AFFYMETRIX, INC. 1998 STOCK INCENTIVE PLAN (AS ADOPTED EFFECTIVE SEPTEMBER 29, 1998)

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EXHIBIT 99.1

AFFYMETRIX, INC.

1998 STOCK INCENTIVE PLAN

(AS ADOPTED EFFECTIVE SEPTEMBER 29, 1998)

TABLE OF CONTENTS

		Page
ARTICLE 1. INTRODUCTION		1
ARTICLE 2. ADMINISTRATION		1
2.1	Committee Composition	1
2.2	Committee Responsibilities	1
ARTICLE 3. SHARES AVAILABLE FOR GRANTS		1
3.1	Basic Limitation	1
3.2	Additional Shares	1
ARTICLE 4. ELIGIBILITY		1
ARTICLE 5. OPTIONS		1
5.1	Stock Option Agreement	1
5.2	Number of Shares	2
5.3	Exercise Price	2
5.4	Exercisability and Term	2
5.5	Effect of Change in Control	2
5.6	Modification or Assumption of Options	2
5.7	Buyout Provisions	2
ARTICLE 6. PAYMENT FOR OPTION SHARES		2
6.1	General Rule	2
6.2	Surrender of Stock	2
6.3	Exercise/Sale	2
6.4	Exercise/Pledge	2
6.5	Promissory Note	3
6.6	Other Forms of Payment	3
ARTICLE 7. RESTRICTED SHARES		3
7.1	Restricted Stock Agreement	3
7.2	Payment for Awards	3
7.3	Vesting Conditions	3
7.4	Voting and Dividend Rights	3
ARTICLE 8. PROTECTION AGAINST DILUTION		3
8.1	Adjustments	3
8.2	Dissolution or Liquidation	4
8.3	Reorganizations	4
ARTICLE 9. DEFERRAL OF DELIVERY OF SHARES		4
ARTICLE 10. AWARDS UNDER OTHER PLANS		4
ARTICLE 11. LIMITATION ON RIGHTS		4
11.1	Retention Rights	4
11.2	Stockholders' Rights	4
11.3	Regulatory Requirements	5
ARTICLE 12. WITHHOLDING TAXES		5
12.1	General	5
12.2	Share Withholding	5
ARTICLE 13. FUTURE OF THE PLAN		5
13.1	Term of the Plan	5
13.2	Amendment or Termination	5
ARTICLE 14. DEFINITIONS		5
ARTICLE 15. EXECUTION		7

AFFYMETRIX, INC.

1998 STOCK INCENTIVE PLAN

ARTICLE 1. INTRODUCTION.

The Plan was adopted by the Board effective September 29, 1998. The purpose of the Plan is to promote the long-term success of the Company and the creation of stockholder value by (a) encouraging Employees and Consultants to focus on critical long-range objectives, (b) encouraging the attraction and retention of Employees and Consultants with exceptional qualifications and (c) linking Employees and Consultants directly to stockholder interests through increased stock ownership. The Plan seeks to achieve this purpose by providing for Awards in the form of Restricted Shares or Options (which shall constitute nonstatutory stock options).

The Plan shall be governed by, and construed in accordance with, the laws of the State of Delaware (except their choice-of-law provisions).

ARTICLE 2. ADMINISTRATION.

2.1 Committee Composition. The Plan shall be administered by the Committee. The Committee shall consist exclusively of one or more directors of the Company, who shall be appointed by the Board.

2.2 Committee Responsibilities. The Committee shall (a) select the Employees and Consultants who are to receive Awards under the Plan, (b) determine the type, number, vesting requirements and other features and conditions of such Awards, (c) interpret the Plan and (d) make all other decisions relating to the operation of the Plan. The Committee may adopt such rules or guidelines as it deems appropriate to implement the Plan. The Committee's determinations under the Plan shall be final and binding on all persons.

ARTICLE 3. SHARES AVAILABLE FOR GRANTS.

3.1 Basic Limitation. Common Shares issued pursuant to the Plan may be authorized but unissued shares or treasury shares. The aggregate number of Options and Restricted Shares awarded under the Plan shall not exceed (a) one million plus (b) the additional Common Shares described in Section 3.2. The limitation of this Section 3.1 shall be subject to adjustment pursuant to Article 8.

3.2 Additional Shares. If Options are forfeited or terminate for any other reason before being exercised, then the corresponding Common Shares shall again become available for the grant of Options or Restricted Shares under the Plan. If Restricted Shares or Common Shares issued upon the exercise of Options are forfeited, then such Common Shares shall again become available for the grant of Options and Restricted Shares under the Plan.

ARTICLE 4. ELIGIBILITY.

Employees and Consultants shall be eligible for the grant of Awards, except that members of the Board and individuals who are considered officers of the Company under the rules of the National Association of Securities Dealers shall not be eligible for the grant of Awards.

ARTICLE 5. OPTIONS.

5.1 Stock Option Agreement. Each grant of an Option under the Plan shall be evidenced by a Stock Option Agreement between the Optionee and the Company. Such Option shall be subject to all applicable terms of the Plan and may be subject to any other terms that are not inconsistent with the Plan. The provisions of the various Stock Option Agreements entered into under the Plan need not be identical. Options may be granted in consideration of a reduction in the Optionee's other compensation. A Stock Option Agreement may provide that a new Option will be granted

automatically to the Optionee when he or she exercises a prior Option and pays the Exercise Price in the form described in Section 6.2.

5.2 Number of Shares. Each Stock Option Agreement shall specify the number of Common Shares subject to the Option and shall provide for the adjustment of such number in accordance with Article 8.

5.3 Exercise Price. Each Stock Option Agreement shall specify the Exercise Price; provided that the Exercise Price shall in no event be less than 100% of the Fair Market Value of a Common Share on the date of grant. A Stock Option Agreement may specify an Exercise Price that varies in accordance with a predetermined formula while the Option is outstanding.

5.4 Exercisability and Term. Each Stock Option Agreement shall specify the date or event when all or any installment of the Option is to become exercisable. The Stock Option Agreement shall also specify the term of the Option. A Stock Option Agreement may provide for accelerated exercisability in the event of the Optionee's death, disability or retirement or other events and may provide for expiration prior to the end of its term in the event of the termination of the Optionee's service.

5.5 Effect of Change in Control. The Committee may determine, at the time of granting an Option or thereafter, that such Option shall become exercisable as to all or part of the Common Shares subject to such Option in the event that a Change in Control occurs with respect to the Company.

5.6 Modification or Assumption of Options. Within the limitations of the Plan, the Committee may modify, extend or assume outstanding options or may accept the cancellation of outstanding options (whether granted by the Company or by another issuer) in return for the grant of new options for the same or a different number of shares and at the same or a different exercise price. The foregoing notwithstanding, no modification of an Option shall, without the consent of the Optionee, alter or impair his or her rights or obligations under such Option.

5.7 Buyout Provisions. The Committee may at any time (a) offer to buy out for a payment in cash or cash equivalents an Option previously granted or (b) authorize an Optionee to elect to cash out an Option previously granted, in either case at such time and based upon such terms and conditions as the Committee shall establish.

ARTICLE 6. PAYMENT FOR OPTION SHARES.

6.1 General Rule. The entire Exercise Price of Common Shares issued upon exercise of Options shall be payable in cash or cash equivalents at the time when such Common Shares are purchased, unless the Committee accepts payment in any other form(s) described in this Article 6.

6.2 Surrender of Stock. To the extent that this Section 6.2 is applicable, all or any part of the Exercise Price may be paid by surrendering, or attesting to the ownership of, Common Shares that are already owned by the Optionee. Such Common Shares shall be valued at their Fair Market Value on the date when the new Common Shares are purchased under the Plan. The Optionee shall not surrender, or attest to the ownership of, Common Shares in payment of the Exercise Price if such action would cause the Company to recognize compensation expense (or additional compensation expense) with respect to the Option for financial reporting purposes.

6.3 Exercise/Sale. To the extent that this Section 6.3 is applicable, all or any part of the Exercise Price and any withholding taxes may be paid by delivering (on a form prescribed by the Company) an irrevocable direction to a securities broker approved by the Company to sell all or part of the Common Shares being purchased under the Plan and to deliver all or part of the sales proceeds to the Company.

6.4 Exercise/Pledge. To the extent that this Section 6.4 is applicable, all or any part of the Exercise Price and any withholding taxes may be paid by delivering (on a form prescribed by the

Company) an irrevocable direction to pledge all or part of the Common Shares being purchased under the Plan to a securities broker or lender approved by the Company, as security for a loan, and to deliver all or part of the loan proceeds to the Company.

6.5 Promissory Note. To the extent that this Section 6.5 is applicable, all or any part of the Exercise Price and any withholding taxes may be paid by delivering (on a form prescribed by the Company) a full-recourse promissory note. However, the par value of the Common Shares being purchased under the Plan, if newly issued, shall be paid in cash or cash equivalents.

6.6 Other Forms of Payment. To the extent that this Section 6.6 is applicable, all or any part of the Exercise Price and any withholding taxes may be paid in any other form that is consistent with applicable laws, regulations and rules.

ARTICLE 8. RESTRICTED SHARES.

7.1 Restricted Stock Agreement. Each grant of Restricted Shares under the Plan shall be evidenced by a Restricted Stock Agreement between the recipient and the Company. Such Restricted Shares shall be subject to all applicable terms of the Plan and may be subject to any other terms that are not inconsistent with the Plan. The provisions of the various Restricted Stock Agreements entered into under the Plan need not be identical.

7.2 Payment for Awards. Subject to the following sentence, Restricted Shares may be sold or awarded under the Plan for such consideration as the Committee may determine, including (without limitation) cash, cash equivalents, full-recourse promissory notes, past services and future services. To the extent that an Award consists of newly issued Restricted Shares, the Award recipient shall furnish consideration with a value not less than the par value of such Restricted Shares in the form of cash, cash equivalents or past services rendered to the Company (or a Parent or Subsidiary), as the Committee may determine.

7.3 Vesting Conditions. Each Award of Restricted Shares may or may not be subject to vesting. Vesting shall occur, in full or in installments, upon satisfaction of the conditions specified in the Restricted Stock Agreement. A Restricted Stock Agreement may provide for accelerated vesting in the event of the Participant's death, disability or retirement or other events. The Committee may determine, at the time of granting Restricted Shares or thereafter, that all or part of such Restricted Shares shall become vested in the event that a Change in Control occurs with respect to the Company.

7.4 Voting and Dividend Rights. The holders of Restricted Shares awarded under the Plan shall have the same voting, dividend and other rights as the Company's other stockholders. A Restricted Stock Agreement, however, may require that the holders of Restricted Shares invest any cash dividends received in additional Restricted Shares. Such additional Restricted Shares shall be subject to the same conditions and restrictions as the Award with respect to which the dividends were paid.

ARTICLE 8. PROTECTION AGAINST DILUTION.

8.1 Adjustments. In the event of a subdivision of the outstanding Common Shares, a declaration of a dividend payable in Common Shares, a declaration of a dividend payable in a form other than Common Shares in an amount that has a material effect on the price of Common Shares, a combination or consolidation of the outstanding Common Shares (by reclassification or otherwise) into a lesser number of Common Shares, a recapitalization, a spin-off or a similar occurrence, the Committee shall make such adjustments as it, in its sole discretion, deems appropriate in one or more of (a) the number of Options and Restricted Shares available for future Awards under Article 3, (b) the number of Common Shares covered by each outstanding Option or (c) the Exercise Price under each outstanding Option. Except as provided in this Article 8, a Participant shall have no rights by reason of any issue by the Company of stock of any class or securities convertible into stock of any

class, any subdivision or consolidation of shares of stock of any class, the payment of any stock dividend or any other increase or decrease in the number of shares of stock of any class.

8.2 Dissolution or Liquidation. To the extent not previously exercised, Options shall terminate immediately prior to the dissolution or liquidation of the Company.

8.3 Reorganizations. In the event that the Company is a party to a merger or other reorganization, outstanding Options and Restricted Shares shall be subject to the agreement of merger or reorganization. Such agreement shall provide for (a) the continuation of the outstanding Awards by the Company, if the Company is a surviving corporation, (b) the assumption of the outstanding Awards by the surviving corporation or its parent or subsidiary, (c) the substitution by the surviving corporation or its parent or subsidiary of its own awards for the outstanding Awards, (d) full exercisability or vesting and accelerated expiration of the outstanding Awards or (e) settlement of the full value of the outstanding Awards in cash or cash equivalents followed by cancellation of such Awards.

ARTICLE 9. DEFERRAL OF DELIVERY OF SHARES.

The Committee (in its sole discretion) may permit or require an Optionee to have Common Shares that otherwise would be delivered to such Optionee as a result of the exercise of an Option converted into amounts credited to a deferred compensation account established for such Optionee by the Committee as an entry on the Company's books. Such amounts shall be determined by reference to the Fair Market Value of such Common Shares as of the date when they otherwise would have been delivered to such Optionee. A deferred compensation account established under this Article 9 may be credited with interest or other forms of investment return, as determined by the Committee. An Optionee for whom such an account is established shall have no rights other than those of a general creditor of the Company. Such an account shall represent an unfunded and unsecured obligation of the Company and shall be subject to the terms and conditions of the applicable agreement between such Optionee and the Company. If the conversion of Options is permitted or required, the Committee (in its sole discretion) may establish rules, procedures and forms pertaining to such conversion, including (without limitation) the settlement of deferred compensation accounts established under this Article 9.

ARTICLE 10. AWARDS UNDER OTHER PLANS.

The Company may grant awards under other plans or programs. Such awards may be settled in the form of Common Shares issued under this Plan. Such Common Shares shall be treated for all purposes under the Plan like Restricted Shares and shall, when issued, reduce the number of Common Shares available under Article 3.

ARTICLE 11. LIMITATION ON RIGHTS.

11.1 Retention Rights. Neither the Plan nor any Award granted under the Plan shall be deemed to give any individual a right to remain an Employee or Consultant. The Company and its Parents, Subsidiaries and Affiliates reserve the right to terminate the service of any Employee or Consultant at any time, with or without cause, subject to applicable laws, the Company's certificate of incorporation and by-laws and a written employment agreement (if any).

11.2 Stockholders' Rights. A Participant shall have no dividend rights, voting rights or other rights as a stockholder with respect to any Common Shares covered by his or her Award prior to the time when a stock certificate for such Common Shares is issued or, in the case of an Option, the time when he or she becomes entitled to receive such Common Shares by filing a notice of exercise and paying the Exercise Price. No adjustment shall be made for cash dividends or other rights for which the record date is prior to such time, except as expressly provided in the Plan.

11.3 Regulatory Requirements. Any other provision of the Plan notwithstanding, the obligation of the Company to issue Common Shares under the Plan shall be subject to all applicable laws, rules and regulations and such approval by any regulatory body as may be required. The Company reserves the right to restrict, in whole or in part, the delivery of Common Shares pursuant to any Award prior to the satisfaction of all legal requirements relating to the issuance of such Common Shares, to their registration, qualification or listing or to an exemption from registration, qualification or listing.

ARTICLE 12. WITHHOLDING TAXES.

12.1 General. To the extent required by applicable federal, state, local or foreign law, a Participant or his or her successor shall make arrangements satisfactory to the Company for the satisfaction of any withholding tax obligations that arise in connection with the Plan. The Company shall not be required to issue any Common Shares or make any cash payment under the Plan until such obligations are satisfied.

12.2 Share Withholding. The Committee may permit a Participant to satisfy all or part of his or her withholding or income tax obligations by having the Company withhold all or a portion of any Common Shares that otherwise would be issued to him or her or by surrendering all or a portion of any Common Shares that he or she previously acquired. Such Common Shares shall be valued at their Fair Market Value on the date when taxes otherwise would be withheld in cash.

ARTICLE 13. FUTURE OF THE PLAN.

13.1 Term of the Plan. The Plan, as set forth herein, shall become effective on September 29, 1998. The Plan shall remain in effect until it is terminated under Section 13.2.

13.2 Amendment or Termination. The Board may, at any time and for any reason, amend or terminate the Plan. An amendment of the Plan shall be subject to the approval of the Company's stockholders only to the extent required by applicable laws, regulations or rules. No Awards shall be granted under the Plan after the termination thereof. The termination of the Plan, or any amendment thereof, shall not affect any Award previously granted under the Plan.

ARTICLE 14. DEFINITIONS.

14.1 "Affiliate" means any entity other than a Subsidiary, if the Company and/or one or more Subsidiaries own not less than 50% of such entity.

14.2 "Award" means any award of an Option or a Restricted Share under the Plan.

14.3 "Board" means the Company's Board of Directors, as constituted from time to time.

14.4 "Change in Control" shall mean:

(a) The consummation of a merger or consolidation of the Company with or into another entity or any other corporate reorganization, if more than 50% of the combined voting power of the continuing or surviving entity's securities outstanding immediately after such merger, consolidation or other reorganization is owned by persons who were not stockholders of the Company immediately prior to such merger, consolidation or other reorganization; or

(b) The sale, transfer, exchange or other disposition of all or substantially all of the Company's assets; or

(c) A change in the composition of the Board, as a result of which fewer than 80% of the directors are directors who either (i) had been directors of the Company on the date 24 months prior to the date of the event that may constitute a Change in Control (the "original directors") or (ii) were elected, or nominated for election, to the Board with the affirmative votes of at least a

majority of the aggregate of the original directors who were still in office at the time of the election or nomination and the directors whose election or nomination was previously so approved; or

(d) Any transaction as a result of which any person is the "beneficial owner" (as defined in Rule 13d-3 under the Exchange Act), directly or indirectly, of securities of the Company representing at least 50% of the total voting power represented by the Company's then outstanding voting securities. For purposes of this Subsection (d), the term "person" shall have the same meaning as when used in sections 13(d) and 14(d) of the Exchange Act but shall exclude (i) a trustee or other fiduciary holding securities under an employee benefit plan of the Company, a Parent or Subsidiary and (ii) a corporation owned directly or indirectly by the stockholders of the Company in substantially the same proportions as their ownership of the common stock of the Company.

A transaction shall in no event constitute a Change in Control if its sole purpose is to change the state of the Company's incorporation or to create a holding company that will be owned in substantially the same proportions by the persons who held the Company's securities immediately before such transaction.

14.5 "Code" means the Internal Revenue Code of 1986, as amended.

14.6 "Committee" means a committee of the Board, as described in Article 2.

14.7 "Common Share" means one share of the common stock of the Company.

14.8 "Company" means Affymetrix, Inc., a Delaware corporation.

14.9 "Consultant" means a consultant or adviser who provides bona fide services to the Company, a Parent, a Subsidiary or an Affiliate as an independent contractor, including (without limitation) a member of the Company's Scientific Advisory Board. Service as a Consultant shall be considered employment for all purposes of the Plan.

14.10 "Employee" means a common-law employee of the Company, a Parent, a Subsidiary or an Affiliate.

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

14.12 "Exercise Price" means the amount for which one Common Share may be purchased upon exercise of such Option, as specified in the applicable Stock Option Agreement.

14.13 "Fair Market Value" means the market price of Common Shares, determined by the Committee in good faith on such basis as it deems appropriate. Whenever possible, the determination of Fair Market Value by the Committee shall be based on the prices reported in The Wall Street Journal. Such determination shall be conclusive and binding on all persons.

14.14 "NSO" means a stock option not described in sections 422 or 423 of the Code.

14.15 "Option" means an NSO granted under the Plan and entitling the holder to purchase Common Shares.

14.16 "Optionee" means an individual or estate who holds an Option.

14.17 "Parent" means any corporation (other than the Company) in an unbroken chain of corporations ending with the Company, if each of the corporations other than the Company owns stock possessing 50% or more of the total combined voting power of all classes of stock in one of the other corporations in such chain. A corporation that attains the status of a Parent on a date after the adoption of the Plan shall be considered a Parent commencing as of such date.

14.18 "Participant" means an individual or estate who holds an Award.

14.19 "Plan" means this Affymetrix, Inc. 1998 Stock Incentive Plan, as amended from time to time.

14.20 "Restricted Share" means a Common Share awarded under the Plan.

14.21 "Restricted Stock Agreement" means the agreement between the Company and the recipient of a Restricted Share that contains the terms, conditions and restrictions pertaining to such Restricted Share.

14.22 "Stock Option Agreement" means the agreement between the Company and an Optionee that contains the terms, conditions and restrictions pertaining to his or her Option.

14.23 "Subsidiary" means any corporation (other than the Company) in an unbroken chain of corporations beginning with the Company, if each of the corporations other than the last corporation in the unbroken chain owns stock possessing 50% or more of the total combined voting power of all classes of stock in one of the other corporations in such chain. A corporation that attains the status of a Subsidiary on a date after the adoption of the Plan shall be considered a Subsidiary commencing as of such date.

ARTICLE 15. EXECUTION.

To record the adoption of the Plan by the Board, the Company has caused its duly authorized officer to execute this document in the name of the Company.

		AFFYMETRIX, INC.

		By:		/s/ XXXX XXXXXXX

		Title:		Sr. V.P. General Counsel and Corporate Secretary

EXHIBIT A

AFFYMETRIX, INC. 1998 STOCK INCENTIVE PLAN

TERMS AND CONDITIONS OF GRANT

Tax Treatment		This option is intended to be a nonstatutory option, as provided in the Notice of Stock Option Grant.
Vesting		This option becomes exercisable in installments, as shown in the Notice of Stock Option Grant.
		In addition, this option becomes exercisable in full if:
		(a) The Company is subject to a "Change in Control" (as defined in the Plan) while you are an employee, consultant or director of the Company (or a subsidiary of the Company); and
		(b) This option does not remain outstanding after the Change in Control, this option is not assumed by the surviving corporation (or its parent) as part of the Change in Control, and the surviving corporation (or its parent) does not substitute an option with substantially the same terms for this option as part of the Change in Control.
		No additional shares become exercisable after your service as an employee, consultant or director of the Company (or a subsidiary of the Company) has terminated for any reason.
Term		This option expires in any event at the close of business at Company headquarters on the day before the 10th anniversary of the Date of Grant, as shown in the Notice of Stock Option Grant. (It will expire earlier if your service terminates, as described below.)
Regular Termination		If your service as an employee, consultant or director of the Company or a subsidiary of the Company terminates for any reason except death or total and permanent disability, then this option will expire at the close of business at Company headquarters on the date three months after your termination date. The Company determines when your service terminates for this purpose.
Death		If you die as an employee, consultant or director of the Company or a subsidiary of the Company, then this option will expire at the close of business at Company headquarters on the date 12 months after the date of death.
Disability		If your service as an employee, consultant or director of the Company or a subsidiary of the Company terminates because of your total and permanent disability, then this option will expire at the close of business at Company headquarters on the date 12 months after your termination date.
		For all purposes under this Agreement, "total and permanent disability" means that you are unable to engage in any substantial gainful activity by reason of any medically determinable physical or mental impairment which can be expected to result in death or which has lasted, or can be expected to last, for a continuous period of not less than one year.

Leaves of Absence		For purposes of this option, your service does not terminate when you go on a military leave, a sick leave or another bona fide leave of absence, if the leave was approved by the Company in writing and if continued crediting of service is required by the terms of the leave or by applicable law. But your service terminates when the approved leave ends, unless you immediately return to active work.
Restrictions on Exercise		The Company will not permit you to exercise this option if the issuance of shares at that time would violate any law or regulation.
Notice of Exercise		When you wish to exercise this option, you must notify the Company by filing the proper "Notice of Exercise" form at the address given on the form. Your notice must specify how many shares you wish to purchase. Your notice must also specify how your shares should be registered (in your name only or in your and your spouse's names as community property or as joint tenants with right of survivorship). The notice will be effective when it is received by the Company.
		If someone else wants to exercise this option after your death, that person must prove to the Company's satisfaction that he or she is entitled to do so.
Form of Payment		When you submit your notice of exercise, you must include payment of the option exercise price for the shares you are purchasing. Payment may be made in one (or a combination of two or more) of the following forms:
		• Your personal check, a cashier's check or a money order.
		• Certificates for shares of Company stock that you own, along with any forms needed to effect a transfer of those shares to the Company. The value of the shares, determined as of the effective date of the option exercise, will be applied to the option exercise price. Instead of surrendering shares of Company stock, you may attest to the ownership of those shares on a form provided by the Company and have the same number of shares subtracted from the option shares issued to you. However, you may not surrender, or attest to the ownership of, shares of Company stock in payment of the exercise price if your action would cause the Company to recognize compensation expense (or additional compensation expense) with respect to this option for financial reporting purposes.
		• Irrevocable directions to a securities broker approved by the Company to sell all or part of your option shares and to deliver to the Company from the sale proceeds an amount sufficient to pay the option exercise price and any withholding taxes. (The balance of the sale proceeds, if any, will be delivered to you.) The directions must be given by signing a special "Notice of Exercise" form provided by the Company.

		• Irrevocable directions to a securities broker or lender approved by the Company to pledge option shares as security for a loan and to deliver to the Company from the loan proceeds an amount sufficient to pay the option exercise price and any withholding taxes. The directions must be given by signing a special "Notice of Exercise" form provided by the Company.
Withholding Taxes and Stock		You will not be allowed to exercise this option unless you make arrangements acceptable to the Withholding Company to pay any withholding taxes that may be due as a result of the option exercise. These arrangements may include withholding shares of Company stock that otherwise would be issued to you when you exercise this option. The value of these shares, determined as of the effective date of the option exercise, will be applied to the withholding taxes.
Restrictions on Resale		By signing this Agreement, you agree not to sell any option shares at a time when applicable laws, Company policies or an agreement between the Company and its underwriters prohibit a sale. This restriction will apply as long as you are an employee, consultant or director of the Company or a subsidiary of the Company.
Transfer of Option		Prior to your death, only you may exercise this option. You cannot transfer or assign this option. For instance, you may not sell this option or use it as security for a loan. If you attempt to do any of these things, this option will immediately become invalid. You may, however, dispose of this option in your will or a beneficiary designation.
		Regardless of any marital property settlement agreement, the Company is not obligated to honor a notice of exercise from your former spouse, nor is the Company obligated to recognize your former spouse's interest in your option in any other way.
Retention Rights		Your option or this Agreement do not give you the right to be retained by the Company or a subsidiary of the Company in any capacity. The Company and its subsidiaries reserve the right to terminate your service at any time, with or without cause.
Stockholder Rights		You, or your estate or heirs, have no rights as a stockholder of the Company until you have exercised this option by giving the required notice to the Company and paying the exercise price. No adjustments are made for dividends or other rights if the applicable record date occurs before you exercise this option, except as described in the Plan.
Adjustments		In the event of a stock split, a stock dividend or a similar change in Company stock, the number of shares covered by this option and the exercise price per share may be adjusted pursuant to the Plan.
Applicable Law		This Agreement will be interpreted and enforced under the laws of the State of Delaware (without regard to their choice-of-law provisions).

The Plan and Other Agreements

The text of the Plan is incorporated in this Agreement by reference. This Agreement and the Plan constitute the entire understanding between you and the Company regarding this option. Any prior agreements, commitments or negotiations concerning this option are superseded. This Agreement may be amended only by another written agreement, signed by both parties.

BY SIGNING THE COVER SHEET OF THIS AGREEMENT, YOU AGREE TO ALL OF THE TERMS AND CONDITIONS DESCRIBED ABOVE AND IN THE PLAN.

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AFFYMETRIX, INC. 1998 STOCK INCENTIVE PLAN (AS ADOPTED EFFECTIVE SEPTEMBER 29, 1998)
TABLE OF CONTENTS
AFFYMETRIX, INC. 1998 STOCK INCENTIVE PLAN
EXHIBIT A
AFFYMETRIX, INC. 1998 STOCK INCENTIVE PLAN TERMS AND CONDITIONS OF GRANT