive Officer
through all of 2001 and the Corporation achieves the budgeted revenue and
operating income figures for the full year; and (ii) an additional amount based
on the extent to which the Corporation achieves its revenue and operating income
targets included in the Corporation's budget for the last six months of 2001, as
calculated in accordance with the following sentence.  The amount payable
pursuant to (ii) shall be determined by adding the percentages of budgeted
revenues and operating income for the last six months of 2001 which are
represented by the actual revenues and operating income, respectively, for that
period, dividing that sum by 2, and then multiplying that percentage by
$750,000.  By way of example, if the actual revenue for the last six months of
2001 is 100% of the budgeted revenue for that period, and operating income for
the last six months of 2001 is 90% of budgeted operating income, the bonus for
the period will be $712,500 (i.e., 95% times $750,000). The $1,500,000
guaranteed bonus will be paid by no later than August 31, 2001 and the bonus
payable in respect of the last six months will be paid by no later than February
28, 2002.

             (c)         Commencing in the year 2002 and continuing in each
subsequent year through the end of the Term, the Minimum Salary will be
increased as of January 1st of each year by 5% over the Minimum Salary in effect
on December 31st of the preceding year.  In addition, during each of those
years, Executive will be entitled to a bonus based on the extent to which the
Corporation achieves its revenue and operating income targets budgeted for that
year, calculated as follows: add the percentages of budgeted revenues and
operating income for the year which are represented by the actual revenues and
operating income, respectively, for that year, dividing that sum by 2, and then
multiplying that percentage by $1,500,000.  The bonus amount for any year shall
be paid no later than the 60th day following the end of that year.

             3.          Failure to be Elected, or Removal, as a Director of the
Corporation or Chairman of the Board.  The Corporation acknowledges and agrees
that if, at any time during the Term, Executive is not reelected as a director
of the Corporation or is removed as a director of the Corporation without his
consent, or is not reappointed as Chairman of the Board or is removed as
Chairman of the Board without his consent, such action will constitute a
termination of employment of Executive without Cause under the Employment
Agreement, and will entitle him to all the rights and obligations that are
granted Executive under the Employment Agreement in the event of a termination
of employment without Cause.

             4.          Office Space and Support Staff.  The Corporation will
furnish office space and support staff to Executive in connection with
Executive's performance of his services as Chairman of the Board and Chief
Strategist on terms and conditions to be agreed upon.

             5.          Not a Termination of Employment.  The parties
acknowledge and agree that the changes to the Employment Agreement effected
hereby will not constitute a Voluntary Retirement on the part of Executive or
any other termination of employment within the meaning or usage of such terms in
the Employment Agreement.

             6.          Continuing Effect of Employment Agreement.  Except as
expressly modified herein, the Employment Agreement will continue in full force
and effect from and after the date hereof, and nothing herein shall be construed
to modify any rights or obligations of the parties under the Employment
Agreement prior to the date hereof.

             IN WITNESS WHEREOF, the parties hereto have executed this
Modification Agreement as of the date first above written.

 

AVANT! CORPORATION           By: /s/ Dan Taylor   By: /s/ Toyohiko Muraki  

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  Dan Taylor   Toyohiko Muraki   Compensation Committee   Compensation Committee
                  /s/ Gerald C. Hsu      

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      Gerald C. Hsu