AFFYMETRIX INC
S-1/A, 1996-05-20
COMMERCIAL PHYSICAL & BIOLOGICAL RESEARCH
Previous: ARRIS PHARMACEUTICAL CORP/DE/, 10-Q, 1996-05-20
Next: GUNTHER INTERNATIONAL LTD, 424B3, 1996-05-20



<PAGE>
   
      AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON MAY 20, 1996
    
 
                                                       REGISTRATION NO. 333-3648
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
 
                            ------------------------
 
   
                                AMENDMENT NO. 2
                                       TO
                                    FORM S-1
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
    
 
                            ------------------------
 
                                AFFYMETRIX, INC.
             (Exact Name of Registrant as Specified in Its Charter)
 
   
<TABLE>
<S>                              <C>                            <C>
          CALIFORNIA                         8731                  77-0319159
 (State or Other Jurisdiction    (Primary Standard Industrial   (I.R.S. Employer
              of                 Classification Code Number)     Identification
Incorporation or Organization)                                      Number)
</TABLE>
    
 
     3380 CENTRAL EXPRESSWAY, SANTA CLARA, CALIFORNIA 95051; (408) 522-6000
 
         (Address, Including Zip Code, and Telephone Number, Including
            Area Code, of Registrant's Principal Executive Offices)
 
  KENNETH J. NUSSBACHER, EXECUTIVE VICE PRESIDENT AND CHIEF FINANCIAL OFFICER
     3380 CENTRAL EXPRESSWAY, SANTA CLARA, CALIFORNIA 95051; (408) 522-6000
 
       (Name, Address Including Zip Code, and Telephone Number, Including
                        Area Code, of Agent For Service)
 
                            ------------------------
 
                                   COPIES TO:
 
<TABLE>
<S>                                       <C>
           Julian N. Stern                            Alan K. Austin
          August J. Moretti                         Elizabeth R. Flint
         Stephen C. Ferruolo                        Elizabeth M. Kurr
   Heller Ehrman White & McAuliffe          Wilson, Sonsini, Goodrich & Rosati
        525 University Avenue                       650 Page Mill Road
     Palo Alto, California 94301               Palo Alto, California 94304
            (415) 324-7000                            (415) 493-9300
</TABLE>
 
                            ------------------------
 
        APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC:
    AS SOON AS PRACTICABLE FOLLOWING THE EFFECTIVENESS 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,  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 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. / /
 
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
<PAGE>
                                AFFYMETRIX, INC.
                             CROSS-REFERENCE SHEET
 
<TABLE>
<CAPTION>
                        ITEM AND HEADING
           FOR S-1 REGISTRATION STATEMENT PROSPECTUS                             LOCATION IN PROSPECTUS
----------------------------------------------------------------  -----------------------------------------------------
<C>        <S>                                                    <C>
       1.  Forepart of the Registration Statement and Outside
            Front Cover Page of Prospectus......................  Outside Front Cover Page; Additional Information
       2.  Inside Front and Outside Back Cover Pages of
            Prospectus..........................................  Inside Front Cover Page
       3.  Summary Information, Risk Factors and Ratio of
            Earnings to Fixed Charges...........................  Summary; Risk Factors
       4.  Use of Proceeds......................................  Summary; Use of Proceeds
       5.  Determination of Offering Price......................  Outside Front Cover Page; Underwriting
       6.  Dilution.............................................  Dilution
       7.  Selling Security Holders.............................  Not Applicable
       8.  Plan of Distribution.................................  Outside and Inside Front Cover Pages; Underwriting
       9.  Description of Securities to be Registered...........  Summary; Capitalization; Description of Capital Stock
      10.  Interests of Named Experts and Counsel...............  Legal Matters; Experts
      11.  Information with Respect to the Registrant...........  Outside and Inside Front Cover Pages; Summary; Risk
                                                                   Factors; Use of Proceeds; Dividend Policy;
                                                                   Capitalization; Dilution; Selected Financial Data;
                                                                   Management's Discussion and Analysis of Financial
                                                                   Condition and Results of Operations; Business;
                                                                   Management; Certain Transactions; Principal
                                                                   Shareholders; Description of Capital Stock; Shares
                                                                   Eligible for Future Sale; Financial Statements
      12.  Disclosure of Commission Position on Indemnification
            for Securities Act Liabilities......................  Not Applicable
</TABLE>
<PAGE>
INFORMATION   CONTAINED  HEREIN  IS  SUBJECT   TO  COMPLETION  OR  AMENDMENT.  A
REGISTRATION STATEMENT  RELATING TO  THESE SECURITIES  HAS BEEN  FILED WITH  THE
SECURITIES  AND EXCHANGE  COMMISSION. THESE SECURITIES  MAY NOT BE  SOLD NOR MAY
OFFERS TO BUY BE ACCEPTED PRIOR  TO THE TIME THE REGISTRATION STATEMENT  BECOMES
EFFECTIVE.  THIS  PROSPECTUS  SHALL  NOT  CONSTITUTE AN  OFFER  TO  SELL  OR THE
SOLICITATION OF AN OFFER TO BUY NOR SHALL THERE BE ANY SALE OF THESE  SECURITIES
IN  ANY STATE IN WHICH SUCH OFFER,  SOLICITATION OR SALE WOULD BE UNLAWFUL PRIOR
TO REGISTRATION OR QUALIFICATION UNDER THE SECURITIES LAWS OF ANY SUCH STATE.
<PAGE>
   
                   SUBJECT TO COMPLETION, DATED MAY 20, 1996
    
 
                                      LOGO
 
                                5,000,000 SHARES
 
                                  COMMON STOCK
 
    All of the 5,000,000 shares of Common Stock offered hereby are being sold by
Affymetrix, Inc. ("Affymetrix" or the "Company"). Prior to this offering,  there
has  been no public market for the Common  Stock of the Company. It is currently
estimated that the  initial public  offering price  will be  between $11.00  and
$13.00  per share. See "Underwriting" for  information relating to the method of
determining the initial public offering price.
                               ------------------
 
          THE COMMON STOCK OFFERED HEREBY INVOLVES A HIGH DEGREE OF RISK.
                    SEE "RISK FACTORS" BEGINNING ON PAGE 6.
                                ----------------
 
THESE SECURITIES  HAVE  NOT  BEEN  APPROVED OR  DISAPPROVED  BY  THE  SECURITIES
   AND  EXCHANGE  COMMISSION  OR  ANY  STATE  SECURITIES  COMMISSION  NOR HAS
     THE  COMMISSION  OR  ANY  STATE  SECURITIES  COMMISSION  PASSED   UPON
       THE    ACCURACY    OR   ADEQUACY    OF   THIS    PROSPECTUS.   ANY
              REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.
 
<TABLE>
<CAPTION>
---------------------------------------------------------------------------------
---------------------------------------------------------------------------------
                                                   UNDERWRITING
                                    PRICE TO       DISCOUNTS AND     PROCEEDS TO
                                     PUBLIC         COMMISSIONS      COMPANY (1)
---------------------------------------------------------------------------------
<S>                               <C>              <C>              <C>
Per Share.....................          $                $                $
---------------------------------------------------------------------------------
Total (2).....................          $                $                $
---------------------------------------------------------------------------------
---------------------------------------------------------------------------------
</TABLE>
 
(1) Before deducting expenses payable by the Company estimated at $800,000.
 
(2) The Company has granted the Underwriters  a 30-day option to purchase up  to
    an additional        shares of Common Stock solely to cover over-allotments,
    if  any. See "Underwriting." If such option  is exercised in full, the total
    Price to Public,  Underwriting Discounts  and Commissions,  and Proceeds  to
    Company will be $     , $      , and $      , respectively.
                               ------------------
 
    The Common Stock is offered by the Underwriters as stated herein, subject to
receipt and acceptance by them and subject to their right to reject any order in
whole  or in  part. It  is expected that  delivery of  such shares  will be made
through the offices of Robertson, Stephens & Company LLC ("Robertson, Stephens &
Company"), San Francisco, California, on or about       , 1996.
 
ROBERTSON, STEPHENS & COMPANY
 
                                 CS FIRST BOSTON
 
                                                           MONTGOMERY SECURITIES
 
                  The date of this Prospectus is       , 1996
<PAGE>
Affymetrix GeneChip-TM- Technology Opportunities
--------------------------------------------
 
   
      All genomics programs  are expected to  be research  collaborations.
      All diagnostic product opportunities are in research and development
      with  the indicated collaborators, except  for HIV, which Affymetrix
      introduced  as  a  "Research  Use  Only"  product  in  April   1996.
      Diagnostic use of the Company's products would be subject to FDA and
      other  applicable regulatory approvals, which  have not been applied
      for or received, and which may not be obtained for several years, if
      at all.
    
 
--------------------------------------------------------------------------------
IN CONNECTION  WITH THIS  OFFERING, THE  UNDERWRITERS MAY  OVER-ALLOT OR  EFFECT
TRANSACTIONS WHICH STABILIZE OR MAINTAIN THE MARKET PRICE OF THE COMMON STOCK OF
THE  COMPANY AT  A LEVEL ABOVE  THAT WHICH  MIGHT OTHERWISE PREVAIL  IN THE OPEN
MARKET. SUCH TRANSACTIONS  MAY BE  EFFECTED ON  THE NASDAQ  NATIONAL MARKET,  OR
OTHERWISE. SUCH STABILIZING, IF COMMENCED, MAY BE DISCONTINUED AT ANY TIME.
 
   
DURING  THIS OFFERING, CERTAIN PERSONS  AFFILIATED WITH PERSONS PARTICIPATING IN
THE DISTRIBUTION MAY ENGAGE  IN TRANSACTIONS FOR THEIR  OWN ACCOUNTS OR FOR  THE
ACCOUNTS  OF OTHERS IN THE COMMON STOCK PURSUANT TO EXEMPTIONS FROM RULES 10B-6,
10B-7, AND 10B-8 UNDER THE SECURITIES EXCHANGE ACT OF 1934.
    
<PAGE>
Affymetrix GeneChip Technology
-----------------------------------------
 
                             [Depictions of genes,
                                double helix and
                           probe array in cartridge]
 
Affymetrix GeneChip probe arrays provide  the capacity to acquire, analyze,  and
manage complex genetic information.
 
Integrated GeneChip System
 
<TABLE>
<S>                            <C>                            <C>
[PICTURE]                      [PICTURE]                      [PICTURE]
 
GeneChip Fluidics Station      GeneChip Scanner               GeneChip Software
Controls hybridization of the  Quantitatively detects         Analyzes and manages genetic
test sample to the probe       hybridization of test sample   information from the scanner.
array.                         to the probe array.
</TABLE>
 
<PAGE>
              GeneChip Probe Array
             A GeneChip probe array currently contains
             from 16,000 to more than 100,000 different
             DNA probes. Each probe array is packaged
             in a catridge.
 
                                          Probe Array Image
                                        A GeneChip scanner image of an
                                        HIV probe array for sequencing the
                                        reverse transcriplase and protease
                                        genes. Each small square represents
                                        the quantitative hybridization
                                        intensity of a labeled test sample to
                                        a specific DNA probe.
 
             [PICTURE]
 
             [PICTURE]
 
              GeneChip Software
             GeneChip software translates the quantitative hybridization
             intensities into sequence information which can also be used for
             gene expression analysis and genetic mapping. The red "a" in the
             Sequences window indicates a mutation in HIV causing resistance to
             a class of HIV protease inhibitor drugs.
<PAGE>
    NO  DEALER, SALES REPRESENTATIVE OR ANY  OTHER PERSON HAS BEEN AUTHORIZED TO
GIVE ANY INFORMATION  OR TO  MAKE ANY  REPRESENTATIONS IN  CONNECTION WITH  THIS
OFFERING  OTHER THAN THOSE CONTAINED  IN THE PROSPECTUS, AND,  IF GIVEN OR MADE,
SUCH INFORMATION  OR REPRESENTATIONS  MUST NOT  BE RELIED  UPON AS  HAVING  BEEN
AUTHORIZED  BY  THE  COMPANY  OR  ANY  UNDERWRITER.  THIS  PROSPECTUS  DOES  NOT
CONSTITUTE AN  OFFER  TO  SELL, OR  A  SOLICITATION  OF AN  OFFER  TO  BUY,  ANY
SECURITIES  OTHER THAN THE REGISTERED SECURITIES TO WHICH IT RELATES OR AN OFFER
TO, OR SOLICITATION OF, ANY PERSON IN ANY JURISDICTION IN WHICH SUCH AN OFFER OR
SOLICITATION WOULD BE UNLAWFUL. NEITHER THE DELIVERY OF THIS PROSPECTUS NOR  ANY
SALE  MADE HEREUNDER SHALL, UNDER ANY CIRCUMSTANCES, CREATE ANY IMPLICATION THAT
THERE HAS BEEN NO CHANGE IN THE AFFAIRS OF THE COMPANY SINCE THE DATE HEREOF  OR
THAT  THE INFORMATION CONTAINED HEREIN  IS CORRECT AS OF  ANY TIME SUBSEQUENT TO
THE DATE HEREOF.
 
    UNTIL        , 1996 (25 DAYS AFTER THE DATE OF THIS PROSPECTUS), ALL DEALERS
EFFECTING  TRANSACTIONS   IN  THE   REGISTERED   SECURITIES,  WHETHER   OR   NOT
PARTICIPATING  IN THIS  DISTRIBUTION, MAY BE  REQUIRED TO  DELIVER A PROSPECTUS.
THIS DELIVERY  REQUIREMENT IS  IN  ADDITION TO  THE  OBLIGATIONS OF  DEALERS  TO
DELIVER  A  PROSPECTUS WHEN  ACTING AS  UNDERWRITERS AND  WITH RESPECT  TO THEIR
UNSOLD ALLOTMENTS OR SUBSCRIPTIONS.
 
                               ------------------
 
                               TABLE OF CONTENTS
 
   
<TABLE>
<CAPTION>
                                                                            PAGE
                                                                            ----
<S>                                                                         <C>
Summary...................................................................    4
Risk Factors..............................................................    6
Use of Proceeds...........................................................   18
Dividend Policy...........................................................   18
Capitalization............................................................   19
Dilution..................................................................   20
Selected Financial Data...................................................   21
Management's Discussion and Analysis of Financial Condition and Results of
 Operations...............................................................   22
Business..................................................................   26
Management................................................................   48
Certain Transactions......................................................   54
Principal Shareholders....................................................   56
Description of Capital Stock..............................................   58
Shares Eligible for Future Sale...........................................   60
Underwriting..............................................................   62
Legal Matters.............................................................   63
Experts...................................................................   63
Additional Information....................................................   63
Glossary..................................................................   64
Index to Financial Statements.............................................  F-1
</TABLE>
    
 
                               ------------------
 
    The Company's  executive offices  are located  at 3380  Central  Expressway,
Santa Clara, California 95051. The Company's telephone number is (408) 522-6000.
 
    GeneChip-TM-  and Affymetrix-TM-  are trademarks of  the Company. Tradenames
and trademarks of other companies appearing in this Prospectus are the  property
of their respective holders.
 
                                       3
<PAGE>
                                    SUMMARY
 
   
    THE  FOLLOWING SUMMARY  IS QUALIFIED  IN ITS  ENTIRETY BY  THE MORE DETAILED
INFORMATION, INCLUDING "RISK  FACTORS", AND THE  FINANCIAL STATEMENTS AND  NOTES
THERETO,  APPEARING  ELSEWHERE  IN  THIS  PROSPECTUS.  THIS  PROSPECTUS CONTAINS
FORWARD-LOOKING STATEMENTS WHICH INVOLVE RISKS AND UNCERTAINTIES. THE  COMPANY'S
ACTUAL   RESULTS  COULD  DIFFER  MATERIALLY  FROM  THOSE  ANTICIPATED  IN  THESE
FORWARD-LOOKING STATEMENTS AS A RESULT  OF CERTAIN FACTORS, INCLUDING THOSE  SET
FORTH  UNDER  "RISK FACTORS"  AND ELSEWHERE  IN THIS  PROSPECTUS. A  GLOSSARY OF
TECHNICAL TERMS USED IN THIS PROSPECTUS APPEARS AT PAGE 64 OF THIS PROSPECTUS.
    
                                  THE COMPANY
 
    Affymetrix has developed and intends to establish its GeneChip system as the
platform of  choice  for  acquiring,  analyzing  and  managing  complex  genetic
information  in  order to  improve the  diagnosis,  monitoring and  treatment of
disease. The Company's system consists of disposable DNA probe arrays containing
gene sequences on a chip, instruments to process the probe arrays, and  software
to  analyze  and manage  genetic information.  The Company  commenced commercial
sales of the GeneChip system  and an HIV probe array  for research use in  April
1996.
 
    The  Company  manufactures  its DNA  probe  arrays using  an  innovative and
proprietary process that combines photolithographic fabrication techniques  from
the  semicondutor  industry with  solid phase  DNA  synthesis to  assemble large
amounts of genetic information on a small  glass chip called a probe array.  The
Company can manufacture a number of identical DNA probe arrays on a glass wafer,
which  is then diced  into individual probe arrays.  Currently, each probe array
manufactured by the Company contains from 16,000 to more than 100,000  different
DNA probes.
 
    Genes  provide  the fundamental  basis  for understanding  human  health and
disease. Increased  knowledge  of  how  genes encode  the  functions  of  living
organisms  has generated  a worldwide effort  to identify and  sequence genes of
many organisms, including the estimated  100,000 genes within the human  genome.
This  effort is  being led  by the  Human Genome  Project and  related academic,
government and industry research  projects. Once the  genes and their  sequences
are identified, it is anticipated that many years of additional research will be
required  to  understand the  specific function  of  each gene  and its  role in
disease. Affymetrix believes that the GeneChip system can play an important role
in this research and  its application in drug  discovery and the development  of
new  diagnostic  products. The  Company  intends to  commercialize  the GeneChip
system in  two  principal areas:  genomics,  or the  study  of genes  and  their
function, and diagnostics.
 
   
    In  genomics,  Affymetrix  intends  to  sell  custom  DNA  probe  arrays  to
pharmaceutical and biotechnology companies through collaborative agreements. The
Company would receive revenues in the form of probe array design and development
fees, and subsequently through the sale of DNA probe arrays and instruments.  In
addition,  the  Company  may  receive  milestone  payments  and  royalties  from
discoveries made  through the  use  of the  DNA  probe arrays.  Affymetrix  also
intends  to  use  the  GeneChip  technology  to  help  create  and commercialize
databases containing information  on the  function of  genes and  their role  in
disease.  There  can be  no assurance  that  the Company  will be  successful in
marketing its GeneChip system for these genomics applications.
    
 
   
    In diagnostics, Affymetrix intends  to develop DNA  probe arrays to  analyze
genetic  information from patient  samples to improve the  accuracy and speed of
diagnosis. The Company is pursuing diagnostic products and research applications
in infectious  diseases,  cancer  and  other  areas,  such  as  monitoring  drug
metabolism.  The  Company intends  to  market its  diagnostic  GeneChip products
directly  and  through  collaborative  partnerships.  Affymetrix  believes   its
GeneChip  technology can  also be  used as a  discovery tool  for new diagnostic
markers to be used in conventional immunoassays. There can be no assurance  that
the  Company  will be  successful  in marketing  its  GeneChip system  for these
diagnostic applications.
    
 
    The  Company's  first  application  for  the  GeneChip  system  is  to  help
researchers  identify mutations in HIV that cause resistance to antiviral drugs,
such as AZT. The Company believes  that monitoring such mutations may become  an
important  aspect  of  managing  patients  with  AIDS.  As  of  March  31, 1996,
Affymetrix had placed five prototype GeneChip systems for the HIV application in
academic research centers and pharmaceutical companies for research use.
 
    An important part of  the Company's strategy is  to work with  collaborative
partners  to expand the applications of  the Company's technology and to acquire
access to complementary  technologies and  resources such  as manufacturing  and
marketing. Affymetrix has two agreements with Genetics Institute, Inc. ("GI") to
apply  the Company's technology  to understand the function  of human genes. The
Company will design, manufacture and supply custom probe arrays for use in  GI's
drug  discovery  programs. Affymetrix  also has  a collaborative  agreement with
Hewlett-Packard Company ("HP"), whereby HP will develop advanced instruments  to
read  the  GeneChip probe  arrays. In  addition, in  collaboration with  HP, the
Company will develop and manufacture certain probe arrays to be marketed by HP.
 
   
    Affymetrix  began  operations  in  1991  as  a  division  of  Affymax   N.V.
("Affymax"),  was incorporated in  California in March  1992 and began operating
independently as a wholly-owned  subsidiary of Affymax in  March 1993. In  March
1995,  Glaxo plc, now Glaxo Wellcome  plc ("Glaxo"), purchased Affymax. Prior to
this offering, Glaxo indirectly  owns approximately 46% of  the Common Stock  of
Affymetrix.
    
   
                                  RISK FACTORS
    
 
   
    An  investment in the shares of Common  Stock offered hereby involves a high
degree of risk. The Company's GeneChip system and other potential products  will
require  significant additional development and  investment. While the Company's
initial product sales for  research use have  not required regulatory  approval,
the  Company  expects  that  such  approval  will  be  required  for  diagnostic
applications in the  future. There  can be no  assurance that  the Company  will
obtain  any required  regulatory approval  for the  GeneChip system  or that the
GeneChip system will be successfully commercialized or obtain market acceptance.
Other  risk  factors   include  the  Company's   early  stage  of   development,
uncertainties  relating  to  technological  approaches,  history  of  losses and
expectation of future losses,  intense competition, rapid technological  change,
limited  manufacturing  capability and  sales and  marketing experience  and the
Company's dependence on proprietary technology. See "Risk Factors."
    
 
                                       4
<PAGE>
                                  THE OFFERING
 
   
<TABLE>
<S>                                             <C>
Common Stock Offered by the Company...........  5,000,000 shares
Common Stock Outstanding after the Offering...  21,239,231 shares (1)
Use of Proceeds...............................  For  research  and   development  (including   product
                                                development  and core  research), capital expenditures
                                                (manufacturing  scale-up,  facilities  and  laboratory
                                                equipment),  expansion of sales and marketing, working
                                                capital and other general corporate purposes. See "Use
                                                of Proceeds."
Proposed Nasdaq National Market Symbol........  AFFX
</TABLE>
    
 
                             SUMMARY FINANCIAL DATA
                     (in thousands, except per share data)
 
<TABLE>
<CAPTION>
                                                                                                   THREE MONTHS ENDED
                                                              YEAR ENDED DECEMBER 31,                  MARCH 31,
                                                    --------------------------------------------  --------------------
                                                     1991     1992     1993     1994      1995      1995       1996
                                                    -------  -------  -------  -------  --------  ---------  ---------
<S>                                                 <C>      <C>      <C>      <C>      <C>       <C>        <C>
STATEMENT OF OPERATIONS DATA:
Contract and grant revenue........................  $ --     $    43  $ 1,413  $ 1,574  $  4,625  $     854  $   1,416
Operating expenses:
    Research and development......................    1,576    4,106    6,566    9,483    12,420      2,274      4,177
    General and administrative....................      261      582      577    2,303     3,833        777      1,649
                                                    -------  -------  -------  -------  --------  ---------  ---------
      Total operating expenses....................    1,837    4,688    7,143   11,786    16,253      3,051      5,826
                                                    -------  -------  -------  -------  --------  ---------  ---------
Loss from operations..............................   (1,837)  (4,645)  (5,730) (10,212)  (11,628)    (2,197)    (4,410)
Interest income (expense), net....................    --         (15)     138      532       881         23        489
                                                    -------  -------  -------  -------  --------  ---------  ---------
Net loss..........................................  $(1,837) $(4,660) $(5,592) $(9,680) $(10,747) $  (2,174) $  (3,921)
                                                    -------  -------  -------  -------  --------  ---------  ---------
                                                    -------  -------  -------  -------  --------  ---------  ---------
Pro forma net loss per share......................                    $ (0.52) $ (0.55) $  (0.61) $   (0.12) $   (0.22)
                                                                      -------  -------  --------  ---------  ---------
                                                                      -------  -------  --------  ---------  ---------
Pro forma weighted average shares outstanding.....                     10,715   17,653    17,664     17,663     17,664
</TABLE>
 
<TABLE>
<CAPTION>
                                                                      MARCH 31, 1996
                                                                 ------------------------
                                                                                  AS
                                                                  ACTUAL      ADJUSTED (2)
                                                                 --------     -----------
<S>                                                              <C>          <C>
BALANCE SHEET DATA:
Cash, cash equivalents, and short-term investments............... $ 34,837    $ 89,837
Total assets.....................................................   41,185      96,185
Long-term obligation.............................................      898         898
Deficit accumulated during development stage.....................  (36,437)    (36,437)
Total shareholders' equity.......................................   34,652      89,652
</TABLE>
 
-------------
(1) Excludes  2,191,518  shares  of  Common  Stock  issuable  upon  exercise  of
    outstanding  options  under the  Company's  1993 Stock  Plan.  Also excludes
    203,881 shares  issuable upon  the exercise  of warrants  outstanding as  of
    March  31, 1996.  See "Management  -- Stock  Plans" and  Note 6  of Notes to
    Financial Statements.
 
(2) As adjusted to  reflect the  sale of the  5,000,000 shares  of Common  Stock
    offered by the Company hereby at an assumed initial public offering price of
    $12.00  per share and  the receipt of the  estimated net proceeds therefrom.
    See "Use of Proceeds."
 
    UNLESS OTHERWISE INDICATED, ALL INFORMATION CONTAINED IN THIS PROSPECTUS (I)
ASSUMES NO EXERCISE OF THE UNDERWRITERS' OVER-ALLOTMENT OPTION; (II) REFLECTS  A
2-FOR-3  REVERSE STOCK  SPLIT PRIOR  TO THE  EFFECTIVENESS OF  THIS REGISTRATION
STATEMENT; AND (III) GIVES EFFECT TO THE CONVERSION OF ALL OUTSTANDING SHARES OF
PREFERRED STOCK INTO COMMON STOCK UPON THE CLOSING OF THIS OFFERING.
 
                                       5
<PAGE>
                                  RISK FACTORS
 
    In  addition to the other information in this Prospectus, the following risk
factors should  be  considered  carefully  in evaluating  the  Company  and  its
business  before  purchasing shares  of the  Common  Stock offered  hereby. This
Prospectus  contains  forward-looking   statements  which   involve  risks   and
uncertainties.  The Company's actual results  could differ materially from those
anticipated in these forward-looking statements as a result of certain  factors,
including  those set forth in  the following risk factors  and elsewhere in this
Prospectus.
 
EARLY STAGE OF DEVELOPMENT
 
    The Company  is  at an  early  stage of  development.  The Company  has  not
commercialized  significant quantities of products based on its technologies. As
of March 31, 1996,  the Company had  placed only nine  GeneChip systems, all  of
which  have  been solely  for  research use  and only  five  of which  have been
purchased by customers. Substantially  all of the  Company's revenues have  been
derived from payments from collaborative research and development agreements and
government research grants.
 
    The  Company's  GeneChip system  and other  potential products  will require
significant additional development and investment, including testing to  further
validate  performance and  demonstrate cost  effectiveness. While  the Company's
initial product sales for  research use have  not required regulatory  approval,
the  Company expects  that such  approval will  be required  in the  future. The
Company may need to undertake costly  and time-consuming efforts to obtain  this
approval.  There  can be  no assurance  that any  products will  be successfully
developed, be  proven  to be  accurate  and  efficacious in  any  markets,  meet
applicable  regulatory standards in a timely manner or at all, be protected from
competition by others,  avoid infringing  the proprietary rights  of others,  be
manufactured  in sufficient  quantities or at  reasonable costs,  or be marketed
successfully.
 
    The Company has experienced significant operating losses since inception and
expects these losses to  continue for at least  the next several years.  Whether
the  Company  can  successfully  manage  the  transition  to  a commercial-scale
enterprise will  depend upon  a  number of  factors including  establishing  its
commercial  manufacturing  capability,  developing  its  marketing capabilities,
establishing a direct sales force  and entering into collaborative  arrangements
to  market its  products. Failure to  make such a  transition successfully would
have a material adverse  effect on the  Company's business, financial  condition
and  results  of  operations.  See  "Management's  Discussion  and  Analysis  of
Financial Condition and Results of Operations."
 
   
UNCERTAINTIES RELATING TO TECHNOLOGICAL APPROACHES; NEED FOR ADDITIONAL RESEARCH
AND DEVELOPMENT
    
 
    The Company  intends  to  develop  its  GeneChip  system  for  genomics  and
diagnostics applications. The GeneChip system involves several new technologies,
including  a complex  chemical synthesis process  necessary to  create DNA probe
arrays. In addition, technicians using the GeneChip system require new technical
skills and  training.  There can  be  no  assurance that  technicians  will  not
experience difficulties with the system that would prevent or limit its use. The
instrumentation  and software that comprise the GeneChip system are new and have
not been previously used in commercial  applications. As the system is used,  it
is  possible that previously unrecognized defects  will emerge. In addition, DNA
probe arrays are  tested only  on a random  sample basis,  and quality  problems
could  develop with the  untested arrays. Further,  in order for  the Company to
address new applications for the GeneChip system, the Company may be required to
reduce the size of its  probe arrays, increase the  number of features on  these
arrays,  develop  instruments capable  of processing  the information  from such
probe arrays, and design  software capable of  managing such information.  There
can  be no assurance that the Company will be capable of validating or achieving
the improvements in  the components  of the  GeneChip system  necessary for  its
successful  commercialization. The Company's GeneChip  technology will also need
to  compete  against  well-established  techniques  and  enhancements  to   such
techniques  for analyzing genes  and for diagnostics. There  can be no assurance
that the GeneChip system will  replace or compete successfully against  existing
techniques  and instruments.  Furthermore, there  can be  no assurance  that the
Company's GeneChip technology  will be  useful in providing  information on  the
function of genes or for the analysis of larger sequences of genes.
 
    The  development  of  diagnostic  and  therapeutic  products  based  on  the
Company's technologies will be subject to  the risks of failure inherent in  the
development   of  products  based  on  new  technologies.  These  risks  include
possibilities that any products based on these technologies will be found to  be
ineffective, unreliable or
 
                                       6
<PAGE>
unsafe,  or  otherwise fail  to  receive necessary  regulatory  clearances; that
products will  be  difficult  to  manufacture  on  a  large  scale  or  will  be
uneconomical  to market; that proprietary rights  of third parties will preclude
the Company or its collaborative partners from marketing products; or that third
parties will market superior or  equivalent products. Furthermore, there can  be
no  assurance that the Company's research and development activities will result
in any commercially viable products. See "Business -- Technology."
 
UNCERTAINTY OF MARKET ACCEPTANCE
 
    The commercial success  of the  Company's GeneChip system  will depend  upon
market acceptance by academic research centers, pharmaceutical and biotechnology
companies  and  reference laboratories.  Market acceptance  will depend  on many
factors, including  convincing  researchers  that  the  GeneChip  system  is  an
attractive alternative to current technologies for the acquisition, analysis and
management  of genetic information; the receipt  of regulatory clearances in the
United States, Europe, Japan and elsewhere; the need for laboratories to license
other technologies, such as amplification  technologies that may be required  to
use  the GeneChip system  for certain applications; and  the availability of new
proprietary markers  that may  be  important to  the diagnosis,  monitoring  and
treatment  of disease  for incorporation on  the Company's  probe arrays. Market
acceptance may be adversely affected by ethical concerns that may limit the  use
of  the GeneChip system  for certain diagnostic applications  or the analysis of
genetic  information.  In  addition,  potential  customers  will  need   skilled
laboratory  technicians to operate the GeneChip system. Market acceptance of the
GeneChip system could also  be adversely affected  by limited funding  available
for  academic research  centers and  other research  organizations that  are the
potential customers for the GeneChip system.
 
    Potential customers  of  the  GeneChip  system  will  need  to  acquire  the
Company's  fluidics station and probe array scanner  in order to utilize the DNA
probe arrays.  The cost  of  this instrumentation  may deter  certain  potential
customers  from purchasing probe arrays. The Company may be required to discount
the price of its GeneChip  system in order to  place the system with  customers.
The failure of the Company to place sufficient quantities of the instruments for
the  GeneChip system would have a material adverse effect on its ability to sell
the disposable probe arrays.  There can be no  assurance that academic  research
centers,  pharmaceutical  or biotechnology  companies or  reference laboratories
will replace existing instrumentation and  techniques with the GeneChip  system.
Because of these and other factors, there can be no assurance that the Company's
products will gain market acceptance.
 
    The  Company  expects that  its customers  will be  concentrated in  a small
number of academic research centers, pharmaceutical and biotechnology  companies
and reference laboratories. As a result, the Company's financial performance may
depend  on large orders from a limited number of customers. There are only three
major reference laboratories in the United  States, two of which are  associated
with  large pharmaceutical companies. There can be no assurance that the Company
will  be  able  to  successfully   market  the  GeneChip  system  to   reference
laboratories  or that the affiliation  of these laboratories with pharmaceutical
companies will not adversely affect their decision to purchase GeneChip systems.
The Company's dependence on sales to a few large reference laboratories may also
strengthen the purchasing  leverage of  these potential  customers, which  could
reduce  the sales price of the GeneChip  system. Also, the Company believes that
the sales cycle  for the  GeneChip system  will be lengthy  due to  the need  to
educate  potential  customers  about  its characteristics.  The  failure  of the
Company to gain additional customers, the loss of any customer or a  significant
reduction  in the level of  sales to any customer  would have a material adverse
effect on the Company's business, financial condition and results of operations.
See "Business -- Business Strategy" and "-- Sales and Marketing."
 
UNCERTAINTIES RELATED TO THE HIV PROBE ARRAY
 
    The first commercial application of the Company's GeneChip system is an  HIV
probe array designed to detect mutations in HIV, the virus that causes AIDS. The
HIV probe array provides sequence information from the reverse transcriptase and
protease  genes of HIV and the system includes a fluidics station, a scanner and
related software. In April 1996, the Company introduced the HIV probe array  for
research  purposes only. The  Company has placed  only five HIV  probe arrays at
customer sites to date,  all in the  United States. These  systems have been  in
operation  for only a  limited period of  time, and their  accuracy and efficacy
have not been fully demonstrated. There are other uncertainties relating to  the
system,  including that  the Company  has no  prior experience  in introducing a
commercial product, that technicians may encounter difficulties with the  system
that would prevent
 
                                       7
<PAGE>
or limit its use, and that the Company will rely on third parties to manufacture
and  service its  instruments. Furthermore, there  can be no  assurance that the
accuracy of the HIV probe array in providing sequence information from HIV  will
be better than current technologies, such as gel-based sequencing techniques.
 
    As  new  therapies  and  combinations  of  therapies  for  treating  HIV are
employed, new mutations in the HIV  genome may be discovered that would  require
the  Company to redesign  its current probe  array or develop  new probe arrays.
Advanced therapies could be discovered that target other components of the virus
or which  do  not  generate  drug  resistance.  In  addition,  cost  containment
pressures  for treating HIV patients may limit the price the Company may be able
to charge potential customers for its HIV probe array. There can be no assurance
that  the  HIV  probe  array  will  provide  useful  diagnostic  and  monitoring
information,  that it will  operate without difficulties,  that technicians will
have adequate  training  to  use  the  system, or  that  the  Company  will  not
experience  manufacturing or marketing difficulties  selling the HIV probe array
to academic  research centers,  pharmaceutical and  biotechnology companies  and
reference  laboratories. Furthermore,  there can  be no  assurance that  the HIV
probe array  will  gain regulatory  approval  for clinical  use.  The  Company's
product  revenues in the  near term are dependent  upon the commercialization of
the HIV probe  array. There  can be  no assurance  that these  revenues will  be
realized  in the near  term, or at  all. Failure of  the Company to successfully
commercialize the HIV probe  array could have a  material adverse effect on  the
Company's  business,  financial condition  and  results of  operations,  and may
adversely affect the Company's ability  to commercialize any future products  it
may develop. See "Business -- Business Strategy" and "-- Sales and Marketing."
 
   
HISTORY OF LOSSES AND EXPECTATION OF FUTURE LOSSES
    
 
    The  Company has incurred operating losses in each year since its inception,
including net  losses  of approximately  $10.7  million during  the  year  ended
December  31,  1995, and,  at March  31,  1996, the  Company had  an accumulated
deficit of  approximately  $36.4 million.  The  Company's losses  have  resulted
principally from costs incurred in research and development and from general and
administrative  costs associated with the Company's operations. These costs have
exceeded the Company's interest  income and revenues which,  to date, have  been
generated principally from collaborative research and development agreements and
government  research grants. The Company expects to incur substantial additional
operating losses over the  next several years  as a result  of increases in  its
expenses for research and product development, manufacturing scale-up, expanding
sales  and marketing and capital  expenditures. See "Management's Discussion and
Analysis of Financial Condition and Results of Operations."
 
PROFITABILITY UNCERTAIN
 
    The Company has experienced substantial operating losses and has never  been
profitable.  The Company expects that  it may have to  discount the price of the
GeneChip system to gain  market acceptance, which  could adversely affect  gross
margins. The Company's future gross margins, if any, will be dependent on, among
other  factors,  the  Company's  ability  to  cost-effectively  manufacture  the
GeneChip system,  product mix  and the  degree of  price discounts  required  to
market   its  products   to  academic   research  centers,   pharmaceutical  and
biotechnology  companies  and  reference  laboratories.  The  amount  of  future
operating  losses and  time required by  the Company to  reach profitability, if
ever, are  highly  uncertain.  The Company's  ability  to  generate  significant
revenues  and become profitable is dependent in large part on the ability of the
Company to enter into additional  collaborative arrangements and on the  ability
of  the  Company and  its collaborative  partners to  successfully commercialize
products developed under the collaborations.  In addition, delays in receipt  of
any  necessary  regulatory approvals  by the  Company  or its  collaborators, or
receipt of  approvals  by competitors,  could  adversely affect  the  successful
commercialization  of the Company's technologies. There can be no assurance that
the Company will successfully commercialize any product or that the Company will
achieve product  revenues or  profitability.  See "Management's  Discussion  and
Analysis of Financial Condition and Results of Operations."
 
FLUCTUATIONS IN OPERATING RESULTS
 
    The  Company's quarterly operating  results will depend  upon the volume and
timing of orders for  GeneChip systems and probe  arrays received and  delivered
during  the  quarter,  variations in  payments  under  collaborative agreements,
including milestones, royalties, license fees, and other contract revenues,  and
the  timing of new product introductions by the Company. The Company's quarterly
operating results may also fluctuate  significantly depending on other  factors,
including    the    introduction   of    new    products   by    the   Company's
 
                                       8
<PAGE>
competitors; regulatory actions;  market acceptance of  the GeneChip system  and
other   potential   products;  adoption   of  new   technologies;  manufacturing
capabilities;  variations   in  gross   margins  of   the  Company's   products;
competition;  the cost, quality and availability of reagents and components; the
mix  of  products   sold;  changes  in   government  funding;  and   third-party
reimbursement  policies. See "Management's Discussion  and Analysis of Financial
Condition and Results of Operations."
 
INTENSE COMPETITION; RAPID TECHNOLOGICAL CHANGE
 
    Competition in genomics and diagnostics is intense and expected to increase.
Further, the  technologies for  discovering  genes associated  with  significant
diseases  and  approaches  for  commercializing those  discoveries  are  new and
rapidly evolving.
 
    Currently,  the  Company's   principal  competition   comes  from   existing
technologies  that are used to perform many  of the same functions for which the
Company plans to  market its GeneChip  systems. In the  diagnostic field,  these
technologies  are provided by  established diagnostic companies,  such as Abbott
Laboratories,  Boehringer  Mannheim  GmbH,  Hoffmann-LaRoche,  Inc.   ("Roche"),
Johnson  &  Johnson and  SmithKline Beecham  plc.  These technologies  include a
variety of  established  assays,  such  as  immunoassays,  histochemistry,  flow
cytometry  and  culture,  and newer  DNA  probe diagnostics  to  analyze certain
amounts of genetic information. In the genomics field, competitive  technologies
include gel-based sequencing using instruments provided by companies such as the
Applied  Biosystems division of Perkin Elmer  and Pharmacia Biotech AB. In order
to compete against existing technologies,  the Company will need to  demonstrate
to  potential customers that  the GeneChip system  provides improved performance
and capabilities.
 
    The market for diagnostic products derived from gene discovery is  currently
limited  and  will  be highly  competitive.  Many companies  are  developing and
marketing DNA probe tests  for genetic and other  diseases. Other companies  are
conducting  research on new technologies for  diagnostic tests based on advances
in  genetic  information.   Established  diagnostic   companies  could   provide
significant  competition to Affymetrix through  the development of new products.
These companies have the strategic commitment to diagnostics, the financial  and
other resources to invest in new technologies, substantial intellectual property
portfolios,  substantial  experience  in  new  product  development,  regulatory
expertise, manufacturing capabilities and  the distribution channels to  deliver
products   to  customers.  These  companies  also  have  an  installed  base  of
instruments in several markets,  including clinical and reference  laboratories,
which  are not compatible with the GeneChip system. In addition, these companies
have formed  alliances with  genomics  companies which  provide them  access  to
genetic information that may be incorporated into their diagnostic tests.
 
    In  the genomics  field, future competition  will likely  come from existing
competitors as well as other companies  seeking to develop new technologies  for
sequencing  and analyzing  genetic information. In  addition, pharmaceutical and
biotechnology companies, such as  Genome Therapeutics Corporation, Human  Genome
Sciences,    Inc.,   Incyte   Pharmaceuticals,   Inc.   ("Incyte"),   Millennium
Pharmaceuticals, Inc., Myriad Genetics, Inc. and Sequana Therapeutics, Inc. have
significant needs for genomic information and  may choose to develop or  acquire
competing technologies to meet these needs.
 
    Genomics  and  diagnostic technologies  have undergone  and are  expected to
continue to undergo rapid and  significant change. The Company's future  success
will depend in large part on its ability to maintain a competitive position with
respect to these technologies. Rapid technological development by the Company or
others  may result in  products or technologies  becoming obsolete. In addition,
products offered by the Company would be made obsolete by less expensive or more
effective  tests  based  on  other   technologies  or  by  new  therapeutic   or
prophylactic  agents  that  obviate  the  need  for  diagnostic  and  monitoring
information. There is no  assurance that the  Company will be  able to make  the
enhancements  to  its technology  necessary to  compete successfully  with newly
emerging technologies.  See  "Business  -- Research  and  Development"  and  "--
Competition."
 
                                       9
<PAGE>
DEPENDENCE UPON COLLABORATIVE PARTNERS
 
    An   important  element   of  the   Company's  business   strategy  involves
collaborations with pharmaceutical, diagnostic and biotechnology companies  that
have discovered genes and may seek to use the Company's technologies to discover
genetic  mutations or develop  diagnostic and therapeutic  products. The Company
has significant collaborations with HP and GI.
 
   
    In November 1994, the Company entered into a collaborative agreement with HP
to develop an advanced scanner  for use with the  GeneChip probe arrays. The  HP
scanner  is currently under development and, in 1997 the Company expects that HP
will be the sole source of its scanners. Accordingly, if the HP scanner does not
become available on a  timely basis or  fails to meet  its performance and  cost
specifications,  it  would  have  a material  adverse  effect  on  the Company's
business.
    
 
    The Company has  two agreements with  GI, dated November  1994 and  December
1995, relating to use of GeneChip technology to measure gene expression in order
for GI to develop new therapeutic proteins. If GI is not successful in using the
GeneChip  technology  or  if  the  Company  fails  to  maintain  a  satisfactory
relationship with  GI,  the Company  could  lose significant  revenues  and  its
ability  to  obtain  additional  collaborations with  other  companies  would be
impaired.
 
    The Company  has  received  a  substantial portion  of  its  revenues  since
inception   from  its   collaborative  partners   and  intends   to  enter  into
collaborative arrangements with  other companies to  apply its technology,  fund
development,  commercialize potential  future products, and  assist in obtaining
regulatory approval. There can be no assurance that any of the Company's present
or future collaborative partners will  perform their obligations as expected  or
will  devote  sufficient  resources  to  the  development,  clinical  testing or
marketing  of   the   Company's   potential   products   developed   under   the
collaborations.   Any  parallel   development  by   a  partner   of  alternative
technologies or components  of the  GeneChip system, preclusion  of the  Company
from entering into competitive arrangements, failure to obtain timely regulatory
approvals,  premature termination  of an agreement,  or failure by  a partner to
devote sufficient  resources to  the development  and commercialization  of  the
Company's  products  could  have  a material  adverse  effect  on  the Company's
business, financial condition and results of operations.
 
    The Company's  agreements with  consultants and  collaborators are  complex.
There  may  be provisions  within such  agreements which  give rise  to disputes
regarding the rights and  obligations of the parties.  These and other  possible
disagreements  could lead  to delays  in collaborative  research, development or
commercialization of certain products, or could require or result in  litigation
or  arbitration, which would  be time-consuming and expensive,  and could have a
material adverse  effect  on the  Company's  business, financial  condition  and
results of operations.
 
    There  can be no assurance that the Company will be able to negotiate future
collaborative arrangements  on  acceptable  terms,  if  at  all,  or  that  such
collaborations will be successful. See "Business -- Collaborative Agreements and
Grants."
 
NEED FOR ADDITIONAL FUNDING; UNCERTAINTY OF ACCESS TO CAPITAL
 
   
    The  Company anticipates that its  existing capital resources, together with
the net proceeds of this offering and interest earned thereon, will enable it to
maintain currently  planned  operations through  at  least 1998.  However,  this
expectation is based on the Company's current operating plan, which could change
as  a result of many  factors, and the Company  could require additional funding
sooner than anticipated. In addition, the Company may choose to raise additional
capital due to  market conditions  or strategic  considerations even  if it  has
sufficient  funds  for  its  operating  plan.  The  Company's  requirements  for
additional capital  will  be  substantial  and  will  depend  on  many  factors,
including  payments received  under existing  and possible  future collaborative
agreements; the availability of government research grant payments; the progress
of  the  Company's  collaborative  and  independent  research  and   development
projects;  the  costs  of  preclinical and  clinical  trials  for  the Company's
products; the prosecution, defense  and enforcement of  patent claims and  other
intellectual  property rights;  and development of  manufacturing, marketing and
sales capabilities.  The  Company has  no  credit facility  or  other  committed
sources  of capital.  To the extent  capital resources are  insufficient to meet
future capital requirements, the Company will have to raise additional funds  to
continue  the development  of its technologies.  There can be  no assurance that
such funds will be available on favorable  terms, or at all. To the extent  that
    
 
                                       10
<PAGE>
additional  capital is  raised through  the sale  of equity  or convertible debt
securities, the issuance  of such  securities could  result in  dilution to  the
Company's  shareholders. If adequate funds are not available, the Company may be
required to curtail operations significantly or to obtain funds through entering
into collaboration agreements on unattractive terms. The Company's inability  to
raise  capital would have a material effect on the Company's business, financial
condition and results of operations. See "Use of Proceeds."
 
ETHICAL, LEGAL AND SOCIAL IMPLICATIONS OF GENETIC PREDISPOSITION TESTING
 
    The Company's success  will depend  in part  upon the  Company's ability  to
develop  genetic tests for  genes discovered by the  Company and others. Genetic
tests, such as  certain of  the Company's GeneChip  tests, may  be difficult  to
perform  and interpret and may lead  to misinformation or misdiagnosis. Further,
even when  a  genetic  test  identifies  the  existence  of  a  mutation  in  an
individual,   the  interpretation  of  the  result   is  often  limited  to  the
identification of  a statistical  probability that  the tested  individual  will
develop  the disease or condition for which  the test is performed. In addition,
once available, such tests may be  subject to ethical concerns or reluctance  to
administer  or pay for tests for conditions  that are not treatable. Further, it
is possible that gene-based diagnostic  tests marketed by other companies  could
encounter specific difficulties, resulting in societal and governmental concerns
regarding genetic testing.
 
    The  prospect of broadly available genetic predisposition testing has raised
issues  regarding  the  appropriate  utilization  and  the  confidentiality   of
information  provided by  such testing.  It is  possible that  discrimination by
insurance companies could occur through the  raising of premiums by insurers  to
prohibitive  levels,  outright  cancellation of  insurance  or  unwillingness to
provide coverage  to  patients shown  to  have  a genetic  predisposition  to  a
particular  disease. In addition, employers could discriminate against employees
with a positive  genetic predisposition due  to the increased  risk for  disease
resulting  in possible cost increases for health insurance and the potential for
lost employment time.  Finally, governmental  authorities could,  for social  or
other purposes, limit the use of genetic testing or prohibit testing for genetic
predisposition to certain conditions which could adversely affect the use of the
Company's  products.  There  can be  no  assurance that  ethical  concerns about
genetic testing will not  materially adversely affect  market acceptance of  the
Company's GeneChip system. See "Business -- Government Regulation."
 
LIMITED MANUFACTURING CAPABILITY; SOLE SOURCE SUPPLIERS
 
    The  Company has  limited experience  manufacturing products  for commercial
purposes. To date,  the Company  has a  small scale  facility providing  limited
quantities  of probe arrays for internal  and collaborative purposes and initial
sales of the GeneChip system to  the research market. To achieve the  production
levels  of  probe  arrays  necessary  for  successful  commercialization  of its
products, the Company  will need  to scale-up its  manufacturing facilities  and
establish  automated manufacturing  capabilities. The  Company may  also need to
comply with the current good  manufacturing practices ("GMP") prescribed by  the
United  States Food and Drug Administration ("FDA")  for sale of products in the
United States, ISO standards for  sale of products in  Europe, as well as  other
standards  prescribed by various federal, state and local regulatory agencies in
the United States and other countries.  Although the Company does not  currently
need  to comply with GMP to manufacture probe arrays and related instrumentation
for sale for research purposes,  it may need to be  GMP compliant to sell  these
products to clinical reference laboratories, and it will need to be compliant to
sell   these  products  for  clinical  use.  There  can  be  no  assurance  that
manufacturing and  quality  control  problems  will not  arise  as  the  Company
attempts  to scale-up its manufacturing facilities  or that such scale-up can be
achieved in a timely manner or at commercially reasonable costs.
 
    The Company's probe array  manufacturing process is  complex and involves  a
number  of technologies that have never  before been combined in the manufacture
of a single  product. The  Company tests only  selected probe  arrays from  each
wafer  and only selected  probes on each  probe array. It  is therefore possible
that defective probe arrays might not be identified before they are shipped. The
Company therefore relies  on quality control  procedures, including controls  on
the  manufacturing process and sample testing,  to verify the correct completion
of the manufacturing process. In addition,  there may be certain aspects of  the
Company's  manufacturing that  are not  fully understood  and cannot  be readily
replicated for commercial  use. If the  Company is unable  to manufacture  probe
arrays  on  a timely  basis because  of  these or  other factors,  its business,
financial condition and results of operations could be adversely affected.
 
                                       11
<PAGE>
    As the  Company's  technologies  evolve, new  manufacturing  techniques  and
systems  will be required. For example,  it is anticipated that batch processing
systems will be needed  to meet the Company's  future probe array  manufacturing
needs.   Further,  as  products  requiring   increased  density  are  developed,
miniaturization of the features on the  arrays will be necessary, requiring  new
or  modified  manufacturing  equipment  and  processes.  Further,  the Company's
manufacturing equipment  requires significant  capital investment.  The  Company
will  rely  on a  single manufacturing  facility  for its  probe arrays  for the
foreseeable future. This manufacturing facility is subject to natural  disasters
such  as earthquakes and floods. The former are of particular significance since
the manufacturing facility is located in an earthquake prone area. In the  event
that  its manufacturing  facility were to  be affected by  accidental or natural
disasters, the Company would  be unable to manufacture  products for sale  until
the facility was replaced or restored to operation.
 
    Certain  key parts of the GeneChip system,  such as the probe array scanner,
the fluidics station, and certain reagents, are currently available only from  a
single  source or a few  sources. The Company currently  obtains the scanner for
its GeneChip probe arrays from Molecular Dynamics, Inc. ("Molecular  Dynamics").
The  Company is dependent on Molecular  Dynamics for quality testing and service
of this instrument. The Company has entered into an agreement with HP to  supply
a new scanner for the GeneChip system, which the Company expects to be available
for  commercialization in 1997.  The Company's ability  to commercialize a probe
array with more  features is  dependent upon  successful development  of the  HP
scanner. The Company has contracted with RELA, Inc. ("RELA"), a private company,
to supply the fluidics station that is part of the GeneChip system. The fluidics
stations of the nine GeneChip systems placed to date are prototypes manufactured
by  the Company and not  supplied by RELA. No assurance  can be given that probe
array scanners, fluidics stations  or reagents will  be available in  commercial
quantities  at acceptable costs. If the  Company is required to seek alternative
sources of supply, it  could be time consuming  and expensive. In addition,  the
Company is dependent on its vendors to provide components of appropriate quality
and reliability and to meet applicable regulatory requirements. Consequently, in
the event that supplies from these suppliers were delayed or interrupted for any
reason,  the  Company's ability  to  develop and  supply  its products  could be
impaired, which could have a material adverse effect on the Company's  business,
financial condition and results of operations.
 
    The  GeneChip system is a complex set  of instruments and includes DNA probe
arrays, which  are  produced  in an  innovative  and  complicated  manufacturing
process. During the beta testing phase of the GeneChip system's development, the
Company  and its  vendors have encountered  and addressed a  number of technical
problems, including software failures, improper alignment of probe array wafers,
valve and  tube failures  in  the fluidics  station,  sensor wiring  issues  and
scanner control problems. Due to the complexity and lack of operating history of
these  products, the Company anticipates  that additional technical problems may
occur or  be discovered  as more  systems are  placed into  operation. If  these
problems  cannot be  readily addressed,  they could  cause delays  in shipments,
warranty expenses  and damages  to customer  relationships, which  would have  a
material  adverse  effect on  the  Company's business,  financial  condition and
results of operations. See "Business -- Manufacturing."
 
LIMITED SALES AND MARKETING EXPERIENCE
 
    The Company  does  not  have a  direct  sales  force and  has  only  limited
experience  in sales and marketing. As of March 31, 1996, the Company had placed
nine GeneChip systems, of  which only five  had been sold.  The Company has  not
placed  any  of its  GeneChip  systems outside  the  United States.  The Company
intends to market its products to academic research centers, pharmaceutical  and
biotechnology  companies  and  reference laboratories.  The  Company  intends to
market diagnostic tests through a direct sales force to its potential  customers
for  research use only.  The Company intends  to market the  GeneChip system for
genomic   applications   through   collaborations   with   pharmaceutical    and
biotechnology  companies. The Company  anticipates a long  sales cycle to market
the GeneChip system to its potential customers. The Company will be required  to
enter  into  collaboration  or distribution  arrangements  to  commercialize its
products outside the United States. There  can be no assurance that the  Company
will  be able to establish a direct sales force or to establish collaborative or
distribution arrangements to market its products. Failure to do so would have  a
material  adverse  effect on  the  Company's business,  financial  condition and
results of operations. See "Business -- Sales and Marketing."
 
UNCERTAINTIES RELATED TO GOVERNMENT FUNDING
 
    A significant portion of the Company's products for research use are  likely
to   be  sold   to  universities,  government   research  laboratories,  private
foundations  and   other   institutions   where  funding   is   dependent   upon
 
                                       12
<PAGE>
grants  from  government  agencies such  as  the National  Institutes  of Health
("NIH"). Research  funding  by the  government,  however, may  be  significantly
reduced  under several  budget proposals  being discussed  by the  United States
Congress. Any such reduction may materially affect the ability of the  Company's
prospective  research customers to purchase  the Company's products for research
use.
 
    The Company  has received  and expects  to continue  to receive  significant
funds  under various United States  Government research and technology programs.
While the programs are generally multi-year awards, they are subject to a yearly
appropriations process in the United States Congress. Proposed legislation being
debated in the  United States  Congress would  eliminate or  reduce the  program
under which the Company's Advanced Technology Program ("ATP") grant is funded by
the  Department of  Commerce. There  can be no  assurance that  the Company will
receive the entire  $20.8 million  of funding designated  for it  under the  ATP
grant,  and termination of the ATP grant could have a material adverse effect on
the Company's business, financial condition and results of operations.
 
    The Company's grants from the Departments of Commerce and Energy and the NIH
give the  government  certain rights  to  license  for its  own  use  inventions
resulting  from  funded  work. There  can  be  no assurance  that  the Company's
proprietary position  will  not  be adversely  affected  should  the  government
exercise these rights. See "Business -- Collaborative Agreements and Grants."
 
UNCERTAINTIES RELATED TO THIRD-PARTY REIMBURSEMENT
 
    The  Company's ability to successfully commercialize its products may depend
on the Company's ability to obtain adequate levels of third-party  reimbursement
for  use of  certain diagnostic  tests in  the United  States, Europe  and other
countries. Currently, availability of  third-party reimbursement is limited  and
uncertain for genetic tests.
 
    In  the United States,  the cost of  medical care is  funded, in substantial
part, by  government insurance  programs,  such as  Medicare and  Medicaid,  and
private  and  corporate  health  insurance plans.  Third-party  payors  may deny
reimbursement if they determine that a prescribed device or diagnostic test  has
not received appropriate FDA or other governmental regulatory clearances, is not
used  in accordance with  cost-effective treatment methods  as determined by the
payor, or is experimental, unnecessary  or inappropriate. The Company's  ability
to  commercialize certain of its products  successfully may depend on the extent
to which appropriate  reimbursement levels for  the costs of  such products  and
related  treatment  are  obtained from  government  authorities,  private health
insurers and  other  organizations,  such as  health  maintenance  organizations
("HMOs"). Third-party payors are increasingly challenging the prices charged for
medical  products and  services. The  trend towards  managed health  care in the
United States and  the concurrent growth  of organizations such  as HMOs,  which
could  control or significantly  influence the purchase  of health care services
and products, as well as legislative  proposals to reform health care or  reduce
government insurance programs, may all result in lower prices for certain of the
Company's products. The cost containment measures that health care providers are
instituting  and the  results of  any health care  reform could  have an adverse
effect on the Company's ability to sell  certain of its products and may have  a
material  adverse  effect on  the  Company's business,  financial  condition and
results of operations.
 
GOVERNMENT REGULATION; NO ASSURANCE OF REGULATORY APPROVAL
 
    The  Company  anticipates  the  manufacturing,  labeling,  distribution  and
marketing of some or all of the Company's diagnostic products will be subject to
regulation in the United States and in certain other countries.
 
    In the United States, the FDA regulates, as medical devices, most diagnostic
tests  and  IN  VITRO  reagents  that are  marketed  as  finished  test  kits or
equipment. Some  clinical laboratories,  however, purchase  individual  reagents
intended  for  specific analytes,  and develop  and  prepare their  own finished
diagnostic tests.  Although  the  FDA has  not  generally  exercised  regulatory
authority  over these  individual reagents or  the finished  tests prepared from
them by the clinical laboratories. The FDA has recently proposed a rule that, if
adopted, would regulate the  reagents sold to  clinical laboratories as  medical
devices.  The  proposed rule  would  also restrict  sales  of these  reagents to
clinical laboratories certified under Clinical Laboratory Improvement Amendments
of 1988 ("CLIA") as high complexity testing laboratories. The Company intends to
market some diagnostic products as finished test kits or equipment and others as
individual reagents;  consequently,  some  or  all of  these  products  will  be
regulated as medical devices.
 
                                       13
<PAGE>
    Medical  devices  generally  require  FDA  approval  or  clearance  prior to
marketing in  the United  States. The  process of  obtaining FDA  clearances  or
approvals  necessary to market medical  devices can be time-consuming, expensive
and uncertain, and  there can  be no assurance  that any  clearance or  approval
sought  by  the Company  will be  granted or  that FDA  review will  not involve
delays, adversely affecting the  marketing and sale  of the Company's  products.
Further,  clearance  or  approval  may  place  substantial  restrictions  on the
indications for which the product may be marketed or to whom it may be marketed.
Additionally, there can  be no assurance  that FDA will  not request  additional
data or request that the Company conduct further clinical studies.
 
    If  approval  or  clearance is  obtained,  the  Company will  be  subject to
continuing FDA obligations. When manufacturing medical devices, the Company will
be required to adhere  to regulations setting forth  current GMP, which  require
that  the  Company  manufacture  its  products and  maintain  its  records  in a
prescribed manner with  respect to  manufacturing, testing  and quality  control
activities.  In addition, among other requirements, the Company will be required
to comply  with FDA  requirements  for labeling  and  promotion of  its  medical
devices.  Further, if the Company wanted to  make changes on a product after FDA
clearance or approval, including changes in indications or intended use or other
significant  modifications  to  labeling,   manufacturing  or  product   design,
additional clearances or approvals would be required from the FDA.
 
    Failure  to obtain required  regulatory approval or  clearance or failure to
obtain timely approval or clearance, or the imposition of stringent labeling  or
sales  restrictions on  the Company's  products, could  have a  material adverse
effect on the Company. In addition, failure to comply with applicable regulatory
requirements could subject the Company to enforcement action, including  product
seizures,  recalls, withdrawal  of clearances  or approvals,  restrictions on or
injunctions against marketing  the Company's  products, and  civil and  criminal
penalties,  any one or more of which could have a material adverse effect on the
Company.
 
    Medical device laws  and regulations are  also in effect  in many  countries
outside  the  United  States.  These range  from  comprehensive  device approval
requirements for  some  or all  of  the  Company's medical  device  products  to
requests  for  product data  or certifications.  The number  and scope  of these
requirements are increasing. Failure to comply with applicable state and foreign
medical device laws and  regulations may have a  material adverse effect on  the
Company's business, financial condition and results of operations.
 
    The  Company is also  subject to numerous environmental  and safety laws and
regulations, including  those  governing  the  use  and  disposal  of  hazardous
materials.  Any violation of, and the cost of compliance with, these regulations
could adversely affect  the Company's  operations. See  "Business --  Government
Regulation."
 
DEPENDENCE ON PROPRIETARY TECHNOLOGY AND UNPREDICTABILITY OF PATENT PROTECTION
 
   
    As  of April  15, 1996, Affymetrix  had exclusive licenses  from Affymax for
over 20 patents  and patent  applications in the  United States  related to  its
business in the fields of clinical diagnostics and research supply. In addition,
Affymetrix  is  the assignee  of 52  United States  patent applications  and one
issued patent in the United States. Many of these patents and applications  have
been  filed  and/or issued  in one  or more  foreign countries.  Affymetrix also
relies upon  those  patents,  copyright  protection,  trade  secrets,  know-how,
continuing  technological innovation and licensing  opportunities to develop and
maintain its competitive position. The Company's success will depend in part  on
its  ability  to obtain  patent protection  for its  products and  processes, to
preserve its copyright and trade secrets  and to operate without infringing  the
proprietary rights of third parties.
    
 
    The  Company  is  party  to  various  license  option  agreements (including
agreements with Affymax, Stanford University  and the University of  California)
which  give it  rights to  use certain technologies.  Failure of  the Company to
maintain rights to such technology could  have a material adverse effect on  the
Company's  business, financial condition and results of operations. For example,
inability of the  Company to  exercise the  option for  the Stanford  technology
under  commercially reasonable terms could have an adverse effect on the ability
of the Company to sell certain of its products.
 
    The patent positions of pharmaceutical, biopharmaceutical and  biotechnology
companies,  including the Company,  are generally uncertain  and involve complex
legal and factual questions. There can be no assurance that any of the Company's
pending patent applications will result in issued patents, that the Company will
develop additional  proprietary  technologies  that  are  patentable,  that  any
patents issued to the Company or its strategic partners will provide a basis for
commercially  viable products or  will provide the  Company with any competitive
advantages or will not be  challenged by third parties,  or that the patents  of
others will not have an
 
                                       14
<PAGE>
adverse effect on the ability of the Company to do business. In addition, patent
law  relating  to the  scope of  claims in  the technology  fields in  which the
Company operates is  still evolving.  The degree  of future  protection for  the
Company's proprietary rights, therefore, is uncertain. Furthermore, there can be
no  assurance that others will not  independently develop similar or alternative
technologies, duplicate any of  the Company's technologies,  or, if patents  are
issued  to the Company, design around the patented technologies developed by the
Company. In addition, the Company could incur substantial costs in litigation if
it is required to defend itself in  patent suits brought by third parties or  if
it initiates such suits.
 
    Others  may  have  filed  and  in  the  future  are  likely  to  file patent
applications that are similar or identical to those of the Company. To determine
the priority of inventions, the Company may have to participate in  interference
proceedings declared by the United States Patent and Trademark Office that could
result  in substantial cost to  the Company. No assurance  can be given that any
such patent application will not have priority over patent applications filed by
the Company.
 
    The commercial success of  the Company also depends  in part on the  Company
neither  infringing patents or proprietary rights of third parties nor breaching
any licenses that  may relate to  the Company's technologies  and products.  For
example,  the Company,  its collaborators  and customers  may need  to acquire a
license for an amplification technology to use the GeneChip system, and there is
no assurance such a license will be available on commercially reasonable  terms.
The  Company is aware  of third-party patents  that may relate  to the Company's
technology, including reagents used in probe array synthesis and in probe  array
assays,    probe   array   scanners,   synthesis   techniques,   oligonucleotide
amplification techniques, assays, and  probe arrays. There  can be no  assurance
that  the Company will not infringe  these patents, other patents or proprietary
rights of third parties. In  addition, the Company has  received and may in  the
future  receive  notices claiming  infringement from  third  parties as  well as
invitations to take licenses under third party patents. Any legal action against
the Company or its collaborative partners claiming damages and seeking to enjoin
commercial activities relating to the affected products and processes could,  in
addition  to subjecting the Company to  potential liability for damages, require
the Company  or  its collaborative  partner  to obtain  a  license in  order  to
continue to manufacture or market the affected products and processes. There can
be  no assurance that the Company or its collaborative partners would prevail in
any such  action or  that  any license  (including  licenses proposed  by  third
parties)  required under any such patent would be made available on commercially
acceptable terms, if at all. There are a significant number of United States and
foreign patents and patent applications in the Company's areas of interest,  and
the  Company believes that  there may be significant  litigation in the industry
regarding patent and other intellectual property rights. If the Company  becomes
involved  in  such litigation,  it could  consume a  substantial portion  of the
Company's managerial  and  financial  resources, which  could  have  a  material
adverse  effect on  the Company's business,  financial condition  and results of
operations.
 
    The enactment of legislation implementing the General Agreement on Trade and
Tariffs has resulted in certain changes in United States patent laws that became
effective on  June 8,  1995. Most  notably, the  term of  patent protection  for
patent  applications filed  on or after  June 8, 1995  is no longer  a period of
seventeen years from the date  of grant. The new  term of United States  patents
will  commence on  the date  of issuance  and terminate  twenty years  after the
earliest effective filing date of the application. Because the time from  filing
to  issuance  of  biotechnology patent  applications  in the  Company's  area of
interest is often more than three years, a twenty-year term after the  effective
date  of filing may  result in a  substantially shortened term  of the Company's
patent protection which may adversely affect the Company's patent position.
 
    The Company also relies upon copyright  and trade secret protection for  its
confidential  and proprietary information.  There can be  no assurance, however,
that such  measures will  provide adequate  protection for  the Company's  trade
secrets or other proprietary information. In addition, there can be no assurance
that  proprietary  information  will  not be  disclosed,  that  others  will not
independently  develop  substantially  equivalent  proprietary  information  and
techniques  or  otherwise  gain access  to  the Company's  copyrights  and trade
secrets or  disclose  such technology,  or  that the  Company  can  meaningfully
protect its trade secrets.
 
    The Company's academic collaborators have certain rights to publish data and
information  in which the Company has  rights. There is considerable pressure on
academic institutions to publish discoveries in the
 
                                       15
<PAGE>
genetics and genomics fields.  There can be no  assurance that such  publication
would not adversely affect the Company's ability to obtain patent protection for
some  genes  in  which it  may  have  a commercial  interest.  See  "Business --
Intellectual Property."
 
ATTRACTION AND RETENTION OF KEY EMPLOYEES AND CONSULTANTS
 
    The Company is highly dependent on  the principal members of its  management
and  scientific staff. The loss of services of any of these persons could have a
material   adverse   effect   on   the   Company's   product   development   and
commercialization  objectives. In  addition, recruiting  and retaining qualified
scientific personnel to  perform future  research and development  work will  be
critical  to the Company's success.  There can be no  assurance that the Company
will be able to attract and retain such personnel.
 
    Product development and commercialization will require additional  personnel
in  areas  such as  diagnostic  testing, regulatory  affairs,  manufacturing and
marketing. The inability to acquire such  services or to develop such  expertise
could  have  a  material adverse  effect  on the  Company's  business, financial
condition and results of operations.
 
    In addition, the  Company relies on  its scientific advisors  to assist  the
Company  in  formulating  its  research and  development  strategy.  All  of the
scientific advisors are employed  by employers other than  the Company and  have
commitments  to other entities that may limit their availability to the Company.
Some of the Company's scientific advisors also consult for companies that may be
competitors of the Company. See "Business -- Scientific Advisory Board."
 
EXPOSURE TO PRODUCT LIABILITY CLAIMS
 
    The Company's business exposes it to potential product liability claims that
are inherent  in  the  testing,  manufacturing,  marketing  and  sale  of  human
diagnostic  and therapeutic  products. The  Company intends  to acquire clinical
liability insurance. There can be  no assurance that it  will be able to  obtain
such  insurance or general product liability insurance on acceptable terms or at
reasonable costs or that such insurance will be in sufficient amounts to provide
the Company  with adequate  coverage against  potential liabilities.  A  product
liability  claim or recall could have a material adverse effect on the Company's
business, financial condition and results of operations.
 
   
BROAD DISCRETION IN ALLOCATION AND USE OF PROCEEDS
    
 
   
    Although the Company  expects to  use approximately $46,000,000  of the  net
proceeds  of  this  offering  for research  and  development,  including product
development and core research, manufacturing  scale-up, and to expand sales  and
marketing  capabilities, the Company has not yet identified the specific amounts
and uses of approximately  $9,000,000 (approximately 16%)  of the net  proceeds.
The  Company's Board of Directors and management will retain broad discretion as
to the allocation of the net proceeds of the offering. See "Use of Proceeds."
    
 
CONTROL BY GLAXO, MANAGEMENT AND RELATED PERSONS
 
    Upon completion of  this offering,  Glaxo will  indirectly beneficially  own
35.9%  of  the  Company's  outstanding  Common  Stock  and  executive  officers,
directors  and  principal  shareholders  (other  than  Glaxo)  will   indirectly
beneficially  own 15.0% of the  Company's outstanding Common Stock. Accordingly,
Glaxo and these shareholders may be able to influence the outcome of shareholder
votes, including  votes  concerning  the  election  of  directors,  adoption  of
amendments to the Company's Articles of Incorporation and Bylaws and approval of
mergers and other significant corporate transactions. Glaxo and the Company have
executed  a  governance  agreement  that  confers  rights  on  Glaxo  in certain
circumstances. See "Principal Shareholders" and "Certain Transactions."
 
ANTI-TAKEOVER EFFECT OF CERTAIN CHARTER PROVISIONS
 
    Certain provisions of the Company's Articles of Incorporation and Bylaws and
certain other contractual  provisions could have  the effect of  making it  more
difficult  for a third party  to acquire, or of  discouraging a third party from
attempting to acquire, or control the  Company. Such provisions could limit  the
price that certain investors might be willing to pay in the future for shares of
the  Company's Common  Stock. Certain of  these provisions allow  the Company to
issue Preferred Stock with  rights senior to those  of the Common Stock  without
any  further  vote  or  action  by  the  shareholders,  eliminate  the  right of
shareholders to  act by  written  consent which  could  make it  more  difficult
 
                                       16
<PAGE>
for  shareholders to  affect certain  corporate actions.  These provisions could
also have  the effect  of delaying  or preventing  a change  in control  of  the
Company.  The issuance of Preferred Stock  could decrease the amount of earnings
and assets available for  distribution to the holders  of Common Stock or  could
adversely  affect the rights and powers, including voting rights, of the holders
of the Common  Stock. In  certain circumstances,  such issuance  could have  the
effect of decreasing the market price of the Common Stock.
 
NO PRIOR TRADING MARKET FOR COMMON STOCK; POSSIBLE VOLATILITY OF STOCK PRICE;
DILUTION
 
    Prior  to this offering, there  has been no public  market for the Company's
Common Stock, and there can  be no assurance that  an active public market  will
develop  or be sustained after this  offering. The initial public offering price
will be determined by negotiations among the Company and the Representatives  of
the  Underwriters  and  may  not  be indicative  of  future  market  prices. See
"Underwriting" for a discussion of the  factors to be considered in  determining
the  initial public  offering price. The  trading price of  the Company's Common
Stock could be subject to significant fluctuations in response to  announcements
of  results  of  research  activities,  collaborative  agreements, technological
innovations, or new commercial products  by the Company, collaborative  partners
or  competitors, changes in government  regulations, regulatory actions, changes
in patent laws, developments concerning proprietary rights, quarterly variations
in operating results,  litigation and other  events. The stock  market has  from
time  to time experienced  significant price and  volume fluctuations which have
particularly affected the market prices  of the stocks of technology  companies,
and which may be unrelated to the operating performance of particular companies.
Further, there has been particular volatility in the market prices of securities
of biotechnology and other life sciences companies.
 
    Purchasers  of  the Common  Stock will  incur  an immediate  and substantial
dilution in the net  tangible book value  of the Common  Stock from the  initial
public  offering price. Additional dilution is  likely to occur upon exercise of
options granted by the Company. See "Dilution."
 
SHARES ELIGIBLE FOR FUTURE SALE; POSSIBLE ADVERSE EFFECT ON FUTURE MARKET PRICE
 
   
    Future sales of  substantial amounts of  the Company's Common  Stock in  the
public market after this offering could adversely affect the market price of the
Common Stock. Of the 21,239,231 shares to be outstanding after the offering, the
5,000,000  shares of  Common Stock offered  hereby (plus any  shares issued upon
exercise of the  Underwriters' over-allotment option)  will be freely  tradeable
without  restriction. Beginning 90 days  after the Effective Date, approximately
50,100 additional shares will be eligible for sale in the public market  subject
to  compliance with Rule 701. In addition, beginning 90 days after the Effective
Date approximately 186,140 shares  subject to vested  options will be  available
for  sale  subject to  compliance  with Rule  701.  Certain shareholders  of the
Company, including the officers, directors, employees and the affiliates of  the
Company are subject to contractual "lock-up" agreements generally providing that
they  will not offer, sell, contract to sell  or grant any option to purchase or
otherwise dispose of the shares of Common Stock of the Company or any securities
exercisable for or convertible into the Company's Common Stock owned by them for
a period of 180 days  after the effective date  of the offering (the  "Effective
Date")  without the prior written consent of  Robertson Stephens & Company. As a
result of  these  contractual  restrictions,  notwithstanding  possible  earlier
eligibility for sale under the provisions of Rules 144, 144(k) and 701 under the
Securities  Act of  1933, as amended  (the "Securities Act"),  shares subject to
lock-up agreements will  not be  saleable until  such agreements  expire or  are
waived  by Robertson Stephens & Company.  Beginning 180 days after the Effective
Date, approximately 10,411,408 additional shares  will become eligible for  sale
subject  to the provisions  of Rule 144 or  Rule 701 upon  the expiration of the
lock-up agreements  not  to sell  such  shares.  Beginning 180  days  after  the
Effective  Date,  approximately  183,366  additional  shares  subject  to vested
options will be available for sale subject to compliance with Rule 701 upon  the
expiration  of lock-up agreements not to sell such shares. Robertson, Stephens &
Company may, in its sole discretion and at any time without notice, release  all
or any portion of the securities subject to lock-up agreements. In addition, the
Company intends to register on Form S-8 under the Securities Act within 180 days
after  the Effective Date shares of Common Stock issued or reserved for issuance
under the Company's 1993 Stock Plan (the "Stock Plan"), and the 1996 Nonemployee
Directors Stock Option Plan (the  "Directors Plan") and such registrations  will
be effective on filing. As of March 31, 1996, there were outstanding options for
the  purchase of  2,191,518 shares  under the Stock  Plan, of  which options for
158,490 shares were exercisable.  No shares have been  issued to date under  the
Directors  Plan. As of  April 30, 1996, the  holders of approximately 15,834,537
shares are entitled to certain registration rights with respect to such  shares.
If a large
    
 
                                       17
<PAGE>
number  of such shares were registered and sold in the public market, such sales
could have an adverse effect on the market price for the Company's Common Stock.
If the Company were required to include in a Company-initiated registration  the
shares  held  by such  holders pursuant  to the  exercise of  their registration
rights, such sales may have an adverse effect on the Company's ability to  raise
needed  capital. See "Management -- Stock  Plans," "Description of Capital Stock
-- Registration Rights  of Certain  Shareholders," "Shares  Eligible for  Future
Sale," and "Underwriting."
 
                                USE OF PROCEEDS
 
    The  net proceeds to  the Company from  the sale of  the 5,000,000 shares of
Common Stock offered by the Company hereby at an assumed initial public offering
price of  $12.00  per  share  are  estimated  to  be  approximately  $55,000,000
($63,370,000  assuming the  Underwriters' over-allotment option  is exercised in
full), after deducting the underwriting discounts and commissions and  estimated
offering expenses payable by the Company.
 
   
    The  Company intends to use  the net proceeds from  this offering to develop
new products and  applications for  the GeneChip  system. Such  products may  be
developed  by the Company internally or through collaborative arrangements using
the Company's  existing technology  and products  or complementary  products  or
technologies   acquired  from  third  parties.  While  such  collaborations  and
acquisitions may represent a significant use of the proceeds of the offering, no
significant acquisitions  are  currently planned.  The  Company expects  to  use
approximately  $25  million  for  research  and  development,  including product
development  and   core  research;   approximately  $15   million  for   capital
expenditures,  including  scale-up of  manufacturing, facilities  and laboratory
equipment; and approximately $6  million for expansion  of sales and  marketing.
The  Company will  use the  $9 million  balance (approximately  16%) of  the net
proceeds for working capital and other general corporate purposes. The Company's
Board of  Directors  and management  will  retain  broad discretion  as  to  the
allocation of the net proceeds of the offering.
    
 
    The  amounts  actually expended  for  each purpose  and  the timing  of such
expenditures will  depend upon  numerous  factors, including  payments  received
under existing and possible future collaborative agreements; the availability of
government  research grant payments; the progress of the Company's collaborative
and independent research and development projects; the costs of preclinical  and
clinical  trials  for  the  Company's  products;  the  prosecution,  defense and
enforcement of  patent  claims  and  other  intellectual  property  rights;  and
development  of manufacturing,  marketing and  sales capabilities.  Pending such
uses, the  Company  intends to  invest  the net  proceeds  of this  offering  in
short-term, investment-grade, interest-bearing securities.
 
                                DIVIDEND POLICY
 
    The Company has never paid dividends since its inception and does not intend
to pay any dividends in the foreseeable future. The Company currently intends to
retain any future earnings to fund the development of its business.
 
                                       18
<PAGE>
                                 CAPITALIZATION
 
    The following table sets forth the capitalization of the Company as of March
31, 1996, (i) on a pro forma basis to give effect to the automatic conversion of
all  outstanding shares of the Company's  Preferred Stock into Common Stock upon
the closing of this offering and (ii) as adjusted to reflect the receipt of  the
estimated  net proceeds from  the sale of  the 5,000,000 shares  of Common Stock
offered hereby, at an assumed initial public offering price of $12.00 per share,
after  deducting  the  underwriting  discounts  and  commissions  and  estimated
offering  expenses  payable  by  the  Company.  This  table  should  be  read in
conjunction with the financial statements of  the Company and the notes  thereto
included elsewhere in this Prospectus.
 
<TABLE>
<CAPTION>
                                                                                                MARCH 31, 1996
                                                                                           ------------------------
                                                                                            PRO FORMA   AS ADJUSTED
                                                                                           -----------  -----------
                                                                                                (in thousands)
<S>                                                                                        <C>          <C>
Noncurrent portion of capital lease obligation (1).......................................   $     898    $     898
Shareholders' equity:
  Preferred stock; no par value, 27,500,000 shares authorized; pro forma and as adjusted,
   no shares issued and outstanding......................................................      --           --
  Common stock; no par value, 50,000,000 shares authorized;
   pro forma 16,239,231 issued and outstanding; as adjusted,
   21,239,231 issued and outstanding (2).................................................      73,528      128,528
  Notes receivable from officers.........................................................         (41)         (41)
  Unrealized gain on available-for-sale securities.......................................           1            1
  Deferred compensation..................................................................      (2,399)      (2,399)
  Deficit accumulated during the development stage.......................................     (36,437)     (36,437)
                                                                                           -----------  -----------
    Total shareholders' equity...........................................................      34,652       89,652
                                                                                           -----------  -----------
      Total capitalization...............................................................   $  35,550    $  90,550
                                                                                           -----------  -----------
                                                                                           -----------  -----------
</TABLE>
 
------------
(1) See  Note  5 of  Notes  to Financial  Statements  for a  description  of the
    Company's obligation under capital lease.
 
(2) Excludes (i)  203,881  shares of  Common  Stock issuable  upon  exercise  of
    outstanding warrants at an exercise price of $8.25 per share, (ii) 2,191,518
    shares issuable upon exercise of outstanding options at March 31, 1996, at a
    weighted average price of $0.65 per share and (iii) 965,228 shares of Common
    Stock  reserved  for future  issuance under  the  Stock Plan.  Also excludes
    300,000 shares reserved  for issuance  under the Directors  Plan, which  was
    adopted  in April 1996. See "Management --  Stock Plans" and Note 6 of Notes
    to Financial Statements.
 
                                       19
<PAGE>
                                    DILUTION
 
    The pro forma net tangible  book value of the Company  as of March 31,  1996
was $34,652,000 or
approximately  $2.13  per share.  Pro forma  net tangible  book value  per share
represents the  amount  of  the  Company's  total  tangible  assets  less  total
liabilities,  divided by  the number  of shares  of Common  Stock outstanding at
March 31, 1996. Pro forma net tangible book value dilution per share  represents
the  difference between  the amount  per share paid  by purchasers  of shares of
Common Stock in the  offering made hereby  and the pro  forma net tangible  book
value  per share  immediately after  completion of  this offering.  After giving
effect to the estimated net  proceeds from the sale  of the 5,000,000 shares  of
Common  Stock  offered hereby  at an  assumed initial  public offering  price of
$12.00 per share, after deducting the underwriting discounts and commissions and
estimated offering expenses payable by the  Company, the pro forma net  tangible
book  value of the Company  as of March 31, 1996  would have been $89,652,000 or
approximately $4.22  per share  of Common  Stock. This  represents an  immediate
increase  in net tangible book value of $2.09 per share to existing shareholders
and an immediate  dilution in pro  forma net  tangible book value  of $7.78  per
share  to  purchasers of  Common  Stock in  this  offering. The  following table
illustrates this per share dilution:
 
<TABLE>
<S>                                                                    <C>        <C>
Assumed public offering price........................................             $   12.00
  Pro forma net tangible book value as of March 31, 1996.............  $    2.13
  Increase attributable to new investors.............................       2.09
                                                                       ---------
Pro forma net tangible book value after the offering.................                  4.22
                                                                                  ---------
Dilution to new investors............................................             $    7.78
                                                                                  ---------
                                                                                  ---------
</TABLE>
 
    The following table summarizes, on a pro  forma basis as of March 31,  1996,
the  number of shares of Common Stock purchased from the Company, the total cash
consideration paid  and  the  average  price per  share  paid  by  the  existing
shareholders  and by new  investors before deducting  the underwriting discounts
and commissions and estimated  offering expenses payable by  the Company at  the
assumed initial public offering price of $12.00 per share:
 
<TABLE>
<CAPTION>
                                           SHARES PURCHASED         TOTAL CONSIDERATION
                                        -----------------------  -------------------------  AVERAGE PRICE
                                           NUMBER      PERCENT       AMOUNT       PERCENT     PER SHARE
                                        ------------  ---------  --------------  ---------  -------------
<S>                                     <C>           <C>        <C>             <C>        <C>
Existing shareholders.................    16,239,231       76.5% $   70,860,000       54.1%   $    4.36
New investors.........................     5,000,000       23.5      60,000,000       45.9        12.00
                                        ------------  ---------  --------------  ---------
  Total...............................    21,239,231      100.0% $  130,860,000      100.0%
                                        ------------  ---------  --------------  ---------
                                        ------------  ---------  --------------  ---------
</TABLE>
 
    The  foregoing table  assumes no  exercise of  outstanding stock  options or
warrants. As of  March 31,  1996, there  were outstanding  warrants to  purchase
203,881  shares of  Common Stock  at an  exercise price  of $8.25  per share and
outstanding options to purchase an aggregate of 2,191,518 shares of Common Stock
at a weighted average exercise price of $0.65 per share. To the extent that  any
of  these options or  warrants or additional options  or warrants are exercised,
there will be further dilution to new investors. See "Management -- Stock Plans"
and Note 6 of Notes to Financial Statements.
 
                                       20
<PAGE>
                            SELECTED FINANCIAL DATA
 
   
    The statement  of  operations data  set  forth  below for  the  years  ended
December  31, 1993, 1994 and 1995 and the  balance sheet data as of December 31,
1994 and 1995 are  derived from financial statements  of the Company audited  by
Ernst  & Young LLP,  independent auditors, which are  included elsewhere in this
Prospectus. The statement of  operations data for the  years ended December  31,
1991 and 1992 and the balance sheet data as of December 31, 1991, 1992, and 1993
are  derived from financial statements  audited by Ernst &  Young LLP, which are
not included in this Prospectus.  The balance sheet data  at March 31, 1996  and
the  statement of operations data for the  three months ended March 31, 1995 and
1996 and for the period from inception  (January 1, 1991) to March 31, 1996  are
derived   from  unaudited  financial  statements   included  elsewhere  in  this
prospectus.  The  unaudited  financial   statements  include  all   adjustments,
consisting  only  of normal  recurring adjustments,  that the  Company considers
necessary for  a fair  presentation of  the financial  position and  results  of
operations for these periods. Operating results for the three months ended March
31,  1996 are not necessarily indicative of the results that may be expected for
the entire year ending December 31, 1996. The Company has never declared or paid
any cash dividends  on shares of  its capital  stock. The data  set forth  below
should  be read  in conjunction  with "Management's  Discussion and  Analysis of
Financial Condition and  Results of  Operations" and  the Financial  Statements,
related  Notes thereto,  and other  financial information  included elsewhere in
this Prospectus.
    
 
<TABLE>
<CAPTION>
                                                                                                                PERIOD FROM
                                                                                                                 INCEPTION
                                                                                         THREE MONTHS ENDED     (JANUARY 1,
                                                                                                               1991) THROUGH
                                                YEAR ENDED DECEMBER 31,                      MARCH 31,           MARCH 31,
                                 -----------------------------------------------------  --------------------  ---------------
                                   1991       1992       1993       1994       1995       1995       1996          1996
                                 ---------  ---------  ---------  ---------  ---------  ---------  ---------  ---------------
                                                            (in thousands, except per share data)
<S>                              <C>        <C>        <C>        <C>        <C>        <C>        <C>        <C>
STATEMENT OF OPERATIONS DATA:
Contract and grant revenue.....  $  --      $      43  $   1,413  $   1,574  $   4,625  $     854  $   1,416     $   9,071
Operating expenses:
  Research and development.....      1,576      4,106      6,566      9,483     12,420      2,274      4,177        38,328
  General and administrative...        261        582        577      2,303      3,833        777      1,649         9,205
                                 ---------  ---------  ---------  ---------  ---------  ---------  ---------       -------
    Total operating expenses...      1,837      4,688      7,143     11,786     16,253      3,051      5,826        47,533
                                 ---------  ---------  ---------  ---------  ---------  ---------  ---------       -------
Loss from operations...........     (1,837)    (4,645)    (5,730)   (10,212)   (11,628)    (2,197)    (4,410)      (38,462)
  Interest income..............     --              3        211        575      1,301        183        517         2,607
  Interest expense.............     --            (18)       (73)       (43)      (420)      (160)       (28)         (582)
                                 ---------  ---------  ---------  ---------  ---------  ---------  ---------       -------
Net loss.......................  $  (1,837) $  (4,660) $  (5,592) $  (9,680) $ (10,747) $  (2,174) $  (3,921)    $ (36,437)
                                 ---------  ---------  ---------  ---------  ---------  ---------  ---------       -------
                                 ---------  ---------  ---------  ---------  ---------  ---------  ---------       -------
Pro forma net loss per share
 (1)...........................                        $   (0.52) $   (0.55) $   (0.61) $   (0.12) $   (0.22)
                                                       ---------  ---------  ---------  ---------  ---------
                                                       ---------  ---------  ---------  ---------  ---------
Pro forma weighted average
 shares outstanding (1)........                           10,715     17,653     17,664     17,663     17,664
</TABLE>
 
<TABLE>
<CAPTION>
                                                                    DECEMBER 31,                        MARCH 31,
                                                -----------------------------------------------------  -----------
                                                  1991       1992       1993       1994       1995        1996
                                                ---------  ---------  ---------  ---------  ---------  -----------
                                                                   (in thousands)
<S>                                             <C>        <C>        <C>        <C>        <C>        <C>
BALANCE SHEET DATA:
Cash, cash equivalents and short-term
 investments..................................  $  --      $      94  $  20,392  $  17,805  $  38,883   $  34,837
Working capital...............................          1       (320)    17,452     15,677     36,070      31,729
Total assets..................................          1        813     22,817     19,861     44,552      41,185
Long-term obligations.........................     --            564     --          7,135        948         898
Deficit accumulated during development
 stage........................................     (1,837)    (6,497)   (12,089)   (21,769)   (32,516)    (36,437)
Total shareholders' equity (net capital
 deficiency)..................................          1       (181)    19,214      9,170     38,519      34,652
</TABLE>
 
---------------
(1) See  Note 1  of Notes  to Financial  Statements for  an explanation  of  the
    determination  of the number of shares used  in computing pro forma net loss
    per share.
 
                                       21
<PAGE>
                      MANAGEMENT'S DISCUSSION AND ANALYSIS
                OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
 
    The following Management's  Discussion and Analysis  of Financial  Condition
and  Results  of Operations  contains  forward-looking statements  which involve
risks and uncertainties.  The Company's actual  results could differ  materially
from  those  anticipated  in these  forward-looking  statements as  a  result of
certain factors, including those set forth under "Risk Factors" and elsewhere in
this Prospectus.
 
OVERVIEW
 
    Affymetrix is  a  development stage  company  which is  developing  GeneChip
systems  and related applications and technologies for the acquisition, analysis
and management of complex  genetic information. The  business and operations  of
Affymetrix were commenced in 1991 by Affymax and were initially conducted within
Affymax.  In March 1992, Affymetrix was incorporated as a California corporation
and became a wholly-owned subsidiary  of Affymax. In September 1993,  Affymetrix
issued  equity  securities  through  a private  financing  of  approximately $21
million that reduced  Affymax' ownership  to approximately 65%.  In March  1995,
Glaxo  acquired  Affymax,  including  its then  majority  ownership  interest in
Affymetrix. In August 1995, Affymetrix issued equity securities through a second
private financing  of  approximately  $39  million,  further  reducing  Affymax'
percentage  ownership.  Glaxo  currently indirectly  owns  approximately  46% of
Affymetrix.
 
    The Company  has a  limited operating  history that,  to date,  has  focused
primarily on the development of its technology. Based on its GeneChip technology
platform, Affymetrix is developing a portfolio of products for academic research
centers,  pharmaceutical and biotechnology companies and reference laboratories.
As of March 31, 1996, the Company  had placed nine of its GeneChip systems  with
customers  for validation,  initial testing  and certain  research applications.
Only five of the systems have been  purchased by customers, three of which  were
for  the HIV application. The  payments received from the  sale of these systems
were recorded  as  contract revenues  pursuant  to development  agreements.  The
Company  commercially introduced its first product,  the GeneChip system and the
HIV probe array for research use only, in April 1996. Failure of the Company  to
successfully  develop, manufacture and market  additional products over the next
several years  or to  realize product  revenues would  have a  material  adverse
effect on the Company's business, financial condition and results of operations.
 
   
    The  Company has incurred operating losses in each year since its inception,
including net  losses  of approximately  $10.7  million during  the  year  ended
December 31, 1995, and at March 31, 1996, the Company had an accumulated deficit
of  approximately $36.4 million. The  Company's losses have resulted principally
from  costs  incurred  in  research   and  development  and  from  general   and
administrative  costs associated with the Company's operations. These costs have
exceeded the Company's  interest income  and revenues  which to  date have  been
generated principally from collaborative research and development agreements and
government  research grants. The Company expects to incur substantial additional
operating losses over the  next several years  as a result  of increases in  its
expenses  for  research  and product  development,  manufacturing  and marketing
capabilities.
    
 
    The Company's quarterly operating  results will depend  upon the volume  and
timing  of orders for  GeneChip systems and probe  arrays received and delivered
during the  quarter,  variations  in payments  under  collaborative  agreements,
including  milestones, royalties, license fees, and other contract revenues, and
the timing of new product introductions by the Company. The Company's  quarterly
operating  results may also fluctuate  significantly depending on other factors,
including the  introduction  of  new  products  by  the  Company's  competitors;
regulatory actions; market acceptance of the GeneChip system and other potential
products;  adoption of new  technologies; manufacturing capabilities; variations
in gross margins of the Company's  products; competition; the cost, quality  and
availability  of reagents and  components; the mix of  products sold; changes in
government funding; and third-party reimbursement policies.
 
    The Company expects that it may have  to discount the price of the  GeneChip
system  to gain market  acceptance, which could  adversely affect gross margins.
The Company's future gross  margins, if any, will  be dependent on, among  other
factors,  the  Company's ability  to  cost-effectively manufacture  the GeneChip
system, product mix  and the degree  of price discounts  required to market  its
products to academic research centers,
 
                                       22
<PAGE>
pharmaceutical  companies  and  reference  laboratories.  The  amount  of future
operating losses and  time required by  the Company to  reach profitability,  if
ever,  are  highly  uncertain.  The Company's  ability  to  generate significant
revenues and become profitable is dependent in large part on the ability of  the
Company  to enter into additional collaborative  arrangements and on the ability
of the  Company and  its collaborative  partners to  successfully  commercialize
products  incorporating  the  Company's  technologies.  In  addition,  delays in
receipt  of  any  necessary   regulatory  approvals  by   the  Company  or   its
collaborators,  or receipt of  approvals by competitors,  could adversely affect
the successful commercialization of the Company's technologies.
 
   
    From inception  through March  31,  1996, the  Company has  generated  $11.7
million  from government  grants, collaborative agreements  and interest income.
The Company has  significant collaborative relationships  with GI and  HP and  a
significant  grant  from the  National Institute  of Standards  and Technology's
Advanced Technology  Program. The  Company began  its collaboration  with GI  in
November   1994  to  develop   applications  of  the   GeneChip  system  to  the
identification of new genes and new  uses of genes using expression  monitoring.
Under  this  agreement,  GI  funded  the  Company's  research  to  determine the
feasibility of  this  application of  GeneChip  technology and  agreed  to  make
milestone  and royalty payments. In  December 1995, GI and  the Company signed a
second agreement for  the supply  of custom  probe arrays  to GI  in return  for
up-front  fees, milestone payments and royalties for products developed from use
of the  probe arrays.  As of  March 31,  1996, the  Company recognized  contract
revenues  totaling  $1.3  million from  GI.  As  a result  of  entering  into an
agreement with Incyte in April 1996, Affymetrix is required to refund 30% of the
development funding  received  from  GI  and future  funding  from  GI  will  be
proportionally  reduced.  The Company  recorded  an accrued  liability  for this
refund and believes that the reduction of future funding from GI will not have a
material effect on its operations. See "Business -- Collaborative Agreements and
Grants."
    
 
    The Company  entered  into a  collaboration  with  HP in  November  1994  to
develop,  manufacture  and  supply a  more  advanced  scanner for  use  with the
Company's GeneChip probe arrays and for  the Company, in collaboration with  HP,
to  develop,  manufacture and  supply certain  probe  arrays to  HP for  sale in
certain markets. As of March 31, 1996, the Company recognized contract  revenues
totaling $1.5 million from HP.
 
    In  October 1994,  the Company and  Molecular Dynamics  received a five-year
grant from  the  National  Institute  of  Standards  and  Technology's  Advanced
Technology  Program in the amount of $31.5 million to develop a miniaturized DNA
diagnostic system  based on  the Company's  technology. Pursuant  to the  grant,
$20.8  million is  designated for the  Company and its  subcontractors and $10.7
million is designated for Molecular Dynamics and its subcontractors, subject  to
the  requirements of each company  to match such funding.  As of March 31, 1996,
the Company's revenues from this grant totaled $1.6 million.
 
    Collaborations will continue  to be  an important element  of the  Company's
business  strategy. There can be  no assurance that the  Company will be able to
maintain existing collaborations,  enter into future  collaborations to  develop
applications  of its GeneChip system or that any such collaborative arrangements
will be successful.
 
RESULTS OF OPERATIONS
 
   
  THREE MONTHS ENDED MARCH 31, 1996 AND MARCH 31, 1995
    
 
   
    Contract and grant revenue increased by 66% for the three months ended March
31, 1996 to  $1.4 million from  $854,000 for  the three months  ended March  31,
1995.  The  increase was  principally due  to  the sale  of one  GeneChip system
pursuant to a development agreement in the first quarter of 1996, as compared to
none in the first quarter of 1995, and an increase in ATP grant revenue.
    
 
    Research and development expenses  increased to $4.2  million for the  first
quarter  of  1996 compared  to $2.3  million for  the same  period of  1995. The
increase was attributable  primarily to  the hiring of  additional research  and
development   personnel,  costs  incurred  to  further  product  development  in
anticipation of Affymetrix'  initial product  launch, and  purchase of  research
supplies.  Affymetrix anticipates  that research  and development  expenses will
continue to increase in future periods.
 
    General and administrative expenses increased to $1.6 million for the  three
months  ended March 31, 1996  compared to $777,000 for  the comparable period in
1995. The  increase  in general  and  administrative expenses  was  attributable
primarily  to the hiring of additional management personnel and the incurring of
legal and other
 
                                       23
<PAGE>
professional fees  in connection  with the  overall scale-up  of operations  and
business  development efforts. General and  administrative expenses are expected
to increase significantly in future periods to support Affymetrix operations and
business development efforts.
 
    Interest income  was $517,000  for the  three months  ended March  31,  1996
compared  to  $183,000  for the  comparable  period  in 1995.  The  increase was
primarily attributable to the  investment of the net  proceeds from the  private
placement  of Series  B Senior  Convertible Preferred  Stock in  August 1995 and
higher interest  rates.  Interest  expense  in 1996  decreased  by  $132,000  as
compared to 1995, primarily due to the conversion of a $6.0 million subordinated
convertible promissory note held by Affymax in August 1995.
 
  YEARS ENDED DECEMBER 31, 1995 AND DECEMBER 31, 1994
 
    Contract  and grant  revenue increased  to $4.6  million for  1995 from $1.6
million for 1994 as a result primarily of its ATP grant and revenue earned  from
collaborative agreements with GI and HP.
 
    Research  and  development  expenses  increased to  $12.4  million  for 1995
compared to $9.5  million for  1994. The  increase in  research and  development
expenses  was attributable  primarily to the  hiring of  additional research and
development  personnel,  costs  incurred  to  establish  a  pilot  manufacturing
facility, and increased purchases of research supplies.
 
    General  and  administrative expenses  increased  to $3.8  million  for 1995
compared to $2.3 million  for 1994. The increase  in general and  administrative
expenses  was  attributable primarily  to  the hiring  of  additional management
personnel and the incurring of legal  and other professional fees in  connection
with the overall scale-up of operations and business development efforts.
 
    Interest income was $1.3 million for 1995 compared to $575,000 for 1994. The
increase  resulted from the investment of  net proceeds from Affymetrix' private
placement of  Series  B  Senior  Convertible Preferred  Stock  in  August  1995.
Interest  expense resulted from lease  financing for manufacturing equipment and
facilities.
 
  YEARS ENDED DECEMBER 31, 1994 AND DECEMBER 31, 1993
 
    Contract and grant  revenue increased  to $1.6  million for  1994 from  $1.4
million for 1993 as a result of additional funding from government grants.
 
    Research  and  development  expenses  increased  to  $9.5  million  for 1994
compared to $6.6  million for  1993. The  increase in  research and  development
expenses  was attributable  primarily to the  hiring of  additional research and
development personnel and increased purchases of research supplies.
 
    General and  administrative  expenses increased  to  $2.3 million  for  1994
compared  to  $577,000  for 1993.  The  increase in  general  and administrative
expenses was attributable primarily to  the hiring of additional  administrative
personnel  and the incurring of legal  and other professional fees in connection
with the expansion of Affymetrix' operations.
 
    Interest income was  $575,000 for 1994  compared to $211,000  for 1993.  The
increase resulted from the investment of net proceeds from the private placement
of Series A Senior Convertible Preferred Stock in September 1993.
 
LIQUIDITY AND CAPITAL RESOURCES
 
   
    Since  inception, Affymetrix  has financed its  operations primarily through
private placements of equity securities, contributions from Affymax,  government
grants, collaborative agreements, issuances of convertible debt, equipment lease
financings  and interest income. Through March 31, 1996, Affymetrix has received
net cash of $71.4 million  from financing activities, consisting principally  of
approximately  $53.6 million from issuances of common and preferred stock, $10.6
million from  contribution by  Affymax,  $7.1 million  from issuances  of  notes
payable, and $1.3 million in lease financing. As of March 31, 1996, $1.1 million
of  notes have been  repaid, $6.0 million  of convertible notes  held by Affymax
have been converted into shares of Series B Senior Convertible Preferred  Stock,
and $10.6 million of contributions from Affymax have been converted to shares of
Series 1 Subordinated Convertible Preferred Stock.
    
 
    Affymetrix'  net cash used in operating  activities was $3.1 million for the
three months ended March 31, 1996, $10.2 million for 1995, $7.4 million for 1994
and   $3.2   million   for   1993.   The   cash   used   for   operations    was
 
                                       24
<PAGE>
   
primarily  to fund research and  development expenses and manufacturing start-up
costs  related  to  the  introduction  and  support  of  Affymetrix'   products.
Affymetrix has also received collaborative research and government grant funding
totaling  $11.0 million, of  which $9.1 million has  been recognized as contract
and grant revenue.
    
 
   
    The cash used  by the Company  in investing activities  since its  inception
through  March  31, 1996  totaled  $41.0 million.  Capital  expenditures totaled
$701,000 for the three months ended March 31, 1996. Capital expenditures totaled
$2.3 million in 1995, $1.2 million in  1994 and $1.5 million in 1993.  Purchases
of  available-for-sale securities were  $2.0 million for  the three months ended
March 31, 1996  and $38.4  million, $3.0 million,  and $14.0  million for  1995,
1994,   and  1993,   respectively.  Proceeds   from  sales   and  maturities  of
available-for-sale-securities were $3.6 million for the three months ended March
31, 1996 and  $14.0 million and  $5.3 million for  1995 and 1994,  respectively.
There were no sales or maturities in 1993.
    
 
   
    As  of March 31, 1996, Affymetrix had cash, cash equivalents, and short-term
investments of  $34.8  million.  The Company  anticipates  that  these  existing
capital  resources, together with the net proceeds of this offering and interest
earned thereon, will enable it to maintain currently planned operations  through
at  least  1998. However,  this expectation  is based  on the  Company's current
operating plan,  which could  change and  the Company  could require  additional
funding  sooner than anticipated.  In addition, the Company  may choose to raise
additional capital due to market conditions or strategic considerations even  if
it  continues to  have sufficient  funds for  its operating  plan. The Company's
requirements for additional capital will be substantial and will depend on  many
factors,  including payments received under  existing and possible collaborative
agreements; the availability of government research grant payments; the progress
of  the  Company's  collaborative  and  independent  research  and   development
projects;  the  costs  of  preclinical and  clinical  trials  for  the Company's
products; the prosecution, defense  and enforcement of  patent claims and  other
intellectual  property rights; and  the development of  manufacturing, sales and
marketing capabilities. The Company  has no credit  facility or other  committed
sources  of capital.  To the extent  capital resources,  including payments from
existing and possible future collaborative agreements and grants, together  with
the  net  proceeds  of the  offering  are  insufficient to  meet  future capital
requirements, the Company will  have to raise additional  funds to continue  the
development  of its technologies. There can be no assurance that such funds will
be available  on favorable  terms, or  at  all. To  the extent  that  additional
capital is raised through the sale of equity or convertible debt securities, the
issuance   of  such  securities  could  result  in  dilution  to  the  Company's
shareholders. If adequate funds are not  available, the Company may be  required
to  curtail operations  significantly or to  obtain funds  through entering into
collaborative agreements on unattractive terms. The Company's inability to raise
capital would  have  a  material  adverse  effect  on  the  Company's  business,
financial condition and results of operations.
    
 
   
    Affymetrix  expects  its  capital  requirements to  increase  over  the next
several years as it expands its facilities and acquires scientific equipment  to
support  manufacturing  and  research  and  development  efforts.  The Company's
expenditure requirements will depend on numerous factors, including the progress
of its research and  development programs; the  development of commercial  scale
manufacturing  capabilities;  its  ability  to  maintain  existing collaborative
arrangements and  establish and  maintain  new collaborative  arrangements;  the
costs  involved  in  preparing,  filing,  prosecuting,  defending  and enforcing
intellectual property  rights; the  effectiveness of  product  commercialization
activities and arrangements and other factors.
    
 
    At  December  31, 1995,  Affymetrix'  net operating  loss  carryforwards and
research tax credit  carryforwards for  income tax  purposes were  approximately
$22.0 million and $1.2 million, respectively. Because Affymetrix has experienced
ownership  changes, future utilization of these  carryforwards may be subject to
certain limitations  as  defined by  Internal  Revenue Code  and  similar  state
regulations. If not utilized,the carryforwards expire at various dates beginning
in  2008 through 2010. As a result of  the annual limitation, a portion of these
carryforwards may expire before ultimately  becoming available to reduce  income
tax liabilities.
 
                                       25
<PAGE>
                                    BUSINESS
 
    The  following  Business section  contains forward-looking  statements which
involve risks  and  uncertainties. The  Company's  actual results  could  differ
materially  from  those anticipated  in  these forward-looking  statements  as a
result of certain factors,  including those set forth  under "Risk Factors"  and
elsewhere in this Prospectus.
 
OVERVIEW
 
    Affymetrix has developed and intends to establish its GeneChip system as the
platform  of  choice  for  acquiring,  analyzing  and  managing  complex genetic
information in  order to  improve  the diagnosis,  monitoring and  treatment  of
disease. The Company's system consists of disposable DNA probe arrays containing
gene  sequences on a chip, instruments to process the probe arrays, and software
to analyze  and manage  genetic information.  The Company  commenced  commercial
sales  of the GeneChip  system and a HIV  probe array for  research use in April
1996.
 
BACKGROUND
 
  GENES AND DISEASE
 
    Genes provide  the  fundamental basis  for  understanding human  health  and
disease.  Genomics, the  study of  genes and their  functions, will  lead to new
approaches to diagnose, monitor and treat disease.
 
    The entire genetic content of an organism is known as its genome. DNA is the
molecule that  makes  up  genes  and encodes  the  genetic  instructions.  These
instructions  are embodied in the sequence of the four nucleotide bases (A, C, G
and T) that  are the  chemical building  blocks of DNA.  The DNA  molecule is  a
combination  of two strands  held together by  chemical bonds between nucleotide
bases on one strand and the other strand. Only certain pairs of nucleotide bases
can form these bonds:  A always pairs with  T, and C always  pairs with G.  Such
paired  DNA  strands are  said to  be  complementary. When  two DNA  strands are
complementary, they bind  together to form  a double helix  in a process  called
hybridization.  In humans, the DNA molecule  contains 3 billion nucleotide pairs
organized into 46  chromosomes. The  human genome  is believed  to contain  over
100,000 genes.
 
    Cells  carry  out  their  normal biological  functions  through  the genetic
instructions encoded  in their  DNA.  This process,  known as  gene  expression,
involves several steps. In the first step, nucleotides in a gene are copied into
a  related nucleic acid  molecule called messenger  RNA. Messenger RNA instructs
the cell to produce  proteins. Proteins are molecules  that regulate or  perform
most  of  the  physiological  functions  of  the  body.  Because  the  order  of
nucleotides in each  gene is different,  each gene directs  the production of  a
different   protein.  Each   organism's  characteristics   are  thus  ultimately
determined by proteins encoded in its DNA. This process is illustrated below.
 
                                   [DIAGRAM]
 
                                       26
<PAGE>
    The diversity of living organisms results from variability in their genomes.
Variability  stems  from  differences  in  the  sequences  of  genes  and   from
differences  in gene expression. Changes in the sequences of normal genes may be
introduced by environmental or other factors,  such as errors in replication  of
genes.  These changes are known as polymorphisms,  and the affected genes can be
passed from  generation to  generation.  In some  cases, polymorphisms  have  no
effect  on the  organism. However, in  other cases, polymorphisms  can result in
altered function of  the protein  encoded by  the gene.  Such polymorphisms  are
called  mutations. Mutations in single genes  have been associated with diseases
such as cystic fibrosis,  and mutations in multiple  genes have been  associated
with  diseases  such as  cancer and  cardiovascular  disease. Similarly,  it has
recently been discovered that polymorphisms in the genome of HIV, the virus that
causes AIDS,  enable  that  virus  to develop  resistance  to  antiviral  drugs,
resulting  in disease progression  and ultimately death.  In order to understand
how mutations in particular genes  cause disease, scientists must compare  genes
from  healthy  and  diseased  people.  These  efforts  are  laborious  and  time
consuming, requiring the  repeated sequencing of  genes from a  large number  of
people.
 
    The  genes expressed, as  well as the  order and level  of their expression,
determine differences  among cell  types  in an  organism. Although  most  cells
contain  an organism's full set  of genes, only a small  fraction of this set is
expressed in each cell. The expression of  the wrong or defective genes, or  the
expression  of  too  much or  too  little  of genes  normally  expressed, causes
disease. Such abnormalities in gene  expression have been associated with  human
diseases, including many types of cancer. The role of gene expression in disease
requires  an  understanding  of how  genes  interact  to cause  disease  and how
external stimuli, such as drugs, cause variations in gene expression.
 
  THE ROLE OF GENOMICS IN UNDERSTANDING DISEASE
 
    Increased knowledge  of how  DNA molecules  encode the  functions of  living
organisms  has generated  a worldwide effort  to identify and  sequence genes of
many organisms, including the estimated  100,000 genes within the human  genome.
This  effort is  being led  by the  Human Genome  Project and  related academic,
government and industry research projects.  Once the genes and their  nucleotide
sequences  are  identified,  it is  anticipated  that many  years  of additional
research will be required to understand  the specific function of each gene  and
its  role in disease. This research, commonly  referred to as genomics, may lead
to new opportunities in drug discovery and diagnostics.
 
    The general processes by which researchers are attempting to discover  genes
fall   into  two  principal  categories:  genetic  mapping  and  high-throughput
sequencing.  Once  a  gene  has  been  identified,  either  through  mapping  or
high-throughput sequencing, researchers must understand the function of the gene
and  how variability in the  gene leads to disease.  Many diseases are caused by
either changes in the sequence  of the gene or by  changes in the expression  of
the  gene.  Understanding  the  role  of  a  gene  in  disease  requires  either
quantitative gene expression monitoring or large scale polymorphism screening.
 
                                       27
<PAGE>
                                    [CHART]
 
             THE  CHART  ABOVE   ILLUSTRATES  TECHNIQUES  USED   TO
             IDENTIFY  GENES AND UNDERSTAND  THEIR FUNCTIONS, WHICH
             CAN LEAD  TO THE  DEVELOPMENT  OF NEW  DIAGNOSTIC  AND
             THERAPEUTIC OPPORTUNITIES.
 
    GENETIC  MAPPING.  Researchers  use genetic mapping to  identify the gene or
genes causing an observable and well-characterized disease or genetic  disorder.
The  gene mapping process is extensive and typically begins by assembling tissue
samples and histories from families where the disease of interest is  prevalent.
Researchers  then attempt to locate the position of the gene responsible for the
disease using a technique called linkage analysis. This technique relies on  the
identification  of  genes using  DNA  sequences called  markers,  whose specific
locations are known among the three billion  base pairs of the human genome.  By
comparing the patterns of markers in generations of healthy and diseased people,
researchers  can link genes  to markers and thereby  determine that a particular
marker is  located near  the gene  responsible for  the disease.  By using  more
markers,  genes can be more precisely mapped. Since many major diseases, such as
diabetes and atherosclerosis,  are believed  to be  caused by  the interplay  of
numerous   genes,  it   is  often  necessary   to  try  to   map  several  genes
simultaneously. This mapping process requires extensive efforts and  significant
computational  capabilities.  It  is  expected  that  increasing  the  speed and
accuracy of genetic  mapping and  improving the ability  to analyze  information
from thousands of different markers may accelerate the identification of disease
genes.
 
    HIGH-THROUGHPUT  SEQUENCING.    High-throughput  sequencing  involves  first
identifying genes and subsequently determining their function and possible  role
in  disease. When a  gene is expressed in  a particular cell,  its DNA is copied
into messenger RNA. In this process, sequences that do not code for an expressed
gene are removed. Thus,  messenger RNA contains  only expressed gene  sequences.
Using high-throughput sequencing methods, DNA copies of the messenger RNA can be
sequenced  and thereby  reveal the sequence  of a gene.  Corporate, academic and
government efforts have been successful  in identifying a substantial number  of
the 100,000 genes in the human genome using such techniques.
 
    GENE  EXPRESSION MONITORING.  By monitoring the expression of a large number
of genes, researchers seek  to correlate changes in  expression patterns with  a
particular disease. The effectiveness of monitoring gene
 
                                       28
<PAGE>
expression  is  a  function  of  the  number  of  genes  that  can  be monitored
simultaneously,  the  sensitivity  (ability  to  measure  low  levels  of   gene
expression)   and  the  ability  of  the  method  used  to  provide  qualitative
information.  Relative  levels  of  gene  expression  are  currently   monitored
primarily  through  an intensive  process of  sequencing  many copies  of genes.
Scientists believe that the development of technologies that can  quantitatively
monitor  thousands of  genes simultaneously  will increase  the effectiveness of
gene expression monitoring  as a tool  for understanding the  roles of genes  in
disease.
 
    POLYMORPHISM  SCREENING.  Using polymorphism  screening, researchers seek to
correlate variability  in the  sequence of  genes with  a specific  disease.  By
sequencing  a  gene of  interest from  a  large number  of healthy  and diseased
persons, researchers are able to statistically correlate specific gene mutations
with the disease. Currently,  the polymorphism screening  process is done  using
gel-based  sequencing. A  typical polymorphism  screening project  might require
sequencing 10 genes of 5,000 nucleotide bases each in up to 1,000 patients, or a
total of 50  million bases,  to understand  the role of  these 10  genes in  one
disease.  Using high-throughput sequencing  techniques, even at  a cost of cents
per base, such projects  are expensive and time  consuming. It is expected  that
new  technologies will  be needed  to effectively  screen the  more than 100,000
human genes for polymorphisms that correlate with many known diseases.
 
  OPPORTUNITIES IN DIAGNOSTICS AND THERAPEUTICS
 
    Current diagnostic tests can monitor  the physiological effects of  disease,
detect infectious organisms by growing them in culture, or use specific markers,
such  as proteins, known to be associated with disease. Diagnostic tests rely on
a patient  sample of  tissue,  blood, or  urine,  and detect  the  physiological
effect,  the  infectious organism  or the  marker, in  the sample.  For example,
immunoassays detect and measure specific proteins already known to be associated
with a  disease  using antibodies  generated  against those  proteins.  However,
protein  markers  are  not  available  or are  not  useful  for  diagnosing many
diseases. Diagnostic tests that monitor  physiological effects are also  limited
because  different diseases can cause the  same effect. For example, an elevated
white blood cell  count can  be caused by  appendicitis, an  acute infection  or
leukemia.
 
    Most  infectious  diseases  are  viral, bacterial  or  fungal.  Diagnosis of
bacterial and  fungal infections  is generally  achieved by  growing a  culture,
which  may take several days. Even  after the infectious organism is identified,
further analysis may be required to determine which antibiotics, if any, may  be
effective  in  treating the  disease.  In the  case  of many  viruses, diagnosis
depends on immunoassay tests that detect antibodies to the virus. However, these
tests provide  no information  as to  whether  the virus  is resistant  to  drug
therapy or if the infection is active or latent.
 
    Recent  advances  in  gene-based  diagnostic  tests  using  DNA  probes, DNA
amplification techniques and sequencing technologies have begun to address these
shortcomings by directly  examining the  genes associated with  a given  disease
rather  than  relying on  physiological parameters  or antibodies.  For example,
amplification of specific genes from an infectious organism eliminates the  need
to grow that organism in culture.
 
    However,  current techniques for gathering genetic information for diagnosis
and monitoring of  disease have limitations.  For example, gel-based  sequencing
techniques   used  in  some  approaches   are  time-consuming,  require  skilled
operators, and can analyze only limited lengths of contiguous DNA sequences in a
given run. Gene-based diagnosis often requires rapid turnaround and  examination
of  noncontiguous DNA sequences. As a result, new techniques and tools are being
developed to improve the diagnosis, monitoring and treatment of disease.
 
                                       29
<PAGE>
    Using  genetic mapping and high-throughput  sequencing, scientists have been
successful in discovering many  genes. Technological improvements that  increase
the  speed and decrease the cost  of gene expression monitoring and polymorphism
screening will improve the ability of researchers to understand the function  of
these  genes  and  their role  in  disease.  Such knowledge  may  assist  in the
development of therapeutics  with greater  efficacy and fewer  side effects,  as
well as diagnostic products with greater sensitivity and accuracy.
 
BUSINESS STRATEGY
 
    Affymetrix' objective is to establish the GeneChip system as the platform of
choice  for  acquiring, analyzing  and managing  complex genetic  information in
order to  improve  the  diagnosis,  monitoring and  treatment  of  disease.  The
Company's  GeneChip system  consists of  disposable DNA  probe arrays containing
gene sequences on a chip, instruments to process the probe arrays, and  software
to  analyze and  manage genetic information  from the probe  arrays. The Company
intends to commercialize the  GeneChip system in  two principal areas:  genomics
and diagnostics.
 
  GENOMICS
 
    - ESTABLISH  GENECHIP TECHNOLOGY  AS A  PLATFORM FOR  GENOMICS RESEARCH. The
      Company intends  to  develop  the  GeneChip  system  for  use  in  several
      applications  where Affymetrix believes it has substantial advantages over
      conventional tools used for DNA sequence analysis in the identification of
      genes and their role  in disease. Initially,  four such applications  have
      been  identified: gene discovery, gene mapping, gene expression monitoring
      and polymorphism screening, all of which require analyzing and  processing
      large amounts of genetic information.
 
    - COMMERCIALIZE  CUSTOM  PROBE  ARRAYS THROUGH  CORPORATE  PARTNERSHIPS. The
      Company  intends  to  sell  custom  probe  arrays  to  pharmaceutical  and
      biotechnology companies through collaborative agreements. The Company will
      seek  to receive revenues  through design and  development fees, milestone
      payments  and  sales  of   DNA  probe  arrays   and  instruments  to   the
      collaborative  partner.  If  the collaborative  partner  is  successful in
      discovering products  through  the use  of  the GeneChip  technology,  the
      Company  would  also  seek to  receive  royalties  from the  sale  of such
      products.
 
    - PARTICIPATE IN  THE COLLECTION  AND  APPLICATION OF  GENETIC  INFORMATION.
      Affymetrix  intends to use  the DNA sequence  analysis capabilities of the
      GeneChip  technology  to  measure  gene  expression  in  order  to  create
      databases  containing information on the function  of genes and their role
      in disease. Affymetrix anticipates that  such databases will be  developed
      and   commercialized   through   partnerships   with   pharmaceutical  and
      biotechnology companies.
 
  DIAGNOSTICS
 
    - IMPROVE ACCURACY AND SPEED OF DIAGNOSIS. Affymetrix intends to develop DNA
      probe arrays to obtain  genetic information from  patient samples so  that
      specific diseases can be rapidly diagnosed. Furthermore, such probe arrays
      will   be   designed   to  simultaneously   collect   additional  relevant
      information, including drug resistance data.
 
    - ESTABLISH DIRECT  SALES EFFORTS  AND PARTNERSHIPS.  Affymetrix intends  to
      initially market its GeneChip products, for research use only, directly to
      academic  research  centers and  reference  laboratories that  conduct the
      majority of gene-based  diagnostic tests.  In addition,  the Company  will
      seek  to partner  with, or  license technology  to, established diagnostic
      companies which could develop, seek regulatory approval, and commercialize
      probe arrays for broader clinical use.
 
    - DISCOVER NOVEL DIAGNOSTIC MARKERS. The Company intends to use  information
      from  the  Human  Genome Project  and  related efforts  to  identify genes
      associated with particular diseases and use the proteins encoded by  these
      genes  in  new diagnostic  tests. The  Company will  seek to  partner with
      established diagnostic companies by providing these novel protein  markers
      for development and commercialization as conventional immunoassays.
 
   
    There   can  be  no  assurance  that  the  Company  will  be  successful  in
implementing its strategy or  marketing its GeneChip  system for these  genomics
and    diagnostic    applications.   The    Company's   GeneChip    system   and
    
 
                                       30
<PAGE>
   
other potential  products will  require significant  additional development  and
investment,  including testing  to further validate  performance and demonstrate
cost effectiveness. While the Company's  initial product sales for research  use
have  not required regulatory  approval, the Company  expects that such approval
will be required for diagnostic applications in the future. The Company may need
to undertake costly and  time-consuming efforts to  obtain this approval.  There
can  be no assurance that any products will be successfully developed, be proven
to be  accurate  and efficacious  in  any markets,  meet  applicable  regulatory
standards in a timely manner or at all, be protected from competition by others,
avoid infringing the proprietary rights of others, be manufactured in sufficient
quantities or at reasonable costs, or be marketed successfully.
    
 
TECHNOLOGY
 
   
    Affymetrix'  probe  array  technology  and  systems  integrate semiconductor
fabrication techniques, molecular biology,  solid phase chemistry, software  and
robotics.  The  Company's GeneChip  system  consists of  four  integrated parts:
disposable DNA probe arrays containing genetic information on a chip housed in a
cartridge, a  fluidics station  for introducing  the test  sample to  the  probe
arrays,  a  scanner to  read the  data from  the probe  arrays, and  software to
control the  instruments,  analyze  and  manage  the  genetic  information.  The
GeneChip  system  is  designed  for  use  by  pharmaceutical  and  biotechnology
companies, academic research  centers and reference  laboratories. The price  of
the   Company's  GeneChip  system,  excluding  probe  arrays,  is  approximately
$120,000. The HIV probe  array, currently being  sold commercially for  research
use, is priced at $45 per array.
    
 
    DNA PROBE ARRAYS.  The Company produces its DNA probe arrays using a process
based  on semiconductor photolithographic  fabrication techniques, which enables
it to assemble vast amounts of genetic information on a small glass chip  called
a  probe array. The genetic information is  contained in sequences of DNA probes
that are  built on  the  probe array.  This  process uses  technology  initially
developed  at  Affymax  and exclusively  licensed  to the  Company  for selected
applications. The Company  believes that this  technology enables the  efficient
use  of a large number of  DNA probes to analyze DNA  or RNA sequences in a test
sample.
 
          ILLUSTRATION OF THE LIGHT DIRECTED PROBE ARRAY SYNTHESIS PROCESS
 
                               [DIAGRAM]
 
    The Company  uses  photolithography  to  synthesize  large  numbers  of  DNA
sequences simultaneously in specific locations on a glass chip. Photolithography
is  a  technique  which uses  light  to  induce chemical  reactions  that create
exposure patterns on the glass chip. The process begins by coating the chip with
light-sensitive chemical compounds (defined as "protecting" groups) that prevent
chemical coupling. Lithographic masks,  which consist of predetermined  patterns
that  either block  or transmit  light, are  used to  selectively illuminate the
glass surface of the chip. Only those areas exposed to light are deprotected and
thus activated  for chemical  coupling through  removal of  the  light-sensitive
protecting    groups.   The   entire   surface    is   then   flooded   with   a
 
                                       31
<PAGE>
solution containing the first in a series of DNA building blocks (A, C, G or T).
Coupling only  occurs  in those  regions  which have  been  deprotected  through
illumination. The new DNA building block also bears a light-sensitive protecting
group  so that the cycle can be repeated.  This process of exposure to light and
subsequent chemical  coupling can  be repeated  on  the same  chip in  order  to
generate  an array of  DNA sequences. The  intricate illumination patterns allow
the Company to build arrays of many  diverse DNA sequences in a small area.  The
Company  can manufacture a large number of identical DNA probe arrays on a large
glass wafer, which is then diced into single probe arrays.
 
    Each probe array  contains thousands  of "features."  Each feature  contains
millions  of  copies of  the same  single-stranded DNA  sequence, or  probe. The
patterns of photolithographic masks and the order of DNA building blocks used in
the synthesis process dictate the sequence of the probes in each feature on  the
chip  surface. The number of  synthesis cycles determines the  length of the DNA
probes in each feature.
 
                               [DIAGRAM]
 
    The Company's GeneChip  technology enables  it to  effectively synthesize  a
large  number  of  DNA sequences,  which  would  not be  possible  with existing
technologies. Unlike  conventional  synthesis,  which generally  uses  a  linear
process   to   create   compounds,  the   Company's   synthesis   technology  is
combinatorial, in that the number  of compounds synthesized grows  exponentially
with  the number of cycles in the synthesis. For example, in a 40 cycle process,
Affymetrix has  produced a  probe array  with over  one million  features,  each
containing  a  unique DNA  sequence. This  process would  take over  ten million
cycles using standard DNA synthesis techniques.
 
    The function of each single-stranded probe on the GeneChip probe array is to
bind to its complementary single strand of  DNA or RNA from the patient  sample.
Each  feature on the GeneChip probe array  contains identical copies of a single
strand of DNA. The nucleic acid to be tested is isolated from a sample, such  as
blood  or biopsy  tissue, and fluorescently  labeled by one  of several standard
biochemical methods. The test sample is then washed over the probe array surface
and the labeled test sample binds, or hybridizes, to the complementary probes if
they are present in the probe array.  When scanned by the laser in the  GeneChip
scanner, the hybridized test sample generates a fluorescent signal. The presence
and  sequence of the  nucleic acid sample  can be determined  by detecting these
signals since the sequence and position  of each complementary DNA probe on  the
probe array are known. The Company's currently manufactured probe arrays contain
from 16,000 to more than 100,000 features.
 
                                       32
<PAGE>
    INSTRUMENTATION.  The fluidics station controls the introduction of the test
sample to the probe array and the hybridization process. A technician places the
test  sample in a small container in  the fluidics station, which introduces the
test sample into the  cartridge containing the DNA  probe array. The  technician
uses  a  computer  to  control  the delivery  of  reagents  and  the  timing and
temperature required for hybridization  of the test sample  to the probe  array.
The  process concludes with a reagent wash  that leaves only the hybridized test
sample bound to  the probe array.  The fluidics station  can process four  probe
arrays  simultaneously, typically  taking less  than one  hour to  process these
arrays.
 
    After completion of  hybridization on the  fluidics station, the  technician
places  the cartridge in the  scanner which reads the  probe array. The GeneChip
scanner consists of a  laser, high resolution optics,  robotics to position  and
scan  the  cartridge, a  fluorescence detector  and an  interface to  a personal
computer. The label on the test sample emits fluorescent signals when excited by
the light from the laser. The intensity of the fluorescent signal is recorded by
the scanner and stored in the  computer. The current scanner can read  1.28X1.28
centimeter probe arrays with up to 64,000 features. An advanced scanner is being
developed to read 1.28X1.28 centimeter probe arrays with up to 400,000 features.
However,  there  can be  no  assurance that  this  scanner will  be successfully
developed or commercialized.
 
    SOFTWARE.   The  GeneChip  product  software is  supplied  as  part  of  the
integrated  system and  runs on a  Windows platform.  The fluorescence intensity
data captured  from the  scanner are  used in  conjunction with  computer  files
containing  the sequence and  location of all  the probes on  the probe array to
determine the  nucleotide sequence  of the  test sample.  For the  HIV  GeneChip
product,  the analysis takes  less than 90  seconds for one  probe array and the
resulting sequence is displayed on the computer. Customized software enables the
technician to rapidly identify polymorphisms in  the test sample and to  compare
genetic sequences across test samples.
 
GENOMICS APPLICATION AREAS
 
    Affymetrix  is applying  the GeneChip  technology to  create a  platform for
genomics  and  pharmaceutical  research.  Genomics  applications  include   gene
discovery, genetic mapping, expression monitoring and polymorphism screening.
 
    GENE  DISCOVERY.   The  discovery  of genes  may  be an  important  means to
understand disease and  to design  new therapies. A  large number  of the  genes
identified  to date have been classified into families based on common sequences
within these genes. One approach to  gene discovery uses these common  sequences
to search for and identify previously unknown members of these gene families. To
facilitate  this approach,  the Company  designs DNA  probe arrays  containing a
large number of  probes for  both common and  variable regions  of known  genes.
Using  this technology,  samples containing DNA  are screened  against the probe
arrays, and, for  genes that  are already known,  both the  variable and  common
regions  are detected  from the sample.  For previously unknown  genes, only the
common regions are detected, thus identifying a new gene.
 
    The Company believes that this approach to gene discovery may accelerate the
rate of  new gene  identification. In  November 1994,  Affymetrix established  a
collaboration  with GI to apply the GeneChip  technology to the discovery of new
genes and uses of genes in selected  gene areas. As part of this  collaboration,
GI  and the  Company have  undertaken a  three-year research  project whereby GI
provides research funding. In addition, Affymetrix supplies custom probe  arrays
to GI for specified fees and may receive milestone payments and royalties.
 
    GENETIC  MAPPING.    Genetic  mapping is  an  important  method  for linking
diseases to particular genes. Over the last five years, over 60 genes have  been
linked  to known diseases by this  method. However, the current technologies for
mapping genes are  slow and labor  intensive. This problem  is exacerbated  when
looking at complex diseases such as diabetes, asthma, and cardiovascular disease
which  are believed to be associated with multiple genes. Using genetic mapping,
researchers attempt  to find  disease genes  by using  markers. The  correlation
between  markers in diseased and healthy people enables researchers to link such
genes to a particular disease state.  Research to identify markers is  currently
being  conducted by  various academic and  scientific groups  to improve genetic
mapping techniques.  The  Company  has  established  a  collaboration  with  the
Whitehead  Institute for Biomedical  Research at the  Massachusetts Institute of
Technology ("MIT")  to  design  probe  arrays with  new  markers  identified  by
Whitehead    scientists.    The    Company    intends    to    develop   mapping
 
                                       33
<PAGE>
   
probe arrays  based upon  publicly available  markers as  well as  custom  probe
arrays  based  upon proprietary  markers. The  Company  intends to  market these
arrays to  pharmaceutical and  biotechnology  companies for  conducting  genetic
mapping.  There  can be  no  assurance that  these  arrays will  be successfully
developed or marketed to these or other customers.
    
 
    EXPRESSION  MONITORING.    Currently,  large  amounts  of  genetic  sequence
information  are being generated,  through the Human  Genome Project and related
efforts, yet relatively little is understood  about the function of most  genes.
Affymetrix   believes  that  monitoring  gene   expression  is  fundamental  for
understanding the function of genes and their role in disease. To facilitate the
monitoring of gene expression, the Company designs probe arrays with DNA  probes
that  are complementary to  a sequence within  a gene of  interest. By providing
sequence information, these probe arrays may enable researchers to identify  the
particular  gene and quantitatively measure its  level of expression compared to
other genes of interest in the test sample. By synthesizing specific probes  for
multiple  genes on a single probe array, the Company also enables researchers to
quickly, quantitatively and  simultaneously monitor  the expression  of a  large
number  of genes  of interest.  By monitoring  the expression  of such  genes at
different times,  researchers  can  use  the probe  arrays  to  understand  gene
expression  and how it  is related to disease  progression. The Company believes
that such  information will  be an  important  tool in  the development  of  new
therapeutics.
 
    Under its collaboration with GI established in November 1994, the Company is
receiving   research  funding  to  develop  probe  arrays  for  gene  expression
monitoring. The Company will also  design, manufacture, and supply custom  probe
arrays for GI pursuant to a second agreement executed in December 1995. Multiple
custom  DNA  probe  arrays  will  be designed  by  the  Company  to  monitor the
expression patterns of  approximately 15,000  genes to  be specified  by GI.  GI
retains  all rights to  discovered genes and their  uses. Affymetrix will supply
custom probe arrays for  specified fees and may  receive milestone payments  and
royalties  on certain  therapeutic products  based on  the discovered  genes. In
April 1996, the Company  also entered into an  agreement with Incyte to  explore
the potential use of DNA probe arrays in the area of gene expression.
 
    POLYMORPHISM  SCREENING.  As  the identity of  genes in the  human genome is
determined, the  need  to understand  the  significance of  the  variability  of
nucleotide  sequences in these  genes increases. Researchers  must determine the
normal sequence  of the  gene, which  mutations exist  and how  these  mutations
correlate  with a disease. This requires the  sequencing of samples from a large
number of  affected  and  unaffected individuals.  Using  sequencing  strategies
developed  for  the HIV  probe array,  Affymetrix  believes that  GeneChip probe
arrays could significantly reduce the  cost and time of polymorphism  screening,
which  is  currently  done  through more  labor  intensive  gel-based sequencing
techniques. In May  1996, the Company  entered into an  agreement with Glaxo  to
design,  test  and supply  probe  arrays to  demonstrate  use of  the  arrays in
detecting polymorphisms in specific genes. Glaxo and Affymetrix will design  and
test  a probe array containing several genes specified by Glaxo. If successfully
developed, Affymetrix will supply Glaxo's requirements of such probe arrays  for
research purposes.
 
   
    There  can be  no assurance that  the Company's  collaborative partners will
perform their obligations as expected or will devote sufficient resources to the
development, testing or marketing of the Company's potential products  developed
under  the collaborations. Further, there can  be no assurance that any products
for genomics  applications  will be  successfully  developed, be  proven  to  be
accurate  and  efficacious  in any  markets,  be protected  from  competition by
others, avoid infringing the  proprietary rights of  others, be manufactured  in
sufficient quantities or at reasonable costs, or be marketed successfully.
    
 
DIAGNOSTIC PRODUCTS AND RESEARCH APPLICATIONS
 
    Affymetrix  intends to use the GeneChip  platform in conjunction with public
and private  gene databases  to discover  and develop  diagnostic products.  The
Company  is pursuing diagnostic products and research applications in infectious
diseases, cancer and other areas, including drug metabolism.
 
    INFECTIOUS DISEASES.    The Company  believes  its GeneChip  technology  may
enable  it  to  develop tests  which,  by  sequencing large  amounts  of genetic
information and quantitatively measuring levels of gene expression, can  provide
information that could improve treatments for many infectious diseases.
 
                                       34
<PAGE>
    Industry sources estimate that in North America and Europe approximately 1.5
million persons are infected with HIV and that approximately 100,000 persons are
diagnosed  with AIDS annually.  Many HIV symptomatic  patients receive antiviral
treatment with  reverse  transcriptase  inhibitors, such  as  AZT,  or  protease
inhibitors,  both of which  block proteins required for  the virus to replicate.
The HIV  genome encodes  the reverse  transcriptase and  protease gene  proteins
within  approximately 1,400  bases (or approximately  15%) of  the viral genome.
Mutations in the viral genome result  from errors in replication. Some of  these
mutations  confer resistance  to the antiviral  drugs being  administered to the
patient. It  is  believed  that  the identity  of  nucleotides  in  the  reverse
transcriptase  and  protease  genes will  be  essential  in order  to  monitor a
patient's drug resistance profile.
 
    Affymetrix has developed the GeneChip system with an HIV probe array as  its
first  product for commercialization. The  Company believes this GeneChip system
will  enable  researchers  to  identify  the  mutations  associated  with   drug
resistance  in  HIV  infected patients  and  allow researchers  to  identify new
mutations. The  HIV probe  array  contains DNA  probes in  approximately  20,000
features  that  represent sequences  of the  reverse transcriptase  and protease
genes of the virus. These features can identify mutations at any of the sites in
the genes that have been associated with drug resistance. The Company expects to
initially market the HIV product for research use in identifying the correlation
between mutations in the  virus and drug resistance.  The Company believes  that
monitoring  drug  resistance  related  mutations  during  therapy  may  become a
valuable aspect  of  patient management.  Affymetrix  has placed  five  GeneChip
systems  for  the  HIV  application  in  academic  research  and  pharmaceutical
companies for evaluation and validation. The Company commenced commercial  sales
of  the GeneChip system and HIV probe array for research use only in April 1996.
The  Company  will  rely  on  third  parties  to  manufacture  and  service  its
instruments.  The Company  has no prior  experience in  introducing a commercial
product. There  can  be  no  assurance  that  technicians  will  not  experience
difficulties  with the system that would prevent  or limit its use. In addition,
there can be  no assurance that  the efficiency  and accuracy of  the HIV  probe
array  in providing  sequence information from  HIV will be  better than current
technologies, such as gel-based sequencing.
 
    The Company  intends  to  develop  additional  diagnostic  products  in  the
infectious  disease area that  could determine complex  drug resistance and gene
identification  information.  The  Company  is  evaluating  the  development  of
additional GeneChip probe tests for bacterial, viral and fungal infections, such
as   tuberculosis  and  cytomegalovirus  (CMV).  The  Company  intends  to  seek
collaborators to participate in the funding, development and marketing of  these
tests.
 
    CANCER.  In the United States, approximately 1.1 million new cases of cancer
are  diagnosed  annually and  the incidence  of  cancer deaths  is approximately
520,000 individuals  each year.  Colorectal, breast,  prostate and  lung  cancer
account for approximately half of all diagnoses.
 
    The  p53 gene  encodes a  protein whose normal  function is  to control cell
replication. However, mutations in the p53 gene  can result in the loss of  this
function  and are known to contribute to  the aggressive growth of some types of
cancer, including colorectal,  breast and bladder  cancers. Mutations have  been
observed  to date  at more  than 400  distinct sites  in the  p53 gene sequence.
Currently available diagnostic tests include IN VITRO assays that use antibodies
to detect the accumulation of p53 molecules in cells but cannot directly  detect
mutations  in the p53 gene. Gel-based sequencing methods are impractical because
mutations can occur over a large area  of the genome, requiring many gels to  be
processed  to sequence the entire gene. As a result, these methods are unable to
predict the rate of cancer progression. Understanding the rate of progression is
often necessary  to determine  whether to  treat the  cancer with  chemotherapy,
radiation or surgery.
 
    The Company is currently developing a GeneChip p53 probe array that contains
DNA  probes to detect known mutation sites, as  well as to sequence areas of the
p53 gene where other mutations may occur but have currently not been identified.
Initially, the Company  intends to  market these  p53 probe  arrays to  academic
research  centers and reference laboratories to  study the p53 gene. The Company
also intends to seek regulatory approval to use the p53 probe array for clinical
use to assist in  monitoring cancer progression  and improving patient  therapy.
The  Company  is currently  evaluating other  genes  associated with  cancer for
potential product development.  There can  be no  assurance that  the p53  probe
array  or other cancer products will  be developed, receive regulatory approvals
or be successfully commercialized.
 
                                       35
<PAGE>
    OTHER APPLICATIONS.  The  Company is developing  its GeneChip technology  to
address  other applications in pharmaceutical  research, such as monitoring drug
metabolism.
 
    Monitoring drug metabolism  is an essential  component in drug  development.
Drug  metabolism  determines  how quickly  or  slowly  a drug  is  eliminated or
rendered inactive  and  whether  any of  the  drug  is processed  into  a  toxic
compound.  Genetic differences  among patients are  an important  factor in drug
metabolism. Variations in drug  metabolism are important  to the development  of
new  drugs because these  variations determine how patients  will react to drugs
and which drugs will have relatively uniform effects across a broad  population.
Certain  of  the genes  coding for  metabolic enzymes  have been  identified and
sequenced by researchers. Patients  who have mutations in  these genes are  poor
metabolizers of drugs and may suffer from excessive drug accumulation and severe
toxicity from standard drug doses.
 
    Affymetrix  is collaborating with HP to  develop a GeneChip probe array with
probes containing  the  gene sequence  of  mutations  in two  genes  coding  for
metabolic  enzymes.  Mutations  in these  two  genes have  been  associated with
patients who are  poor metabolizers of  numerous drugs. HP  will have  worldwide
marketing rights for the probe arrays in the nonclinical market, which are to be
manufactured  and supplied by the Company.  The Company is entitled to royalties
and revenues, if any, from the supply of these probe arrays to HP. There can  be
no  assurance that these DNA probe arrays will be developed or commercialized or
will result in revenues to the Company.
 
    NEW DIAGNOSTIC MARKERS.   As genes are discovered  through the Human  Genome
Project  and related efforts, the  Company believes that additional correlations
will be found between genes and disease. Affymetrix believes that by using probe
arrays to monitor the levels of expression of many genes in parallel, it will be
able to identify proteins encoded by these  genes that can serve as new  markers
for   conventional  immunoassays.  The  Company   intends  to  collaborate  with
diagnostic companies  to  incorporate  such  protein  markers  into  established
immunoassay  formats. There can be no assurance that the Company will be able to
identify any new markers, negotiate such collaborative agreements on  acceptable
terms, if at all, or that such collaborations will be successful.
 
   
    There can be no assurance that any products for diagnostic applications will
be  successfully  developed, be  proven to  be accurate  and efficacious  in any
markets, meet applicable regulatory standards in  a timely manner or at all,  be
protected from competition by others, avoid infringing the proprietary rights of
others,  be manufactured in sufficient quantities  or at reasonable costs, or be
marketed successfully.
    
 
MANUFACTURING
 
    The Company's strategy  is to  manufacture its disposable  DNA probe  arrays
in-house  and contract  with third-party  suppliers to  manufacture the fluidics
station and scanner for its GeneChip system.
 
    The Company is  currently manufacturing limited  quantities of probe  arrays
for  internal  and  collaborative purposes  and  for initial  product  sales for
research use. The  Company's probe  array manufacturing  process involves  wafer
preparation,  probe synthesis, dicing of synthesized wafers into chips, assembly
of chips into  cartridges, and quality  control. Glass wafers  are prepared  for
synthesis   through  the  application  of  chemical  coatings.  DNA  probes  are
synthesized on  the wafers  using  the Company's  proprietary  photolithographic
process.  The completed wafers are then  diced to yield individual probe arrays,
which are assembled into  disposable cartridges and  packaged for shipment.  The
Company's  probe array  synthesis, dicing  and assembly  processes currently use
robotics and the  Company's manufacturing  process is  partially automated.  The
Company  intends to further automate the  manufacturing process. There can be no
assurance that manufacturing and quality control problems will not arise as  the
Company  attempts to scale-up its manufacturing facilities or that such scale-up
can be  acheived  in  a  timely manner  or  at  commercially  reasonable  costs.
Affymetrix   has   developed   software  programs   that   automatically  design
photolithographic masks used in probe array manufacturing and control the  probe
array manufacturing lines.
 
    The  Company relies on outside vendors  to manufacture its fluidics stations
and scanners. The Company has a supply agreement with Molecular Dynamics for its
current   scanner,    which   can    read   up    to   64,000    features    per
 
                                       36
<PAGE>
1.28X1.28  centimeter probe array.  The Company's HIV  probe array currently has
20,000 features on a 1.28X1.28 centimeter probe  array and may be used with  the
Molecular  Dynamics  scanner.  The  Company expects  to  purchase  scanners from
Molecular Dynamics through the end of 1996.
 
    As part of the  Company's collaboration with HP,  HP is developing a  higher
resolution  scanner. The HP scanner is designed  to read probe arrays with up to
400,000 features per 1.28X1.28 centimeter probe array. The Company expects  that
the  HP scanner will be commercially available  for use with the Company's probe
arrays in 1997.
 
    The fluidics stations  currently in  the field are  prototype versions  that
were manufactured by the Company. The Company has entered into an agreement with
RELA,  a private company, for  the supply of fluidics  stations. Pursuant to the
Company's supply  agreement with  RELA,  the Company  must provide  a  six-month
rolling  forecast  of its  purchase requirements  for  fluidics stations  and is
obligated to make certain  minimum purchases, at prices  that vary depending  on
the volume ordered.
 
    There   can  be  no  assurance  that   the  HP  scanner  will  be  developed
successfully. Further,  no assurance  can be  given that  probe array  scanners,
fluidics  stations or  reagents will  be available  in commercial  quantities at
acceptable costs. If  the Company  is required  to seek  alternative sources  of
supply,  it could be time  consuming and expensive. In  addition, the Company is
dependent on  its  vendors to  provide  components of  appropriate  quality  and
reliability and to meet applicable regulatory requirements. Consequently, in the
event  that supplies  from these suppliers  were delayed or  interrupted for any
reason, the  Company's ability  to  develop and  supply  its products  could  be
impaired,  which could have a material adverse effect on the Company's business,
financial condition and results of operations.
 
    The GeneChip system is a complex  set of instruments and includes DNA  probe
arrays,  which  are  produced  in an  innovative  and  complicated manufacturing
process. During the beta testing phase of the GeneChip system's development, the
Company and its vendors have  encountered and satisfactorily addressed a  number
of  technical problems, including software failures, improper alignment of probe
array wafers, valve  and tube failures  in the fluidics  station, sensor  wiring
issues and scanner control problems. Due to the complexity and lack of operating
history  of these  products, the  Company anticipates  that additional technical
problems may occur or be discovered  as more systems are placed into  operation.
If  these  problems cannot  be  readily addressed,  they  could cause  delays in
shipments, warranty expenses and damages to customer relationships, which  would
have  a material adverse  effect on the  Company's business, financial condition
and results of operations.
 
    Although the  Company  does  not  currently  need  to  comply  with  GMP  to
manufacture  probe  arrays and  related  instrumentation for  sale  for research
purposes, it may need  to be GMP  compliant to sell  these products to  clinical
reference  laboratories and it will need to  be compliant to sell these products
for clinical  use. There  can be  no assurance  that manufacturing  and  quality
control  problems  will  not  arise  as the  Company  attempts  to  scale-up its
manufacturing facilities  or that  such scale-up  can be  achieved in  a  timely
manner or at a commercially reasonable cost.
 
SALES AND MARKETING
 
    The   Company  intends  to   market  the  GeneChip   system  for  diagnostic
applications through direct  sales efforts and  collaborative arrangements  with
corporate  partners and distributors. The Company intends to market the GeneChip
system for genomics applications through collaborations with corporate partners.
The Company's near  term strategy is  to commercialize the  GeneChip system  for
research  use only.  The Company's  longer term  strategy is  to seek regulatory
approval for  and to  commercialize  GeneChip systems  as diagnostic  tests  for
clinical  use. To date, the Company has  placed nine systems for research use in
the United States. Five of these systems are for HIV applications.
 
    The Company believes that the primary market for diagnostic applications  in
the  United  States  will  be  academic  research  centers,  pharmaceutical  and
biotechnology companies  and  reference  laboratories. The  Company  intends  to
establish  a  direct sales  force  to market  to  these potential  customers for
research use. The Company believes that academic research centers could use  the
GeneChip   system  in  their  disease   related  research.  Affymetrix  believes
pharmaceutical  companies  could  use  the  GeneChip  system  to  study  genetic
variations in patients participating in clinical trials of new drugs. Currently,
there  are three major reference laboratory  companies in the United States, two
of   which    are    associated    with    large    pharmaceutical    companies.
 
                                       37
<PAGE>
These  reference laboratories are specialized laboratories at multiple locations
that conduct complex  testing for the  diagnosis and monitoring  of disease  and
clinical  trials and testing for pharmaceutical and biotechnology companies. The
Company believes that each of these  reference laboratories could be a  customer
for  the  GeneChip system  and  may require  multiple  systems at  each location
depending on the volume and complexity of the tests.
 
    The Company believes that the primary international customers for diagnostic
applications  of  its  GeneChip  system  will  be  academic  research   centers,
pharmaceutical    and   biotechnology   companies,   and   independent   testing
laboratories. The Company initially intends to market to these customers through
collaborative partners. To date, the Company has not placed any of its  GeneChip
systems outside the United States.
 
    Affymetrix  believes that the primary customers for genomics applications of
its GeneChip  system will  be pharmaceutical  and biotechnology  companies  that
would  use the GeneChip system in  the discovery of new therapeutics. Affymetrix
intends to  market  to  these  customers  directly  and  to  form  non-exclusive
contracts  for  the  design, manufacture  and  supply of  custom  GeneChip probe
arrays. Affymetrix currently  has a  small internal technical  support group  to
service  its GeneChip system, which the  Company intends to expand as necessary.
The Company believes  that it will  need to develop  a larger technical  support
infrastructure to service these collaborations.
 
    Under the Company's collaboration with HP, HP has worldwide rights to market
GeneChip  systems in specified nonclinical markets.  Affymetrix has the right to
market the system in the clinical  diagnostic market, subject to HP's option  to
certain rights in selected clinical markets.
 
    Market   acceptance  will  depend  on  many  factors,  including  convincing
researchers  the  GeneChip  system  is  an  attractive  alternative  to  current
technologies   for  the   acquisition,  analysis   and  management   of  genetic
information; the receipt of regulatory clearances in the United States,  Europe,
Japan  and elsewhere; the  need for laboratories  to license other technologies,
such as amplification  technologies that  may be  required to  use the  GeneChip
system for certain applications; and the availability of new proprietary markers
that  may be important to the diagnosis, monitoring and treatment of disease for
incorporation on the Company's probe arrays. Market acceptance may be  adversely
affected  by ethical concerns that may limit  the use of the GeneChip system for
certain diagnostic  applications  or the  analysis  of genetic  information.  In
addition,  potential  customers  will  need  skilled  laboratory  technicians to
operate the GeneChip system. Market acceptance of the GeneChip system could also
be adversely affected by limited funding available for academic research centers
and other research  centers that are  the potential customers  for the  GeneChip
system. The Company anticipates a long sales cycle to market the GeneChip system
to  its potential customers. There can be  no assurance that the Company will be
able to  establish  a  direct  sales force  or  to  establish  collaborative  or
distribution  arrangements to market its products. Failure to do so would have a
material adverse  effect  on the  Company's  business, financial  condition  and
results of operations.
 
RESEARCH AND DEVELOPMENT
 
    The Company believes that substantial investment in research and development
is  essential to obtaining a competitive position in the genetic information and
diagnostics  markets.  Affymetrix  focuses  on  three  types  of  research   and
development:   applied  research,  including  diagnostic  product  research  and
discovery;  core   technology  development,   including  manufacturing   process
refinement,  new instrumentation design, and novel chemical synthesis; and basic
research to explore and  expand the potential  uses of DNA  probe arrays and  to
discover new technologies.
 
    APPLIED  RESEARCH.  Affymetrix  has several diagnostic  research projects in
three major diagnostic fields: infectious disease, cancer and other diseases. In
the infectious disease area, the Company is evaluating probe array  applications
for  several infectious organisms,  such as tuberculosis  and CMV. The Company's
research in cancer  is focused  on monitoring mutations  associated with  cancer
progression  and the discovery of diagnostic  markers for cancers such as breast
and colorectal cancers. The Company has a collaboration with Dr. Francis Collins
at the NIH  for the development  of probe  arrays directed to  the detection  of
certain  mutations  believed to  be associated  with  the development  of breast
cancer.
 
    Other research efforts  at Affymetrix  are currently  focused on  developing
probe  arrays for the diagnosis of genetic diseases and certain other disorders.
Affymetrix  has   conducted   a   feasibility   study   funded   by   Roche   to
 
                                       38
<PAGE>
develop  a probe array  to detect mutations  causing cystic fibrosis. Affymetrix
also intends to initiate research programs based on known markers, such as  HLA,
for  determining compatibility  for tissue  transplants. The  Company intends to
initiate research programs to discover novel markers for prevalent chronic human
diseases, such as cardiovascular disease, osteoporosis and arthritis.
 
    CORE TECHNOLOGY  DEVELOPMENT.   The  Company  conducts research  in  several
areas,   including  novel  and  improved  synthesis  chemistries,  manufacturing
processes, new manufacturing instrumentation, and enhancements in the design  of
fluidics  stations and scanners.  A significant research  effort is dedicated to
designing data analysis software to extract information from DNA probe arrays.
 
    BASIC RESEARCH.  Affymetrix' basic research efforts are focused on expanding
the  applications  of   the  GeneChip   system  and   discovering  related   new
technologies.  These efforts  are focused  on improving  sensitivity, increasing
capacity and conducting more complex assays.
 
    The Company's research and development expenses for the years ended December
31, 1995,  1994 and  1993, were  $12.4 million,  $9.5 million  and $6.6  million
respectively. Research and development expenses for the three-month period ended
March 31, 1996 and 1995 were $4.2 million and $2.3 million, respectively.
 
    Genomics  and  diagnostic technologies  have undergone  and are  expected to
continue  to  undergo   rapid  and  significant   change.  Rapid   technological
development  by the  Company or  others may  result in  products or technologies
becoming obsolete. In  addition, any products  offered by the  Company would  be
made  obsolete  by  less  expensive  or  more  effective  tests  based  on other
technologies or by new therapeutic or prophylactic agents that obviate the  need
for  diagnostic  and  monitoring information.  There  is no  assurance  that the
Company will be  able to make  the enhancements to  its technology necessary  to
compete successfully with newly emerging technologies.
 
COLLABORATIVE AGREEMENTS AND GRANTS
 
    The  Company's strategy regarding collaborative  agreements is to expand the
applications of the Company's technology and to acquire access to  complementary
technologies  and  resources,  such  as manufacturing  and  marketing,  from its
collaborative  partners.   Accordingly,  the   Company's  agreements   emphasize
preserving  the  Company's  rights  to  technological  improvements  and  future
business opportunities rather than large  up-front fees or sizeable  commitments
of research funding from its partners.
 
  GENETICS INSTITUTE, INC.
 
    In  November  1994, the  Company  entered into  a  collaboration with  GI to
develop and  apply new  technologies for  understanding the  functions of  human
genes.  Under the agreement, GI provides research funding to the Company for the
development of DNA probe arrays  used in DNA sequence  analysis to enable GI  to
discover  new genes and uses for genes  and to rapidly screen for the expression
of specified genes in both normal and diseased tissues.
 
   
    The initial term of  the research collaboration with  GI is three years.  In
the  event that  the specified technical  milestones are achieved  prior to such
time, GI  and the  Company may  either conclude  the collaboration  or agree  to
continue  the collaboration with additional milestones  for the remainder of the
three years. The  agreement provides  that if  the Company  enters into  similar
agreements  for gene expression with other third  parties, it may be required to
refund a portion of the development funding received from GI and future  funding
may  be proportionately reduced. As a result  of the agreement entered into with
Incyte in April 1996, the Company expects to refund a portion of such funding to
GI  in  1996.  In  addition,  either  party  has  the  right  to  terminate  the
collaboration  for lack of feasibility or  if the parties cannot reach agreement
on certain matters, in which event the  Company could be obligated to refund  up
to 50% of the funding paid by GI.
    
 
    Until  five years from the end of the research collaboration, Affymetrix has
agreed to  supply  custom  probe  arrays  to GI  for  gene  discovery  and  gene
expression  research  in  certain  designated  fields  in  return  for specified
payments. In addition,  upon the  achievement of technical  milestones, GI  pays
Affymetrix  milestone payments. Until November  1999, the Company cannot develop
probe arrays duplicating  specific characteristics  of those  developed for  GI.
Thereafter,  the Company can sell  such probe arrays, provided  that they do not
contain proprietary sequences or other confidential information belonging to GI.
GI will have all rights to therapeutic
 
                                       39
<PAGE>
compounds discovered through the use of DNA probes provided by the Company,  and
the  Company will receive  royalties on certain  such therapeutic compounds. The
Company retains all  rights to  enhancements to the  GeneChip system  technology
developed in the collaboration.
 
    In December 1995, the Company and GI expanded their relationship by entering
into  a supply agreement in  the field of genomics  under which the Company will
manufacture and supply additional  custom probe arrays  based on specific  genes
identified and selected by GI. Unlike the 1994 agreement with GI, this agreement
does  not provide research funding to the Company. Pursuant to the agreement, GI
is obligated to purchase and the Company is obligated to supply certain  minimum
quantities  of the custom probe arrays developed  for GI until the later of 2001
or four years  after development  of specified  probe arrays.  The Company  will
receive  fees for the design and delivery of the custom probe arrays, as well as
certain milestone  payments  and  royalties on  most  therapeutic  compounds  if
developed  by GI using these  probe arrays. GI has  exclusive rights to specific
probe arrays supplied by the Company.
 
    As of March 31, 1996, the Company had received a total of $1.8 million  from
GI, a portion of which is subject to refund.
 
  HEWLETT-PACKARD COMPANY
 
    In November 1994, the Company entered into a collaborative agreement with HP
to combine the Company's GeneChip technology and HP's measurement and instrument
capabilities  to develop  and manufacture a  more advanced scanner  for use with
GeneChip probe arrays.
 
    Pursuant to the agreement,  the Company will  develop and manufacture  probe
arrays  and HP will develop and manufacture instruments to read the arrays. Each
of the parties is obligated to supply the components of the system developed  by
it  to the other party.  Under certain circumstances, if  either party ceases to
supply its component, the other party  could obtain the manufacturing rights  to
such component.
 
    The agreement also specifies marketing rights outside of the clinical market
in  certain non-clinical  fields. HP has  primary rights to  market the GeneChip
system to the bioanalytical market, and the Company has primary rights to market
the GeneChip system in the biomedical research market. The Company has rights to
market the system for clinical use, subject to HP's option to certain rights  in
selected clinical markets. The Company also has reserved rights to supply custom
probe arrays for collaborations in the genomics field.
 
    As  of March 31, 1996, the Company had received a total of $3.0 million from
HP under this collaboration,  consisting of research  funding, license fees  and
option  payments.  The Company  is also  entitled  to receive  certain milestone
payments and royalties on HP's sales of  the GeneChip system and HP is  entitled
to  receive royalties on any  systems sold by the  Company. The collaboration is
for  a  five-year  term  and  is  renewable  for  consecutive  three-year  terms
thereafter, subject to either party's right to terminate on six months notice.
 
    Pursuant  to  the agreement,  the Company,  in  collaboration with  HP, will
manufacture and supply a limited number of custom probe array designs for HP  in
the nonclinical field. HP also has a one-year option, to sponsor the development
of  custom  probe arrays  in certain  specified fields  and to  obtain exclusive
rights to such probe  arrays. In the  event that HP  exercises such option,  the
Company  will be required to develop the probe  arrays on a timely basis. If the
Company fails to  provide the  requested probe arrays,  it will  be required  to
grant  HP rights to  develop and manufacture  such probe arrays,  subject to the
payment of established royalty rates to the Company.
 
  ADVANCED TECHNOLOGY PROGRAM (UNITED STATES DEPARTMENT OF COMMERCE)
 
    In October 1994,  the Company and  Molecular Dynamics were  awarded a  $31.5
million  five-year grant to develop novel point-of-care diagnostic systems under
the  National  Institute  of  Standards  and  Technology's  Advanced  Technology
Program.  Pursuant to the grant, $20.8 million is designated for the Company and
its  subcontractors  and   $10.7  million   for  Molecular   Dynamics  and   its
subcontractors subject to the requirement of each company to match such funding.
The  grant specifies  the development of  an advanced  miniaturized nucleic acid
diagnostic device  intended to  reduce  the costs  and  increase the  speed  and
reliability  of DNA diagnostic tests. The  device would be used in point-of-care
settings,  such  as  hospitals,  clinics  and  doctors'  offices.  The  research
agreements  between the Company and its  subcontractors under the ATP grant (the
University of
 
                                       40
<PAGE>
California, Stanford University and the  University of Washington) require  that
the universities assign the rights to any project inventions made by them to the
Company  subject to specified royalty payments.  The ATP agreement provides that
the Company and Molecular Dynamics retain  rights in their respective fields  to
intellectual property developed as part of the project.
 
    The  ATP grant is administered by  the United States Department of Commerce.
As of March 31, 1996, the Company had received $1.4 million under the ATP grant.
The grant is subject to yearly appropriations by the United States Congress  for
the  ATP program, and legislation has  been introduced to eliminate the program.
There can be no assurance that funding  for the ATP program will not be  reduced
or  eliminated at any time. The reduction  or elimination of the ATP grant could
have a material adverse  effect on the  Company's business, financial  condition
and results of operations.
 
  NATIONAL INSTITUTES OF HEALTH
 
    In  August 1995, the  Company received a  three-year grant for approximately
$6.0 million  from the  NIH National  Center for  Human Genome  Research, for  a
project  entitled  "Sequencing and  Mapping with  DNA  Probe Arrays."  Under the
project, the Company is developing applications  of DNA probe arrays for  larger
scale  gene  sequencing and  creating a  laboratory  at the  Company for  use by
outside researchers.  The  grant  also  includes  a  subcontract  with  Stanford
University  to  continue  research  and  development  of  the  DNA  probe  array
technology. The  Company has  been awarded  approximately $2.0  million for  the
first  year  of the  grant,  and the  remaining  amounts are  subject  to yearly
appropriations by the NIH. There  can be no assurance  that the NIH will  obtain
the  necessary funding from the United States  Congress to continue to fund this
grant.
 
  OTHER AGREEMENTS
 
   
    The Company has agreements with several  entities to develop and test  probe
arrays  for the  detection of  certain gene  sequences, mutations  or organisms.
These include a  one-year feasibility  agreement with  Roche Molecular  Systems,
Inc.,  entered  into  in  November  1995,  for  detection  of  certain mutations
associated with  the  cystic fibrosis  transmembrane  regulator (CFTR)  gene,  a
six-month  feasibility  agreement with  Incyte, entered  into  in April  1996 to
evaluate the use of  DNA probe arrays  to generate gene  expression data, and  a
development  and  supply  agreement entered  into  in  May 1996  with  Glaxo for
detection of polymorphisms in specific  genes, which has a  term of up to  three
years.  Under such agreements,  the Company is typically  paid a development fee
and may receive milestone payments upon achievement of certain technical  goals.
The  Company also has research agreements with several universities and research
organizations. For  example,  the Company  has  an agreement  with  Dr.  Francis
Collins  at  the NIH  for  the development  of  probe arrays  to  detect certain
mutations believed to be associated with  the development of breast cancer,  and
an  agreement with  Dr. Eric  Lander at  the Whitehead  Institute for Biomedical
Research at  MIT  to  collaborate  in the  investigation  of  single  nucleotide
polymorphism markers using DNA probe arrays.
    
 
    The  Company generally obtains rights  to intellectual property arising from
these agreements. If a  project is successful, the  Company and the  third-party
collaborator  would negotiate the right to commercialize products resulting from
such project. The  Company has received  a substantial portion  of its  revenues
since  inception  from  its collaborative  partners  and intends  to  enter into
collaborative arrangements with  other companies to  apply its technology,  fund
development,  commercialize potential  future products, and  assist in obtaining
regulatory approval. There can be no assurance that any of the Company's present
or future collaborative partners will  perform their obligations as expected  or
will  devote  sufficient  resources  to  the  development,  clinical  testing or
marketing  of   the   Company's   potential   products   developed   under   the
collaborations.  There can  be no  assurance that  the Company  will be  able to
maintain its  current collaborations,  negotiate collaborative  arrangements  on
acceptable terms, if at all, or that any collaborations will be successful.
 
INTELLECTUAL PROPERTY
 
   
    As  of April  15, 1996, Affymetrix  had exclusive licenses  from Affymax for
over 20 patents  and patent  applications in the  United States  related to  its
business in the fields of clinical diagnostics and research supply. In addition,
Affymetrix  is  the assignee  of 52  United States  patent applications  and one
issued patent in the United States. Many of these patents and applications  have
been  filed  and/or issued  in one  or more  foreign countries.  Affymetrix also
relies  upon   copyright  protection,   trade  secrets,   know-how,   continuing
technological
    
 
                                       41
<PAGE>
innovation  and licensing opportunities to  develop and maintain its competitive
position. The Company's  success will depend  in part on  its ability to  obtain
patent  protection for its products and processes, to preserve its copyright and
trade secrets and to operate without infringing the proprietary rights of  third
parties.
 
    In  1993 Affymetrix and Affymax entered  into a technology license agreement
(the "Technology  License  Agreement")  pursuant to  which  Affymax  granted  to
Affymetrix   an  exclusive,  worldwide,  royalty-free   license  with  right  to
sublicense, among other things, certain patents and patent applications (and any
foreign counterparts) to develop,  make, use and sell  certain products for  the
clinical  diagnostic and research  supply markets, including  rights to sell DNA
probe  arrays.  The  patents  licensed  to  Affymetrix  include  those  for  the
light-directed   synthesis  technology  and   for  several  other  technologies.
Affymetrix has the exclusive  right to sell DNA  probe array technology for  DNA
sequencing and sequence analysis. The Company's rights to the other technologies
are for the fields of diagnostics and analytical and bioanalytical tests, and do
not include other fields such as drug discovery. In addition, Affymax granted to
Affymetrix an exclusive license to certain trademarks, including "Affymetrix."
 
    Pursuant  to  the  Technology  License Agreement,  Affymax  also  granted to
Affymetrix certain rights to future inventions made by, or on behalf of, Affymax
to use such inventions for the development and commercialization of, among other
things, certain  products  in  the  clinical  diagnostics  and  research  supply
markets,  including rights  to sell  DNA probe  arrays. These  rights consist of
either an exclusive, worldwide royalty-free license with right to sublicense  or
a  right of  first negotiation covering  such inventions made  during the period
until July 2000. In turn, Affymetrix granted to Affymax certain parallel  rights
to future inventions made by, or on behalf of, Affymetrix during the same period
for  the development  and commercialization  of products  in drug  discovery and
related fields, not including those related to DNA sequence analysis. The rights
granted to Affymax consist of an exclusive, worldwide royalty-free license  with
right  to sublicense, to develop and commercialize any new Affymetrix technology
that is  dominated  by  one or  more  patents  licensed to  Affymetrix  in  drug
discovery and related fields, and the right of first negotiation with respect to
other  Affymetrix inventions in these fields, not including those related to DNA
sequence analysis. In addition, Affymetrix  agreed to notify Affymax in  advance
of  its intention  to sell  certain products  in the  research supply  market to
ensure that such products cannot be used for drug discovery, as reagents for  IN
VIVO imaging or certain other related purposes.
 
    The Company is party to various license option agreements with third parties
(including  Stanford University and the University  of California) which give it
rights to use certain technologies. Failure of the Company to maintain rights to
such technology could have a material adverse effect on the Company's  business,
financial  condition and  results of operations.  For example,  inability of the
Company to exercise the  option for the  Stanford technology under  commercially
reasonable  terms could have an adverse effect  on the ability of the Company to
sell certain of its products.
 
    The patent positions of pharmaceutical, biopharmaceutical and  biotechnology
companies,  including the Company,  are generally uncertain  and involve complex
legal and factual questions. There can be no assurance that any of the Company's
pending patent applications will result in issued patents, that the Company will
develop additional  proprietary  technologies  that  are  patentable,  that  any
patents issued to the Company or its strategic partners will provide a basis for
commercially  viable products or  will provide the  Company with any competitive
advantages or will not be  challenged by third parties,  or that the patents  of
others  will not  have an  adverse effect on  the ability  of the  Company to do
business. In  addition,  patent law  relating  to the  scope  of claims  in  the
technology fields in which the Company operates is still evolving. The degree of
future protection for the Company's proprietary rights, therefore, is uncertain.
Furthermore,  there  can  be no  assurance  that others  will  not independently
develop similar  or alternative  technologies, duplicate  any of  the  Company's
technologies,  or,  if patents  are  issued to  the  Company, design  around the
patented technologies developed by the  Company. In addition, the Company  could
incur  substantial costs  in litigation  if it is  required to  defend itself in
patent suits brought by third parties or if it initiates such suits.
 
    The commercial success of  the Company also depends  in part on the  Company
neither  infringing patents or proprietary rights of third parties nor breaching
any licenses that  may relate to  the Company's technologies  and products.  For
example,  the Company,  its collaborators  and customers  may need  to acquire a
license for an amplification technology to use the GeneChip system, and there is
no assurance such a license will be available on commercially reasonable  terms.
The  Company is aware  of third-party patents  that may relate  to the Company's
technology, including reagents used in probe array synthesis and in probe  array
assays, probe array
 
                                       42
<PAGE>
scanners,   synthesis  techniques,   oligonucleotide  amplification  techniques,
assays, and probe arrays. There  can be no assurance  that the Company will  not
infringe on these patents, other patents or proprietary rights of third parties.
In  addition, the Company  has received and  may in the  future receive a notice
claiming infringement from third parties as well as invitations to take licenses
under third  party  patents.  Any  legal  action  against  the  Company  or  its
collaborative  partners  claiming  damages  and  seeking  to  enjoin  commercial
activities relating to the affected products and processes could, in addition to
subjecting the Company to potential  liability for damages, require the  Company
or  its  collaborative partner  to  obtain a  license  in order  to  continue to
manufacture or  market the  affected products  and processes.  There can  be  no
assurance  that the Company  or its collaborative partners  would prevail in any
such action or that any license  (including licenses proposed by third  parties)
required  under  any  such  patent  would  be  made  available  on  commercially
acceptable terms, if at all. There are a significant number of United States and
foreign patents and patent applications in the Company's areas of interest,  and
the  Company believes that  there may be significant  litigation in the industry
regarding patent and other intellectual property rights. If the Company  becomes
involved  in  such litigation,  it could  consume a  substantial portion  of the
Company's managerial  and  financial  resources, which  could  have  a  material
adverse  effect on  the Company's business,  financial condition  and results of
operations.
 
    Others may  have  filed  and  in  the  future  are  likely  to  file  patent
applications that are similar or identical to those of the Company. To determine
the  priority of inventions, the Company may have to participate in interference
proceedings declared by the United States Patent and Trademark Office that could
result in substantial cost to  the Company. No assurance  can be given that  any
such patent application will not have priority over patent applications filed by
the Company.
 
    The enactment of legislation implementing the General Agreement on Trade and
Tariffs has resulted in certain changes in United States patent laws that became
effective  on June  8, 1995.  Most notably,  the term  of patent  protection for
patent applications filed  on or after  June 8, 1995  is no longer  a period  of
seventeen  years from the date  of grant. The new  term of United States patents
will commence  on the  date of  issuance and  terminate twenty  years after  the
earliest  effective filing date of the application. Because the time from filing
to issuance  of  biotechnology patent  applications  in the  Company's  area  of
interest  is often more than three years, a twenty-year term after the effective
date of filing  may result in  a substantially shortened  term of the  Company's
patent protection which may adversely affect the Company's patent position.
 
    The  Company also relies upon copyright  and trade secret protection for its
confidential and proprietary  information. There can  be no assurance,  however,
that  such measures  will provide  adequate protection  for the  Company's trade
secrets or other proprietary information. In addition, there can be no assurance
that proprietary  information  will  not  be disclosed,  that  others  will  not
independently  develop  substantially  equivalent  proprietary  information  and
techniques or  otherwise  gain access  to  the Company's  copyrights  and  trade
secrets  or disclose such technology, or  that the Company can meaningly protect
its trade secrets.
 
    The Company's academic collaborators have certain rights to publish data and
information in which the Company has  rights. There is considerable pressure  on
academic  institutions  to  publish  discoveries in  the  genetics  and genomics
fields. There can  be no  assurance that  such publication  would not  adversely
affect the Company's ability to obtain patent protection for some genes in which
it may have a commercial interest.
 
COMPETITION
 
    Competition in genomics and diagnostics is intense and expected to increase.
Further,  the  technologies for  discovering  genes associated  with significant
diseases and  approaches  for  commercializing those  discoveries  are  new  and
rapidly evolving.
 
    Currently,   the  Company's   principal  competition   comes  from  existing
technologies that are used to perform many  of the same functions for which  the
Company  plans to  market its GeneChip  systems. In the  diagnostic field, these
technologies are provided  by established  diagnostic companies  such as  Abbott
Laboratories, Boehringer Mannheim GmbH, Roche, Johnson & Johnson, and SmithKline
Beecham plc. These technologies include a variety of established assays, such as
immunoassays,  histochemistry, flow cytometry  and culture, and  newer DNA probe
diagnostics to analyze certain  limited amounts of  genetic information. In  the
genomics  field,  competitive  technologies include  gel-based  sequencing using
instruments provided by companies such as the
 
                                       43
<PAGE>
Applied Biosystems division of Perkin Elmer  and Pharmacia Biotech AB. In  order
to  compete against existing technologies, the  Company will need to demonstrate
to potential customers  that the GeneChip  system provides improved  performance
and capabilities.
 
    The  market for diagnostic products derived from gene discovery is currently
limited and  will  be highly  competitive.  Many companies  are  developing  and
marketing  DNA probe tests  for genetic and other  diseases. Other companies are
conducting research on new technologies  for diagnostic tests based on  advances
in   genetic  information.   Established  diagnostic   companies  could  provide
significant competition to Affymetrix through  the development of new  products.
These  companies have the strategic commitment to diagnostics, the financial and
other resources to invest in new technologies, substantial intellectual property
portfolios,  substantial  experience  in  new  product  development   regulatory
expertise,  manufacturing capabilities and the  distribution channels to deliver
products  to  customers.  These  companies  also  have  an  installed  base   of
instruments  in several markets, including  clinical and reference laboratories,
which are not compatible with the GeneChip system. In addition, these  companies
have  formed  alliances with  genomics companies  which  provide them  access to
genetic information that may be incorporated into their diagnostic tests.
 
    In the genomics  field, future  competition will likely  come from  existing
competitors  as well as other companies  seeking to develop new technologies for
sequencing and analyzing  genetic information. In  addition, pharmaceutical  and
biotechnology  companies, such as Genome  Therapeutics Corporation, Human Genome
Sciences, Inc., Incyte, Millenium  Pharmaceuticals, Inc., Myriad Genetics,  Inc.
and  Sequana Therapeutics, Inc.  have significant needs  for genomic information
and may choose to develop or acquire competing technologies to meet these needs.
 
GOVERNMENT REGULATION
 
    The Company anticipates that  the manufacturing, labeling, distribution  and
marketing of some or all of the Company's diagnostic products will be subject to
government regulation in the United States and in certain other countries.
 
    In the United States, the FDA regulates, as medical devices, most diagnostic
tests  and  IN  VITRO  reagents  that are  marketed  as  finished  test  kits or
equipment. Some  clinical laboratories,  however, purchase  individual  reagents
intended  for  specific  analytes, and,  using  those reagents,  to  develop and
prepare their own finished diagnostic tests. Although the FDA has not  generally
exercised  regulatory authority over  these individual reagents  or the finished
tests prepared from  them by  the clinical  laboratories. The  FDA has  recently
proposed  a  rule that,  if adopted,  would regulate  reagents sold  to clinical
laboratories as medical devices. The proposed rule would also restrict sales  of
these  reagents to clinical laboratories certified under CLIA as high complexity
laboratories. The Company intends to market some diagnostic products as finished
test kits or equipment and others as individual reagents; consequently, some  or
all of these products will be regulated as medical devices.
 
    The Food, Drug, and Cosmetic Act requires that medical devices introduced to
the  United  States market,  unless exempted  by regulation,  be the  subject of
either a premarket notification clearance (known  as a "510(k)") or an  approved
premarket approval ("PMA"). Some of the Company's products may require a PMA and
others may require a 510(k). With respect to devices reviewed through the 510(k)
process,  a Company may not market a device  until an order is issued by the FDA
finding the product to be substantially equivalent to a legally marketed  device
known  as a "predicate device." A 510(k) submission may involve the presentation
of a substantial  volume of  data, including clinical  data, and  may require  a
substantial  review.  The  FDA  may  agree  that  the  product  is substantially
equivalent to a predicate  device and allow  the product to  be marketed in  the
United  States.  The FDA,  however, may  (i)  determine that  the device  is not
substantially equivalent and require a PMA, or (ii) require further information,
such as additional test data, including data from clinical studies, before it is
able to make  a determination regarding  substantial equivalence. By  requesting
additional  information,  the FDA  can further  delay  market introduction  of a
company's products. If the FDA indicates that  a PMA is required for any of  the
Company's  products, the  application will  require extensive  clinical studies,
manufacturing information and likely  review by a panel  of experts outside  the
FDA. Clinical studies to support either a 510(k) submission or a PMA application
would  need  to be  conducted in  accordance with  FDA requirements.  Failure to
comply with FDA  requirements could result  in the FDA's  refusal to accept  the
data  or the imposition of regulatory sanctions. FDA review of a PMA application
could take significantly longer than that for a 510(k).
 
                                       44
<PAGE>
    There can be no assurance  that the Company will be  able to meet the  FDA's
requirements  or that any  necessary approval will be  received. Once granted, a
510(k) clearance or PMA approval may  place substantial restrictions on how  the
device  is marketed or to whom  it may be sold. Even  where a device is exempted
from 510(k) clearance or  PMA approval, the FDA  may impose restrictions on  its
marketing.  In addition to requiring clearance or approval for new products, the
FDA may  require clearance  or approval  prior to  marketing products  that  are
modifications of existing products. There can be no assurance that any necessary
510(k)  clearance or PMA approval  will be granted on a  timely basis or at all.
FDA imposed restrictions could limit the number of customers to whom  particular
products  could  be  marketed  or  what  may  be  communicated  about particular
products. Delays  in receipt  of  or failure  to  receive any  necessary  510(k)
clearance  or PMA, or the imposition  of stringent restrictions on the Company's
labeling and sales of its products could  have a material adverse effect on  the
Company.
 
    As  a medical  device manufacturer,  the Company  would also  be required to
register and list its products with the  FDA. In addition, the Company would  be
required  to comply with  the FDA's GMP regulations,  which require that medical
devices be manufactured and  records be maintained in  a prescribed manner  with
respect  to manufacturing, testing and  control activities. Further, the Company
would be required to comply with FDA requirements for labeling and promotion  of
its  medical devices. For example, the FDA prohibits cleared or approved devices
from being marketed for uncleared or  unapproved uses. In addition, the  medical
device  reporting regulation would require  that the Company provide information
to the FDA  whenever there is  evidence to  reasonably suggest that  one of  its
devices  may have caused  or contributed to  a death or  serious injury, or that
there has occurred a malfunction that would be likely to cause or contribute  to
a death or serious injury if the malfunction were to recur.
 
    Medical  device manufacturers are subject to periodic inspections by the FDA
and state agencies. Additionally, FDA will conduct a preapproval inspection  for
all  PMA  devices and  in some  cases for  510(k)  devices as  well. If  the FDA
believes  that  a  company  is  not  in  compliance  with  applicable  laws   or
regulations, it can institute proceedings to issue a warning letter apprising of
violative  conduct,  detain or  seize products,  issue  a recall,  enjoin future
violations and  assess civil  and criminal  penalties against  the company,  its
officers  or  its  employees.  In addition,  clearances  or  approvals  could be
withdrawn in  appropriate  circumstances.  Failure  to  comply  with  regulatory
requirements  or any  adverse regulatory  action could  have a  material adverse
effect on the Company.
 
    Medical device  laws and  regulations are  also  in effect  in many  of  the
countries  in which the Company may do business outside the United States. These
range from comprehensive  device approval requirements  for some or  all of  the
Company's   medical   device  products   to   requests  for   product   data  or
certifications. The  number  and scope  of  these requirements  are  increasing.
Medical  device laws and regulations are also  in effect in some states in which
the Company  does business.  There can  be no  assurance that  the Company  will
obtain regulatory approvals in such countries or that it will not be required to
incur  significant  costs in  obtaining  or maintaining  its  foreign regulatory
approvals. In addition,  the export by  the Company of  certain of its  products
which  have not  yet been  cleared for  domestic commercial  distribution may be
subject to FDA export restrictions. The failure to obtain product approvals in a
timely fashion  or to  comply with  state  or foreign  medical device  laws  and
regulations may have a material adverse impact on the Company.
 
    In  addition, federal, state and foreign  laws and regulations regarding the
manufacture and  sale of  medical devices  are subject  to future  changes.  For
example,  the FDA is currently considering significant changes to its GMP and to
other regulations. The Company cannot predict what impact, if any, such  changes
might  have on its business; however, such  changes could have a material impact
on the Company.
 
    Any of the Company's customers using its diagnostic devices for clinical use
in the United States may be regulated under the CLIA. CLIA is intended to ensure
the quality and  reliability of clinical  laboratories in the  United States  by
mandating   specific  standards  in  the   areas  of  personnel  qualifications,
administration, participation in proficiency  testing, patient test  management,
quality  control, quality assurance and inspections. The regulations promulgated
under CLIA establish  three levels  of diagnostic  tests ("waived,"  "moderately
complex"  and  "highly  complex") and  the  standards applicable  to  a clinical
laboratory depend on the level of  the tests it performs. CLIA requirements  may
prevent   some  clinical  laboratories  from  using  certain  of  the  Company's
 
                                       45
<PAGE>
diagnostic products.  Therefore,  there  can  be  no  assurance  that  the  CLIA
regulations  and future administrative  interpretations of CLIA  will not have a
material adverse impact on the Company by limiting the potential market for  the
Company's products.
 
    The  Company is also  subject to numerous environmental  and safety laws and
regulations, including  those  governing  the  use  and  disposal  of  hazardous
materials.  Any violation of, and the cost of compliance with, these regulations
could have  a  material adverse  effect  on the  Company's  business,  financial
condition and results of operations.
 
REIMBURSEMENT
 
    The  Company's ability to successfully commercialize its products may depend
on the Company's ability to obtain adequate levels of third-party  reimbursement
for  use of certain diagnostic  tests, in the United  States, European and other
countries. Currently, the availability  of third-party reimbursement is  limited
and uncertain for genetic tests.
 
    In  the United States,  the cost of  medical care is  funded, in substantial
part, by  government insurance  programs,  such as  Medicare and  Medicaid,  and
private  and  corporate  health  insurance plans.  Third-party  payors  may deny
reimbursement if they determine that a prescribed device or diagnostic test  has
not received appropriate FDA or other governmental regulatory clearances, is not
used  in accordance with  cost-effective treatment methods  as determined by the
payor, or is experimental, unnecessary  or inappropriate. The Company's  ability
to  commercialize certain of its products  successfully may depend on the extent
to which appropriate  reimbursement levels for  the costs of  such products  and
related  treatment  are  obtained from  government  authorities,  private health
insurers  and  other  organizations,  such  as  HMOs.  Third-party  payors   are
increasingly  challenging the prices charged  for medical products and services.
The trend towards managed  health care in the  United States and the  concurrent
growth  of  organizations such  as HMOs,  which  could control  or significantly
influence the  purchase  of  health  care services  and  products,  as  well  as
legislative  proposals  to reform  health  care or  reduce  government insurance
programs, may all result in lower prices for certain of the Company's  products.
The cost containment measures that health care providers are instituting and the
impact  of any health care reform could  have an adverse effect on the Company's
ability to sell certain of its products  and may have a material adverse  effect
on the Company's business, financial condition and results of operations.
 
EMPLOYEES
 
    As  of March 31,  1996, Affymetrix had  117 full-time employees,  29 of whom
hold Ph.D. degrees.  The employee group  includes chemists, engineers,  computer
scientists,  mathematicians  and  molecular biologists  with  experience  in the
diagnostic products,  medical  products,  semiconductor,  computer  software  or
electronics  industries. None  of the  Company's employees  is represented  by a
collective bargaining agreement, nor has the Company experienced work stoppages.
The Company believes that its relations with its employees are good.
 
FACILITIES
 
   
    Affymetrix subleases  47,000 square  feet in  Santa Clara,  California  from
Affymax  for  research laboratories  and  administrative offices  under  a lease
expiring in 1996. The Company has an option to renew the lease on this  facility
for  an additional seven years.  The Company leases 20,000  square feet of space
for manufacturing operations in Sunnyvale, California under a lease that expires
in 2000.  The  Company  has options  to  renew  this lease  for  two  successive
three-year  terms. The  Company also leases  31,000 square feet  of research and
development space in Sunnyvale, California under  a lease that expires in  1999.
The  Company expects to add to its  existing facilities over the next few years.
See "Certain Transactions."
    
 
LEGAL PROCEEDINGS
 
    The Company is not a party to any legal proceedings.
 
SCIENTIFIC ADVISORY BOARD
 
    The Company's scientific advisors have made significant contributions to the
development of Affymetrix technologies.  Each scientific advisor spends  between
one day per week and one day per quarter working on Company projects. Scientific
advisors  are compensated on  a retainer or  per diem basis  and have options to
acquire Common Stock of the Company subject to vesting during continued service.
 
                                       46
<PAGE>
    PAUL BERG,  PH.D., is  Cahill  Professor in  Cancer Research,  Professor  of
Biochemistry  and  Director  of the  Beckman  Center for  Molecular  and Genetic
Medicine at Stanford University School of Medicine. He received the Nobel  Prize
in  Chemistry in 1980, the National Medal of  Science in 1983 and is a member of
the National Academy  of Sciences,  the Royal  Society, London,  and the  French
Academy  of Sciences. Dr. Berg also serves as a member of the Company's Board of
Directors.
 
    RONALD W.  DAVIS,  PH.D.,  is  Professor of  Biochemistry  and  Genetics  at
Stanford  University Medical School.  He was elected to  the National Academy of
Sciences in 1983 and has received  numerous awards for his contributions to  the
field  of genetics. He has  published more than 155  papers. Dr. Davis' research
focuses on  developing new  technologies and  instrumentation to  study  genomic
organization  and whole genome analysis,  including whole genome DNA sequencing,
gene expression, gene  deletion, functional analysis,  protein interaction,  and
point mutational analysis.
 
    ERIC  LANDER, D. PHIL., is a  director of Whitehead Institute/MIT Center for
Genome Research  and Professor  of  Biology at  the Massachusetts  Institute  of
Technology. Dr. Lander was a MacArthur Prize Fellow from 1987 to 1992 and serves
as  Chair of  the Genome  Research Review Committee  of the  National Center for
Human Genome  Research. Dr.  Lander's research  focuses on  genetic mapping  and
genome  structure in the  mouse and human, genetic  analysis of polygenic traits
and population genetics of human diseases.
 
    JOSHUA  LEDERBERG,  PH.D.,  is  Sackler  Foundation  Scholar  and   Research
Geneticist  at Rockefeller University, where he was President from 1978 to 1990.
Dr. Lederberg received the Nobel Prize in  Medicine in 1958 for his research  in
the genetic structure and function of microorganisms and in 1989 was awarded the
National  Medal  of  Science.  Dr. Lederberg  has  been  involved  in artificial
intelligence programs and has served on the Advisory Health Research Council  of
the World Health Organization for many years.
 
    RICHARD  A. MATHIES, PH.D.,  is Professor of Chemistry  at the University of
California, Berkeley. Dr. Mathies is an expert on the development of new methods
for the  detection  and  analysis  of  biomolecules,  such  as  capillary  array
electrophoresis  and photolithographic chemical analysis systems. Dr. Mathies is
assisting Affymetrix with high sensitivity fluorescence detection methodologies,
photophysics and the development of  microchemical nucleic acid preparation  and
analysis  systems.  Dr. Mathies  received an  NIH  Merit Award  in 1991  and the
American Society  for  Photobiology Research  Award  in 1989.  He  has  received
fellowships from the Helen Hay Whitney and Alfred P. Sloan Foundations.
 
    R.  FABIAN PEASE, PH.D., is Professor  of Electrical Engineering at Stanford
University. Dr. Pease's current research focuses on micro- and nano-lithography,
novel ultra-small electron devices, and  advanced packaging concepts. From  1971
to  1978,  he  was  supervisor  of the  electron  beam  exposure  group  at Bell
Laboratories,  where  he  and  his   colleagues  developed  the  electron   beam
mask-making  process that  was the  semiconductor industry  standard for  over a
decade. Dr. Pease  is assisting Affymetrix  with the application  of very  large
scale  integrated  circuit  technology  to  the  development  of  the  Company's
light-directed synthesis technology.
 
    CALVIN F.  QUATE, PH.D.,  is  Professor of  Applied Physics  and  Electrical
Engineering  at Stanford University. Dr. Quate  served as senior Research Fellow
of the Xerox Palo Alto  Research Center from 1984 to  1994. He is a director  of
Tencor  Instruments and Park Scientific  Instruments. Dr. Quate's awards include
the IEEE  Morris  N. Liebmann  Award  (1981), Rank  Prize  for  Opto-Electronics
(1982), IEEE Achievement Award, Ultraoxics, Ferroelectrics and Frequency Control
Society  (1986),  IEEE  Medal of  Honor  (1988), President's  National  Medal of
Science (1992) and Foreign Member Royal Society (1995).
 
    LUBERT STRYER, M.D., Chairman  of the Scientific  Advisory Board, is  Winzer
Professor  in the School  of Medicine and Professor  of Neurobiology at Stanford
University. He served as President  and Scientific Director of Affymax  Research
Institute and Managing Director of Affymax in 1989 and 1990. He is a co-inventor
of  the Company's light-directed synthesis  technology. Dr. Stryer has pioneered
the development of novel fluorescence detection techniques and holds ten patents
involving fluorescence and light-activated chemical synthesis. Dr. Stryer is the
author of BIOCHEMISTRY, a  major text used widely  in colleges and  universities
around  the world.  Dr. Stryer received  the American Chemical  Society Award in
Biological Chemistry  (the Eli  Lilly Award)  and is  a member  of the  National
Academy  of  Sciences  and  received  an honorary  Doctor  of  Science  from the
University of Chicago.
 
                                       47
<PAGE>
                                   MANAGEMENT
 
EXECUTIVE OFFICERS AND DIRECTORS
    The executive officers and  directors of the Company,  and their ages as  of
March 31, 1996, are as follows:
 
<TABLE>
<CAPTION>
                   NAME                         AGE                                 POSITION
------------------------------------------      ---      ---------------------------------------------------------------
<S>                                         <C>          <C>
John D. Diekman...........................          53   Chairman and Chief Executive Officer
Stephen P.A. Fodor........................          42   President, Chief Operating Officer and Director
Paul M. Kaplan............................          50   Vice President of Product Development
Vernon A. Norviel.........................          37   Vice President and General Counsel
Kenneth J. Nussbacher.....................          43   Executive Vice President and Chief Financial Officer
Richard P. Rava...........................          38   Vice President of Research and Engineering
Paul Berg (1).............................          69   Director
Douglas M. Hurt (2).......................          39   Director
Vernon R. Loucks, Jr......................          61   Director
Barry C. Ross.............................          47   Director
David B. Singer (2).......................          33   Director
John A. Young (1)(2)......................          64   Director
Alejandro C. Zaffaroni (1)................          73   Director
</TABLE>
 
------------
(1) Member of the Compensation Committee
 
(2) Member of the Audit Committee
 
    JOHN D. DIEKMAN, PH.D., has served as a Director of the Company and Chairman
since  the Company's inception and was appointed Chief Executive Officer in July
1995. Dr. Diekman  served as President  and Chief Operating  Officer of  Affymax
from  July 1991 to March 1995 and as  Chairman of the Affymax Board of Directors
from July 1994 to July 1995. Prior  to 1991, Dr. Diekman served as President  of
Monoclonal  Antibodies Inc. (now  Quidel Corp.), a  diagnostic products company;
Salutar, Inc.,  an  IN VITRO  diagnostic  company; and  Zoecon  Corporation,  an
agrochemical  company. Dr. Diekman also currently serves as a director of Quidel
Corp.
 
    STEPHEN P.A. FODOR, PH.D., is the  President and Chief Operating Officer  of
the  Company and has  been a Director  of the Company  since February 1993. From
September 1994 to July 1995, he served as President and Chief Technical  Officer
and,  from February 1993 until September 1994, as Chief Technical Officer of the
Company. Dr.  Fodor  previously was  Vice  President and  Director  of  Physical
Sciences   at  the  Affymax  Research  Institute.   For  the  invention  of  the
photolithographic synthesis technology  used by the  Company to manufacture  its
probe  arrays,  Dr.  Fodor  and  his  colleagues  were  awarded  the  1992  AAAS
Newcomb-Cleveland Prize for the best  research article published in SCIENCE  and
the  1993 "Distinguished Inventor Award"  from the Intellectual Property Owners'
Association.
 
    PAUL M. KAPLAN, PH.D., has been Vice President of Product Development  since
joining  the Company in April 1994. From 1988 to 1994, Dr. Kaplan served as Vice
President, Research  and Development  of the  Diagnostic Division  at  Centocor,
Inc.,   where  he  was  responsible  for  the  identification,  development  and
commercialization of a variety of proprietary immunoassay products.
 
    VERNON A. NORVIEL, J.D., was appointed Vice President and General Counsel of
the Company in February 1996. From 1989 to 1996, as a partner with Townsend  and
Townsend  and Crew LLP  ("Townsend"), Mr. Norviel  led the intellectual property
and patent  prosecution efforts  of  the Company.  Mr.  Norviel continues  as  a
partner with Townsend on a part time basis.
 
    KENNETH  J.  NUSSBACHER,  J.D.,  joined the  Company  in  September  1995 as
Executive Vice President  and Chief Financial  Officer. From 1989  to 1995,  Mr.
Nussbacher    held    various    management   positions    at    Affymax,   most
 
                                       48
<PAGE>
recently as Executive Vice President for Business and Legal Affairs and Managing
Director of Affymax Technologies  N.V. Prior to  1989, Mr. Nussbacher  practiced
intellectual  property law  in the high  technology field as  General Counsel of
Daisy Systems, as  Vice President,  Intellectual Property for  Atari, Inc.,  and
with Kirkland & Ellis, in Chicago.
 
    RICHARD  P.  RAVA,  PH.D., has  served  as  Vice President  of  Research and
Engineering since September 1994. Dr. Rava  joined the Company in February  1993
as  Director of Biomedical Engineering. From 1992 to 1993, Dr. Rava was a Senior
Scientist at Affymax Research Institute. From  1990 to 1992, he was a  Principal
Research  Scientist in the George R. Harrison Spectroscopy Laboratory at MIT and
the research coordinator for the NIH Laser Biomedical Research Center at MIT.
 
    PAUL BERG, PH.D., has been a Director of the Company since August 1993.  Dr.
Berg  is  Cahill Professor  in Cancer  Research,  Professor of  Biochemistry and
Director of the Beckman  Center for Molecular and  Genetic Medicine at  Stanford
University School of Medicine. He received the Nobel Prize in Chemistry in 1980,
the National Medal of Science in 1983 and is a member of the National Academy of
Sciences,  the Royal  Society, London, and  the French Academy  of Sciences. Dr.
Berg also serves as a member of the Company's Scientific Advisory Board.
 
   
    DOUGLAS M. HURT, a Director of the  Company since June 1995, is Senior  Vice
President  and  Chief Financial  Officer  of Glaxo.  Mr.  Hurt has  held various
financial management positions at Glaxo since  1983 and was designated by  Glaxo
to serve on the Board of Directors.
    
 
    VERNON R. LOUCKS, JR., has been a Director of the Company since August 1993.
Mr.  Loucks has served  as Chief Executive Officer  of Baxter International Inc.
("Baxter") since 1980 and Chairman of Baxter since 1987. Mr. Loucks also  serves
as a director of The Dun and Bradstreet Corp., Emerson Electric Co., Quaker Oats
Co. and Anheuser-Busch Companies, Inc.
 
   
    BARRY C. ROSS, PH.D., a Director of the Company since March 1995, has served
as  Director of Group Research Strategy and Alliances at Glaxo Wellcome Research
and Development Ltd. since  1995. Dr. Ross  joined Glaxo in  1984 and served  as
Director,  Medicinal Chemistry from 1989-93 and was designated by Glaxo to serve
on the Board of Directors.
    
 
    DAVID B. SINGER, a  Director of the Company  since February 1993, served  as
Vice Chairman from July 1995 to April 1996. From February 1993 to June 1995, Mr.
Singer  was President and Chief  Executive Officer of the  Company. He served as
Vice President of  Finance and Treasurer  of Affymax  from 1991 to  1993 and  as
Director of Corporate Development at Affymax from 1990 to 1991.
 
    JOHN  A. YOUNG, a Director of the  Company since August 1993, is the retired
President and  Chief Executive  Officer of  Hewlett-Packard Co.  Mr. Young  also
serves as a director of Wells Fargo & Company, Chevron Corp., SmithKline Beecham
Corp.,  Novell, Inc., Ciphergen  Bio Systems, Inc.,  General Magic, Inc., Shaman
Pharmaceuticals, Inc. and is a member of the Business Council.
 
    ALEJANDRO C. ZAFFARONI,  PH.D., a founder  of the Company,  has served as  a
Director since February 1993. Dr. Zaffaroni is also the founder of Affymax, ALZA
Corporation  ("ALZA"), DNAX Research Institute  of Molecular & Cellular Biology,
Inc. and a  co-founder of Syntex.  Dr. Zaffaroni served  as Chairman of  Affymax
from  its inception  to July  1994 and as  Chief Executive  Officer and Managing
Director of Affymax from its inception  until its acquisition by Glaxo  Wellcome
in  March 1995. He served  as Chairman and Chief  Executive Officer of ALZA from
1968 to 1987 and has been Co-Chairman of ALZA since 1987.
 
BOARD OF DIRECTORS COMMITTEES AND OTHER INFORMATION
 
    All directors are  elected at the  annual meeting of  shareholders and  hold
office  until the  election and  qualification of  their successors  at the next
annual meeting of shareholders. Officers of the Company serve at the  discretion
of the Board of Directors. There are no family relationships among the Company's
directors and executive officers.
 
    The  Board of Directors currently has  an Audit Committee and a Compensation
Committee. The  Audit Committee  oversees  the actions  taken by  the  Company's
independent auditors and reviews the Company's
 
                                       49
<PAGE>
internal  financial  and  accounting  controls  and  policies.  The Compensation
Committee is responsible for determining salaries, incentives and other forms of
compensation for officers  and other  employees of the  Company and  administers
various incentive compensation and benefit plans.
 
DIRECTOR COMPENSATION
 
    During  the fiscal year  ending December 31, 1995,  John D. Diekman, Stephen
P.A. Fodor and David  B. Singer received the  cash compensation described  under
"Management  -- Executive Compensation." During the same fiscal year each of the
remaining directors received a cash payment of $2,500 for each meeting  attended
plus  reasonable expenses. In December  1995, each nonemployee director received
an option to purchase 33,333  shares of Common Stock  at $0.675 per share  under
the Company's Stock Plan.
 
COMPENSATION COMMITTEE INTERLOCKS AND INSIDER PARTICIPATION
 
    The   Compensation  Committee  is   responsible  for  determining  salaries,
incentives and other forms of compensation  for officers and other employees  of
the  Company and administers  various incentive compensation  and benefit plans.
The Compensation Committee consists of Paul Berg, John A. Young and Alejandro C.
Zaffaroni. Stephen  P.A. Fodor,  President and  Chief Operating  Officer of  the
Company,  participates in all  discussions and decisions  regarding salaries and
incentive compensation for all employees and consultants of the Company,  except
that  Dr.  Fodor  is excluded  from  discussions  regarding his  own  salary and
incentive compensation.
 
EXECUTIVE COMPENSATION
 
    The following table sets forth certain  compensation paid by the Company  in
the  year  ended December  31, 1995  to the  Company's Chief  Executive Officer,
former Chief Executive Officer,  and to the  Company's other executive  officers
who earned in excess of $100,000 (collectively, the "Named Executive Officers"):
 
                           SUMMARY COMPENSATION TABLE
 
<TABLE>
<CAPTION>
                                                                                        LONG-TERM
                                                                                      COMPENSATION
                                                                                         AWARDS
                                                                                      -------------
                                                               ANNUAL COMPENSATION     SECURITIES
                                                             -----------------------   UNDERLYING      ALL OTHER
NAME AND PRINCIPAL POSITION                                     SALARY       BONUS       OPTIONS     COMPENSATION
-----------------------------------------------------------  ------------  ---------  -------------  -------------
<S>                                                          <C>           <C>        <C>            <C>
John D. Diekman
 Chief Executive Officer and Chairman......................  $   97,304(1) $  --          166,666     $   --
David B. Singer
 Former President and Chief Executive Officer..............     183,010       --           33,333         6,189
Stephen P.A. Fodor
 President and Chief Operating Officer.....................     188,819       --          166,666         --
Paul M. Kaplan
 Vice President of Product Development.....................     146,218       --           26,666        33,638(2)
Richard P. Rava
 Vice President of Research and Engineering................     136,962       --           60,000         --
</TABLE>
 
------------
(1) Represents  Dr.  Diekman's compensation  commencing  July 1,  1995,  when he
    joined the Company. Prior to March 1996 when he became a full-time employee,
    Dr. Diekman devoted 80% of his time to the Company and 20% to Affymax.
 
(2) Includes reimbursement  for  certain  relocation  expenses  of  $21,556  and
    housing allowances of $12,082.
 
                                       50
<PAGE>
STOCK OPTION GRANTS
 
    The  following table contains information concerning the stock option grants
made to each of  the Named Executive  Officers for the  year ended December  31,
1995:
 
                 OPTION GRANTS IN YEAR ENDED DECEMBER 31, 1995
 
<TABLE>
<CAPTION>
                                                  INDIVIDUAL GRANTS
                              ---------------------------------------------------------  POTENTIAL REALIZABLE VALUE
                                NUMBER OF                                                AT ASSUMED ANNUAL RATES OF
                               SECURITIES      % OF TOTAL                                 STOCK PRICE APPRECIATION
                               UNDERLYING    OPTIONS GRANTED    EXERCISE                    FOR OPTION TERMS (1)
                                 OPTIONS     TO EMPLOYEES IN    PRICE PER    EXPIRATION  --------------------------
NAME                           GRANTED (2)     FISCAL YEAR        SHARE         DATE          5%           10%
----------------------------  -------------  ---------------  -------------  ----------  ------------  ------------
<S>                           <C>            <C>              <C>            <C>         <C>           <C>
John D. Diekman.............      100,000            9.7%       $   0.675     07/01/05   $  1,887,300  $  3,045,300
                                   66,666            6.5            0.675     12/20/05      1,258,200     2,030,200
David B. Singer.............       33,333            3.2            0.675     12/20/05        629,100     1,015,100
Stephen P.A. Fodor..........      166,666           16.2            0.675     12/20/05      3,145,500     5,075,500
Paul M. Kaplan..............       26,666            2.6            0.675     12/20/05        503,300       812,100
Richard P. Rava.............       60,000            5.8            0.675     12/20/05      1,132,400     1,827,200
</TABLE>
 
------------
(1) Assumes a value of $12.00 for each share of Common Stock (the initial public
    offering  price for this offering) on the date of grant. Potential gains are
    net of the exercise price but before taxes associated with the exercise. The
    5% and  10%  assumed  annual  rates of  compounded  stock  appreciation  are
    mandated  by the rules of the Securities  and Exchange Commission and do not
    represent the Company's estimate  or projection of  the future Common  Stock
    price.  Actual gains, if any, on stock option exercises are dependent on the
    future financial performance of the  Company, overall market conditions  and
    the option holders' continued employment through the vesting period.
 
(2)  Grants generally  vest at  a rate of  20% each  year following  the date of
    grant, as long as the optionee  remains an employee with, consultant to,  or
    director  of, the Company.  The maximum term  of each option  granted is ten
    years from the date of grant. The exercise price is equal to the fair market
    value of  the  stock  on the  grant  date  as determined  by  the  Board  of
    Directors.
 
    The  following table  sets forth  for each  of the  Named Executive Officers
certain information with respect to the  exercise of options to purchase  Common
Stock  during the year ended December 31,  1995 and the number of shares subject
to both exercisable and unexercisable stock options as of December 31, 1995.
 
    AGGREGATE OPTION EXERCISES IN FISCAL YEAR-END AND FISCAL YEAR-END VALUES
 
   
<TABLE>
<CAPTION>
                                                        NUMBER OF SECURITIES
                                                       UNDERLYING UNEXERCISED     VALUE OF UNEXERCISED IN-
                                                             OPTIONS AT             THE-MONEY OPTIONS AT
                             SHARES                      DECEMBER 31, 1995         DECEMBER 31, 1995 (1)
                           ACQUIRED ON     VALUE     --------------------------  --------------------------
NAME                        EXERCISE    REALIZED (2) EXERCISABLE  UNEXERCISABLE  EXERCISABLE  UNEXERCISABLE
-------------------------  -----------  -----------  -----------  -------------  -----------  -------------
<S>                        <C>          <C>          <C>          <C>            <C>          <C>
John D. Diekman..........      --           --           --           166,666        --        $ 1,887,500
David B. Singer..........      --           --           50,000        33,333     $ 566,200        377,500
Stephen P.A. Fodor.......      --           --           20,000       246,666       226,500      2,793,500
Paul M. Kaplan...........      --           --            8,000        58,666        92,600        672,000
Richard P. Rava..........      10,000    $   3,750        1,333        88,666        15,000      1,013,000
</TABLE>
    
 
------------
(1) Based on an  assumed initial offering  price of $12.00  per share minus  the
    exercise price.
 
(2) Based on the fair market value at the date of exercise, as determined by the
    Board of Directors, minus the exercise price.
 
                                       51
<PAGE>
STOCK PLANS
 
  1993 STOCK PLAN
 
    The  Company's Stock Plan was adopted by  the Board of Directors in February
1993, approved  by the  shareholders  in July  1993  and has  been  subsequently
amended.  As of March 31, 1996, a total of 3,700,000 shares of Common Stock have
been reserved for issuance under the Stock  Plan. As of March 31, 1996,  options
to  purchase a total  of 543,254 shares  of Common Stock  had been exercised (of
which 148,889 are subject to repurchase  by the Company), options to purchase  a
total  of 2,191,518  shares at  a weighted average  exercise price  of $0.65 per
share were outstanding, and 965,228 shares remain available for future option or
purchase rights grants.
 
    The purpose of the Stock Plan  is to attract, retain and motivate  officers,
key  employees,  consultants and  directors of  the Company  by giving  them the
opportunity to acquire Stock ownership in  the Company. The Stock Plan  provides
for  the granting to  employees of the Company  (including officers and employee
directors) of "incentive stock options" within the meaning of Section 422 of the
Code, for the grant of nonstatutory  stock options to employees and  consultants
of  the Company, and for  the grant of purchase  rights providing for the direct
sale of  stock to  eligible participants,  subject to  the Company's  repurchase
rights.  To the extent an optionee would have  the right in any calendar year to
exercise for  the  first time  incentive  stock  options for  shares  having  an
aggregate  fair market value (under all plans  of the Company and determined for
each share as of the grant date) in excess of $100,000, any such excess  options
shall be automatically converted to a nonstatutory stock option.
 
    The  Stock Plan is administered by the  Board of Directors or a committee of
the Board of Directors (the  "Administrator"). The Administrator determines  the
type  and terms  of options  and purchase rights  granted under  the Stock Plan,
including the number  of shares covered,  exercise or purchase  price, term  and
condition  for exercise of the  option or purchase right.  The exercise price of
all stock options granted under  the Stock Plan must be  at least 100% (85%  for
purchase  rights) of the fair market value of the Common Stock of the Company on
the grant date. The term of an  incentive stock option may not exceed ten  years
from  the  date  of  grant.  With respect  to  any  participant  who  owns stock
possessing more than  10% of the  voting power of  all classes of  stock of  the
Company,  the exercise price of any stock  option granted shall be at least 110%
(100% for purchase rights) of the fair  market value of the Common Stock on  the
grant date and the term of such option may not exceed five years. Payment of the
exercise   price  may  be  in  cash,  check,   or,  at  the  discretion  of  the
administrator, by promissory notes  or shares of stock  held by the optionee  or
purchaser, or a combination thereof.
 
    No  option may be transferred by the optionee other than by will or the laws
of descent and distribution or pursuant to a qualified domestic relations  order
("QDRO").  During  the  lifetime  of  an optionee,  only  the  optionee  (or the
optionee's spouse pursuant to a QDRO) may exercise an option. An option shall be
exercisable on or after each vesting date in accordance with the terms set forth
in the option agreement; provided, however, that the right to exercise an option
must vest at the rate of  at least 20% per year  over five years from the  grant
date.
 
    In  the event  of certain  changes in control  of the  Company or  a sale of
substantially all  its assets,  the Administrator  may cancel  each  outstanding
option  upon payment in cash to the optionee of the amount by which any cash and
any other property  which the  optionee would have  received for  the shares  of
stock  covered by the vested portion of the option exceeds the exercise price of
the option. The Board may amend, suspend or terminate the Stock Plan as long  as
such  action does not adversely affect  any outstanding option or purchase right
and provided that shareholder  approval shall be required  for any amendment  to
(i)  increase the number  of shares subject  to the Stock  Plan, (ii) materially
change eligibility  for  the grant  of  options  or purchase  rights,  or  (iii)
materially  increase the  benefits accruing  to participants.  If not terminated
earlier, the Stock Plan will terminate in 2003.
 
  1996 NONEMPLOYEE DIRECTORS STOCK OPTION PLAN
 
    The Company's Directors Plan was adopted by the Board of Directors in  March
1996 and approved by the shareholders in April 1996. There are 300,000 shares of
Common  Stock reserved for  issuance under the  Directors Plan. Only nonemployee
directors of the Company are eligible  to participate in the Directors Plan  and
 
                                       52
<PAGE>
only nonstatutory stock options can be granted. The Directors Plan provides that
option  grants to nonemployee directors  of the Company are  made on a mandatory
basis and not on a discretionary  basis. The Directors Plan may be  administered
by the Board of Directors or the Board may delegate its authority to a committee
composed  of not less  than two outside directors  (the "Administrator") and may
delegate routine matters to management.
 
    If a person who is neither an officer nor an employee of the Company and who
has not previously been a member of the Board is elected or appointed  director,
the  Company  is required  to grant  that  person an  initial 10-year  option to
purchase 33,333 shares of the Company's Common Stock at an exercise price  equal
to  the fair market value of Common Stock on the date of grant. Each such option
will become exercisable at the rate of one-fifth of the number of shares covered
by the option on each anniversary of the  grant date so long as the director  is
serving on the Board with full vesting over five years.
 
    In  addition, on the date of each  annual meeting of the shareholders of the
Company held  after  January 1,  2001  for existing  nonemployee  directors  who
continue  on the Board and after 54 months after the initial option grant to new
nonemployee directors who continue on the Board, the Company will grant to  each
nonemployee director a ten-year option to purchase 6,667 shares of the Company's
Common  Stock, at  an exercise price  equal to  the fair market  value of Common
Stock on the date of grant. These options will vest one year after grant.
 
    The consideration  payable  in connection  with  any option  (including  any
related  taxes)  may be  paid in  cash,  by promissory  note of  the nonemployee
director or  by delivery  of shares  of  Common Stock  of the  Company.  Options
generally  terminate three months after a nonemployee director ceases to be, for
any reason,  a director  of the  Company, with  the following  exceptions: if  a
nonemployee  director  ceases  to be  a  director  due to  death,  disability or
retirement, the option may be exercised for 18 months after the termination.
 
    The Board may amend, alter, or discontinue the Directors Plan or any  option
at  any  time, except  that  the consent  of a  participant  is required  if the
participant's existing rights under an outstanding option would be impaired.  In
addition,  to the extent  required under applicable tax  and securities laws and
regulations, the  shareholders  of  the  Company  must  approve  any  amendment,
alteration,  or discontinuance  of the  Directors Plan  that would  increase the
total number of shares  reserved under the Directors  Plan and in certain  other
circumstances  as the  Board may  deem advisable  to comply  with such  laws and
regulations. In addition, the  provisions of the plan  governing who is  granted
options,  the number of shares  covered by each option,  the exercise price, and
the period of exercisability and the timing of option grants may not be  amended
more  than once  every six  months, other  than for  changes to  comply with the
Internal Revenue Code of 1986 or the Employee Retirement Income Security Act  of
1974.
 
    In the event of a merger, consolidation, sale of all or substantially all of
the Company's assets, or any like occurrence, the options will vest at twice the
rates set forth above.
 
LIMITATION OF DIRECTORS' LIABILITY AND INDEMNIFICATION
 
    The Company's Articles of Incorporation limit the liability of directors for
monetary  damages  to  the  maximum extent  permitted  by  California  law. Such
limitation of liability has no effect on the availability of equitable remedies,
such as injunctive relief or rescission. The Company is also empowered under its
Articles of  Incorporation to  enter into  indemnification agreements  with  its
directors and officers and to purchase insurance on behalf of any person whom it
is  required to  indemnify. The Company's  Bylaws provide that  the Company will
indemnify its  directors  and officers  as  a contractural  obligation  and  may
indemnify  its employees and  agents against certain  liabilities to the fullest
extent permitted by California law. The Company has entered into indemnification
agreements  with  each  of  its  current  directors  and  officers  or   persons
controlling the Company pursuant to the foregoing provisions.
 
                                       53
<PAGE>
                              CERTAIN TRANSACTIONS
 
    In  September 1993,  the Company  sold an  aggregate of  6,000,000 shares of
Series A  Preferred Stock  (the "Series  A") at  $3.50 per  share in  a  private
placement transaction. In August 1995, in another private placement transaction,
the  Company sold an aggregate  of 8,666,666 shares of  Series B Preferred Stock
(the "Series B") at $4.50 per share.
 
    The purchasers of the  Series A and Series  B (collectively, the  "Preferred
Stock")  included, among others, the  following executive officers and directors
of the Company  and investors  known to  own beneficially  more than  5% of  the
Company's  outstanding  Common  Stock (assuming  conversion  of  all outstanding
shares of Preferred Stock into Common Stock) (see "Principal Shareholders"):
<TABLE>
<CAPTION>
                                                                                    NUMBER OF SHARES
                                                                                 ----------------------
DIRECTORS AND EXECUTIVE OFFICERS                                                  SERIES A    SERIES B
-------------------------------------------------------------------------------  ----------  ----------
<S>                                                                              <C>         <C>
John D. Diekman................................................................      20,000      40,000
Paul A. Berg...................................................................      10,000      15,000
John A. Young..................................................................      20,000      40,000
Vernon R. Loucks, Jr...........................................................      --          40,000
Alejandro C. Zaffaroni.........................................................      --         450,000
 
<CAPTION>
 
5% SHAREHOLDERS
-------------------------------------------------------------------------------
<S>                                                                              <C>         <C>
Glaxo Wellcome plc (indirectly through Affymax N.V.)...........................   1,250,000   1,333,333
College Retirement Equities Fund...............................................   1,428,570     800,000
R.A. Investment Group..........................................................     570,000     856,000
</TABLE>
 
   
    In July  1995,  the  Company  and  Glaxo  entered  into  an  agreement  (the
"Governance  Agreement") pursuant  to which Glaxo  has the right  to designate a
number of directors based on the  percentage of voting stock then held  directly
or  indirectly by  Glaxo and is  obligated to vote  its shares for  the slate of
directors recommended  to the  shareholders. Glaxo  currently has  the right  to
designate  four  of  the  nine  directors of  the  Company.  See  "Management --
Executive Officers and Directors." Pursuant  to the Governance Agreement,  Glaxo
also  agreed that any merger, consolidation  or business combination whereby the
Company would become a direct or  indirect wholly-owned subsidiary of Glaxo  and
any  material transaction between  the Company and  Glaxo must be  approved by a
majority of the independent directors of  the Company. In addition, pursuant  to
the  Governance Agreement, the Company granted Glaxo certain registration rights
with respect to its shares. See "Description of Stock -- Registration Rights  of
Certain Shareholders."
    
 
    In  December 1994,  Affymax provided  a bridge  loan to  the Company  in the
principal amount  of $6.0  million. The  loan was  evidenced by  a  subordinated
convertible  promissory note, the terms of  which were amended by the Governance
Agreement (the "Convertible Note")  and was converted  into 1,333,333 shares  of
Series  B Senior  Convertible Preferred  Stock in  August 1995.  Interest on the
Convertible Note  through the  date of  conversion, amounting  to $319,856,  was
satisfied by the Company issuing Affymax three five-year warrants to purchase an
aggregate of 202,441 shares of Series 2 Subordinated Convertible Preferred Stock
at $5.50 per share.
 
    In  connection  with the  lease agreement  between the  Company and  a third
party, in  December 1994,  Affymax  agreed to  relieve  the Company  of  certain
financial  covenants  and to  guarantee  its obligation  to  the third  party in
exchange for warrants  to purchase Series  2 Subordinated Convertible  Preferred
Stock.  In  December  1994, Affymax  received  a five-year  warrant  to purchase
103,382 shares of Series 2 Subordinated Convertible Preferred Stock at $5.50 per
share pursuant to this agreement.
 
    Effective January 1, 1993, the  Company entered into the Technology  License
Agreement  with Affymax whereby  the Company was  granted an exclusive worldwide
royalty free license  from Affymax,  with the  right to  sublicense, to  certain
technology  and  to certain  future inventions  to be  used in  the development,
production and sale  of products  and services  in the  clinical diagnostic  and
research  supply  markets.  See  "Intellectual Property."  In  August  1993, the
Company agreed  to  issue Affymax  8,500,000  shares of  Series  1  Subordinated
Convertible   Preferred  Stock  as  consideration  for  the  Technology  License
Agreement and funding the Company's operations through September 1993.
 
                                       54
<PAGE>
    The Company and Affymax Research Institute, a subsidiary of Affymax ("ARI"),
entered into a Services Agreement dated  October 1, 1993, pursuant to which  ARI
agreed  to  perform  certain  administrative  and  management  services  for the
Company. For the fiscal year ended December 31, 1995, the Company made  payments
to  ARI in the  aggregate amount of $834,000.  John D. Diekman  is a director of
ARI.
 
    In February 1994, the Company entered into a sublease with Affymax providing
for the Company to sublease facilities in Santa Clara from Affymax until October
1, 1995. The sublease provides for its term to be extended until August 31, 2003
in the event  that, at the  Company's request, Affymax  exercises its option  to
extend  the underlying  lease until  that date.  In April  1995, the  option was
exercised to extend the lease to October 1, 1996.
 
   
    The Company believes that the agreements  with Affymax are on terms no  less
favorable to the Company than would be obtained from unaffiliated third parties.
    
 
    In May 1996, the Company entered into an agreement with Glaxo to develop and
supply  probe arrays to detect polymorphisms in specific genes. See "Business --
Genomics Application Areas" and "-- Collaborative Agreements and Grants."
 
   
    In December 1993, in  connection with grants to  each of Stephen P.A.  Fodor
and  David B.  Singer of rights  to purchase  133,333 shares of  Common Stock at
$0.30 per share,  subject to  repurchase at  the Company's  option, the  Company
entered  into Loan and Pledge Agreements with  each of Dr. Fodor and Mr. Singer.
Pursuant to those  agreements, the Company  lent Dr. Fodor  and Mr. Singer  each
$40,000,  which loans are evidenced by secured promissory notes due in July 1998
or when their employment is terminated. These notes bear interest at the rate of
5.07% per annum. Interest payments  on the notes are  due and payable each  year
until the loan is repaid.
    
 
    In  November 1994, the Company  agreed to guarantee a  loan in the amount of
$117,000 of Stephen P. A. Fodor.
 
   
    In June 1995, the Company entered into an agreement with David B. Singer  in
connection  with his assumption of  the position of Vice  Chairman of the Board.
Pursuant to Mr. Singer's transition from President, Chief Executive Officer  and
Chief  Financial  Officer to  Vice  Chairman, Mr.  Singer  continues to  be paid
$14,583 per month and may receive health care coverage until December 15,  1996.
In  addition, pursuant to  the agreement, the Company  relinquished its right to
repurchase any of the 133,333 shares of  Common Stock acquired by Mr. Singer  in
December  1993, amended  the option  to purchase  100,000 shares  granted to Mr.
Singer in December 1994 to  fully vest 50,000 shares  as of September 1995,  and
waived  its right  to demand repayment  of Mr. Singer's  $40,000 promissory note
until July 1998.  Pursuant to the  agreement, Mr. Singer  agreed to continue  to
serve as a Director of the Company if nominated and elected by the shareholders,
to  serve as Vice Chairman  of the Board, and  to provide consulting services to
the Company relating  to the  financing of  the Company,  grants and  government
relations.
    
 
   
    The Company and Symyx, Inc. ("Symyx") have entered into a sublease agreement
for  a portion  of the  property leased  to the  Company in  Sunnyvale at market
rates. Kenneth J.  Nussbacher is  a director, and  Alejandro C.  Zaffaroni is  a
director and greater than 10% stockholder, of Symyx.
    
 
    The  Company has  entered into indemnification  agreements with  each of its
directors and  executive  officers.  Such  agreements  require  the  Company  to
indemnify  such persons to  the fullest extent permitted  by California law. See
"Management -- Limitation of Liability and Indemnification Matters."
 
                                       55
<PAGE>
                             PRINCIPAL SHAREHOLDERS
 
    The following  table sets  forth  certain information  with respect  to  the
beneficial  ownership of the Common Stock as  of April 30, 1996, and as adjusted
to reflect the sale  of the shares  of Common Stock offered  hereby by (i)  each
person who is known by the Company to be the beneficial owner of more than 5% of
the  Common Stock, (ii) each of the Company's directors, (iii) each of the Named
Executive Officers and (iv)  all current directors and  executive officers as  a
group.
 
<TABLE>
<CAPTION>
                                                                                               PERCENTAGE OF SHARES
                                                                                                   BENEFICIALLY
                                                                                                   OWNED (1)(2)
                                                                                    SHARES     ---------------------
                                                                                  BENEFICIALLY  PRIOR TO     AFTER
BENEFICIAL OWNER                                                                   OWNED (1)    OFFERING   OFFERING
--------------------------------------------------------------------------------  -----------  ----------  ---------
<S>                                                                               <C>          <C>         <C>
Glaxo Wellcome plc (3)..........................................................   7,705,067        46.8%      35.9%
Greenford Road
Greenford, Middlesex, UBG OHE, UK
College Retirement Equities Fund................................................   1,507,991         9.3%       7.1%
730 Third Avenue
New York, NY 10017
R.A. Investment Group...........................................................     959,554         5.9%       4.5%
200 West Madison, Suite 3800
Chicago, IL 60606
Paul A. Berg, Ph.D (4)..........................................................      38,488       *           *
John D. Diekman, Ph.D (5).......................................................      76,177       *           *
Stephen P.A. Fodor, Ph.D (6)....................................................     153,333       *           *
Douglas M. Hurt (7).............................................................   7,705,067        46.8 %     35.9%
Paul M. Kaplan (8)..............................................................      13,334       *           *
Vernon R. Loucks, Jr............................................................      59,999       *           *
Richard P. Rava, Ph.D (9).......................................................      11,333       *           *
Barry C. Ross, Ph.D (7).........................................................   7,705,067        46.8 %     35.9%
David B. Singer.................................................................     160,666       *           *
John A. Young...................................................................      41,643       *           *
Alejandro C. Zaffaroni, Ph.D (10)...............................................     140,000       *           *
All directors and executive officers as a group (13 persons) (11)...............   8,426,706        50.9 %     39.1%
</TABLE>
 
------------
 * Represents beneficial ownership of less than one percent of the Common Stock.
 
 (1)  Beneficial ownership  is determined  in accordance  with the  rules of the
    Securities and  Exchange  Commission.  In computing  the  number  of  Shares
    beneficially  owned  by a  person and  the percentage  of ownership  of that
    person, shares of Common Stock subject  to options held by that person  that
    are  currently exercisable or  exercisable within 60 days  of April 30, 1996
    are deemed outstanding. Such shares, however, are not deemed outstanding for
    the purpose of computing the percentage ownership of each other person.  The
    persons  named  in this  table have  sole voting  and investment  power with
    respect to all shares of Common  Stock shown as beneficially owned by  them,
    subject  to community property laws where applicable and except as indicated
    in the other footnotes to this table.
 
 (2) Percentage of beneficial ownership is based on 16,248,148 shares of  Common
    Stock outstanding as of April 30, 1996 and 21,248,148 shares of Common Stock
    outstanding after completion of this offering.
 
 (3) Held through its subsidiary, Affymax N.V.  Includes 203,881 shares issuable
    upon exercise of outstanding warrants at $8.25 per share.
 
                                       56
<PAGE>
 (4)  Includes 3,333 shares issuable upon exercise of options exercisable within
    60 days of April 30, 1996.
 
 (5) Includes 40,000 shares issuable upon exercise of options within 60 days  of
    April 30, 1996.
 
 (6)  Includes 20,000 shares issuable upon exercise of options within 60 days of
    April 30, 1996.
 
 (7) Represents 7,705,067 shares beneficially owned by Glaxo, of which Mr.  Hurt
    and Dr. Ross disclaim beneficial ownership.
 
 (8)  Represents  13,334 shares  issuable upon  exercise of  options exercisable
    within 60 days of April 30, 1996.
 
 (9) Includes 1,333 shares issuable upon  exercise of options within 60 days  of
    April 30, 1996.
 
(10)  Includes 6,667 shares issuable upon exercise  of options within 60 days of
    April 30, 1996  and excludes any  shares Dr. Zaffaroni  may purchase in  the
    offering. See "Underwriting."
 
(11)  Includes 98,000 shares issuable upon exercise of options within 60 days of
    April 30, 1996. Also includes 7,705,067 shares owned by Glaxo, of which  Mr.
    Hurt  and Dr.  Ross disclaim beneficial  ownership. Excludes  any shares Dr.
    Zaffaroni may purchase in the offering. See "Underwriting."
 
                                       57
<PAGE>
                          DESCRIPTION OF CAPITAL STOCK
 
    Upon the  closing of  this offering,  the authorized  capital stock  of  the
Company  will consist of  50,000,000 shares of  Common Stock, no  par value, and
27,500,000 shares of Preferred Stock, no par value (the "Undesignated  Preferred
Stock").
 
COMMON STOCK
 
    At  March 31,  1996, assuming  the conversion  of all  outstanding Preferred
Stock and  the  issuance of  203,881  shares of  Common  Stock pursuant  to  the
exercise  or  conversion of  outstanding warrants,  16,443,112 shares  of Common
Stock were outstanding and held of  record by shareholders. Options to  purchase
an  aggregate of  2,191,518 shares  of Common  Stock were  also outstanding. See
"Management -- Stock Plans."
 
    The holders  of Common  Stock are  entitled to  one vote  per share  on  all
matters to be voted upon by the shareholders. Subject to preferences that may be
applicable  to any outstanding Preferred Stock,  the holders of Common Stock are
entitled to receive ratably such dividends, if any, as may be declared from time
to time by the Board of Directors  out of funds legally available therefor.  See
"Dividend  Policy." In the event of a  liquidation, dissolution or winding up of
the Company, the holders of  Common Stock are entitled  to share ratably in  all
assets  remaining  after  payment of  liabilities,  subject to  prior  rights of
Preferred Stock, if any, then outstanding. The Common Stock has no preemptive or
conversion rights  or other  subscription  rights. There  are no  redemption  or
sinking fund provisions available to the Common Stock. All outstanding shares of
Common Stock are fully paid and non-assessable.
 
PREFERRED STOCK
 
    Effective  upon the closing of this offering, the Company will be authorized
to issue  27,500,000  shares  of  Undesignated Preferred  Stock.  The  Board  of
Directors  will have the authority to  issue the Undesignated Preferred Stock in
one or more series and to determine  the powers, preferences and rights and  the
qualifications, limitation or restrictions granted to or imposed upon any wholly
unissued  shares of  Undesignated Preferred Stock  and fix the  number of shares
constituting any series and the designation of such series, without any  further
vote or action by the shareholders. The issuance of Undesignated Preferred Stock
may  have the effect of delaying, deferring or preventing a change in control of
the Company without further action by the shareholders and may adversely  affect
the  voting and  other rights of  the holders  of Common Stock.  At present, the
Company has no plans to issue any shares of Undesignated Preferred Stock.
 
REGISTRATION RIGHTS OF CERTAIN SHAREHOLDERS
 
    Certain holders of Common Stock or their transferees are entitled to certain
rights with respect to the registration of such shares under the Securities Act.
Registration rights are held  with respect to 9,871,185  shares of Common  Stock
issuable  upon the conversion  of Preferred Stock under  the terms of agreements
between the Company and  the holders of  Series A and  B Senior Preferred  Stock
(collectively  the "Registrable Securities"). Subject  to certain limitations in
the agreements, the holders of Registrable Securities have "piggyback" rights to
request that their shares be registered for public resale with respect to up  to
four  registrations  of the  Company's  securities. However,  if  such piggyback
rights are  exercised  in  connection  with  an  underwritten  offering  of  the
Company's Common Stock, the underwriter of such offering has the right to reduce
to  20% of the  total the number  of such shares  to be included  in such public
offering or, in the case of the initial public offering, to exclude such  shares
entirely.  In  addition, at  a time  when  the Company  is eligible  to register
securities on Form S-3, holders of Registrable Securities not already registered
may demand  that  the Company  file  a Form  S-3,  provided that  the  aggregate
offering  price of the Registrable Securities  would be at least $2,000,000. The
Company will  pay  certain expenses  in  connection  with the  exercise  of  the
foregoing  rights. These registration rights expire  five years after an initial
public offering of the Company's securities.
 
    Pursuant to the Governance Agreement, the Company also has granted to Glaxo,
as long as  Glaxo and its  subsidiaries hold  more than 10%  of the  outstanding
Common  Stock of the Company, the right to  demand, at any time after six months
following the  Company's  initial public  offering,  that the  Company  file  an
underwritten registration statement covering the registration of at least 40% of
the Common Stock held by Glaxo and its subsidiaries. Glaxo's registration rights
cover 7,705,067 shares of Common Stock issuable on conversion of Preferred Stock
(including Series 1 Subordinated Convertible Preferred and Series 2 Subordinated
Convertible
 
                                       58
<PAGE>
Preferred  Stock, issuable  upon exercise of  warrants). If such  demand is made
after the time the Company is, or normally would have been, eligible to register
securities on Form S-3, the Company will pay certain expenses incurred by  Glaxo
in  exercising these demand rights. Glaxo has  this demand right with respect to
up to  four  registrations  of the  Company's  securities  on Form  S-1  and  an
unlimited  number of  registrations on  Form S-3.  In addition,  pursuant to the
Governance Agreement,  Glaxo  has piggyback  rights  similar to  those  held  by
holders of the Registrable Securities.
 
WARRANTS
 
   
    Pursuant  to the terms of an  agreement between Affymetrix and Affymax dated
December 29,  1994,  whereby  Affymax  agreed  to  guarantee  Affymetrix'  lease
obligations  to a  third party,  Affymetrix has issued  to Affymax  a warrant to
purchase 103,382 shares  of Series 2  Subordinated Convertible Preferred  Stock.
The  warrants  have an  exercise price  of  $5.50 and  expire in  December 1999.
Pursuant to the  terms of  a note agreement,  Affymetrix has  issued to  Affymax
warrants  to  purchase  202,441  shares  of  Series  2  Subordinated Convertible
Preferred Stock for certain interest payments otherwise due on the note  through
August  1995, at which time  the note was converted  into Preferred Stock. These
warrants have an exercise  price of $5.50  and expire from  March to July  2000.
After  the offering, as a result of  automatic conversion of the Preferred Stock
upon the closing  of this offering  and the 2-for-3  reverse stock split,  these
warrants will be exercisable for a total of 203,881 shares of Common Stock at an
exercise price of $8.25 per share. See "Certain Transactions."
    
 
TRANSFER AGENT AND REGISTRAR
 
    The  Transfer Agent and Registrar for the Company's Common Stock is American
Stock Transfer & Trust Company.
 
                                       59
<PAGE>
                        SHARES ELIGIBLE FOR FUTURE SALE
 
    Upon  completion  of  this  offering,  the  Company  will  have  outstanding
21,239,231 shares of Common Stock. Of these shares, the 5,000,000 shares sold in
this  offering  (plus  any  shares issued  upon  exercise  of  the Underwriters'
over-allotment option) will  be freely tradeable  without restriction under  the
Securities  Act, unless purchased or held by "affiliates" of the Company as that
term is  defined  in Rule  144  under the  Securities  Act and  the  regulations
promulgated thereunder.
 
    The  remaining  16,239,231  shares  of  Common  Stock  outstanding  (or  any
securities exercisable for or convertible into the Company's Common Stock)  held
by  officers, directors,  employees, consultants  and certain  shareholders, are
"restricted securities" within the meaning of Rule 144 under the Securities  Act
("Restricted  Shares"). Restricted Shares may be  sold in the public market only
if registered or if they qualify for an exemption from registration under  Rules
144,  144(k) or 701  promulgated under the Securities  Act, which are summarized
below. Sales of the Restricted Shares in the public market, or the  availability
of  such shares for sale, could adversely  affect the market price of the Common
Stock. None  of  the Restricted  Shares  will be  available  for sale  upon  the
Effective  Date. Approximately  50,100 of these  shares of Common  Stock will be
eligible for sale in the public market 90 days after the Effective Date  subject
to the provisions of Rule 701. In addition, an additional 186,140 shares subject
to  vested options will be  available for sale 90  days after the Effective Date
subject to compliance with Rule 701.
 
    The officers, directors, certain employees  and shareholders of the  Company
have entered into contractual "lock-up" agreements generally providing that they
will  not  offer, sell,  contract to  sell or  grant any  option to  purchase or
otherwise dispose of the shares of Common Stock of the Company or any securities
exercisable for or convertible into the Company's Common Stock owned by them for
a period of 180 days after the Effective Date without the prior written  consent
of  Robertson, Stephens  & Company.  Pursuant to the  Stock Plan,  all shares of
Common Stock  issued upon  exercise of  options are  also subject  to a  lock-up
arrangement  for  a  period of  180  days  after the  date  of  this prospectus.
Robertson, Stephens  & Company  may, in  its  sole discretion  and at  any  time
without  notice, release all or any portion of the securities subject to lock-up
agreements.
 
    As a  result of  these  contractual restrictions,  notwithstanding  possible
earlier  eligibility for sale under the provisions of Rules 144, 144(k) and 701,
shares subject to lock-up agreements will not be saleable until such  agreements
expire  or are waived by Robertson, Stephens & Company. Beginning 180 days after
the Effective Date, approximately  10,411,408 additional Restricted Shares  will
become  eligible for sale subject to the provisions of Rule 144 or Rule 701 upon
the expiration of the lock-up agreements  not to sell such shares. In  addition,
beginning  180  days  after the  Effective  Date, an  additional  183,366 shares
subject to vested options will be available for sale subject to compliance  with
Rule  701 upon  the expiration  of lock-up agreements  not to  sell such shares.
Robertson, Stephens  & Company  may, in  its  sole discretion  and at  any  time
without  notice, release all or any portion of the securities subject to lock-up
agreements.
 
    In general, under Rule 144, as currently in effect, beginning 90 days  after
the  Effective Date, a person  (or persons whose shares  are aggregated) who has
beneficially owned Restricted Shares for at least two years would be entitled to
sell within any three-month period a number  of shares that does not exceed  the
greater  of:  (i) one  percent  of the  number of  shares  of Common  Stock then
outstanding (which  will equal  approximately 212,392  shares immediately  after
this  offering); or (ii) the  average weekly trading volume  of the Common Stock
during the four calendar weeks preceding the  filing of a Form 144 with  respect
to  such sale. Sales under  Rule 144 are also subject  to certain manner of sale
provisions and notice  requirements and  to the availability  of current  public
information  about the Company. Under Rule 144(k), a person who is not deemed to
have been an affiliate of the Company at any time during the 90 days preceding a
sale, and who has beneficially owned the shares proposed to be sold for at least
three years, is entitled to sell  such shares without complying with the  manner
of sale, public information, volume limitation or notice provisions of Rule 144.
 
    Beginning  90  days after  the Effective  Date,  certain shares  issued upon
exercise of options granted by the Company prior to the date of this  Prospectus
will  also be available for sale in the public market pursuant to Rule 701 under
the Securities Act. Any  employee, officer or director  of or consultant to  the
Company  who purchased his or her shares pursuant to a written compensatory plan
or contract may be entitled to rely  on the resale provisions of Rule 701.  Rule
701  permits affiliates  to sell  their Rule 701  shares under  Rule 144 without
 
                                       60
<PAGE>
complying with the  holding period requirements  of Rule 144.  Rule 701  further
provides  that  non-affiliates may  sell  such shares  in  reliance on  Rule 144
without having  to comply  with  the public  information, volume  limitation  or
notice  provisions of Rule  144. In both cases,  a holder of  Rule 701 shares is
required to wait until 90 days after the date of this Prospectus before  selling
such shares.
 
    The Company intends to file registration statements under the Securities Act
180  days after the Effective  Date to register shares  of Common Stock reserved
for issuance under the  Stock Plan and the  Directors Plan, thus permitting  the
resale of such shares by non-affiliates in the public market without restriction
under  the Securities Act. Such  registration statements will become immediately
upon filing.
 
    As of April  30, 1996, the  holders of approximately  15,834,537 shares  are
entitled  to certain registration rights with respect to such shares. If a large
number of such shares were registered and sold in the public market, such  sales
could have an adverse effect on the market price for the Company's Common Stock.
If  the Company were required to include in a Company-initiated registration the
shares held  by such  holders pursuant  to the  exercise of  their  registration
rights,  such sales may have an adverse effect on the Company's ability to raise
needed capital.  See "Description  of Capital  Stock --  Registration Rights  of
Certain Shareholders."
 
    Prior to this offering, there has been no public market for the Common Stock
of  the Company and  no predictions can be  made as to the  effect, if any, that
market sales of shares of Common Stock prevailing from time to time may have  on
the market price of the Common Stock. Nevertheless, sales of significant numbers
of  shares of  the Common Stock  in the  public market may  adversely affect the
market price of the Common Stock  offered hereby and could impair the  Company's
future ability to raise capital through an offering of its equity securities.
 
                                       61
<PAGE>
                                  UNDERWRITING
 
    The   Underwriters  named   below  acting   through  their  representatives,
Robertson, Stephens & Company  LLC, CS First  Boston Corporation and  Montgomery
Securities  (the "Representatives"), have severally agreed, subject to the terms
and conditions of the  Underwriting Agreement to purchase  from the Company  the
number  of  shares of  Common Stock  set forth  opposite their  respective names
below. The Underwriters are committed to purchase and pay for all of such shares
if any are purchased:
 
<TABLE>
<CAPTION>
                                                                                              NUMBER OF
                                        UNDERWRITER                                             SHARES
--------------------------------------------------------------------------------------------  ----------
<S>                                                                                           <C>
Robertson, Stephens & Company LLC...........................................................
CS First Boston Corporation.................................................................
Montgomery Securities.......................................................................
 
                                                                                              ----------
    Total...................................................................................   5,000,000
                                                                                              ----------
                                                                                              ----------
</TABLE>
 
    The Company has been  advised by the  Representatives that the  Underwriters
propose  to offer the shares of Common Stock to the public at the initial public
offering price set forth  on the cover  page of this  Prospectus and to  certain
dealers at such price, less a concession of not more than $  per share, of which
$      may be reallowed to other dealers. After the initial public offering, the
public offering price, concession and reallowances to dealers may be reduced  by
the Representatives.
 
    The  Underwriters may offer  up to $3  million worth of  the Common Stock to
Alejandro C. Zaffaroni, a  founder and director of  the Company, at the  initial
public  offering  price set  forth on  the  cover page  of this  Prospectus. The
Underwriters would not  receive an  underwriting discount or  commission on  the
sale of any of these shares of Common Stock to Dr. Zaffaroni.
 
    The  Company has granted  to the Underwriters  an option, exercisable during
the 30-day  period after  the date  of this  Prospectus, to  purchase up  to  an
additional  750,000 shares of  Common Stock at  the same price  per share as the
Company receives for the 5,000,000 shares  that the Underwriters have agreed  to
purchase.  To the extent that the Underwriters exercise such option, each of the
Underwriters will  have a  firm commitment  to purchase  approximately the  same
percentage  of such additional shares that the  number of shares of Common Stock
to be purchased by it shown in the above table represents as a percentage of the
5,000,000 shares offered hereby.  If purchased, such  additional shares will  be
sold  by the  Underwriters on  the same  terms as  those on  which the 5,000,000
shares are being sold. The Company will be obligated, pursuant to the option, to
sell shares  to the  Underwriters to  the extent  the option  is exercised.  The
Underwriters  may exercise  such option  only to  cover over-allotments  made in
connection with the sale of shares of Common Stock offered hereby.
 
    The Underwriting  Agreement  contains  covenants of  indemnity  between  the
Underwriters  and  the  Company  against  certain  civil  liabilities, including
liabilities under the Securities Act of 1933, as amended, and liability  arising
from  breaches of representations  and warranties contained  in the Underwriting
Agreement.
 
    Each  officer,   director   and  certain   shareholders   together   holding
approximately   12,643,742  shares  of   Common  Stock  have   agreed  with  the
Representatives that, until 180 days from the Effective Date, subject to certain
limited exceptions, they will not, directly or indirectly, sell, offer  contract
to sell, pledge, grant any option to purchase or otherwise dispose of any shares
of  Common Stock or any securities convertible into, or exchangeable for, or any
rights to purchase or  acquire, shares of Common  Stock, owned directly by  such
holders or with respect to which they have the power of disposition, without the
prior  written  consent  of  Robertson, Stephens  &  Company  LLC. Approximately
10,411,408 of such shares will be  eligible for immediate public sale  following
expiration  of the  lock-up period pursuant  to Rule 144.  Robertson, Stephens &
Company LLC may, in its sole discretion and at any time without notice,  release
all or any portion of the securities subject to lock-up agreements. In addition,
the Company has agreed that, until 180 days from the Effective Date, the Company
will  not, without  the prior written  consent of Robertson,  Stephens & Company
LLC, subject to certain  limited exceptions, sell or  otherwise dispose of,  any
shares   of   Common   Stock,  any   options   or  warrants   to   purchase  any
 
                                       62
<PAGE>
shares of Common Stock  or any securities convertible  into, exercisable for  or
exchangeable  for shares of Common Stock other than the Company's sale of shares
in this  offering,  the  issuance of  Common  Stock  upon the  exercise  of  the
outstanding  warrants or options, or the Company's grant of options and issuance
of stock  under existing  employee stock  option or  stock purchase  plans.  See
"Shares Eligible for Future Sale."
 
    The  Underwriters do not intend to confirm sales to accounts over which they
exercise discretionary authority.
 
    Prior to this offering, there has been no public market for the Common Stock
of the Company. Consequently, the initial  public offering price for the  Common
Stock   was  determined  through  negotiations   between  the  Company  and  the
Representatives. The  material  factors  considered in  such  negotiations  were
prevailing  market conditions, certain  financial information of  the Company in
recent periods, market valuations  of other companies that  the Company and  the
Representatives  believed  to be  comparable to  the  Company, estimates  of the
business  potential  of  the  Company,  the  present  state  of  the   Company's
development and the Company's management.
 
    A   managing  director   of  CS  First   Boston  Corporation,   one  of  the
Representatives, is the beneficial owner of 7,407 shares of Common Stock.
 
                                 LEGAL MATTERS
 
    The validity of the Common Stock offered hereby will be passed upon for  the
Company  by Heller  Ehrman White &  McAuliffe, Palo Alto,  California. Julian N.
Stern, the  beneficial owner  of 26,980  shares  of Common  Stock, is  the  sole
shareholder  and employee  of a  professional corporation  that is  a partner of
Heller Ehrman White & McAuliffe. Certain legal matters relating to the  offering
will  be passed upon for the Underwriters by Wilson, Sonsini, Goodrich & Rosati,
Palo Alto, California.
 
                                    EXPERTS
 
    The financial statements of  Affymetrix at December 31,  1994 and 1995,  and
for  the  years  ended December  31,  1993,  1994 and  1995,  appearing  in this
Prospectus and Registration Statement  have been audited by  Ernst & Young  LLP,
independent  auditors, as set forth in  their report thereon appearing elsewhere
herein, and are included in reliance  upon such report given upon the  authority
of such firm as experts in accounting and auditing.
 
    The  statements in  this Prospectus  as set  forth under  the captions "Risk
Factors -- Dependence on Proprietary  Technology and Unpredictability of  Patent
Protection"  and "Business  -- Intellectual Property"  have been  passed upon by
Townsend and Townsend and Crew LLP, Palo Alto, California, patent counsel to the
Company, as experts on  such matters, and are  included herein in reliance  upon
that review and approval.
 
                             ADDITIONAL INFORMATION
 
   
    The  Company  has filed  with the  Securities  and Exchange  Commission (the
"Commission") a Registration Statement, of  which this Prospectus constitutes  a
part,  under  the Securities  Act with  respect  to the  shares of  Common Stock
offered hereby.  This  Prospectus omits  certain  information contained  in  the
Registration  Statement, and reference is made to the Registration Statement and
the exhibits and schedules thereto for  further information with respect to  the
Company  and  the  Common Stock  offered  hereby. Statements  contained  in this
Prospectus as to the provisions of  any referenced contracts or other  documents
summarize the material elements of such contracts or documents. Such statements,
however, are not necessarily complete, and in each instance reference is made to
the  copy of such  document filed as  an exhibit to  the Registration Statement.
Each such  statement  is  qualified  in its  entirety  by  such  reference.  The
Registration Statement, including exhibits and schedules filed therewith, may be
inspected  without charge at  the public reference  facilities maintained by the
Commission at Room 1024,  Judiciary Plaza, 450  Fifth Street, N.W.,  Washington,
D.C.  20549 and  at the regional  offices of  the Commission located  at 7 World
Trade Center, Suite 1300, New York, New York 10048 and Citicorp Center, 500 West
Madison Street, Suite 1400,  Chicago, Illinois 60661.  Copies of such  materials
may  be obtained from the Public Reference Section of the Commission, Room 1024,
Judiciary Plaza, 450 Fifth Street, N.W., Washington, D.C. 20549, and its  public
reference  facilities in New York, New York and Chicago, Illinois, at prescribed
rates.
    
 
                                       63
<PAGE>
   
                                    GLOSSARY
    
 
   
<TABLE>
<S>                                 <C>
Amplification.....................  An  increase in the number of  copies of specific DNA or
                                    RNA fragments.
Base..............................  The nucleotides that comprise DNA.
Chromosomes.......................  The  self-replicating   genetic  structures   in   cells
                                    containing the cellular DNA that bears in its nucleotide
                                     sequence the linear array of genes.
Complementary sequence............  Nucleic   acid   base   sequences   that   can   form  a
                                    double-stranded structure  by matching  base pairs;  the
                                     complementary sequence to GTAC is CATG.
DNA (deoxyribonucleic acid).......  The  molecule that encodes genetic information. DNA is a
                                    double-stranded molecule  held  together by  weak  bonds
                                     between base pairs. The four nucleotides in DNA contain
                                     the  bases adenine  (A), guanine (G),  cytosine (C) and
                                     thymine (T). In nature, base pairs form only between  A
                                     and  T and between G and  C; thus, the base sequence of
                                     each single  strand can  be deduced  from that  of  its
                                     complementary sequence.
DNA sequence......................  The  relative order of base pairs, whether in a fragment
                                    of DNA, a gene, a chromosome, or an entire genome.
DNA synthesis.....................  The process  of  building strands  of  nucleotide  bases
                                    through controlled chemical reactions.
Feature...........................  A  discrete section of a probe array containing millions
                                    of copies  of  the  same DNA  probe.  Each  probe  array
                                     contains  from 16,000  to more  than 100,000 individual
                                     features.
Fluorescent label.................  A compound that may be attached to another molecule  and
                                    that is capable of emitting light. The emitted light may
                                     be  detected to  determine the presence  or location of
                                     the molecule.
Gel-based sequencing..............  Determination  of   the  order   of  nucleotides   (base
                                    sequences)  in  a  DNA  molecule  using  a  matrix  of a
                                     polymeric molecule  to  form  a  gel,  which  separates
                                     pieces  of DNA  in an  electric field  based upon their
                                     sizes.
Gene..............................  The  fundamental   physical  and   functional  unit   of
                                    heredity.  A gene is an  ordered sequence of nucleotides
                                     located  in  a  particular  position  on  a  particular
                                     chromosome that encodes a specific functional product.
Gene expression...................  The  process by which a gene's coded information creates
                                    the  structures  present  and  operating  in  the  cell.
                                     Expressed genes include those that are transcribed into
                                     mRNA  and then  translated into protein  and those that
                                     are  transcribed  into  RNA  but  not  translated  into
                                     protein.
Gene expression monitoring........  The  process of correlating the level and timing of gene
                                    expression with abnormal cellular behavior and disease.
Genetic code......................  The sequence of nucleotides, coded in triplets along the
                                    mRNA, that  determines the  sequence of  amino acids  in
                                     protein  synthesis. The DNA  sequence of a  gene can be
                                     used to predict the mRNA sequence, and the genetic code
                                     can in turn be used to predict the amino acid sequence.
</TABLE>
    
 
                                       64
<PAGE>
   
<TABLE>
<S>                                 <C>
Genetic mapping...................  Determining the  relative positions  of genes  on a  DNA
                                    molecule and the distance between them.
Genetic marker....................  An identifiable physical location on a chromosome, whose
                                     inheritance can be monitored.
Genome............................  All  the  genetic  material  in  the  chromosomes  of  a
                                    particular organism. Genome size  is generally given  as
                                     its total number of base pairs.
Genomics..........................  The study of genes and their function.
High-throughput sequencing........  The   process  of   identifying  and   sequencing  small
                                    stretches of  genes expressed  in  a certain  cell  type
                                     using gel-based sequencing techniques.
HIV...............................  Human  Immunodeficiency Virus, the virus responsible for
                                    HIV  disease   and   its   end-stage,   AIDS   (Acquired
                                     Immunodeficiency Syndrome).
Human Genome Project..............  Collective  name for  several projects begun  in 1986 by
                                    United States Department of  Energy to map and  sequence
                                     the   human  genome  and  develop  new  techniques  and
                                     instruments for detecting and analyzing DNA.
Hybridization.....................  The process of joining two complementary strands of  DNA
                                    or  one each  of DNA and  RNA to  form a double-stranded
                                     molecule.
Immunoassay.......................  A diagnostic test  that uses a  protein produced by  the
                                    immune  system, called  an antibody,  to detect specific
                                     proteins that may be used to aid in the  identification
                                     or treatment of disease.
In vitro..........................  Studies  or phenomena  that take place  outside the body
                                    (for instance, in test tubes).
Linkage analysis..................  Locating of  genes  on chromosomes  by  determining  the
                                    inheritance  patterns of genetic  markers that are close
                                     to one another.
mRNA (messenger RNA)..............  RNA that serves as a template for protein synthesis. See
                                    "Genetic code."
Mutation..........................  A transmissible  change in  the genetic  material of  an
                                    organism, usually in a single gene.
Nucleic acid......................  A large molecule composed of nucleotide subunits.
Nucleotide........................  A subunit of DNA or RNA consisting of a nitrogenous base
                                     (adenine,   guanine,  thymine,  or   cytosine  in  DNA;
                                     adenine,  guanine,  uracil,  or  cytosine  in  RNA),  a
                                     phosphate molecule and a sugar molecule (deoxyribose in
                                     DNA,  ribose  in  RNA).  Thousands  of  nucleotides are
                                     linked to form a DNA or RNA molecule.
Nucleotide pair...................  Two nitrogenous bases  (adenine and  thymine or  guanine
                                    and  cytosine) held together by  weak bonds. Two strands
                                     of DNA are held together in the shape of a double helix
                                     by the bonds between base pairs.
Polymorphism......................  Difference in DNA sequence among individuals.
Polymorphism Screening............  The  process  of  correlating  genetic  variations  with
                                    disease or traits.
Photolithography..................  A technique that uses light to induce chemical reactions
                                    that create exposure patterns on a surface.
</TABLE>
    
 
                                       65
<PAGE>
   
<TABLE>
<S>                                 <C>
Probe.............................  Short  sequence of DNA used to identify longer stretches
                                    of complementary DNA or RNA sequence.
Probe array.......................  Small, disposable chip consisting of densely packed  DNA
                                     sequences  (probes), where the identity and position of
                                     each probe is known on the chip surface.
Protein...........................  A large molecule composed of one or more chains of amino
                                    acids in a  specific order; the  order is determined  by
                                     the  base sequence of nucleotides  in the gene or genes
                                     coding for the protein.  Proteins are required for  the
                                     structure, function and regulation of the body's cells,
                                     tissues,  and  organs,  and  each  protein  has  unique
                                     functions. Examples of proteins are hormones,  enzymes,
                                     and antibodies.
RNA (Ribonucleic acid)............  A  chemical found in the nucleus and cytoplasm of cells;
                                    it plays  an important  role  in protein  synthesis  and
                                     other chemical activities of the cell. The structure of
                                     RNA  is  similar  to  that of  DNA.  There  are several
                                     classes of  RNA  molecules,  including  messenger  RNA,
                                     transfer RNA, ribosomal RNA, and other small RNAs, each
                                     serving a different purpose.
Solid-phase DNA synthesis.........  DNA  synthesis in which the chains of bases are anchored
                                    to a solid substrate, such as glass, as opposed to being
                                     synthesized in solution.
Virus.............................  A noncellular biological entity that can reproduce  only
                                    within  a  host cell.  Viruses  consist of  nucleic acid
                                     covered  by  protein.  Some  animal  viruses  are  also
                                     surrounded  by membrane. Once inside the infected cell,
                                     the virus uses the synthetic capability of the host  to
                                     produce progeny virus.
Wafer.............................  Pieces  of  glass  on which  multiple  probe  arrays are
                                    simultaneously manufactured. The wafers are subsequently
                                     diced to yield individual probe arrays.
</TABLE>
    
 
                                       66
<PAGE>
                                AFFYMETRIX, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                         INDEX TO FINANCIAL STATEMENTS
 
<TABLE>
<CAPTION>
                                                                                                                PAGE
                                                                                                                -----
<S>                                                                                                          <C>
Report of Ernst & Young LLP, Independent Auditors..........................................................         F-2
 
Financial Statements:
  Balance Sheets...........................................................................................         F-3
  Statements of Operations.................................................................................         F-4
  Statement of Shareholders' Equity........................................................................         F-5
  Statements of Cash Flows.................................................................................         F-7
  Notes to Financial Statements............................................................................         F-8
</TABLE>
 
                                      F-1
<PAGE>
               REPORT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS
 
The Board of Directors and Shareholders
Affymetrix, Inc.
 
    We  have  audited the  accompanying balance  sheets  of Affymetrix,  Inc. (a
development stage  company) at  December  31, 1994  and  1995, and  the  related
statements  of operations, shareholders' equity, and  cash flows for each of the
three years  in the  period ended  December 31,  1995 and  for the  period  from
inception (January 1, 1991) to December 31, 1995. These financial statements are
the responsibility of the Company's management. Our responsibility is to express
an opinion on these financial statements based on our audits.
 
    We  conducted  our audits  in  accordance with  generally  accepted auditing
standards. Those standards require that we plan and perform the audit to  obtain
reasonable assurance about whether the financial statements are free of material
misstatement.  An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also  includes
assessing  the  accounting principles  used  and significant  estimates  made by
management, as well as evaluating the overall financial statement  presentation.
We believe that our audits provide a reasonable basis for our opinion.
 
    In  our opinion, the financial statements  referred to above present fairly,
in all  material  respects,  the  financial  position  of  Affymetrix,  Inc.  (a
development stage company) at December 31, 1994 and 1995, and the results of its
operations  and its cash flows  for each of the three  years in the period ended
December 31,  1995  and for  the  period from  inception  (January 1,  1991)  to
December 31, 1995, in conformity with generally accepted accounting principles.
 
                                          ERNST & YOUNG LLP
Palo Alto, California
February 9, 1996,
except for the first paragraph of Note 9 as to which the date is
         , 1996
 
--------------------------------------------------------------------------------
The  foregoing report is in the form that  will be signed upon the completion of
the reverse stock split described in Note 9 of the financial statements.
 
                                          /s/ ERNST & YOUNG LLP
   
Palo Alto, California
May 20, 1996
    
 
                                      F-2
<PAGE>
                                AFFYMETRIX, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                                 BALANCE SHEETS
                      (IN THOUSANDS, EXCEPT SHARE AMOUNTS)
 
                                     ASSETS
 
   
<TABLE>
<CAPTION>
                                                                     DECEMBER 31,
                                                                 --------------------
                                                                   1994       1995
                                                                 ---------  ---------   MARCH 31,     PRO FORMA
                                                                                       -----------  SHAREHOLDERS'
                                                                                          1996        EQUITY AT
                                                                                       -----------    MARCH 31,
                                                                                                    -------------
                                                                                       (UNAUDITED)      1996
                                                                                                    -------------
                                                                                                     (UNAUDITED)
<S>                                                              <C>        <C>        <C>          <C>
Current assets:
  Cash and cash equivalents....................................  $   6,659  $   2,481   $     308
  Short-term investments.......................................     11,146     36,402      34,529
  Contract and grant receivables...............................         90      1,342         636
  Inventories..................................................     --            670       1,469
  Other current assets.........................................         88        260         422
                                                                 ---------  ---------  -----------
    Total current assets.......................................     17,983     41,155      37,364
Property and equipment, at cost:
  Equipment and furniture......................................      2,554      4,254       4,955
  Leasehold improvements.......................................        356        586         587
                                                                 ---------  ---------  -----------
                                                                     2,910      4,840       5,542
  Less accumulated depreciation and amortization...............     (1,047)    (1,583)     (1,863)
                                                                 ---------  ---------  -----------
    Net property and equipment.................................      1,863      3,257       3,679
Other assets...................................................         15        140         142
                                                                 ---------  ---------  -----------
                                                                 $  19,861  $  44,552   $  41,185
                                                                 ---------  ---------  -----------
                                                                 ---------  ---------  -----------
                               LIABILITIES AND SHAREHOLDERS' EQUITY
Current liabilities:
  Accounts payable and other accrued liabilities...............  $   1,046  $   2,469   $   3,278
  Payable to Affymax...........................................        254         89          12
  Deferred revenue.............................................        837      2,340       2,153
  Current portion of capital lease obligation..................        169        187         192
                                                                 ---------  ---------  -----------
    Total current liabilities..................................      2,306      5,085       5,635
Convertible note payable to Affymax............................      6,000     --          --
Noncurrent portion of capital lease obligation.................      1,135        948         898
Advance from collaborative partner.............................      1,250     --          --
Commitments....................................................                            --
Shareholders' equity:
  Convertible preferred stock, no par value; 27,500,000 shares
   authorized; 14,500,000 issued and outstanding at December
   31, 1994, 23,166,666 at December 31, 1995 and March 31, 1996
   (none pro forma); aggregate liquidation preference of
   $70,625 at December 31, 1995 and March 31, 1996.............     31,283     70,439      70,439     $  --
  Common stock, no par value; 50,000,000 shares authorized;
   408,198 shares issued and outstanding at December 31, 1994,
   536,267 at December 31, 1995 and 609,240 at March 31, 1996
   (16,239,231 pro forma)......................................        122      2,717       3,089        73,528
  Notes receivable from officers...............................        (84)       (42)        (41)          (41)
  Unrealized gain(loss) on available-for-sale securities.......       (382)       281           1             1
  Deferred compensation........................................     --         (2,360)     (2,399)       (2,399)
  Deficit accumulated during development stage.................    (21,769)   (32,516)    (36,437)      (36,437)
                                                                 ---------  ---------  -----------  -------------
    Total shareholders' equity.................................      9,170     38,519      34,652     $  34,652
                                                                 ---------  ---------  -----------  -------------
                                                                                                    -------------
                                                                 $  19,861  $  44,552   $  41,185
                                                                 ---------  ---------  -----------
                                                                 ---------  ---------  -----------
</TABLE>
    
 
                            See accompanying notes.
 
                                      F-3
<PAGE>
                                AFFYMETRIX, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                            STATEMENTS OF OPERATIONS
                    (IN THOUSANDS, EXCEPT PER SHARE AMOUNT)
 
   
<TABLE>
<CAPTION>
                                          YEAR ENDED DECEMBER 31,
                                      -------------------------------
                                        1993       1994       1995
                                      ---------  ---------  ---------        THREE MONTHS          PERIOD FROM
                                                                           ENDED MARCH 31,          INCEPTION
                                                                       ------------------------    (JANUARY 1,
                                                                          1995         1996           1991)
                                                                       -----------  -----------      THROUGH
                                                                                                 MARCH 31, 1996
                                                                       (UNAUDITED)  (UNAUDITED)  ---------------
                                                                                                   (UNAUDITED)
<S>                                   <C>        <C>        <C>        <C>          <C>          <C>
Contract and grant revenue..........  $   1,413  $   1,574  $   4,625   $     854    $   1,416      $   9,071
Operating expenses:
  Research and development..........      6,566      9,483     12,420       2,274        4,177         38,328
  General and administrative........        577      2,303      3,833         777        1,649          9,205
                                      ---------  ---------  ---------  -----------  -----------       -------
    Total operating expenses
     (includes related-party expense
     of $1,147, $1,647, $1,432,
     $428, $364 and $4,590,
     respectively)..................      7,143     11,786     16,253       3,051        5,826         47,533
                                      ---------  ---------  ---------  -----------  -----------       -------
Loss from operations................     (5,730)   (10,212)   (11,628)     (2,197)      (4,410)       (38,462)
  Interest income...................        211        575      1,301         183          517          2,607
  Interest expense (includes
   related-party expense of $320 in
   1995 and $128 in the three months
   ended March 31, 1995)............        (73)       (43)      (420)       (160)         (28)          (582)
                                      ---------  ---------  ---------  -----------  -----------       -------
Net loss............................  $  (5,592) $  (9,680) $ (10,747)  $  (2,174)   $  (3,921)     $ (36,437)
                                      ---------  ---------  ---------  -----------  -----------       -------
                                      ---------  ---------  ---------  -----------  -----------       -------
Pro forma net loss per share........                        $   (0.61)  $   (0.12)   $   (0.22)
                                                            ---------  -----------  -----------
                                                            ---------  -----------  -----------
Shares used in computing pro forma
 net loss per share.................                           17,664      17,663       17,664
                                                            ---------  -----------  -----------
                                                            ---------  -----------  -----------
</TABLE>
    
 
                            See accompanying notes.
 
                                      F-4
<PAGE>
                                AFFYMETRIX, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                       STATEMENT OF SHAREHOLDERS' EQUITY
       FOR THE PERIOD FROM INCEPTION (JANUARY 1, 1991) TO MARCH 31, 1996
               (IN THOUSANDS, EXCEPT SHARE AND PER SHARE AMOUNTS)
<TABLE>
<CAPTION>
                                                                                  CONTRI-
                                        CONVERTIBLE                   NOTES       BUTIONS
                                         PREFERRED     COMMON      RECEIVABLE      FROM      UNREALIZED       DEFERRED
                                           STOCK        STOCK     FROM OFFICERS   AFFYMAX    GAIN (LOSS)    COMPENSATION
                                        -----------  -----------  -------------  ---------  -------------  ---------------
<S>                                     <C>          <C>          <C>            <C>        <C>            <C>
Issuance of 666 shares of common stock
 for cash in March 1992 at $0.15 per
 share................................   $  --        $  --         $  --        $  --        $  --           $  --
Contributions from Affymax (1991 and
 1992)................................      --           --            --            6,316       --              --
Net loss (1991 and 1992)..............      --           --            --           --           --              --
                                        -----------  -----------          ---    ---------        -----          ------
Balance at December 31, 1992..........      --           --            --            6,316       --              --
Contributions from Affymax through
 September 1993.......................      --           --            --            4,309       --              --
Issuance of 6,000,000 shares of Series
 A Senior convertible preferred stock
 for cash in September 1993, at $3.50
 per share, net of issuance costs of
 $342.................................      20,658       --            --           --           --              --
Conversion of all contributions from
 Affymax into 8,500,000 shares of
 Series 1 Subordinated convertible
 preferred stock in September 1993 at
 $1.25 per share......................      10,625       --            --          (10,625)      --              --
Issuance of 66,666 shares of common
 stock for cash upon exercise of stock
 options in December 1993 at $0.30 per
 share................................      --               20        --           --           --              --
Issuance of 266,666 shares of common
 stock for notes receivable upon
 exercise of options in December 1993
 at $0.30 per share...................      --               80           (80)      --           --              --
Net loss..............................      --           --            --           --           --              --
                                        -----------  -----------          ---    ---------        -----          ------
Balance at December 31, 1993..........      31,283          100           (80)      --           --              --
Issuance of 74,200 shares of common
 stock for cash upon exercise of stock
 options at $0.30 per share...........      --               22        --           --           --              --
Interest accrued on notes receivable
 from officers........................      --           --                (4)      --           --              --
Unrealized loss on available-for-sale
 securities...........................      --           --            --           --             (382)         --
Net loss..............................      --           --            --           --           --              --
                                        -----------  -----------          ---    ---------        -----          ------
Balance at December 31, 1994..........      31,283          122           (84)      --             (382)         --
Issuance of 7,333,333 shares of Series
 B Senior convertible preferred stock
 for cash in August 1995, at $4.50 per
 share, net of issuance costs of
 $164.................................      32,836       --            --           --           --              --
Conversion of $6,000 note payable into
 1,333,333 shares of Series B Senior
 convertible preferred stock in August
 1995, at $4.50 per share.............       6,000       --            --           --           --              --
Issuance of 62,749 shares of common
 stock for cash upon exercise of stock
 options at $0.30 to $0.675 per
 share................................      --               23        --           --           --              --
Issuance of 65,320 shares of common
 stock for financing commissions in
 August 1995 at $0.675 per share......      --               44        --           --           --              --
 
<CAPTION>
                                           DEFICIT         TOTAL
                                         ACCUMULATED   SHAREHOLDERS'
                                           DURING       EQUITY (NET
                                         DEVELOPMENT      CAPITAL
                                            STAGE       DEFICIENCY)
                                        -------------  -------------
<S>                                     <C>            <C>
Issuance of 666 shares of common stock
 for cash in March 1992 at $0.15 per
 share................................    $  --          $  --
Contributions from Affymax (1991 and
 1992)................................       --              6,316
Net loss (1991 and 1992)..............       (6,497)        (6,497)
                                        -------------  -------------
Balance at December 31, 1992..........       (6,497)          (181)
Contributions from Affymax through
 September 1993.......................       --              4,309
Issuance of 6,000,000 shares of Series
 A Senior convertible preferred stock
 for cash in September 1993, at $3.50
 per share, net of issuance costs of
 $342.................................       --             20,658
Conversion of all contributions from
 Affymax into 8,500,000 shares of
 Series 1 Subordinated convertible
 preferred stock in September 1993 at
 $1.25 per share......................       --             --
Issuance of 66,666 shares of common
 stock for cash upon exercise of stock
 options in December 1993 at $0.30 per
 share................................       --                 20
Issuance of 266,666 shares of common
 stock for notes receivable upon
 exercise of options in December 1993
 at $0.30 per share...................       --             --
Net loss..............................       (5,592)        (5,592)
                                        -------------  -------------
Balance at December 31, 1993..........      (12,089)        19,214
Issuance of 74,200 shares of common
 stock for cash upon exercise of stock
 options at $0.30 per share...........       --                 22
Interest accrued on notes receivable
 from officers........................       --                 (4)
Unrealized loss on available-for-sale
 securities...........................       --               (382)
Net loss..............................       (9,680)        (9,680)
                                        -------------  -------------
Balance at December 31, 1994..........      (21,769)         9,170
Issuance of 7,333,333 shares of Series
 B Senior convertible preferred stock
 for cash in August 1995, at $4.50 per
 share, net of issuance costs of
 $164.................................       --             32,836
Conversion of $6,000 note payable into
 1,333,333 shares of Series B Senior
 convertible preferred stock in August
 1995, at $4.50 per share.............       --              6,000
Issuance of 62,749 shares of common
 stock for cash upon exercise of stock
 options at $0.30 to $0.675 per
 share................................       --                 23
Issuance of 65,320 shares of common
 stock for financing commissions in
 August 1995 at $0.675 per share......       --                 44
</TABLE>
 
                                      F-5
<PAGE>
                                AFFYMETRIX, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                 STATEMENT OF SHAREHOLDERS' EQUITY (CONTINUED)
       FOR THE PERIOD FROM INCEPTION (JANUARY 1, 1991) TO MARCH 31, 1996
               (IN THOUSANDS, EXCEPT SHARE AND PER SHARE AMOUNTS)
<TABLE>
<CAPTION>
                                                                                  CONTRI-
                                        CONVERTIBLE                   NOTES       BUTIONS
                                         PREFERRED     COMMON      RECEIVABLE      FROM      UNREALIZED       DEFERRED
                                           STOCK        STOCK     FROM OFFICERS   AFFYMAX    GAIN (LOSS)    COMPENSATION
                                        -----------  -----------  -------------  ---------  -------------  ---------------
<S>                                     <C>          <C>          <C>            <C>        <C>            <C>
Issuance of warrants in June, July,
 and October 1995 for 202,441 of
 Series 2 Subordinated convertible
 preferred stock at $1.58 per share in
 exchange for interest................         320       --            --           --           --              --
Interest received on notes receivable
 from officers........................      --           --                 2       --           --              --
Reclassification of notes receivable
 from officers to other assets........      --           --                40       --           --              --
Compensation from accelerated
 options..............................      --               40        --           --           --              --
Deferred compensation related to grant
 of stock options.....................      --            2,488        --           --           --              (2,488)
Amortization of deferred
 compensation.........................      --           --            --           --           --                 128
Unrealized gain on available-for-sale
 securities...........................      --           --            --           --              663          --
Net loss..............................      --           --            --           --           --              --
                                        -----------  -----------          ---    ---------        -----          ------
Balance at December 31, 1995..........      70,439        2,717           (42)      --              281          (2,360)
Issuance of 72,973 shares of common
 stock for cash upon exercise of stock
 options at $0.30 to $0.675 per share
 (Unaudited)..........................      --               46        --           --           --              --
Interest received on notes receivable
 from officers (Unaudited)............      --           --                 1       --           --              --
Deferred compensation related to grant
 of stock options (Unaudited).........      --              326        --           --           --                (326)
Amortization of deferred compensation
 (Unaudited)..........................      --           --            --           --           --                 287
Unrealized loss on available-for-sale
 securities (Unaudited)...............      --           --            --           --             (280)         --
Net loss (Unaudited)..................      --           --            --           --           --              --
                                        -----------  -----------          ---    ---------        -----          ------
Balance at March 31, 1996
 (Unaudited)..........................   $  70,439    $   3,089     $     (41)   $  --        $       1       $  (2,399)
                                        -----------  -----------          ---    ---------        -----          ------
                                        -----------  -----------          ---    ---------        -----          ------
 
<CAPTION>
                                           DEFICIT         TOTAL
                                         ACCUMULATED   SHAREHOLDERS'
                                           DURING       EQUITY (NET
                                         DEVELOPMENT      CAPITAL
                                            STAGE       DEFICIENCY)
                                        -------------  -------------
<S>                                     <C>            <C>
Issuance of warrants in June, July,
 and October 1995 for 202,441 of
 Series 2 Subordinated convertible
 preferred stock at $1.58 per share in
 exchange for interest................       --                320
Interest received on notes receivable
 from officers........................       --                  2
Reclassification of notes receivable
 from officers to other assets........       --                 40
Compensation from accelerated
 options..............................       --                 40
Deferred compensation related to grant
 of stock options.....................       --             --
Amortization of deferred
 compensation.........................       --                128
Unrealized gain on available-for-sale
 securities...........................       --                663
Net loss..............................      (10,747)       (10,747)
                                        -------------  -------------
Balance at December 31, 1995..........      (32,516)        38,519
Issuance of 72,973 shares of common
 stock for cash upon exercise of stock
 options at $0.30 to $0.675 per share
 (Unaudited)..........................       --                 46
Interest received on notes receivable
 from officers (Unaudited)............       --                  1
Deferred compensation related to grant
 of stock options (Unaudited).........       --             --
Amortization of deferred compensation
 (Unaudited)..........................       --                287
Unrealized loss on available-for-sale
 securities (Unaudited)...............       --               (280)
Net loss (Unaudited)..................       (3,921)        (3,921)
                                        -------------  -------------
Balance at March 31, 1996
 (Unaudited)..........................    $ (36,437)     $  34,652
                                        -------------  -------------
                                        -------------  -------------
</TABLE>
 
                             See accompanyng notes.
 
                                      F-6
<PAGE>
                                AFFYMETRIX, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                            STATEMENTS OF CASH FLOWS
                INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS
                                 (IN THOUSANDS)
<TABLE>
<CAPTION>
                                                                     YEAR ENDED DECEMBER 31,      THREE MONTHS ENDED MARCH
                                                                 -------------------------------            31,
                                                                   1993       1994       1995     ------------------------
                                                                 ---------  ---------  ---------     1995         1996
                                                                                                  -----------  -----------
                                                                                                  (UNAUDITED)  (UNAUDITED)
<S>                                                              <C>        <C>        <C>        <C>          <C>
Cash flows from operating activities:
  Net loss.....................................................  $  (5,592) $  (9,680) $ (10,747)  $  (2,174)   $  (3,921)
Adjustments to reconcile net loss to net cash used in operating
 activities:
    Depreciation and amortization..............................        465        689        701         150          279
    Amortization of investment premiums and discounts, net.....     --            148       (191)        165          (24)
    Loss on disposal of equipment..............................     --            417        188      --           --
    Compensation due to accelerated vesting....................     --         --             40      --           --
    Amortization of deferred compensation......................     --         --            128      --              287
    Interest payable exchanged for warrants....................     --         --            320      --           --
    Changes in operating assets and liabilities:
      Contract and grant receivables...........................     --            (90)    (1,252)       (675)         706
      Inventories..............................................     --         --           (670)     --             (799)
      Other current assets.....................................       (649)       575       (172)        (19)        (162)
      Other assets.............................................         14        (15)       (80)     --               (2)
      Accounts payable and other accrued liabilities...........        570        295      1,423        (196)         809
      Payable to Affymax.......................................      1,574     (1,320)      (165)         (1)         (77)
      Deferred revenue.........................................        460        377        253        (150)        (187)
      Advance from collaborative partner.......................     --          1,250     --          --           --
                                                                 ---------  ---------  ---------  -----------  -----------
        Net cash used in operating activities..................     (3,158)    (7,354)   (10,224)     (2,900)      (3,091)
                                                                 ---------  ---------  ---------  -----------  -----------
Cash flows from investing activities:
    Capital expenditures.......................................     (1,537)    (1,207)    (2,283)       (580)        (701)
    Proceeds from the sale of available-for-sale securities....     --          5,308      8,538      --            1,466
    Proceeds from maturities of available-for-sale
     securities................................................     --         --          5,485      --            2,156
    Purchases of available-for-sale securities.................    (13,997)    (2,990)   (38,428)     (2,007)      (2,004)
                                                                 ---------  ---------  ---------  -----------  -----------
        Net cash provided by/(used in) investing activities....    (15,534)     1,111    (26,688)     (2,587)         917
                                                                 ---------  ---------  ---------  -----------  -----------
Cash flows from financing activities:
  Contributions from Affymax...................................      4,309     --         --          --           --
  Issuances of common stock....................................         20         22         23      --               46
  Issuances of preferred stock, net............................     20,658     --         32,880      --           --
  Proceeds from capital lease obligation.......................     --          1,307     --          --           --
  Principal payments on capital lease obligation...............     --             (3)      (169)        (41)         (45)
  Issuance of convertible note payable to Affymax..............     --          6,000     --          --           --
  Issuance of notes payable....................................        333     --         --          --           --
  Principal payments on notes payable..........................       (327)      (819)    --          --           --
                                                                 ---------  ---------  ---------  -----------  -----------
        Net cash provided by (used in) financing activities....     24,993      6,507     32,734         (41)           1
                                                                 ---------  ---------  ---------  -----------  -----------
Net increase (decrease) in cash and cash equivalents...........      6,301        264     (4,178)     (5,528)      (2,173)
Cash and cash equivalents at beginning of period...............         94      6,395      6,659       6,659        2,481
                                                                 ---------  ---------  ---------  -----------  -----------
Cash and cash equivalents at end of period.....................  $   6,395  $   6,659  $   2,481   $   1,131    $     308
                                                                 ---------  ---------  ---------  -----------  -----------
                                                                 ---------  ---------  ---------  -----------  -----------
Supplemental disclosure of noncash financing activities:
  Issuance of common stock for note receivable from officers...  $      80  $  --      $  --       $  --        $  --
                                                                 ---------  ---------  ---------  -----------  -----------
                                                                 ---------  ---------  ---------  -----------  -----------
  Conversion of note payable and contributions from
   Affymax to preferred stock..................................  $  10,625  $  --      $   6,000   $  --        $  --
                                                                 ---------  ---------  ---------  -----------  -----------
                                                                 ---------  ---------  ---------  -----------  -----------
  Assets under capital lease obligation........................     --      $   1,297  $  --       $  --        $  --
                                                                 ---------  ---------  ---------  -----------  -----------
                                                                 ---------  ---------  ---------  -----------  -----------
  Issuance of common stock for financing commissions...........  $  --      $  --      $      44   $  --        $  --
                                                                 ---------  ---------  ---------  -----------  -----------
                                                                 ---------  ---------  ---------  -----------  -----------
  Issuance of warrants in exchange for interest payable........  $  --      $  --      $     320   $  --        $  --
                                                                 ---------  ---------  ---------  -----------  -----------
                                                                 ---------  ---------  ---------  -----------  -----------
Supplemental disclosure of cash flow information:
  Interest paid................................................  $      73  $      20  $     122   $      32    $      28
                                                                 ---------  ---------  ---------  -----------  -----------
                                                                 ---------  ---------  ---------  -----------  -----------
 
<CAPTION>
                                                                  PERIOD FROM
                                                                  (JANUARY 1,
                                                                     1991)
                                                                 THROUGH MARCH
                                                                    31, 1996
 
<S>                                                              <C>
Cash flows from operating activities:
  Net loss.....................................................    $  (36,437)
Adjustments to reconcile net loss to net cash used in operating
 activities:
    Depreciation and amortization..............................         2,210
    Amortization of investment premiums and discounts, net.....           (67)
    Loss on disposal of equipment..............................           605
    Compensation due to accelerated vesting....................            40
    Amortization of deferred compensation......................           415
    Interest payable exchanged for warrants....................           320
    Changes in operating assets and liabilities:
      Contract and grant receivables...........................          (636)
      Inventories..............................................        (1,469)
      Other current assets.....................................          (422)
      Other assets.............................................           (98)
      Accounts payable and other accrued liabilities...........         3,278
      Payable to Affymax.......................................            12
      Deferred revenue.........................................           903
      Advance from collaborative partner.......................         1,250
                                                                 --------------
        Net cash used in operating activities..................       (30,096)
                                                                 --------------
Cash flows from investing activities:
    Capital expenditures.......................................        (6,494)
    Proceeds from the sale of available-for-sale securities....        15,312
    Proceeds from maturities of available-for-sale
     securities................................................         7,641
    Purchases of available-for-sale securities.................       (57,419)
                                                                 --------------
        Net cash provided by/(used in) investing activities....       (40,960)
                                                                 --------------
Cash flows from financing activities:
  Contributions from Affymax...................................        10,625
  Issuances of common stock....................................           111
  Issuances of preferred stock, net............................        53,538
  Proceeds from capital lease obligation.......................         1,307
  Principal payments on capital lease obligation...............          (217)
  Issuance of convertible note payable to Affymax..............         6,000
  Issuance of notes payable....................................         1,146
  Principal payments on notes payable..........................        (1,146)
                                                                 --------------
        Net cash provided by (used in) financing activities....        71,364
                                                                 --------------
Net increase (decrease) in cash and cash equivalents...........           308
Cash and cash equivalents at beginning of period...............        --
                                                                 --------------
Cash and cash equivalents at end of period.....................    $      308
                                                                 --------------
                                                                 --------------
Supplemental disclosure of noncash financing activities:
  Issuance of common stock for note receivable from officers...    $       80
                                                                 --------------
                                                                 --------------
  Conversion of note payable and contributions from
   Affymax to preferred stock..................................    $   16,625
                                                                 --------------
                                                                 --------------
  Assets under capital lease obligation........................    $    1,297
                                                                 --------------
                                                                 --------------
  Issuance of common stock for financing commissions...........    $       44
                                                                 --------------
                                                                 --------------
  Issuance of warrants in exchange for interest payable........    $      320
                                                                 --------------
                                                                 --------------
Supplemental disclosure of cash flow information:
  Interest paid................................................    $      262
                                                                 --------------
                                                                 --------------
</TABLE>
 
                            See accompanying notes.
 
                                      F-7
<PAGE>
                                AFFYMETRIX, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                         NOTES TO FINANCIAL STATEMENTS
 
                    (INFORMATION FOR THE THREE MONTHS ENDED
                   MARCH 31, 1995 AND 1996 AND FOR THE PERIOD
                 FROM INCEPTION TO MARCH 31, 1996 IS UNAUDITED)
 
NOTE 1.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
 
ORGANIZATION, OWNERSHIP, AND BUSINESS
 
    Affymetrix,  Inc. ("Affymetrix") is  a development stage  company focused on
developing  GeneChip-TM-  based   products  and  related   technology  for   the
acquisition,  analysis, and management of complex genetic data. The business and
operations of  Affymetrix commenced  in 1991  by Affymax  N.V. and  subsidiaries
("Affymax")  and  were  initially  conducted  within  Affymax.  In  March  1992,
Affymetrix was  incorporated as  a California  corporation and  became a  wholly
owned  subsidiary  of Affymax.  Beginning in  September 1993,  Affymetrix issued
equity securities  which diluted  Affymax' shareholding  in Affymetrix.  Affymax
owns  approximately 46% of Affymetrix at December 31, 1995. In March 1995, Glaxo
plc, now Glaxo Wellcome plc ("Glaxo"), purchased Affymax, including its then 65%
interest in  Affymetrix.  The  accompanying  financial  statements  include  the
operations  of Affymetrix  from inception (January  1, 1991).  The advances from
Affymax through  September  1993  were recorded  as  capital  contributions  and
converted  to convertible  preferred shares  in September  1993. Since September
1993, the  financial  statements  reflect  the operations  of  Affymetrix  on  a
stand-alone basis.
 
    Affymetrix'  success  will  depend in  part  on  its ability  to  obtain and
maintain patent protection  in the  United States  and other  countries for  its
technologies  and products. The commercial success of Affymetrix also depends in
part on neither infringing  patents or proprietary rights  of third parties  nor
breaching any licenses that may relate to Affymetrix' technologies and products.
 
USE OF ESTIMATES
 
    The  preparation of  the financial  statements in  conformity with generally
accepted  accounting  principles  requires  management  to  make  estimates  and
assumptions  that  affect  amounts  reported  in  the  financial  statements and
accompanying notes. Actual results could differ from those estimates.
 
INTERIM FINANCIAL INFORMATION
 
    The financial information at March 31, 1996 and for the three-month  periods
ended  March  31,  1995  and  1996 is  unaudited  but  includes  all adjustments
(consisting only  of normal  recurring adjustments)  which Affymetrix  considers
necessary for a fair presentation of the financial position at such date and the
operating  results and cash flows  for those periods. Results  for the March 31,
1996 period are not necessarily indicative of the results for the entire year.
 
REVENUE RECOGNITION
 
    Contract and  grant revenue  is recorded  as earned  as defined  within  the
specific  agreements. Payments received in  advance under these arrangements are
recorded as deferred revenue  until earned. Direct  costs associated with  these
contracts  and grants are reported as  research and development expense. Revenue
for the  beta  shipments  are  recorded as  contract  revenue  pursuant  to  the
development agreements.
 
    Revenue  from customers representing 10% or more of total contract and grant
revenue during fiscal 1993, 1994, and 1995 is as follows:
 
<TABLE>
<CAPTION>
                1993        1994        1995
             ----------  ----------  ----------
<S>          <C>         <C>         <C>
 Customer:
     A           --          --             25%
     B           --          --             23%
     C           --          --             22%
     D              49%         54%         17%
     E              38%         29%      --
</TABLE>
 
                                      F-8
<PAGE>
                                AFFYMETRIX, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
                    (INFORMATION FOR THE THREE MONTHS ENDED
                   MARCH 31, 1995 AND 1996 AND FOR THE PERIOD
                 FROM INCEPTION TO MARCH 31, 1996 IS UNAUDITED)
 
NOTE 1.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
RESEARCH AND DEVELOPMENT
 
    Research and development  expenses consist of  costs incurred for  internal,
contract  and  grant-sponsored  research and  development.  These  costs include
direct and research-related overhead expenses.
 
NET LOSS PER SHARE
 
    Except as noted below, historical net  loss per share is computed using  the
weighted  average number of common  shares outstanding. Common equivalent shares
are excluded from the computation as their effect is antidilutive, except  that,
pursuant  to  the Securities  and Exchange  Commission ("SEC")  Staff Accounting
Bulletins, common and common equivalent shares (stock options, convertible notes
payable, convertible preferred stock, and warrants) issued during the 12  months
prior to the initial filing of the proposed offering at prices below the assumed
public  offering price  have been  included in the  calculation as  if they were
outstanding for all periods presented (using the treasury stock method for stock
options and  warrants  and the  if-converted  method for  convertible  preferred
stock).
 
    Historical net loss per share information is as follows:
 
<TABLE>
<CAPTION>
                                                                           THREE MONTHS
                                                                              ENDED
                                  YEAR ENDED DECEMBER 31,                   MARCH 31,
                          ----------------------------------------  --------------------------
                              1993          1994          1995          1995          1996
                          ------------  ------------  ------------  ------------  ------------
<S>                       <C>           <C>           <C>           <C>           <C>
Net loss per share......  $      (0.75) $      (1.24) $      (1.38) $      (0.28) $      (0.50)
                          ------------  ------------  ------------  ------------  ------------
                          ------------  ------------  ------------  ------------  ------------
Shares used in computing
 net loss per share.....     7,422,000     7,801,000     7,812,000     7,811,000     7,812,000
                          ------------  ------------  ------------  ------------  ------------
                          ------------  ------------  ------------  ------------  ------------
</TABLE>
 
    Pro  forma net loss per share has  been computed as described above and also
gives effect  to the  conversion of  convertible preferred  shares not  included
above  that will  automatically convert  upon completion  of Affymetrix' initial
public offering  (using  the if-converted  method)  from the  original  date  of
issuance.
 
CASH, CASH EQUIVALENTS AND SHORT-TERM INVESTMENTS
 
    Effective  January  1,  1994,  Affymetrix  adopted  Statement  of  Financial
Accounting Standards No. 115,  "Accounting for Certain  Investments in Debt  and
Equity  Securities." The effect of adopting Statement 115 at January 1, 1994 was
immaterial.
 
    Cash equivalents  and short-term  investments  consist of  debt  securities.
Management  determines the appropriate classification  of debt securities at the
time of  purchase. As  of December  31, 1995,  Affymetrix' debt  securities  are
classified  as available-for-sale and are carried  at fair value with unrealized
gains and losses reported in shareholders' equity. Affymetrix reports all liquid
securities with maturities at date of purchase of three months or less that  are
readily  convertible into cash and have insignificant interest rate risk as cash
equivalents. All other available-for-sale securities are recorded as  short-term
investments.  The  cost  of  debt securities  is  adjusted  for  amortization of
premiums and discounts to  maturity. This amortization  is included in  interest
income.  Realized gains and losses on available-for-sale securities are included
in interest  income.  The cost  of  securities sold  is  based on  the  specific
identification  method.  Interest  and  dividends  on  securities  classified as
available-for-sale  are  included  in  interest  income.  The  fair  values   of
securities are based on quoted market prices.
 
                                      F-9
<PAGE>
                                AFFYMETRIX, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
                    (INFORMATION FOR THE THREE MONTHS ENDED
                   MARCH 31, 1995 AND 1996 AND FOR THE PERIOD
                 FROM INCEPTION TO MARCH 31, 1996 IS UNAUDITED)
 
NOTE 1.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
INVENTORIES
 
    Inventories  are stated at the lower of cost, as determined by the first-in,
first-out method, or market and consist  entirely of finished goods at  December
31, 1995, and $256,000 of raw material and $1,213,000 of finished goods at March
31, 1996.
 
DEPRECIATION AND AMORTIZATION
 
   
    The  costs of property and equipment are depreciated for financial reporting
purposes using the straight-line method over  the estimated useful lives of  the
assets ranging from two to five years. Leasehold improvements are amortized over
the  useful  lives  of  the  assets or  the  lease-term,  whichever  is shorter.
Expenditures for maintenance and repairs are expensed as incurred.
    
 
ACCOUNTS PAYABLE AND OTHER ACCRUED LIABILITIES
 
    Accounts payable and  other accrued  liabilities include  the following  (in
thousands):
 
<TABLE>
<CAPTION>
                                                               DECEMBER 31,       MARCH 31,
                                                           --------------------  -----------
                                                             1994       1995        1996
                                                           ---------  ---------  -----------
<S>                                                        <C>        <C>        <C>
Accounts payable.........................................  $     587  $   1,088   $     963
Accrued compensation.....................................        262        576         617
Collaborative research refund............................     --            360         448
Accrued research.........................................        132        115         533
Legal....................................................     --            222         351
Other....................................................         65        108         366
                                                           ---------  ---------  -----------
                                                           $   1,046  $   2,469   $   3,278
                                                           ---------  ---------  -----------
                                                           ---------  ---------  -----------
</TABLE>
 
STOCK BASED COMPENSATION
 
    In October 1995, the Financial Accounting Standards Board issued "Accounting
for  Stock-Based  Compensation" ("Statement  No.  123") which  is  effective for
fiscal 1996.  Under  Statement  No. 123,  stock-based  compensation  expense  is
measured  using either the  intrinsic-value method as  prescribed in APB Opinion
No. 25  or the  fair value  method described  in Statement  No. 123.  Affymetrix
intends  to adopt the  disclosure only alternative under  Statement No. 123 and,
accordingly, Affymetrix will be required to disclose the pro forma net income or
loss and per share amounts  in the notes to  the financial statements using  the
fair  value based method. Affymetrix has not  yet determined the impact of these
pro forma adjustments.
 
CONCENTRATIONS OF CREDIT RISK
 
    Cash equivalents and investments are financial instruments which potentially
subject Affymetrix to  concentrations of  risk. Corporate  policy restricts  the
amount  of credit exposure to any one issuer  and to any one type of investment,
other than securities issued by the United States Government.
 
NOTE 2.  COLLABORATIVE AGREEMENTS AND GRANTS
    Affymetrix expects  to collaborate  with  various partners  to  successfully
commercialize  its  technology. Total  costs incurred  under contract  and grant
arrangements  are  approximately  $1,412,000   in  1993,  $1,499,000  in   1994,
$5,237,000  in  1995,  $602,000  for  the three  months  ended  March  31, 1995,
$1,759,000 for the  three months  ended March 31,  1996 and  $9,952,000 for  the
period from inception through March 31, 1996.
 
                                      F-10
<PAGE>
                                AFFYMETRIX, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
                    (INFORMATION FOR THE THREE MONTHS ENDED
                   MARCH 31, 1995 AND 1996 AND FOR THE PERIOD
                 FROM INCEPTION TO MARCH 31, 1996 IS UNAUDITED)
 
NOTE 2.  COLLABORATIVE AGREEMENTS AND GRANTS (CONTINUED)
    Affymetrix  began  its  collaboration  with  Genetics  Institute  ("GI")  in
November  1994  to  develop   applications  of  the   GeneChip  system  to   the
identification  of new genes and new  uses of genes using expression monitoring.
Under  this  agreement,  GI  funded   Affymetrix'  research  to  determine   the
feasibility  of  this  application of  GeneChip  technology and  agreed  to make
milestone and royalty payments. Under certain circumstances, Affymetrix may  pay
royalty  payments to GI.  If Affymetrix enters into  similar agreements for gene
expression with third parties, Affymetrix may be required to refund a portion of
the  development  funding   received  from   GI  and  future   funding  may   be
proportionately reduced (see Note 9).
 
    In  December 1995, Affymetrix and GI expanded their relationship by entering
into a supply  agreement in the  field of genomics  under which Affymetrix  will
manufacture  and supply additional  custom probe arrays  based on specific genes
identified and selected by GI. Unlike the 1994 agreement with GI, this agreement
does not provide research funding to  Affymetrix. Pursuant to the agreement,  GI
is  obligated to purchase and Affymetrix  is obligated to supply certain minimum
quantities of custom probe arrays  developed for GI until  the later of 2001  or
four  years after development of specified probe arrays. Affymetrix will receive
fees for the design  and delivery of  the custom probe  arrays, and may  receive
milestone  payments and  royalties on therapeutic  compounds if  developed by GI
using these  probe arrays.  GI has  exclusive rights  to specific  probe  arrays
supplied by Affymetrix.
 
    In  October  1995,  Affymetrix  entered into  a  collaborative  research and
development agreement with Roche Molecular  Systems, Inc. ("Roche"). Under  this
agreement,  Roche agreed to fund certain  research efforts for approximately one
year aimed  at developing  GeneChip based  products designed  to detect  certain
genetic  mutations. Roche  is required  to make  additional payments  if certain
milestones  are  reached.  Under  certain  circumstances,  Affymetrix  may   pay
royalties to Roche.
 
    In  August 1995,  Affymetrix received a  three-year grant  from the National
Institutes of  Health ("NIH")  National  Center for  Human Genome  Research  for
approximately  $6,000,000. Affymetrix has  been awarded approximately $2,000,000
for the first year of the grant, and the remaining amounts are subject to yearly
appropriations by the NIH.
 
   
    Affymetrix entered into a collaboration with Hewlett-Packard Company  ("HP")
in  November 1994 for HP  to manufacture and supply  a more advanced scanner for
the use with Affymetrix'  GeneChip probe arrays and  for Affymetrix to  develop,
manufacture  and supply certain probe arrays to  HP for sale in certain markets.
In exchange for  certain rights,  Affymetrix received and  will receive  certain
payments,  including milestones, as defined  research and development objectives
are achieved. In addition, HP will fund certain research work at Affymetrix. The
collaborative agreement is for an initial  five-year term and shall be  extended
thereafter  for consecutive three-year terms, unless either party terminates the
agreement upon  six  months notice.  In  November 1994,  Affymetrix  received  a
license payment from HP that is classified as deferred revenue and as an advance
from  collaborative  partner  in  1995  and  1994,  respectively.  The agreement
contains terms, expiring in November 1996, that allow the payment to be  applied
towards  the purchase of an equity position in Affymetrix upon agreement of both
parties. Affymetrix  is  required to  pay  royalties to  HP  on HP  and  Company
sponsored probe arrays sold by the Company pursuant to the agreement.
    
 
    In  October 1994,  Affymetrix and  Molecular Dynamics,  Inc. were  awarded a
five-year  matching  grant  for  a  total  of  $31,500,000  under  the  Advanced
Technology  Program within the National Institute of Standards and Technology to
develop a miniaturized DNA diagnostic device, of which approximately $10,700,000
will be available to Molecular  Dynamics. The contract provides that  Affymetrix
will receive funding for approximately
 
                                      F-11
<PAGE>
                                AFFYMETRIX, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
                    (INFORMATION FOR THE THREE MONTHS ENDED
                   MARCH 31, 1995 AND 1996 AND FOR THE PERIOD
                 FROM INCEPTION TO MARCH 31, 1996 IS UNAUDITED)
 
NOTE 2.  COLLABORATIVE AGREEMENTS AND GRANTS (CONTINUED)
50%  of  its  costs up  to  $20,800,000, some  of  which  will be  used  to fund
activities at  collaborating  academic institutions.  The  award is  subject  to
yearly  congressional authorization,  which is uncertain.  Affymetrix expects to
receive payments monthly based on costs incurred.
 
    Affymetrix  recognized  revenues  of   approximately  $1,412,000  in   1993,
$1,499,000  in 1994, $1,034,000 in 1995, and  $212,000 and $51,000 for the three
months ended March 31, 1995 and 1996, respectively, pursuant to other  contracts
and grants.
 
NOTE 3.  AVAILABLE-FOR-SALE SECURITIES
    The  following is a summary of  available-for-sale securities as of December
31, 1994 (in thousands):
 
<TABLE>
<CAPTION>
                                                                GROSS          GROSS
                                                             UNREALIZED     UNREALIZED     ESTIMATED
                                                   COST         GAINS         LOSSES      FAIR VALUE
                                                 ---------  -------------  -------------  -----------
<S>                                              <C>        <C>            <C>            <C>
U.S. Government obligations....................  $  16,503    $  --          $     382     $  16,121
                                                 ---------          ---            ---    -----------
                                                 ---------          ---            ---    -----------
  Amounts included in:
    cash equivalents...........................  $   4,975    $  --          $  --         $   4,975
    short-term investments.....................     11,528       --                382        11,146
                                                 ---------          ---            ---    -----------
    Total securities...........................  $  16,503    $  --          $     382     $  16,121
                                                 ---------          ---            ---    -----------
                                                 ---------          ---            ---    -----------
</TABLE>
 
    The following is a summary  of available-for-sale securities as of  December
31, 1995 (in thousands):
 
<TABLE>
<CAPTION>
                                                                GROSS          GROSS
                                                             UNREALIZED     UNREALIZED     ESTIMATED
                                                   COST         GAINS         LOSSES      FAIR VALUE
                                                 ---------  -------------  -------------  -----------
<S>                                              <C>        <C>            <C>            <C>
U.S. Government obligations....................  $  38,115    $     309      $      27     $  38,397
                                                 ---------          ---            ---    -----------
                                                 ---------          ---            ---    -----------
  Amounts included in:
    cash equivalents...........................  $   1,995    $  --          $  --         $   1,995
    short-term investments.....................     36,120          309             27        36,402
                                                 ---------          ---            ---    -----------
    Total securities...........................  $  38,115    $     309      $      27     $  38,397
                                                 ---------          ---            ---    -----------
                                                 ---------          ---            ---    -----------
</TABLE>
 
    The   gross  realized   gains  and  gross   realized  losses   on  sales  of
available-for-sale securities were immaterial for  the years ended December  31,
1994 and 1995.
 
    The following is a summary of the amortized cost and estimated fair value of
available-for-sale  securities at December 31, 1995, by contractual maturity (in
thousands):
 
<TABLE>
<CAPTION>
                                                                              ESTIMATED FAIR
                                                            AMORTIZED COST        VALUE
                                                            --------------  ------------------
<S>                                                         <C>             <C>
Mature in one year or less................................    $   14,184        $   14,184
Mature after one year through three years.................        23,931            24,213
                                                                 -------           -------
  Total...................................................    $   38,115        $   38,397
                                                                 -------           -------
                                                                 -------           -------
</TABLE>
 
NOTE 4.  RELATED PARTY TRANSACTIONS
    In December 1994,  Affymetrix issued a  $6,000,000 subordinated  convertible
promissory  note to  Affymax. In  August of  1995, the  note was  converted into
1,333,333   shares   of   Series   B   Senior   convertible   preferred    stock
 
                                      F-12
<PAGE>
                                AFFYMETRIX, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
                    (INFORMATION FOR THE THREE MONTHS ENDED
                   MARCH 31, 1995 AND 1996 AND FOR THE PERIOD
                 FROM INCEPTION TO MARCH 31, 1996 IS UNAUDITED)
 
NOTE 4.  RELATED PARTY TRANSACTIONS (CONTINUED)
issued  at  $4.50 per  share.  Affymetrix also  exercised  an option  to satisfy
interest due on the  note through July 1995,  amounting to $319,856, by  issuing
Affymax  five-year warrants to purchase 202,441  shares of Series 2 Subordinated
convertible preferred stock at $5.50 per share.
 
    In December 1994, in  connection with a  lease agreement between  Affymetrix
and  a third party, Affymax, with approval  of the third party lessor, agreed to
release Affymetrix  of  certain  financial  covenants to  the  third  party.  In
exchange  for this release, Affymetrix issued  a five-year warrant to Affymax to
purchase 103,382 shares of Series 2 Subordinated convertible preferred stock  at
$5.50 per share.
 
    Effective  January  1, 1993,  Affymetrix entered  into a  Technology License
Agreement with Affymax  whereby Affymetrix  was granted  an exclusive  worldwide
royalty-free  license from  Affymax, with  the right  to sublicense,  to certain
technology and  to certain  future  inventions for  use  in the  diagnostic  and
research  supply markets including uses of DNA probe arrays. In exchange for the
Technology License Agreement and prior Affymax contributions, Affymetrix  issued
Affymax  8,500,000 shares of  Series 1 Subordinated  convertible preferred stock
using a share price of  $1.25, and agreed to  share certain costs of  developing
certain technology.
 
    Two directors of Affymetrix are employees of a subsidiary of Glaxo.
 
   
    Pursuant   to  a   service  agreement,  Affymax   provided  certain  general
administrative and  legal services  to  Affymetrix from  October 1,  1993  until
December  31, 1994. As  of January 1,  1995, the agreement  was amended to limit
those  services.  Amounts  expensed  by  Affymetrix  under  this  agreement  are
approximately $787,000 in 1993, $806,000 in 1994, $291,000 in 1995, $150,000 for
the  three months ended March 31, 1995, $37,000 for the three months ended March
31, 1996 and $1,921,000  for the period from  inception through March 31,  1996.
General  administrative and legal services were allocated to Affymetrix based on
time spent by Affymax employees exclusively on Affymetrix activities, at a  rate
based  on the  salaries of  the employees involved  plus an  overhead rate. Such
allocation was reasonable in the opinion of Affymetrix management.
    
 
    Since January 1, 1993, Affymetrix has been occupying a research facility  in
Santa  Clara, California subleased  from Affymax (See  Note 7). Amounts expensed
under this  agreement are  approximately  $275,000 in  1993, $472,000  in  1994,
$529,000  in 1995, $134,000 for the three  months ended March 31, 1995, $134,000
for the three months  ended March 31,  1996 and $1,410,000  for the period  from
inception through March 31, 1996.
 
   
    Affymetrix  received legal services from Townsend  and Townsend and Crew LLP
("Townsend") related  to  the  intellectual property  rights  of  Affymetrix.  A
partner  of Townsend was  also an employee  on a part  time basis of Affymetrix.
Legal expenses  related  to services  performed  by Townsend  are  approximately
$85,000  in 1993,  $369,000 in  1994, $612,000 in  1995, $144,000  for the three
months ended March 31, 1995, $193,000 for the three months ended March 31,  1996
and $1,259,000 for the period from inception through March 31, 1996.
    
 
    In  June 1993, the Board  approved the issuance of  secured loans to certain
officers for  a total  of $80,000  at an  interest rate  of 5.07%  per year  and
payable  in  full  at  the  earlier  of July  1,  1998  or  upon  termination of
employment. The  loans  were  originally  recorded  as  "notes  receivable  from
officers"  in  shareholders' equity.  In  June 1995,  one  loan for  $40,000 was
reclassified to "other assets". In November 1994, the Board agreed to  authorize
$115,000  as collateral  to a bank  for an  officer's loan. In  August 1995, the
Board approved the issuance  of a five-year  secured loan to  an employee for  a
total  of $50,000 at an interest rate of 8%  per year and payable in full at the
earlier of October 2, 2000 or upon termination of employment.
 
                                      F-13
<PAGE>
                                AFFYMETRIX, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
                    (INFORMATION FOR THE THREE MONTHS ENDED
                   MARCH 31, 1995 AND 1996 AND FOR THE PERIOD
                 FROM INCEPTION TO MARCH 31, 1996 IS UNAUDITED)
 
NOTE 5.  NOTES PAYABLE AND CREDIT ARRANGEMENTS
 
NOTES PAYABLE
 
    In December 1994,  Affymetrix issued a  $6,000,000 subordinated  convertible
promissory  note to Affymax maturing on December 1, 1997, which was subsequently
converted into 1,333,333 shares of  Series B Senior convertible preferred  stock
in August 1995 at a conversion rate of $4.50 per share (See Note 4).
 
CREDIT ARRANGEMENTS
 
    In  December 1994,  Affymetrix entered into  a financing  arrangement with a
leasing company for existing equipment. Under the terms of the lease, Affymetrix
received a single minimum aggregate lease payment of $1,307,000 at the inception
of the lease. The leaseback contract includes a five-year term expiring  January
2, 2000, with an option to purchase the equipment at the greater of the residual
value  or fair market value. Under certain provisions, the lease may be extended
for an additional year. The amount included in property and equipment related to
the lease is $1,761,000 with  accumulated depreciation of $464,000 and  $818,000
at  December 31, 1994 and December  31, 1995, respectively. Amortization of this
property and equipment is included in depreciation expense. Future minimum lease
payments under the capital lease obligation at December 31, 1995 are as  follows
(in thousands):
 
<TABLE>
<S>                                                           <C>
1996........................................................  $     292
1997........................................................        292
1998........................................................        292
1999........................................................        291
2000........................................................        280
                                                              ---------
Total minimum lease payments................................      1,447
Less amount representing interest...........................       (312)
                                                              ---------
Present value of minimum lease payments.....................      1,135
Less current portion........................................       (187)
                                                              ---------
Noncurrent obligation under capital lease...................  $     948
                                                              ---------
                                                              ---------
</TABLE>
 
NOTE 6.  SHAREHOLDERS' EQUITY
 
PREFERRED SHARES
 
    Affymetrix  is  authorized to  issue 27,500,000  shares of  preferred stock,
designated as  follows:  6,000,000 for  Series  A Senior  convertible  preferred
stock;  8,666,666 for Series B Senior convertible preferred stock; 8,500,000 for
Series 1  Subordinated  convertible  preferred stock;  1,000,000  for  Series  2
Subordinated preferred stock and 3,333,334 shares undesignated.
 
    The following table describes information with respect to the various series
of convertible preferred stock outstanding as of December 31, 1994:
 
<TABLE>
<CAPTION>
                                                                                      TOTAL
                                                 SHARES ISSUED   ISSUANCE PRICE    LIQUIDATION
                                                AND OUTSTANDING     PER SHARE      PREFERENCE
                                                ---------------  ---------------  -------------
<S>                                             <C>              <C>              <C>
Series A......................................       6,000,000      $    3.50     $  21,000,000
Series 1......................................       8,500,000           1.25        10,625,000
                                                ---------------                   -------------
                                                    14,500,000                    $  31,625,000
                                                ---------------                   -------------
                                                ---------------                   -------------
</TABLE>
 
                                      F-14
<PAGE>
                                AFFYMETRIX, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
                    (INFORMATION FOR THE THREE MONTHS ENDED
                   MARCH 31, 1995 AND 1996 AND FOR THE PERIOD
                 FROM INCEPTION TO MARCH 31, 1996 IS UNAUDITED)
 
NOTE 6.  SHAREHOLDERS' EQUITY (CONTINUED)
    The following table describes information with respect to the various series
of convertible preferred stock outstanding as of December 31, 1995 and March 31,
1996:
 
<TABLE>
<CAPTION>
                                                                                      TOTAL
                                                 SHARES ISSUED   ISSUANCE PRICE    LIQUIDATION
                                                AND OUTSTANDING     PER SHARE      PREFERENCE
                                                ---------------  ---------------  -------------
<S>                                             <C>              <C>              <C>
Series A......................................       6,000,000      $    3.50     $  21,000,000
Series B......................................       8,666,666           4.50        39,000,000
Series 1......................................       8,500,000           1.25        10,625,000
                                                ---------------                   -------------
                                                    23,166,666                    $  70,625,000
                                                ---------------                   -------------
                                                ---------------                   -------------
</TABLE>
 
    The  Series A  and Series B  Senior and  Series 1 and  Series 2 Subordinated
convertible  shares  represent   convertible  noncumulative  preferred   shares.
Dividends  for  Series  A  and  B  are  payable  at  $.28  and  $.36  per share,
respectively, in  preference  to  payment  of any  dividends  on  the  Series  1
Subordinated preferred shares, Series 2 Subordinated preferred shares and common
stock,  when and  if declared  by the Board.  Dividends for  Series 1  and 2 are
payable at $.10 and $.44 per  share, respectively. In the event of  liquidation,
dissolution,  or winding  up of  Affymetrix, the  Series A  and Series  B Senior
preferred  shares  will  have  a  liquidation  preference  over  the  Series   1
Subordinated preferred shares, Series 2 Subordinated preferred shares and common
stock. Each share of preferred stock is entitled to the number of votes equal to
the  number of shares of  common stock into which  such share of preferred stock
could be  converted.  Each share  of  preferred  stock is  convertible,  at  the
holder's  option, into  0.6667 share  of common  stock subject  to anti-dilution
adjustment upon the issuance of additional shares of common stock as defined  in
Affymetrix' Articles of Incorporation (See Note 9).
 
    The  Series A  Senior preferred  shares, Series  B Senior  preferred shares,
Series 1  Subordinated  preferred shares  and  Series 2  Subordinated  preferred
shares will be automatically converted (i) upon the closing of a firm commitment
underwritten  public offering  pursuant to  an effective  registration statement
under the Securities Act  of 1933, as  amended, covering the  offer and sale  of
common  stock  to  the  public  at  an  aggregate  offering  price  of  at least
$7,500,000; (ii) immediately upon receipt by Affymetrix of a written request for
conversion of at least  60% of the  then outstanding shares  of that series;  or
(iii)  upon the  conversion of at  least 60% of  the shares of  that series ever
outstanding.
 
STOCK WARRANTS
 
    At December  31,  1995,  the  following  warrants  to  purchase  Affymetrix'
preferred stock were outstanding:
 
<TABLE>
<CAPTION>
                                                            EXERCISE     NUMBER OF                   EXPIRATION
                                                              PRICE       SHARES      ISSUE DATE        DATE
                                                           -----------  -----------  -------------  -------------
<S>                                                        <C>          <C>          <C>            <C>
Series 2 Subordinated convertible preferred..............   $    5.50      103,382          1994           1999
Series 2 Subordinated convertible preferred..............   $    5.50      202,441          1995           2000
</TABLE>
 
STOCK OPTION AND BENEFIT PLANS
 
    In 1993, the Board adopted the Affymetrix 1993 Stock Plan (the "Stock Plan")
under  which incentive  stock options,  nonqualified stock  options and purchase
rights may be granted to employees and outside consultants.
 
    Options granted under the Stock Plan expire no later than ten years from the
date of grant. The option price shall be at least 100% of the fair value on  the
date  of grant (110%  in certain circumstances),  as determined by  the Board of
Directors. Options may be granted with different vesting terms from time to time
but not to exceed five years from the date of grant.
 
                                      F-15
<PAGE>
                                AFFYMETRIX, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
                    (INFORMATION FOR THE THREE MONTHS ENDED
                   MARCH 31, 1995 AND 1996 AND FOR THE PERIOD
                 FROM INCEPTION TO MARCH 31, 1996 IS UNAUDITED)
 
NOTE 6.  SHAREHOLDERS' EQUITY (CONTINUED)
    Activity under the Stock Plan through March 31, 1996 is as follows:
 
<TABLE>
<CAPTION>
                                                                         OUTSTANDING OPTIONS
                                                                --------------------------------------
                                                                NUMBER OF    PRICE PER     AGGREGATE
                                                                  SHARES       SHARE         PRICE
                                                                ----------  ------------  ------------
<S>                                                             <C>         <C>           <C>
Options granted...............................................     714,081  $       0.30  $    214,224
Options exercised.............................................    (333,332)         0.30      (100,000)
                                                                ----------  ------------  ------------
  Balance at December 31, 1993................................     380,749          0.30       114,224
Options granted...............................................     634,238    0.30-0.675       331,547
Options exercised.............................................     (74,200)         0.30       (22,260)
Options canceled..............................................     (38,799)         0.30       (11,640)
                                                                ----------  ------------  ------------
  Balance at December 31, 1994................................     901,988    0.30-0.675       411,871
Options granted...............................................   1,423,917         0.675       961,144
Options exercised.............................................     (62,749)   0.30-0.675       (22,524)
Options canceled..............................................    (104,032)   0.30-0.675       (56,597)
                                                                ----------  ------------  ------------
  Balance at December 31, 1995................................   2,159,124    0.30-0.675     1,293,894
Options granted...............................................     107,500    0.675-4.80       173,281
Options exercised.............................................     (72,973)   0.30-0.675       (45,627)
Options cancelled.............................................      (2,133)   0.30-0.675          (690)
                                                                ----------  ------------  ------------
  Balance at March 31, 1996...................................   2,191,518  $  0.30-4.80  $  1,420,858
                                                                ----------  ------------  ------------
                                                                ----------  ------------  ------------
</TABLE>
 
    At December 31, 1995 and March 31, 1996, options for the purchase of 219,446
and 158,490  shares  were exercisable,  respectively,  and 148,889  shares  were
subject to repurchase.
 
    For  options  granted through  December 31,  1995, Affymetrix  recognized an
aggregate of $2,488,000 as  deferred compensation for the  excess of the  deemed
fair  value for  financial statement presentation  purposes of  the common stock
issuable  on  exercise  of  such  options  over  the  exercise  price.  Deferred
compensation  related to options granted during the three months ended March 31,
1996 was $326,000. The  deferred compensation expense  is being recognized  over
the vesting period of the options.
 
    Affymetrix  employees  have participated  in  the Affymax  stock  option and
benefit plan. The Affymax stock option plan, employees stock purchase plan,  and
investment  savings  plan have  had  no impact  on  the financial  statements of
Affymetrix.
 
NOTE 7.  OPERATING LEASE COMMITMENTS
    Since January 1, 1993, Affymetrix has been occupying a research facility  in
Santa  Clara, California leased by Affymax. In February 1994, Affymetrix entered
into a noncancelable operating  sublease agreement with Affymax  for a 21  month
period.  Affymetrix obtained an  extension through October  1996. The underlying
lease contains an option to renew the lease for an additional term of 82 months.
 
    In December 1994,  Affymetrix entered into  a noncancelable five-year  lease
for  the rental of a manufacturing facility in Sunnyvale, California. Affymetrix
has options to renew the lease for two additional three-year terms.
 
                                      F-16
<PAGE>
                                AFFYMETRIX, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
                    (INFORMATION FOR THE THREE MONTHS ENDED
                   MARCH 31, 1995 AND 1996 AND FOR THE PERIOD
                 FROM INCEPTION TO MARCH 31, 1996 IS UNAUDITED)
 
NOTE 7.  OPERATING LEASE COMMITMENTS (CONTINUED)
    In  October  1995,  Affymetrix  entered  into  a  four-year  lease,  and   a
noncancelable  17 month sublease,  for the rental of  a research and development
facility in Sunnyvale, California.
 
    Future minimum  rental  payments  under noncancelable  operating  leases  at
December 31, 1995 are as follows (in thousands):
 
<TABLE>
<S>                                                           <C>
1996........................................................  $   1,102
1997........................................................      1,042
1998........................................................      1,039
1999........................................................      1,099
2000........................................................        688
Thereafter..................................................      1,664
                                                              ---------
Total minimum rental payments...............................  $   6,634
                                                              ---------
                                                              ---------
</TABLE>
 
    Rent expense related to operating leases was approximately $275,000 in 1993,
$472,000  in 1994, $664,000 in 1995 and $2,005,000 for the period from inception
through December 31, 1995.
 
    Affymetrix entered into certain  noncancelable obligations for the  purchase
of  GeneChip equipment and supplies. The  maximum commitment under the contracts
at December 31, 1995 is $1,735,000, which will be paid as units are received  in
1996.
 
NOTE 8.  INCOME TAXES
    As  of December 31, 1995, Affymetrix has net operating loss carryforwards of
approximately $22,000,000, which will expire at various dates beginning on  2008
through 2010, if not utilized.
 
    Utilization  of the  net operating  losses and credits  may be  subject to a
substantial annual limitation due to  the ownership change limitations  provided
by  the Internal Revenue Code  of 1986. The annual  limitation may result in the
expiration of net operating losses and credits before utilization.
 
    Significant components of Affymetrix deferred  tax assets as of December  31
are as follows (in thousands):
 
<TABLE>
<CAPTION>
                                                                  1993       1994       1995
                                                                ---------  ---------  ---------
<S>                                                             <C>        <C>        <C>
Net operating loss carryforwards..............................  $   1,733  $   4,284  $   8,063
Research credits..............................................        346        708      1,167
Deferred revenue..............................................        156        710      1,041
Other-net.....................................................          7        209        532
                                                                ---------  ---------  ---------
Total deferred tax assets.....................................      2,242      5,911     10,803
Valuation allowance for deferred tax assets...................     (2,242)    (5,911)   (10,803)
                                                                ---------  ---------  ---------
Net deferred tax assets.......................................  $  --      $  --      $  --
                                                                ---------  ---------  ---------
                                                                ---------  ---------  ---------
</TABLE>
 
    The  valuation allowance increased by $2,163,000, $3,669,000, and $4,892,000
during 1993, 1994, and 1995, respectively.
 
NOTE 9.  OTHER EVENTS SUBSEQUENT TO DECEMBER 31, 1995
    On March 7, 1996,  the Board of Directors  approved a two-for-three  reverse
stock  split  of  its common  stock  through  an amendment  to  its  Articles of
Incorporation.  All   common   share   and   per   share   amounts   have   been
 
                                      F-17
<PAGE>
                                AFFYMETRIX, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
                    (INFORMATION FOR THE THREE MONTHS ENDED
                   MARCH 31, 1995 AND 1996 AND FOR THE PERIOD
                 FROM INCEPTION TO MARCH 31, 1996 IS UNAUDITED)
 
NOTE 9.  OTHER EVENTS SUBSEQUENT TO DECEMBER 31, 1995 (CONTINUED)
retroactively  adjusted  to reflect  this event.  The  conversion rates  for the
various issues  of preferred  stock  have also  been retroactively  adjusted  to
reflect  the reverse stock split as well  as the anti-dilution adjustment. As of
the effective date of the offering it is estimated that each share of Series  A,
Series  B and Series  1 preferred stock will  convert into approximately 0.6823,
0.6667, and 0.6775 shares of common stock, respectively.
 
    In addition,  on  March  7, 1996,  the  Board  authorized the  filing  of  a
registration  statement with  the Securities and  Exchange Commission permitting
Affymetix to sell shares of its common  stock to the public. If the offering  is
consummated  under  the  terms  presently  anticipated,  all  of  the  currently
outstanding preferred stock will automatically convert into 15,629,991 shares of
common stock and the warrants will  be exercisable for 203,881 shares of  common
stock  at $8.25 per share. Unaudited pro forma shareholders' equity, as adjusted
for the conversion  of the  preferred stock, is  set forth  in the  accompanying
balance sheets.
 
   
    In   April  1996,   Affymetrix  entered   into  an   agreement  with  Incyte
Pharmaceuticals, Inc. to explore potential uses of DNA probe arrays in the  area
of  gene expression. As  a result of  this agreement, Affymetrix  is required to
refund 30% of the development funding received from GI, and future funding  from
GI will be proportionally reduced. The Company has recorded an accrued liability
for this refund. (See Note 2).
    
 
   
    In May 1996, Affymetrix entered into an agreement with Glaxo to design, test
and  supply  probe  arrays  to  demonstrate  use  of  the  arrays  in  detecting
polymorphisms in specific  genes. Glaxo and  Affymetrix will design  and test  a
probe  array  containing genes  specified by  Glaxo. If  successfully developed,
Affymetrix will supply Glaxo's  requirements of such  probe arrays for  research
purposes.
    
 
                                      F-18
<PAGE>
Affymetrix GeneChip Probe Array Manufacturing
-----------------------------------
 
<TABLE>
<S>                                      <C>
             Combinationatorial                         [PICTURE]
             Synthesis
              Affymetrix is able to
              synthesize tens of
              thousands of different
              DNA probes in parallel. A
              robotic arm is shown
              transporting a wafer on a
              synthesizer.
 
               [PICTURE]                 Photolithography
                                         Affymetrix manufactures wafers of
                                         GeneChip probe arrays using a high
                                         resolution photolithographic
                                         fabrication process adapted from the
                                         semiconductor industry. A wafer is
                                         shown being exposed to ultraviolet
                                         light through a lithographic mask.
 
Wafer-Scale Production                                  [PICTURE]
Affymetrix achieves manufacturing
efficiencies by simultaneously
synthesizing many probe arrays on a
single wafer. A wafer, diced into
individual probe arrays, is shown being
packaged into cartridges.
</TABLE>
 
<PAGE>
                                     [LOGO]
<PAGE>
                                    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 the  Common Stock being registered.  All amounts are estimated
except the SEC  Registration Fee, the  NASD Filing Fee  and the Nasdaq  National
Market Application Fee.
 
<TABLE>
<S>                                                                 <C>
SEC Registration Fee..............................................  $  25,776
NASD Filing Fee...................................................      7,975
Nasdaq National Market Application Fee............................      1,000
Blue Sky Qualification Fees and Expenses..........................     10,000
Accounting Fees and Expenses......................................    150,000
Legal Fees and Expenses (including Blue Sky)......................    300,000
Transfer Agent and Registrar Fees.................................      5,000
Printing and Engraving............................................    150,000
Miscellaneous.....................................................    150,249
                                                                    ---------
    Total.........................................................  $ 800,000
                                                                    ---------
                                                                    ---------
</TABLE>
 
ITEM 14.  INDEMNIFICATION OF DIRECTORS AND OFFICERS
 
    Pursuant  to Section 204(a) and 317  of the California Corporations Code, as
amended, the  registrant  has included  in  its articles  of  incorporation  and
by-laws  provisions regarding the  indemnification of officers  and directors of
the registrant. Article Four of registrant's Restated Articles of Incorporation,
as amended, provides as follows:
 
    "The liability of  the directors  of this corporation  for monetary  damages
shall be eliminated to the fullest extent permissible under California law. This
corporation  is  also  authorized,  to  the  fullest  extent  permissible  under
California law,  to indemnify  its agents  (as  defined in  Section 317  of  the
California  Corporations Code),  whether by  by-law, agreement  or otherwise, in
excess of the indemnification expressly permitted by Section 317 and to  advance
defense  expenses to  its agents  in connection  with such  matters as  they are
incurred, subject to  the limits  on such  excess indemnification  set forth  in
Section 204 of the California Corporations Code. If, after the effective date of
this  Article, California law is amended in a manner which permits a corporation
to limit  the monetary  or other  liability  of its  directors or  to  authorize
indemnification  of, or advancement of such defense expense to, its directors or
other persons, in any such  case to a greater extent  than is permitted on  such
effective date, the references in this Article to "California law" shall to that
extent be deemed to refer to California law as so amended."
 
    Section 29 of the registrant's By-Laws, as amended, provides as follows:
 
    "29. INDEMNIFICATION OF DIRECTORS AND OFFICERS.
 
    (A)  INDEMNIFICATION.   To the  fullest extent  permissible under California
law, the  corporation shall  indemnify its  directors and  officers against  all
expenses,  judgment, fines settlement and  other amounts actually and reasonably
incurred by them in connection with any proceeding, including an action by or in
the right of the corporation, by reason of the fact that such person is or was a
director or officer of the corporation, or  is or was serving at the request  of
the  corporation as a  director, officer, trustee, employee  or agent of another
corporation, or  of a  partnership,  joint venture,  trust or  other  enterprise
(including  service  with respect  to employee  benefit  plans). To  the fullest
extent permissible  under California  law, expenses  incurred by  a director  or
officer  seeking indemnification under  this By-law in  defending any proceeding
shall be advanced by the  corporation as they are  incurred upon receipt by  the
corporation  of an  undertaking by or  on behalf  of the director  or officer to
repay such amount  if it  shall ultimately be  determined that  the director  or
officer is not entitled to be indemnified by the corporation for those expenses.
If,  after the  effective date of  this By-law,  California law is  amended in a
manner  which  permits  the  corporation  to  authorize  indemnification  of  or
advancement of expenses to its
 
                                      II-1
<PAGE>
directors or officers, in any such case to a greater extent than is permitted on
such  effective date, the references in this By-law to "California law" shall to
that extent be  deemed to  refer to  California law  as so  amended. The  rights
granted  by  this By-law  are contractual  in nature  and, as  such, may  not be
altered with respect to  any present or former  director or officer without  the
written consent of that person.
 
    (b)  PROCEDURE.  Upon written request to  the Board of Directors by a person
seeking indemnification under this By-law, the Board shall promptly determine in
accordance with Section 317(e) of  the California Corporations Code whether  the
applicable  standard  of  conduct has  been  met  and, if  so,  the  Board shall
authorize indemnification. If the Board cannot authorize indemnification because
the number of directors who are parties to the proceeding with respect to  which
indemnification  is sought prevents  the formation of a  quorum of directors who
are not parties  to the  proceeding, then, upon  written request  by the  person
seeking  indemnification,  independent  legal  counsel (by  means  of  a written
opinion obtained at the corporation's expense) or the corporation's shareholders
shall determine whether the applicable standard of conduct has been met and,  if
so, shall authorize indemnification.
 
    (c)  DEFINITIONS.   The term "proceeding"  means any  threatened, pending or
completed action  or  proceeding,  whether civil,  criminal,  administrative  or
investigative. The term "expenses" includes, without limitation, attorney's fees
and any expenses of establishing a right to indemnification."
 
ITEM 15.  RECENT SALES OF UNREGISTERED SECURITIES
 
   
    During  the past three  years, the registrant has  issued the securities set
forth below  which were  not registered  under the  Securities Act  of 1933,  as
amended (the "Act"). The share amounts (and purchase and option exercise prices)
set  forth below have been adjusted to  give effect to the two-for-three reverse
stock split of the Common Stock effected in  May 1996 but do not give effect  to
the  conversion of Preferred  Stock into Common  Stock upon the  closing of this
offering.
    
 
   
    (1) COMMON STOCK.   In August  1993, the registrant  issued to Affymax  N.V.
("Affymax"),  an accredited  investor, 667 shares  of Common Stock  at $0.15 per
share. The  issuance was  a  private placement  without general  advertising  or
solicitation to an "accredited investor" within the meaning of Rule 501(a) under
the  Act and was  exempt from registration  under Section 4(2)  of the Act. From
December 1993 to April 30, 1996, the registrant issued 552,169 shares of  Common
Stock  at  prices  ranging between  $0.30  per  share and  $0.675  per  share to
directors, employees and  consultants in  connection with the  exercise by  such
directors,  employees  and  consultants  of  stock  options  held  by  them. All
issuances made  pursuant  to  the  exercise  of  options  were  made  under  the
registrant's  1993 Stock Plan, as amended. In August 1995, the registrant issued
65,320 shares of Common  Stock for financing commissions.  All of the  foregoing
issuances  and exercises  of options were  exempt from  registration pursuant to
Section 3(b) of the Act and Rule 701 promulgated thereunder.
    
 
    (2) SERIES A  SENIOR CONVERTIBLE PREFERRED  STOCK.  In  September 1993,  the
registrant  sold an aggregate of 6,000,000 shares of Series A Convertible Senior
Preferred Stock for $3.50  per share to  approximately 48 accredited  investors.
The sales were private placements without general advertising or solicitation to
"accredited  investors" within the meaning of Rule 501(a) under the Act and were
exempt from registration under Section 4(2) of the Act.
 
    (3) SERIES  B SENIOR  CONVERTIBLE  PREFERRED STOCK.    In August  1995,  the
registrant  sold 8,666,666 shares of Series B Senior Convertible Preferred Stock
at a price  of $4.50 per  share to approximately  100 accredited investors.  The
sales  were private  placements without  general advertising  or solicitation to
"accredited investors" within the meaning of Rule 501(a) under the Act and  were
exempt from registration under Section 4(2) of the Act.
 
    (4)  SERIES 1 SUBORDINATED  CONVERTIBLE PREFERRED STOCK.   In September 1993
the registrant  issued to  Affymax  8,500,000 shares  of Series  1  Subordinated
Preferred  Stock at a price of $1.25 per share. The sale was a private placement
without general advertising or solicitation  to an "accredited investor"  within
the  meaning of Rule 501(a) under the Act and was exempt from registration under
Section 4(2) of the Act.
 
    (5)  WARRANTS  TO  PURCHASE  SERIES  2  SUBORDINATED  CONVERTIBLE  PREFERRED
STOCK.   In December 1994, the registrant issued a five-year warrant to purchase
an aggregate of 103,382 shares of Series 2 Subordinated
 
                                      II-2
<PAGE>
Convertible Preferred  Stock  exercisable  at  $5.50 per  share  to  Affymax  in
consideration  for relieving the  Company of certain  financial covenants and to
guarantee its  obligation to  a  third party.  In  1995, the  registrant  issued
five-year  warrants  to purchase  an  aggregate of  202,441  shares of  Series 2
Subordinated Convertible  Preferred  Stock exercisable  at  $5.50 per  share  to
Affymax  in consideration for certain interest  payments otherwise due on a note
agreement. Affymax is an "accredited investor" within the meaning of Rule 501(a)
under the Act. The sales were private placements without general advertising  or
solicitation and was exempt from registration under Section 4(2) of the Act.
 
   
    (6)    OPTION    ISSUANCES   TO    DIRECTORS,   OFFICERS,    EMPLOYEES   AND
CONSULTANTS.   From July  1993 to  April  30, 1996,  the registrant  has  issued
options  to purchase a total of 2,885,400  shares of Common Stock at an exercise
price ranging  between  $0.30  and  $4.80  per  share  to  directors,  officers,
employees  and  consultants.  As of  the  date of  this  registration statement,
552,169 options have been exercised. All  of such issuances were made under  the
registrant's  1993  Stock Plan,  as amended.  No consideration  was paid  to the
registrant by any recipient of any of the foregoing options for the grant of any
such options. All  of the  foregoing issuances  and exercises  were exempt  from
registration  pursuant  to Section  3(b)  of the  Act  and Rule  701 promulgated
thereunder.
    
 
ITEM 16.  EXHIBITS AND FINANCIAL STATEMENT SCHEDULES
 
    (a)  Exhibits
 
   
<TABLE>
<C>        <S>
      1.1  Form of Underwriting Agreement
    **3.1  Amended and Restated Articles of Incorporation
    **3.2  Form of Amended and Restated Articles, to be effective upon closing
    **3.3  Bylaws
    **3.4  Form of Certificate of Amendment of Amended and Restated Articles of
            Incorporation
    **4.1  Specimen Common Stock Certificate
    **5.1  Opinion of Heller Ehrman White & McAuliffe
   **10.1  1993 Stock Plan, as amended
   **10.2  1996 Nonemployee Directors Stock Option Plan
  **+10.3  Collaboration Agreement by and between Hewlett-Packard Company and Affymetrix,
            Inc. dated November 11, 1994
  **+10.4  Development and Supply Agreement between Affymetrix, Inc. and Genetics
            Institute, Inc. dated November 15, 1994
  **+10.5  Supply Agreement with Genetics Institute, Inc. dated December 8, 1995
  **+10.6  Technology License Agreement among Affymax N.V., Affymax Technologies, N.V.,
            the Affymax Research Institute, and Affymetrix, Inc. dated January 1, 1993
   **10.7  Severance Agreement and Release between Affymetrix, Inc. and David B. Singer
            dated June 15, 1995
   **10.8  Loan and Pledge Agreement between David B. Singer and Affymetrix, Inc.
            effective December 7, 1993.
  **+10.9  ATP Participation Agreement between Affymetrix, Inc. and Molecular Dynamics,
            Inc. dated January 12, 1995 pursuant to the National Institute of Standards
            and Technology's Advanced Technology Program.
  **10.10  Amendment 1 to the ATP Participation Agreement between Affymetrix, Inc. and
            Molecular Dynamics, Inc. effective January 13, 1996.
 **+10.11  Governance Agreement between Affymetrix, Inc. and Glaxo Wellcome plc dated
            July 6, 1995.
  **10.12  Services Agreement between Affymax Research Institute and Affymetrix, Inc.
            effective October 1, 1993.
</TABLE>
    
 
                                      II-3
<PAGE>
   
<TABLE>
<C>        <S>
  **10.13  Loan Agreement between Affymax Technologies N.V. and Affymetrix, Inc. dated
            December 1, 1994.
  **10.14  Lease between Solar Oakmead Joint Venture and Affymetrix, Inc. dated October
            20, 1995.
  **10.15  Sublease between Salutar, Inc. and Affymetrix, Inc. dated October 20, 1995.
  **10.16  Sublease between Affymax Research Institute and Affymetrix, Inc. dated
            February 1, 1994.
 **+10.17  Manufacturing and Supply Agreement between Affymetrix, Inc. and RELA, Inc.
            dated November 27, 1995.
  **10.18  Loan and Pledge Agreement between Stephen P.A. Fodor and Affymetrix, Inc.
            effective December 7, 1993.
  **10.19  Agreement between Stephen P.A. Fodor and Affymetrix, Inc. dated November 1,
            1994.
  **10.20  Form of Director and Officer Indemnification Agreement
 **+10.21  Demonstration Agreement between Affymetrix, Inc. and Glaxo Wellcome, Inc.
            dated May 1, 1996
    10.22  Lease between Harry Locklin and Affymetrix, Inc. dated December 5, 1994.
     11.1  Statement of computation of net loss per share
     23.1  Consent of Ernst & Young LLP, independent auditors
   **23.2  Consent of Heller Ehrman White & McAuliffe
     23.3  Consent of Townsend and Townsend and Crew LLP
   **24.1  Power of Attorney (included on page II-5)
   **24.2  Power of Attorney of Alejandro C. Zaffaroni
     24.3  Power of Attorney of Barry C. Ross
</TABLE>
    
 
------------
**  Previously filed.
 +  Confidential treatment requested.
 
ITEM 17.  UNDERTAKINGS
    A.  The  undersigned  registrant  hereby   undertakes  to  provide  to   the
underwriter   at  the   closing  specified   in  the   underwriting  agreements,
certificates in such denominations and registered  in such names as required  by
the underwriter to permit prompt delivery to each purchaser.
 
    B.  Insofar as indemnification for  liabilities arising under the Securities
Act of 1933 may be permitted to directors, officers, and controlling persons  of
the  registrant  pursuant  to the  provisions  described  in Item  14  above, 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, 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 of  whether  such
indemnification  by it is against public policy as expressed in the Act and will
be governed by the final adjudication of such issue.
 
    C. The undersigned registrant hereby undertakes that:
 
    (1) For purposes of  determining any liability under  the Securities Act  of
1933,  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 Securities Act of 1933 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 of
1933, 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-4
<PAGE>
                                   SIGNATURE
 
   
    Pursuant to the requirements of the Securities Act of 1933, Affymetrix, Inc.
has duly caused this Amendment No. 2 to Registration Statement on Form S-1 to be
signed  on its  behalf by the  undersigned, thereunto duly  authorized, in Santa
Clara, California on May 20, 1996.
    
 
                                          AFFYMETRIX, INC.
                                          By                  *
 
                                            ------------------------------------
   
                                             JOHN D. DIEKMAN, Ph.D.
                                            CHIEF EXECUTIVE OFFICER AND CHAIRMAN
    
 
    Pursuant  to  the  requirements  of   the  Securities  Act  of  1933,   this
Registration  Statement on Form S-1 has been  signed by the following persons in
the capacities and on the dates indicated.
 
   
<TABLE>
<CAPTION>
                      SIGNATURE                                         CAPACITY                        DATE
-----------------------------------------------------  ------------------------------------------  ---------------
 
<C>                                                    <S>                                         <C>
                                    *                  Director, and Chief Executive
     ------------------------------------------         Officer (Principal Executive Officer)       May 20, 1996
               John D. Diekman, Ph.D.
 
                                    *
     ------------------------------------------        Director and President                       May 20, 1996
              Stephen P.A. Fodor, Ph.D.
 
                                    *
     ------------------------------------------        Director                                     May 20, 1996
                  Paul Berg, Ph.D.
 
                                    *
     ------------------------------------------        Director                                     May 20, 1996
                   Douglas M. Hurt
 
                                    *
     ------------------------------------------        Director                                     May 20, 1996
                Vernon R. Loucks, Jr.
 
                                    *
     ------------------------------------------        Director                                     May 20, 1996
                Barry C. Ross, Ph.D.
 
                                    *
     ------------------------------------------        Director                                     May 20, 1996
                   David B. Singer
 
                                    *
     ------------------------------------------        Director                                     May 20, 1996
                    John A. Young
 
                                    *
     ------------------------------------------        Director                                     May 20, 1996
            Alejandro C. Zaffaroni Ph.D.
 
                  /S/ KENNETH J. NUSSBACHER            Chief Financial Officer
     ------------------------------------------         (Principal Financial and                    May 20, 1996
                Kenneth J. Nussbacher                   Accounting Officer)
 
        *By:       /S/ KENNETH J. NUSSBACHER
          -------------------------------------                                                     May 20, 1996
                  Kenneth J. Nussbacher
                   (ATTORNEY-IN-FACT)
</TABLE>
    
 
                                      II-5
<PAGE>
                               INDEX TO EXHIBITS
 
   
<TABLE>
<CAPTION>
 EXHIBIT                                                                                              PAGE
----------                                                                                          ---------
 
<C>         <S>                                                                                     <C>
      1.1   Form of Underwriting Agreement........................................................
 
    **3.1   Amended and Restated Articles of Incorporation........................................
 
    **3.2   Amended and Restated Articles, to be effective upon closing...........................
 
    **3.3   Bylaws................................................................................
 
    **3.4   Form of Certificate of Amendment of Amended and Restated Articles of Incorporation....
 
    **4.1   Specimen Common Stock Certificate.....................................................
 
    **5.1   Opinion of Heller Ehrman White & McAuliffe............................................
 
   **10.1   1993 Stock Plan, as amended...........................................................
 
   **10.2   1996 Nonemployee Directors Stock Option Plan..........................................
 
  **+10.3   Collaboration Agreement by and between Hewlett-Packard Company and Affymetrix, Inc.
            dated November 11, 1994...............................................................
 
  **+10.4   Development and Supply Agreement between Affymetrix, Inc. and Genetics Institute, Inc.
            dated November 15, 1994...............................................................
 
  **+10.5   Supply Agreement with Genetics Institute, Inc. dated December 8, 1995.................
 
  **+10.6   Technology License Agreement among Affymax N.V., Affymax Technologies, N.V., the
            Affymax Research Institute, and Affymetrix, Inc. dated January 1, 1993................
 
   **10.7   Severance Agreement and Release between Affymetrix, Inc. and David B. Singer dated
            June 15, 1995.........................................................................
 
   **10.8   Loan and Pledge Agreement between David B. Singer and Affymetrix, Inc. effective
            December 7, 1993......................................................................
 
  **+10.9   ATP Participation Agreement between Affymetrix, Inc. and Molecular Dynamics, Inc.
            dated January 12, 1995 pursuant to the National Institute of Standards and
            Technology's Advanced Technology Program..............................................
 
   **10.10  Amendment 1 to the ATP Participation Agreement between Affymetrix, Inc. and Molecular
            Dynamics, Inc. effective January 13, 1996.............................................
 
  **+10.11  Governance Agreement between Affymetrix, Inc. and Glaxo Wellcome plc dated July 6,
            1995..................................................................................
 
   **10.12  Services Agreement between Affymax Research Institute and Affymetrix, Inc. effective
            October 1, 1993.......................................................................
 
   **10.13  Loan Agreement between Affymax Technologies N.V. and Affymetrix, Inc. dated December
            1, 1994...............................................................................
 
   **10.14  Lease between Solar Oakmead Joint Venture and Affymetrix, Inc. dated October 20,
            1995..................................................................................
 
   **10.15  Sublease between Salutar, Inc. and Affymetrix, Inc. dated October 20, 1995............
 
   **10.16  Sublease between Affymax Research Institute and Affymetrix, Inc. dated February 1,
            1994..................................................................................
 
  **+10.17  Manufacturing and Supply Agreement between Affymetrix, Inc. and RELA, Inc. dated
            November 27, 1995.....................................................................
</TABLE>
    
<PAGE>
   
<TABLE>
<C>         <S>                                                                                     <C>
   **10.18  Loan and Pledge Agreement between Stephen P.A. Fodor and Affymetrix, Inc. effective
            December 7, 1993......................................................................
 
   **10.19  Agreement between Stephen P.A. Fodor and Affymetrix, Inc. dated November 1, 1994......
 
   **10.20  Form of Director and Officer Indemnification Agreement................................
 
  **+10.21  Demonstration Agreement between Affymetrix, Inc. and Glaxo Wellcome, Inc. dated May 1,
            1996..................................................................................
 
     10.22  Lease between Harry Locklin and Affymetrix, Inc. dated December 5, 1994...............
 
     11.1   Statement of computation of loss per share............................................
 
     23.1   Consent of Ernst & Young LLP, independent auditors....................................
 
   **23.2   Consent of Heller Ehrman White & McAuliffe............................................
 
     23.3   Consent of Townsend and Townsend and Crew LLP.........................................
 
   **24.1   Power of Attorney (included on page II-5).............................................
 
   **24.2   Power of Attorney of Alejandro C. Zaffaroni...........................................
 
     24.3   Power of Attorney of Barry C. Ross....................................................
</TABLE>
    
 
------------
**  Previously filed.
 +  Confidential treatment requested.
<PAGE>
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
 
                       SECURITIES AND EXCHANGE COMMISSION
 
                             WASHINGTON, D.C. 20549
 
                            ------------------------
 
                                    EXHIBITS
                                       TO
                                    FORM S-1
 
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
 
                            ------------------------
 
                                AFFYMETRIX, INC.
 
                                    VOLUME I
 
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
<PAGE>
---------------------------------------------------------
---------------------------------------------------------
 
                       SECURITIES AND EXCHANGE COMMISSION
 
                             WASHINGTON, D.C. 20549
 
                            ------------------------
 
                                    EXHIBITS
                                       TO
                                    FORM S-1
 
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
 
                            ------------------------
 
                                AFFYMETRIX, INC.
 
                                   VOLUME II
 
---------------------------------------------------------
---------------------------------------------------------

<PAGE>

                                5,000,000 SHARES(1)

                                AFFYMETRIX, INC.

                                  COMMON STOCK

                             UNDERWRITING AGREEMENT

                                                              ____________, 1996


ROBERTSON, STEPHENS & COMPANY LLC
CS FIRST BOSTON CORPORATION
MONTGOMERY SECURITIES
  As Representatives of the several Underwriters
c/o Robertson, Stephens & Company LLC
555 California Street
Suite 2600
San Francisco, California  94104

Ladies/Gentlemen:

     Affymetrix, Inc., a California corporation (the "Company"), addresses you
as the Representatives of each of the persons, firms and corporations listed in
Schedule A hereto (herein collectively called the "Underwriters") and hereby
confirms its agreement with the several Underwriters as follows:

     1.   DESCRIPTION OF SHARES.  The Company proposes to issue and sell
5,000,000 shares of its authorized and unissued Common Stock, no par value, (the
"Firm Shares") to the several Underwriters.  The Company also proposes to grant
to the Underwriters an option to purchase up to 750,000 additional shares of the
Company's Common Stock, no par value, (the "Option Shares"), as provided in
Section 7 hereof.  As used in this Agreement, the term "Shares" shall include
the Firm Shares and the Option Shares.  All shares of Common Stock, no par value
of the Company to be outstanding after giving effect to the sales contemplated
hereby, including the Shares, are hereinafter referred to as "Common Stock." 

     2.   REPRESENTATIONS, WARRANTIES AND AGREEMENTS OF THE COMPANY.  The
Company represents and warrants to and agrees with each Underwriter that:

          (a)  A registration statement on Form S-1 (File No. 333-3648) with
respect to the Shares, including a prospectus subject to completion, has been
prepared by the Company in conformity with the requirements of the Securities
Act of 1933, as amended (the "Act"), and the applicable rules and regulations
(the "Rules and Regulations") of the Securities and Exchange Commission (the
"Commission") under the Act and has been filed with the Commission; such
amendments to such registration statement, such amended prospectuses subject to
completion and such abbreviated registration statements pursuant to Rule 462(b)
of the Rules and Regulations as may have been required prior to the date hereof
have been similarly prepared and filed with the Commission; and the Company

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

(1)  Plus an option to purchase up to 750,000 additional shares from the Company
     to cover over-allotments.


                                        
<PAGE>

will file such additional amendments to such registration statement, such
amended prospectuses subject to completion and such abbreviated registration
statements as may hereafter be required.  Copies of such registration statement
and amendments, of each related prospectus subject to completion (the
"Preliminary Prospectuses") and of any abbreviated registration statement
pursuant to Rule 462(b) of the Rules and Regulations have been delivered to you.

          If the registration statement relating to the Shares has been declared
effective under the Act by the Commission, the Company will prepare and promptly
file with the Commission the information omitted from the registration statement
pursuant to Rule 430A(a) or, if Robertson, Stephens & Company LLC, on behalf of
the several Underwriters, shall agree to the utilization of Rule 434 of the
Rules and Regulations, the information required to be included in any term sheet
filed pursuant to Rule 434(b) or (c), as applicable, of the Rules and
Regulations pursuant to subparagraph (1), (4) or (7) of Rule 424(b) of the Rules
and Regulations or as part of a post-effective amendment to the registration
statement (including a final form of prospectus).  If the registration statement
relating to the Shares has not been declared effective under the Act by the
Commission, the Company will prepare and promptly file an amendment to the
registration statement, including a final form of prospectus, or, if Robertson,
Stephens & Company LLC, on behalf of the several Underwriters, shall agree to
the utilization of Rule 434 of the Rules and Regulations, the information
required to be included in any term sheet filed pursuant to Rule 434(b) or (c),
as applicable, of the Rules and Regulations.  The term "Registration Statement"
as used in this Agreement shall mean such registration statement, including
financial statements, schedules and exhibits, in the form in which it became or
becomes, as the case may be, effective (including, if the Company omitted
information from the registration statement pursuant to Rule 430A(a) or files a
term sheet pursuant to Rule 434 of the Rules and Regulations, the information
deemed to be a part of the registration statement at the time it became
effective pursuant to Rule 430A(b) or Rule 434(d) of the Rules and Regulations)
and, in the event of any amendment thereto or the filing of any abbreviated
registration statement pursuant to Rule 462(b) of the Rules and Regulations
relating thereto after the effective date of such registration statement, shall
also mean (from and after the effectiveness of such amendment or the filing of
such abbreviated registration statement) such registration statement as so
amended, together with any such abbreviated registration statement.  The term
"Prospectus" as used in this Agreement shall mean the prospectus relating to the
Shares as included in such Registration Statement at the time it becomes
effective (including, if the Company omitted information from the Registration
Statement pursuant to Rule 430A(a) of the Rules and Regulations, the information
deemed to be a part of the Registration Statement at the time it became
effective pursuant to Rule 430A(b) of the Rules and Regulations); PROVIDED,
HOWEVER, that if in reliance on Rule 434 of the Rules and Regulations and 
with the consent of Robertson, Stephens & Company LLC, on behalf of the 
several Underwriters, the Company shall have provided to the Underwriters a 
term sheet pursuant to Rule 434(b) or (c), as applicable, prior to the time 
that a confirmation is sent or given for purposes of Section 2(10)(a) of the 
Act, the term "Prospectus" shall mean the "prospectus subject to completion" 
(as defined in Rule 434(g) of the Rules and Regulations) last provided to the 
Underwriters by the Company and circulated by the Underwriters to all 
prospective purchasers of the Shares (including the information deemed to be 
a part of the Registration Statement at the time it became effective pursuant 
to Rule 434(d) of the Rules and Regulations). Notwithstanding the foregoing, 
if any revised prospectus shall be provided to the Underwriters by the 
Company for use in connection with the offering of the Shares that differs 
from the prospectus referred to in the immediately preceding sentence 
(whether or not such revised prospectus is required to be filed with the 
Commission pursuant to Rule 424(b) of the Rules and Regulations), the term 
"Prospectus" shall refer to such revised prospectus from and after the time 
it is first provided to the Underwriters for such use.  If in reliance on 
Rule 434 of the Rules and Regulations and with the consent of Robertson, 
Stephens & Company LLC, on behalf of the several Underwriters, the Company 
shall have




                                       -2-
<PAGE>

provided to the Underwriters a term sheet pursuant to Rule 434(b) or (c), as
applicable, prior to the time that a confirmation is sent or given for purposes
of Section 2(10)(a) of the Act, the Prospectus and the term sheet, together,
will not be materially different from the prospectus in the Registration
Statement.  

          (b)  The Commission has not issued any order preventing or suspending
the use of any Preliminary Prospectus or instituted proceedings for that
purpose, and each such Preliminary Prospectus has conformed in all material
respects to the requirements of the Act and the Rules and Regulations and, as of
its date, has not included any untrue statement of a material fact or omitted to
state a material fact necessary to make the statements therein, in the light of
the circumstances under which they were made, not misleading; and at the time
the Registration Statement became or becomes, as the case may be, effective and
at all times subsequent thereto up to and on the Closing Date (hereinafter
defined) and on any later date on which Option Shares are to be purchased,
(i) the Registration Statement and the Prospectus, and any amendments or
supplements thereto, contained and will contain all material information
required to be included therein by the Act and the Rules and Regulations and
will in all material respects conform to the requirements of the Act and the
Rules and Regulations, (ii) the Registration Statement, and any amendments or
supplements thereto, did not and will not include any untrue statement of a
material fact or omit to state a material fact required to be stated therein or
necessary to make the statements therein not misleading, and (iii) the
Prospectus, and any amendments or supplements thereto, did not and will not
include any untrue statement of a material fact or omit to state a material fact
necessary to make the statements therein, in the light of the circumstances
under which they were made, not misleading; PROVIDED, HOWEVER, that none of the
representations and warranties contained in this subparagraph (b) shall apply to
information contained in or omitted from the Registration Statement or
Prospectus, or any amendment or supplement thereto, in reliance upon, and in
conformity with, written information relating to any Underwriter furnished to
the Company by such Underwriter specifically for use in the preparation thereof
which is specified in the last paragraph of Section 3 hereof.

          (c)  The Company has been duly incorporated and is validly existing as
a corporation in good standing under the laws of the jurisdiction of its
incorporation with full power and authority (corporate and other) to own, lease
and operate its properties and conduct its business as described in the
Prospectus; the Company is duly qualified to do business as a foreign
corporation and is in good standing in each jurisdiction in which the ownership
or leasing of its properties or the conduct of its business requires such
qualification, except where the failure to be so qualified or be in good
standing would not have a material adverse effect on the condition (financial or
otherwise), earnings, operations or business as described in the Prospectus of
the Company; no proceeding has been instituted in any such jurisdiction,
revoking, limiting or curtailing, or seeking to revoke, limit or curtail, such
power and authority or qualification; the Company is in possession of and
operating in compliance with all authorizations, licenses, certificates,
consents, orders and permits from state, federal and other regulatory
authorities which are material to the conduct of its business, all of which are
valid and in full force and effect; the Company is not in violation of its
charter or bylaws or in default in the performance or observance of any
obligation, agreement, covenant or condition contained in any material bond,
debenture, note or other evidence of indebtedness, or in any material lease,
contract, indenture, mortgage, deed of trust, loan agreement, joint venture or
other agreement or instrument to which the Company is a party or by which it or
its properties may be bound; and the Company is not in violation of any material
law, order, rule, regulation, writ, injunction, judgment or decree of any court,
government or governmental agency or body, domestic or foreign, having
jurisdiction over the Company


                                       -3-
<PAGE>

or over its properties of which it has knowledge.  The Company does not own or
control, directly or indirectly, any corporation, association or other entity.


          (d)  The Company has full legal right, power and authority to enter
into this Agreement and perform the transactions contemplated hereby.  This
Agreement has been duly authorized, executed and delivered by the Company and is
a valid and binding agreement on the part of the Company, enforceable in
accordance with its terms, except as rights to indemnification hereunder may be
limited by applicable law and except as the enforcement hereof may be limited by
applicable bankruptcy, insolvency, reorganization, moratorium or other similar
laws relating to or affecting creditors' rights generally or by general
equitable principles; the performance of this Agreement and the consummation of
the transactions herein contemplated will not result in a breach or violation of
any of the terms and provisions of, or constitute a default under, (i) any
material bond, debenture, note or other evidence of indebtedness, or under any
material lease, contract, indenture, mortgage, deed of trust, loan agreement,
joint venture or other agreement or instrument to which the Company is a party
or by which it or its properties may be bound, (ii) the charter or bylaws of the
Company, or (iii) any material law, order, rule, regulation, writ, injunction,
judgment or decree of any court, government or governmental agency or body,
domestic or foreign, having jurisdiction over the Company or over its
properties.  No consent, approval, authorization or order of or qualification
with any court, government or governmental agency or body, domestic or foreign,
having jurisdiction over the Company or over its properties is required for the
execution and delivery of this Agreement and the consummation by the Company of
the transactions herein contemplated, except such as may be required under the
Act and the Securities Exchange Act of 1934, as amended (the "Exchange Act"),
which will have been obtained prior to the Closing Date (as hereinafter defined)
and except such as may be required under state or other securities or Blue Sky
laws.

          (e)  There is not any pending or, to the Company's knowledge,
threatened action, suit, claim or proceeding against the Company or any of its
officers or any of its properties, assets or rights before any court, government
or governmental agency or body, domestic or foreign, having jurisdiction over
the Company or over its officers or properties or otherwise which (i) might
result in any material adverse change in the condition (financial or otherwise),
earnings, operations or business as described in the Prospectus of the Company
or might materially and adversely affect its properties, assets or rights,
(ii) might prevent consummation of the transactions contemplated hereby or
(iii) is required to be disclosed in the Registration Statement or Prospectus
and is not so disclosed; and there are no agreements, contracts, leases or
documents of the Company of a character required to be described or referred to
in the Registration Statement or Prospectus or to be filed as an exhibit to the
Registration Statement by the Act or the Rules and Regulations which have not
been accurately described in all material respects in the Registration Statement
or Prospectus or filed as exhibits to the Registration Statement.

          (f)  All outstanding shares of capital stock of the Company have been
duly authorized and validly issued and are fully paid and nonassessable, have
been issued in compliance with all federal and state securities laws, were not
issued in violation of or subject to any preemptive rights or other rights to
subscribe for or purchase securities, and the authorized and outstanding capital
stock of the Company is as set forth in the Prospectus under the caption
"Capitalization" and conforms in all material respects to the statements
relating thereto contained in the Registration Statement and the Prospectus (and
such statements correctly state the substance of the instruments defining the
capitalization of the Company); the Firm Shares and the Option Shares have been
duly authorized for issuance and sale to the Underwriters pursuant to this
Agreement and, when issued and delivered by the Company against payment therefor
in accordance with the terms of this Agreement, will be duly and validly issued
and


                                       -4-
<PAGE>

fully paid and nonassessable, and will be sold free and clear of any pledge,
lien, security interest, encumbrance, claim or equitable interest; and no
preemptive right, co-sale right, registration right, right of first refusal or
other similar right of shareholders exists with respect to any of the Firm
Shares or Option Shares or the issuance and sale thereof other than those that
have been expressly waived prior to the date hereof and those that will
automatically expire upon and will not apply to the consummation of the
transactions contemplated on the Closing Date.  No further approval or
authorization of any shareholder, the Board of Directors of the Company or
others is required for the issuance and sale or transfer of the Shares except as
may be required under the Act  (which will have been obtained prior to the
Closing Date), state or other securities or Blue Sky laws.  Except as disclosed
in the Prospectus and the financial statements of the Company, and the related
notes thereto, included in the Prospectus, the Company has no outstanding
options to purchase, or any preemptive rights or other rights to subscribe for
or to purchase, any securities or obligations convertible into, or any contracts
or commitments to issue or sell, shares of its capital stock or any such
options, rights, convertible securities or obligations.  The description of the
Company's warrants, stock option, stock bonus and other stock plans or
arrangements, and the options or other rights granted and exercised thereunder,
set forth in the Prospectus accurately and fairly presents the information
required to be shown with respect to such warrants, plans, arrangements, options
and rights.

          (g)  Ernst & Young LLP, which has examined the financial statements of
the Company, together with the related schedules and notes, as of December 31,
1995 and 1994 and for each of the years in the three (3) years ended
December 31, 1995 filed with the Commission as a part of the Registration
Statement, which are included in the Prospectus, are independent accountants
within the meaning of the Act and the Rules and Regulations; the audited
financial statements of the Company, together with the related schedules and
notes, and the unaudited financial information, forming part of the Registration
Statement and Prospectus, fairly present the financial position and the results
of operations of the Company at the respective dates and for the respective
periods to which they apply; and all audited financial statements of the
Company, together with the related schedules and notes, and the unaudited
financial information, filed with the Commission as part of the Registration
Statement, have been prepared in accordance with generally accepted accounting
principles consistently applied throughout the periods involved except as may be
otherwise stated therein.  The selected and summary financial and statistical
data included in the Registration Statement present fairly the information shown
therein and have been compiled on a basis consistent with the audited financial
statements presented therein.  No other financial statements or schedules are
required to be included in the Registration Statement.

          (h)  Subsequent to the respective dates as of which information is
given in the Registration Statement and Prospectus, there has not been (i) any
material adverse change in the condition (financial or otherwise), earnings,
operations or business as described in the Prospectus of the Company, (ii) any
transaction that is material to the Company, except transactions entered into in
the ordinary course of business, (iii) any obligation, direct or contingent,
that is material to the Company, incurred by the Company, except obligations
incurred in the ordinary course of business, (iv) any change in the capital
stock or outstanding indebtedness of the Company that is material to the
Company, (v) any dividend or distribution of any kind declared, paid or made on
the capital stock of the Company, or (vi) any loss or damage (whether or not
insured) to the property of the Company which has been sustained or will have
been sustained which has a material adverse effect on the condition (financial
or otherwise), earnings, operations, business as described in the Prospectus of
the Company.


                                       -5-
<PAGE>

          (i)  Except as set forth in the Registration Statement and Prospectus,
(i) the Company has good and marketable title to all properties and assets
described in the Registration Statement and Prospectus as owned by it, free and
clear of any pledge, lien, security interest, encumbrance, claim or equitable
interest, other than such as would not have a material adverse effect on the
condition (financial or otherwise), earnings, operations or business as
described in the Prospectus of the Company, (ii) the agreements to which the
Company is a party described in the Registration Statement and Prospectus are
valid agreements, enforceable by the Company, except as the enforcement thereof
may be limited by applicable bankruptcy, insolvency, reorganization, moratorium
or other similar laws relating to or affecting creditors' rights generally or by
general equitable principles and, to the Company's knowledge, the other
contracting party or parties thereto are not in material breach or material
default under any of such agreements, and (iii) the Company has valid and
enforceable leases and subleases for all properties described in the
Registration Statement and Prospectus as leased by it, except as the enforcement
thereof may be limited by applicable bankruptcy, insolvency, reorganization,
moratorium or other similar laws relating to or affecting creditors' rights
generally or by general equitable principles.  Except as set forth in the
Registration Statement and Prospectus, the Company owns or leases all such
properties as are necessary to its operations as now conducted or as proposed to
be conducted.

          (j)  The Company has timely filed all necessary federal, state and
foreign income and franchise tax returns and has paid all taxes shown thereon as
due, and there is no tax deficiency that has been or, to the Company's
knowledge, might be asserted against the Company that might have a material
adverse effect on the condition (financial or otherwise), earnings, operations,
business as described in the Prospectus of the Company; and all tax liabilities
are adequately provided for on the books of the Company.

          (k)  The Company maintains insurance with insurers of recognized
financial responsibility of the types and in the amounts generally deemed
adequate for its business and consistent with insurance coverage maintained by
similar companies in similar businesses, including, but not limited to,
insurance covering real and personal property owned or leased by the Company
against theft, damage, destruction, acts of vandalism, product liability and all
other risks customarily insured against and with respect to the Company's
directors' and officers' insurance policy, the Company has obtained coverage for
up to $8 million, all of which insurance is in full force and effect; the
Company has not been refused any insurance coverage sought or applied for; and
the Company has no reason to believe that it will not be able to renew its
existing insurance coverage as and when such coverage expires or to obtain
similar coverage from similar insurers as may be necessary to continue its
business at a cost that would not materially and adversely affect the condition
(financial or otherwise), earnings, operations, business as described in the
Prospectus of the Company.

          (l)  To the Company's knowledge, no labor disturbance by the employees
of the Company exists or is imminent; and the Company is not aware of any
existing or imminent labor disturbance by the employees of any of its principal
suppliers, customers, manufacturers, partners or collaborators that might be
expected to result in a material adverse change in the condition (financial or
otherwise), earnings, operations or business as described in the Prospectus of
the Company.  No collective bargaining agreement exists with any of the
Company's employees and, to the Company's knowledge, no such agreement is
imminent.

          (m)  Except as previously disclosed to you in writing, the Company
owns or possesses adequate rights to use all patents, patent rights, inventions,
trade secrets, know-how, trademarks, service marks, trade names and copyrights
which are necessary to conduct its business as described in the 


                                       -6-
<PAGE>

Registration Statement and Prospectus; the expiration of any patents, patent
rights, trade secrets, trademarks, service marks, trade names or copyrights
would not have a material adverse effect on the condition (financial or
otherwise), earnings, operations or business as described in the Prospectus of
the Company; except as previously disclosed to you in writing, the Company has
not received any notice of, and has no knowledge of, any infringement of or
conflict with asserted rights of the Company by others with respect to any
patent, patent rights, inventions, trade secrets, know-how, trademarks, service
marks, trade names or copyrights; and the Company has not received any notice
of, and has no knowledge of, any infringement of or conflict with asserted
rights of others with respect to any patent, patent rights, inventions, trade
secrets, know-how, trademarks, service marks, trade names or copyrights which,
singly or in the aggregate, if the subject of an unfavorable decision, ruling or
finding, might have a material adverse effect on the condition (financial or
otherwise), earnings, operations or business as described in the Prospectus of
the Company.

          (n)  The Common Stock has been approved for quotation on The Nasdaq
National Market, subject to official notice of issuance.

          (o)  The Company has been advised concerning the Investment Company
Act of 1940, as amended (the "1940 Act"), and the rules and regulations
thereunder, and has in the past conducted, and intends in the future to conduct,
its affairs in such a manner as to ensure that it will not become an "investment
company" or a company "controlled" by an "investment company" within the meaning
of the 1940 Act and such rules and regulations.  

          (p)  The Company has not distributed and will not distribute prior to
the later of (i) the Closing Date, or any date on which Option Shares are to be
purchased, as the case may be, and (ii) completion of the distribution of the
Shares, any offering material in connection with the offering and sale of the
Shares other than any Preliminary Prospectuses, the Prospectus, the Registration
Statement and other materials, if any, permitted by the Act.

          (q)  The Company has not at any time during the last five (5) years
(i) made any unlawful contribution to any candidate for foreign office or failed
to disclose fully any contribution in violation of law, or (ii) made any payment
to any federal or state governmental officer or official, or other person
charged with similar public or quasi-public duties, other than payments required
or permitted by the laws of the United States or any jurisdiction thereof.

          (r)  The Company has not taken and will not take, directly or
indirectly, any action designed to or that might reasonably be expected to cause
or result in stabilization or manipulation of the price of the Common Stock to
facilitate the sale or resale of the Shares.

          (s)  Each officer and director of the Company and beneficial owner
of one percent or more of  the Company's outstanding shares of capital
stock as of the date of this Agreement has agreed in writing that such person
will not, for a period of 180 days from the date that the Registration Statement
is declared effective by the Commission (the "Lock-up Period"), offer to sell,
contract to sell, or otherwise sell, dispose of, loan, pledge or grant any
rights with respect to (collectively, a "Disposition") any shares of Common
Stock, any options or warrants to purchase any shares of Common Stock (except
for options held by non-officer employees of the Company) or any securities
convertible into or exchangeable for shares of Common Stock (collectively,
"Securities") now owned or hereafter acquired directly by such person or with
respect to which such person has or hereafter acquires the power of disposition,
otherwise than (i) as a bona fide gift or gifts, provided the donee or


                                       -7-
<PAGE>

donees thereof agree in writing to be bound by this restriction, (ii) as a
distribution to partners or shareholders of such person, provided that the
distributees thereof agree in writing to be bound by the terms of this
restriction, or (iii) with the prior written consent of Robertson, Stephens &
Company LLC.  The foregoing restriction has been expressly agreed to preclude
the holder of the Securities from engaging in any hedging or other transaction
which is designed to or reasonably expected to lead to or result in a
Disposition of Securities during the Lock-up Period, even if such Securities
would be disposed of by someone other than such holder.  Such prohibited hedging
or other transactions would include, without limitation, any short sale (whether
or not against the box) or any purchase, sale or grant of any right (including,
without limitation, any put or call option) with respect to any Securities or
with respect to any security (other than a broad-based market basket or index)
that includes, relates to or derives any significant part of its value from
Securities.  Furthermore, such person has also agreed and consented to the entry
of stop transfer instructions with the Company's transfer agent against the
transfer of the Securities held by such person except in compliance with this
restriction.  The Company has provided to counsel for the Underwriters a
complete and accurate list of all security holders of the Company and the number
and type of securities held by each security holder.  The Company has provided
to counsel for the Underwriters true, accurate and complete copies of all of the
agreements pursuant to which its officers, directors and shareholders have
agreed to such or similar restrictions (the "Lock-up Agreements") presently in
effect or effected hereby.  The Company understands and agrees that the Lock-Up
Agreements are for the benefit of the Underwriters and hereby assigns its rights
under such Lock-Up Agreements to Robertson , Stephens & Company LLC.   The
Company hereby agrees to enforce such Lock-Up Agreements, to not release any of
its officers, directors or other shareholders (except for employees of the
Company who are not officers of the Company) from any Lock-up Agreements
currently existing or hereafter effected without the prior written consent of
Robertson, Stephens & Company LLC and to enter stop transfer instructions with
the Company's transfer agent against the transfer of any Securities held by such
persons except in compliance with the foregoing restriction.

          (t)  Except as set forth in the Registration Statement and Prospectus,
(i) the Company is in compliance with all rules, laws and regulations relating
to the use, treatment, storage and disposal of toxic substances and protection
of health or the environment ("Environmental Laws") which are applicable to its
business, (ii) the Company has received no notice from any governmental
authority or third party of an asserted claim under Environmental Laws, which
claim is required to be disclosed in the Registration Statement and the
Prospectus, (iii) the Company will not be required to make future material
capital expenditures to comply with Environmental Laws and (iv) no property
which is owned, leased or occupied by the Company has been designated as a
Superfund site pursuant to the Comprehensive Response, Compensation, and
Liability Act of 1980, as amended (42 U.S.C. Section 9601, et seq.), or
otherwise designated as a contaminated site under applicable state or local law.

          (u)  The Company maintains a system of internal accounting controls
sufficient to provide reasonable assurances that (i) transactions are executed
in accordance with management's general or specific authorizations,
(ii) transactions are recorded as necessary to permit preparation of financial
statements in conformity with generally accepted accounting principles and to
maintain accountability for assets, (iii) access to assets is permitted only in
accordance with management's general or specific authorization, and (iv) the
recorded accountability for assets is compared with existing assets at
reasonable intervals and appropriate action is taken with respect to any
differences.

          (v)  There are no outstanding loans, advances (except normal advances
for business expenses in the ordinary course of business) or guarantees of
indebtedness by the Company to or for the 


                                       -8-
<PAGE>

benefit of any of the officers or directors of the Company or any of the members
of the families of any of them, except as disclosed in the Registration
Statement and the Prospectus.

          (w)  The Company has complied with all provisions of Section 517.075,
Florida Statutes relating to doing business with the Government of Cuba or with
any person or affiliate located in Cuba.

     3.   PURCHASE, SALE AND DELIVERY OF SHARES.  On the basis of the
representations, warranties and agreements herein contained, but subject to the
terms and conditions herein set forth, the Company agrees to sell to the
Underwriters, and each Underwriter agrees, severally and not jointly, to
purchase from the Company at a purchase price of $_____ per share, the
respective number of Firm Shares as hereinafter set forth except that any Firm
Shares to be sold by the Underwriters to Dr. Alejandro C. Zaffaroni shall be
purchased by the Underwriters from the Company at a purchase price per share
equal to the inital public offering price set forth on the front page of the
Prospectus.  The obligation of each Underwriter to the Company shall be to
purchase from the Company that number of Firm Shares which is set forth opposite
the name of such Underwriter in Schedule A hereto (subject to adjustment as
provided in Section 10).

          Delivery of definitive certificates for the Firm Shares to be
purchased by the Underwriters pursuant to this Section 3 shall be made against
payment of the purchase price therefor by the several Underwriters by  wire
transfer of same-day funds paid to an account designated by the Company in
writing at the offices of Heller Ehrman White & McAuliffe, 525 University
Avenue, Palo Alto, California 94301-1908 (or at such other place as may be
agreed upon among the Representatives and the Company, at 7:00 A.M., San
Francisco time (a) on the third (3rd) full business day following the first day
that Shares are traded, (b) if this Agreement is executed and delivered after
1:30 P.M., San Francisco time, the fourth (4th) full business day following the
day that this Agreement is executed and delivered or -C- at such other time and
date not later than seven (7) full business days following the first day that
Shares are traded as the Representatives and the Company may determine (or at
such time and date to which payment and delivery shall have been postponed
pursuant to Section 10 hereof), such time and date of payment and delivery being
herein called the "Closing Date;" PROVIDED, HOWEVER, that if the Company has not
made available to the Representatives copies of the Prospectus within the time
provided in Section 4(d) hereof, the Representatives may, in their sole
discretion, postpone the Closing Date until no later than two (2) full business
days following delivery of copies of the Prospectus to the Representatives.  The
certificates for the Firm Shares to be so delivered will be made available to
you at such office or such other location including, without limitation, in New
York City, as you may reasonably request for checking at least one (1) full
business day prior to the Closing Date and will be in such names and
denominations as you may request, such request to be made at least two (2) full
business days prior to the Closing Date.  If the Representatives so elect,
delivery of the Firm Shares may be made by credit through full fast transfer to
the accounts at The Depository Trust Company designated by the Representatives.

          It is understood that you, individually, and not as the
Representatives of the several Underwriters, may (but shall not be obligated to)
make payment of the purchase price on behalf of any Underwriter or Underwriters
whose check or checks (or wire transfers, as the case may be) shall not have
been received by you prior to the Closing Date for the Firm Shares to be
purchased by such Underwriter or Underwriters.  Any such payment by you shall
not relieve any such Underwriter or Underwriters of any of its or their
obligations hereunder.


                                       -9-
<PAGE>

          After the Registration Statement becomes effective, the several
Underwriters intend to make an initial public offering (as such term is
described in Section 11 hereof) of the Firm Shares at an initial public offering
price of $_____ per share.  After the initial public offering, the several
Underwriters may, in their discretion, vary the public offering price.

          The information set forth in the last paragraph on the front cover
page (insofar as such information relates to the Underwriters), in the last two
paragraphs on the inside front cover concerning stabilization and over-allotment
by the Underwriters, and under the second, sixth and seventh paragraphs under
the caption "Underwriting" in any Preliminary Prospectus and in the Prospectus
constitutes the only information furnished by the Underwriters to the Company
for inclusion in any Preliminary Prospectus, the Prospectus or the Registration
Statement, and you, on behalf of the respective Underwriters, represent and
warrant to the Company that the statements made therein do not include any
untrue statement of a material fact or omit to state a material fact required to
be stated therein or necessary to make the statements therein, in the light of
the circumstances under which they were made, not misleading.



     4.   FURTHER AGREEMENTS OF THE COMPANY.  The Company agrees with the
several Underwriters that:

          (a)  The Company will use its best efforts to cause the Registration
Statement and any amendment thereof, if not effective at the time and date that
this Agreement is executed and delivered by the parties hereto, to become
effective as promptly as possible; the Company will use its best efforts to
cause any abbreviated registration statement pursuant to Rule 462(b) of the
Rules and Regulations as may be required subsequent to the date the Registration
Statement is declared effective to become effective as promptly as possible; the
Company will notify you, promptly after it shall receive notice thereof, of the
time when the Registration Statement, any subsequent amendment to the
Registration Statement or any abbreviated registration statement has become
effective or any supplement to the Prospectus has been filed; if the Company
omitted information from the Registration Statement at the time it was
originally declared effective in reliance upon Rule 430A(a) of the Rules and
Regulations, the Company will provide evidence satisfactory to you that the
Prospectus contains such information and has been filed, within the time period
prescribed, with the Commission pursuant to subparagraph (1) or (4) of
Rule 424(b) of the Rules and Regulations or as part of a post-effective
amendment to such Registration Statement as originally declared effective which
is declared effective by the Commission; if the Company files a term sheet
pursuant to Rule 434 of the Rules and Regulations, the Company will provide
evidence satisfactory to you that the Prospectus and term sheet meeting the
requirements of Rule 434(b) or (c), as applicable, of the Rules and Regulations,
have been filed, within the time period prescribed, with the Commission pursuant
to subparagraph (7) of Rule 424(b) of the Rules and Regulations; if for any
reason the filing of the final form of Prospectus is required under
Rule 424(b)(3) of the Rules and Regulations, it will provide evidence
satisfactory to you that the Prospectus contains such information and has been
filed with the Commission within the time period prescribed; it will notify you
promptly of any request by the Commission for the amending or supplementing of
the Registration Statement or the Prospectus or for additional information;
promptly upon your request, it will prepare and file with the Commission any
amendments or supplements to the Registration Statement or Prospectus which, in
the opinion of counsel for the several Underwriters ("Underwriters' Counsel"),
may be necessary or advisable in connection with the distribution of the Shares
by the Underwriters; it will promptly prepare and file with the Commission, and
promptly notify you of the filing of, any


                                      -10-
<PAGE>

amendments or supplements to the Registration Statement or Prospectus which may
be necessary to correct any statements or omissions, if, at any time when a
prospectus relating to the Shares is required to be delivered under the Act, any
event shall have occurred as a result of which the Prospectus or any other
prospectus relating to the Shares as then in effect would include any untrue
statement of a material fact or omit to state a material fact necessary to make
the statements therein, in the light of the circumstances under which they were
made, not misleading; in case any Underwriter is required to deliver a
prospectus nine (9) months or more after the effective date of the Registration
Statement in connection with the sale of the Shares, it will prepare promptly
upon request, but at the expense of such Underwriter, such amendment or
amendments to the Registration Statement and such prospectus or prospectuses as
may be necessary to permit compliance with the requirements of Section 10(a)(3)
of the Act; and it will file no amendment or supplement to the Registration
Statement or Prospectus which shall not previously have been submitted to you in
a reasonable time prior to the proposed filing thereof or to which you shall
reasonably object in writing, subject, however, to compliance with the Act and
the Rules and Regulations and the provisions of this Agreement.

          (b)  The Company will advise you, promptly after it shall receive
notice or obtain knowledge, of the issuance of any stop order by the Commission
suspending the effectiveness of the Registration Statement or of the initiation
or threat of any proceeding for that purpose; and it will promptly use its best
efforts to prevent the issuance of any stop order or to obtain its withdrawal at
the earliest possible moment if such stop order should be issued.

          (c)  The Company will use its best efforts to qualify the Shares for
offering and sale under the securities laws of such jurisdictions as you may
designate and to continue such qualifications in effect for so long as may be
required for purposes of the distribution of the Shares, except that the Company
shall not be required in connection therewith or as a condition thereof to
qualify as a foreign corporation or to execute a general consent to service of
process in any jurisdiction in which it is not otherwise required to be so
qualified or to so execute a general consent to service of process.  In each
jurisdiction in which the Shares shall have been qualified as above provided,
the Company will make and file such statements and reports in each year as are
or may be required by the laws of such jurisdiction.

          (d)  The Company will furnish to you, as soon as available, and, in
the case of the Prospectus and any term sheet or abbreviated term sheet under
Rule 434, in no event later than the first (1st) full business day following the
first day that Shares are traded, copies of the Registration Statement (three of
which will be signed and which will include all exhibits), each Preliminary
Prospectus, the Prospectus and any amendments or supplements to such documents,
including any prospectus prepared to permit compliance with Section 10(a)(3) of
the Act, all in such quantities as you may from time to time reasonably request.
Notwithstanding the foregoing, if Robertson, Stephens & Company LLC, on behalf
of the several Underwriters, shall agree to the utilization of Rule 434 of the
Rules and Regulations, the Company shall provide to you copies of a Preliminary
Prospectus updated in all respects through the date specified by you in such
quantities as you may from time to time reasonably request.

          (e)  The Company  will make generally available to its security
holders as soon as practicable, but in any event not later than the forty-fifth
(45th) day following the end of the fiscal quarter first occurring after the
first anniversary of the effective date of the Registration Statement, an
earnings statement (which will be in reasonable detail but need not be audited)
complying with the provisions of Section 11(a) of the Act and covering a twelve
(12) month period beginning after the effective date of the Registration
Statement.


                                      -11-
<PAGE>

          (f)  During a period of five (5) years after the date hereof or until 
an  Acquisition of the Company, the Company will furnish to its shareholders as
soon as practicable after the end of each respective period, annual reports
(including financial statements audited by independent certified public
accountants) and unaudited quarterly reports of operations for each of the first
three quarters of the fiscal year, and will furnish to you and the other several
Underwriters hereunder, upon request (i) concurrently with furnishing such
reports to its shareholders, statements of operations of the Company for each of
the first three (3) quarters in the form furnished to the Company's
shareholders, (ii) concurrently with furnishing to its shareholders, a balance
sheet of the Company as of the end of such fiscal year, together with statements
of operations, of shareholders' equity, and of cash flows of the Company for
such fiscal year, accompanied by a copy of the certificate or report thereon of
independent certified public accountants, (iii) as soon as they are available,
copies of all reports (financial or other) mailed to shareholders, (iv) as soon
as they are available, copies of all reports and financial statements furnished
to or filed with the Commission, any securities exchange or the National
Association of Securities Dealers, Inc. ("NASD"), (v) every material press
release and every material news item or article in respect of the Company or its
affairs which was generally released to shareholders or prepared by the Company,
and (vi) any additional information of a public nature concerning the Company,
or its business which you may reasonably request.  During such five (5) year
period, if the Company shall have active subsidiaries, the foregoing financial
statements shall be on a consolidated basis to the extent that the accounts of
the Company and its subsidiaries are consolidated, and shall be accompanied by
similar financial statements for any significant subsidiary which is not so
consolidated.  An "Acquisition of the Company" shall mean the closing of an
acquisition or merger of the Company (i) whereby all or substantially all of the
capital stock of the Company is sold, directly or indirectly, by the Company's
shareholders of record immediately prior to such closing and (ii) which results
in the Company no longer being required to comply with the reporting
requirements of the Exchange Act. 

          (g)  The Company will apply the net proceeds from the sale of the
Shares being sold by it in the manner set forth under the caption "Use of
Proceeds" in the Prospectus.

          (h)  The Company will maintain a transfer agent and, if necessary
under the jurisdiction of incorporation of the Company, a registrar (which may
be the same entity as the transfer agent) for its Common Stock.

          (i)  The Company will file Form SR in conformity with the requirements
of the Act and the Rules and Regulations.

          (j)  If the transactions contemplated hereby are not consummated by
reason of any failure, refusal or inability on the part of the Company to
perform any agreement on its part to be performed hereunder or to fulfill any
condition of the Underwriters' obligations hereunder, or if the Company shall
terminate this Agreement pursuant to Section 11(a) hereof, or if the
Underwriters shall terminate this Agreement pursuant to Section 11(b)(i), the
Company will reimburse the several Underwriters for all reasonable out-of-pocket
expenses (including fees and disbursements of Underwriters' Counsel) incurred by
the Underwriters in investigating or preparing to market or marketing the
Shares.

          (k)  If at any time during the ninety (90) day period after the
Registration Statement becomes effective, any rumor, publication or event
relating to or affecting the Company shall occur as a result of which in your
opinion the market price of the Common Stock has been or is likely to be
materially affected (regardless of whether such rumor, publication or event
necessitates a supplement 


                                      -12-
<PAGE>

to or amendment of the Prospectus), the Company will, after written notice from
you advising the Company to the effect set forth above, forthwith prepare,
consult with you concerning the substance of and disseminate a press release or
other public statement, reasonably satisfactory to you, responding to or
commenting on such rumor, publication or event.

          (l)  During the Lock-up Period, the Company will not, without the
prior written consent of Robertson Stephens & Company LLC, effect the
Disposition of, directly or indirectly, any Securities other than the (i) sale
of the Firm Shares and the Option Shares hereunder, (ii) the Company's issuance
of options or Common Stock under the Company's presently authorized 1993 Stock
Plan and 1996 Non-Employee Directors Stock Option Plan (the "Option Plans") or
upon exercise of any warrants of the Company outstanding as of the date of this
Agreement (the "Warrants") and (iii) the Company's issuance of shares to a
strategic partner of the Company in conjunction with an agreement involving a
technical, manufacturing and/or marketing collaboration, provided that the
Company shall give you ten days prior written notice of any such collaboration
during such period.  The Company understands and agrees that the Lock-Up
Agreements are for the benefit of the Underwriters and hereby assigns its rights
under such Lock-Up Agreements to Robertson , Stephens & Company LLC.   The
Company hereby agrees to enforce such Lock-Up Agreements, to not release any of
its officers, directors or other shareholders  (except for employees of the
Company who are not officers of the Company) from any Lock-up Agreements
currently existing or hereafter effected without the prior written consent of
Robertson, Stephens & Company LLC and to enter stop transfer instructions with
the Company's transfer agent against the transfer of any Securities held by such
persons except in compliance with the foregoing restriction.

          (m)  During a period of ninety (90) days from the effective date of
the Registration Statement, the Company will not file a registration statement
registering shares under the Option Plans or any other employee benefit plan.

     5.   EXPENSES.

          (a)  The Company agrees with each Underwriter that:

                    (i)  The Company will pay and bear all costs and expenses in
connection with the preparation, printing and filing of the Registration
Statement (including financial statements, schedules and exhibits), Preliminary
Prospectuses and the Prospectus and any amendments or supplements thereto; the
printing of this Agreement, the Agreement Among Underwriters, the Selected
Dealer Agreement, the Preliminary Blue Sky Survey and any Supplemental Blue Sky
Survey, the Underwriters' Questionnaire and Power of Attorney, and any
instruments related to any of the foregoing; the issuance and delivery of the
Shares hereunder to the several Underwriters, including transfer taxes, if any,
the cost of all certificates representing the Shares and transfer agents' and
registrars' fees; the fees and disbursements of counsel for the Company; all
fees and other charges of the Company's independent certified public
accountants; the cost of furnishing to the several Underwriters copies of the
Registration Statement (including exhibits), Preliminary Prospectus and the
Prospectus, and any amendments or supplements to any of the foregoing; NASD
filing fees and the cost of qualifying the Shares under the laws of such
jurisdictions as you may designate (including filing fees and fees and
disbursements of Underwriters' Counsel in connection with such NASD filings and
Blue Sky qualifications); and all other expenses directly incurred by the
Company in connection with the performance of their obligations hereunder.


                                      -13-

<PAGE>

               (ii) In addition to its other obligations under Section 8(a)
hereof, the Company agrees that, as an interim measure during the pendency of
any claim, action, investigation, inquiry or other proceeding described in
Section 8(a) hereof, it will reimburse the Underwriters on a monthly basis for
all reasonable legal or other expenses incurred in connection with investigating
or defending any such claim, action, investigation, inquiry or other proceeding,
notwithstanding the absence of a judicial determination as to the propriety and
enforceability of the Company's obligation to reimburse the Underwriters for
such expenses and the possibility that such payments might later be held to have
been improper by a court of competent jurisdiction.  To the extent that any such
interim reimbursement payment is so held to have been improper, the Underwriters
shall promptly return such payment to the Company together with interest,
compounded daily, determined on the basis of the prime rate listed from time to
time in The Wall Street Journal which represents the base rate on corporate
loans posted by a substantial majority of the nation's thirty (30) largest banks
(the "Prime Rate").  Any such interim reimbursement payments which are not made
to the Underwriters within thirty (30) days of a request for reimbursement shall
bear interest at the Prime Rate from the date of such request.

          (b)  In addition to their other obligations under Section 8(b) hereof,
the Underwriters severally and not jointly agree that, as an interim measure
during the pendency of any claim, action, investigation, inquiry or other
proceeding described in Section 8(b) hereof, they will reimburse the Company on
a monthly basis for all reasonable legal or other expenses incurred in
connection with investigating or defending any such claim, action,
investigation, inquiry or other proceeding, notwithstanding the absence of a
judicial determination as to the propriety and enforceability of the
Underwriters' obligation to reimburse the Company for such expenses and the
possibility that such payments might later be held to have been improper by a
court of competent jurisdiction.  To the extent that any such interim
reimbursement payment is so held to have been improper, the Company shall
promptly return such payment to the Underwriters together with interest,
compounded daily, determined on the basis of the Prime Rate.  Any such interim
reimbursement payments which are not made to the Company within thirty (30) days
of a request for reimbursement shall bear interest at the Prime Rate from the
date of such request.

          (c)  It is agreed that any controversy arising out of the operation of
the interim reimbursement arrangements set forth in Sections 5(a)(ii) and 5(b)
hereof, including the amounts of any requested reimbursement payments, the
method of determining such amounts and the basis on which such amounts shall be
apportioned among the reimbursing parties, shall be settled by arbitration
conducted under the provisions of the Constitution and Rules of the Board of
Governors of the New York Stock Exchange, Inc. or pursuant to the Code of
Arbitration Procedure of the NASD.  Any such arbitration must be commenced by
service of a written demand for arbitration or a written notice of intention to
arbitrate, therein electing the arbitration tribunal.  In the event the party
demanding arbitration does not make such designation of an arbitration tribunal
in such demand or notice, then the party responding to said demand or notice is
authorized to do so.  Any such arbitration will be limited to the operation of
the interim reimbursement provisions contained in Sections 5(a)(ii) and 5(b)
hereof and will take place in San Francisco or Santa Clara, California and will
not resolve the ultimate propriety or enforceability of the obligation to
indemnify for expenses which is created by the provisions of Sections 8(a)and
8(b) hereof or the obligation to contribute to expenses which is created by the
provisions of Section 8(d) hereof.

     6.   CONDITIONS OF UNDERWRITERS' OBLIGATIONS.  The obligations of the
several Underwriters to purchase and pay for the Shares as provided herein shall
be subject to the accuracy, as of the date hereof and the Closing Date and any
later date on which Option Shares are to be purchased, as the case may be, 


                                      -14-
<PAGE>

of the representations and warranties of the Company herein, to the performance
by the Company of its obligations hereunder and to the following additional
conditions:

          (a)  The Registration Statement shall have become effective not later
than 2:00 P.M., San Francisco time, on the date following the date of this
Agreement, or such later date as shall be consented to in writing by you; and no
stop order suspending the effectiveness thereof shall have been issued and no
proceedings for that purpose shall have been initiated or, to the knowledge of
the Company or any Underwriter, threatened by the Commission, and any request of
the Commission for additional information (to be included in the Registration
Statement or the Prospectus or otherwise) shall have been complied with to the
satisfaction of Underwriters' Counsel.

          (b)  All corporate proceedings and other legal matters in connection
with this Agreement, the form of Registration Statement and the Prospectus, and
the registration, authorization, issue, sale and delivery of the Shares, shall
have been reasonably satisfactory to Underwriters' Counsel, and such counsel
shall have been furnished with such papers and information as they may
reasonably have requested to enable them to pass upon the matters referred to in
this Section.

          (c)  Subsequent to the execution and delivery of this Agreement and
prior to the Closing Date, or any later date on which Option Shares are to be
purchased, as the case may be, there shall not have been any change in the
condition (financial or otherwise), earnings, operations, business as described
in the Prospectus of the Company from that set forth in the Registration
Statement or Prospectus, which, in your sole judgment, is material and adverse
and that makes it, in your sole judgment, impracticable or inadvisable to
proceed with the public offering of the Shares as contemplated by the
Prospectus.

          (d)  You shall have received on the Closing Date and on any later date
on which Option Shares are to be purchased, as the case may be, the following
opinion of Heller Ehrman White & McAuliffe, counsel for the Company, dated the
Closing Date or such later date on which Option Shares are to be purchased
addressed to the Underwriters and with reproduced copies or signed counterparts
thereof for each of the Underwriters, to the effect that:

               (i)   The Company has been duly incorporated and is validly
existing as a corporation in good standing under the laws of the jurisdiction of
its incorporation;

               (ii)  The Company has the corporate power and corporate authority
to own, lease and operate its properties and to conduct its business as
described in the Prospectus;

               (iii) The Company is duly qualified to do business as a foreign
corporation and is in good standing in each jurisdiction, if any, in which the
ownership or leasing of its properties or the conduct of its business requires
such qualification, except where the failure to be so qualified or be in good
standing would not have a material adverse effect on the condition (financial or
otherwise), earnings, operations or business of the Company.  To such counsel's
knowledge, the Company does not own or control, directly or indirectly, any
corporation, association or other entity;

               (iv) The authorized, issued and outstanding capital stock of the
Company is as set forth in the Prospectus under the caption "Capitalization" as
of the dates stated therein, the issued and outstanding shares of capital stock
of the Company have been duly and validly issued and are fully paid and
nonassessable, have not been issued in violation of preemptive rights set forth
in the Company's 


                                      -15-
<PAGE>

charter, and to such counsel's knowledge, will not have been issued in violation
of or subject to any co-sale right, registration right, right of first refusal
or other similar right granted by the Company;

               (v)   The Firm Shares or the Option Shares, as the case may be,
to be issued by the Company pursuant to the terms of this Agreement have been
duly authorized and, upon issuance and delivery against payment therefor in
accordance with the terms hereof, will be duly and validly issued and fully paid
and nonassessable, have not been issued in violation of preemptive rights set
forth in the Company's charter, and will not have been issued in violation of or
subject to any co-sale right, registration right, right of first refusal or
other similar right granted by the Company.

               (vi)  The Company has the corporate power and corporate authority
to enter into this Agreement and to issue, sell and deliver to the Underwriters
the Shares to be issued and sold by it hereunder;

               (vii) This Agreement has been duly authorized by all necessary
corporate action on the part of the Company and has been duly executed and
delivered by the Company and, assuming due authorization, execution and delivery
by you, is a valid and binding agreement of the Company, enforceable in
accordance with its terms, except insofar as indemnification provisions may be
limited by applicable law and except as enforceability may be limited by
bankruptcy, insolvency, reorganization, moratorium or similar laws relating to
or affecting creditors' rights generally or by general equitable principles;

               (viii) The Registration Statement has become effective under the
Act and, to such counsel's knowledge, no stop order suspending the effectiveness
of the Registration Statement has been issued and no proceedings for that
purpose have been instituted or are pending or threatened under the Act;
 
               (ix) The Registration Statement and the Prospectus, and each
amendment or supplement thereto (other than the financial statements (including
supporting schedules) and financial data derived therefrom as to which such
counsel need express no opinion), as of the effective date of the Registration
Statement, complied as to form in all material respects with the requirements of
the Act and the applicable Rules and Regulations;

               (x)  The information in the Prospectus under the caption
"Description of Capital Stock," to the extent that it constitutes matters of law
or legal conclusions, has been reviewed by such counsel and is a fair summary of
such matters and conclusions; and the form of certificates evidencing the Common
Stock and filed as an exhibit to the Registration Statement complies with
California law;

               (xi) The description in the Registration Statement and the
Prospectus of the charter and bylaws of the Company and of statutes (other than
statutes opined upon in Section 6(e) by Townsend and Townsend and Crew and in
Section 5(f) by Buc Levitt & Beardsley) is accurate and fairly presents the
information required to be presented by the Act and the applicable Rules and
Regulations;

               (xii) To such counsel's knowledge, there are no agreements,
contracts, leases or documents to which the Company is a party of a character
required to be described or referred to in the Registration Statement or
Prospectus or to be filed as an exhibit to the Registration Statement which are
not described or referred to therein or filed as required;


                                      -16-
<PAGE>

               (xiii) The performance of this Agreement and the consummation of
the transactions herein contemplated (other than performance of the Company's
indemnification obligations hereunder, concerning which no opinion need be
expressed) will not (a) result in any violation of the Company's charter or
bylaws or (b) to such counsel's knowledge, result in a breach or violation of
any of the terms and provisions of, or constitute a default under, any material
bond, debenture, note or other evidence of indebtedness, or any material lease,
contract, indenture, mortgage, deed of trust, loan agreement, joint venture or
other agreement or instrument known to such counsel to which the Company is a
party or by which its properties are bound, or any applicable material statute,
rule or regulation known to such counsel or, to such counsel's knowledge, any
material order, writ or decree of any court, government or governmental agency
or body having jurisdiction over the Company, or over any of its properties or
operations;

               (xiv)  No consent, approval, authorization or order of or
qualification with any court, government or governmental agency or body having
jurisdiction over the Company, or over any of its properties or operations is
necessary in connection with the consummation by the Company of the transactions
herein contemplated, except such as have been obtained under the Act or the
Exchange Act or such as may be required under state or other securities or Blue
Sky laws in connection with the purchase and the distribution of the Shares by
the Underwriters;

               (xv)  To such counsel's knowledge, there are no legal or
governmental proceedings pending or threatened against the Company of a
character required to be disclosed in the Registration Statement or the
Prospectus by the Act or the Rules and Regulations, other than those described
therein;

               (xvi) To such counsel's knowledge, the Company is not presently
(a) in violation of its charter or bylaws, or (b) in breach of any applicable
material statute, rule or regulation known to such counsel or, to such counsel's
knowledge, any material order, writ or decree of any court or governmental
agency or body having jurisdiction over the Company, or over any of its
properties or operations; and

               (xvii) To such counsel's knowledge, except as set forth in the
Registration Statement and Prospectus, no holders of Common Stock or other
securities of the Company have registration rights with respect to securities of
the Company and, except as set forth in the Registration Statement and
Prospectus, all holders of securities of the Company having rights known to such
counsel to registration of such shares of Common Stock or other securities,
because of the filing of the Registration Statement by the Company have, with
respect to the offering contemplated thereby, waived such rights or such rights
have expired by reason of lapse of time following notification of the Company's
intent to file the Registration Statement.

          In addition, such counsel shall state that such counsel has
participated in conferences with officials and other representatives of the
Company, the Representatives, Underwriters' Counsel and the independent
certified public accountants of the Company, at which such conferences the
contents of the Registration Statement and Prospectus and related matters were
discussed, and although they have not verified the accuracy or completeness of
the statements contained in the Registration Statement or the Prospectus,
nothing has come to the attention of such counsel which leads such counsel to
believe that, at the time the Registration Statement became effective and at all
times subsequent thereto up to and on the Closing Date and on any later date on
which Option Shares are to be purchased, the Registration Statement and any
amendment or supplement thereto (other than the financial statements including
supporting schedules and other financial and statistical information derived
therefrom, as to which such counsel need express no comment) contained any
untrue statement of a material fact or omitted to state


                                      -17-
<PAGE>

a material fact required to be stated therein or necessary to make the
statements therein not misleading, or at the Closing Date or any later date on
which the Option Shares are to be purchased, as the case may be, the
Registration Statement, the Prospectus and any amendment or supplement thereto
(except as aforesaid) contained any untrue statement of a material fact or
omitted to state a material fact necessary to make the statements therein, in
the light of the circumstances under which they were made, not misleading.

          Counsel rendering the foregoing opinion may rely as to questions of
law not involving the laws of the United States or the State of California upon
opinions of local counsel, and as to questions of fact upon representations or
certificates of officers of the Company and of government officials, in which
case their opinion is to state that they are so relying and that they have no
knowledge of any material misstatement or inaccuracy in any such opinion,
representation or certificate.  Copies of any opinion, representation or
certificate so relied upon shall be delivered to you, as Representatives of the
Underwriters, and to Underwriters' Counsel.

          (e)  Townsend and Townsend and Crew ("Townsend"), outside patent
counsel for the Company, shall have expertised the statements set forth in the
Prospectus under the caption "Risk Factors--- Dependence on Proprietary
Technology and Unpredictability of Patent Protection" and "Business-Intellectual
Property".  In addition, you shall have received on the Closing Date and on any
later date on which Option Shares are purchased, as the case may be, the
following opinion of  Townsend, dated the Closing Date or such later date on
which Option Shares are purchased, addressed to the Underwriters and with
reproduced copies or signed counterparts thereof for each of the Underwriters,
stating that such counsel is familiar with the technology used by the Company,
its business and the manner of its technology's use thereof, and to the effect
that:

               (i)  To  such counsel's knowledge, except as set forth on Exhibit
1, the Company owns or possesses sufficient licenses or other rights to use all
necessary patents, patent rights, trade secrets, trademarks, service marks,
trade names and copyrights (hereinafter called "Intellectual Property Rights," )
to conduct the business now being or proposed to be conducted by the Company as
described in the Prospectus;

               (ii) To such counsel's knowledge, except as otherwise set forth
on Exhibit 1, there are no actions, suits, proceedings, claims or other legal
actions or governmental proceedings relating to (a) any Intellectual Property
Rights owned or licensed by the Company pending against the Company, Affymax or
any licensor, or (b) a third party's Intellectual Property Rights pending
against the Company or of which the Company has received notice;

               (iii)     To such counsel's knowledge, except as set forth in
Exhibit 1 to the opinion, the Company is not infringing or otherwise violating
any Intellectual Property Rights of others and there are no infringements by
others of any Intellectual Property Rights owned or licensed by the Company
which, in the judgment of such counsel, could affect materially the use thereof
by the Company;


               (iv)      We are not aware of any facts which would preclude the
Company from having clear title to or a valid license to each foreign or
domestic patent and patent application listed on Exhibit 2 (the "Patent
Portfolio") to such opinion, and the Company is the sole assignee or exclusive
licensee thereof, except as indicated on the Patent Portfolio;


                                      -18-
<PAGE>

               (v)   We are not aware of any material defect of form in
preparation or filing of the applications in the Patent Portfolio;

               (vi)  The patent applications in the Patent Portfolio are being
diligently pursued; and

               (vii) The information in the Registration Statement and
Prospectus under the captions "Risk Factors--Dependence on Proprietary
Technology and Unpredictability of Patent Protection and Business--Intellectual
Property" and "--Collaborative Agreements" (the "Intellectual Property
Information") to the extent it constitutes matters of law or legal conclusions,
has been reviewed by such counsel and is a fair and accurate summary of such
matters;

                    In addition, such counsel shall state that such counsel has
participated in conferences with officials and other representatives of the
Company, the Representatives, Underwriters' Counsel and the independent
certified public accountants of the Company, at which such conferences the
contents of the Registration Statement and Prospectus and related matters were
discussed, and although they have not verified the accuracy or completeness of
the statements contained in the Registration Statement or the Prospectus,
nothing has come to the attention of such counsel which leads such counsel to
believe that, at the time the Registration Statement became effective and at all
times subsequent thereto up to and on the Closing Date and on any later date on
which Option Shares are to be purchased, the Intellectual Property Information
in the Registration Statement and any amendment or supplement thereto (other
than financial statements including supporting schedules and other financial and
statistical information derived therefrom, as to which such counsel need express
no comment) did not contain any untrue statement of a material fact or omit to
state a material fact required to be stated therein or necessary to make the
statements therein not misleading, or at the Closing Date or any later date on
which Option Shares are to be purchased, as the case may be, the Intellectual
Property Information in the Prospectus, and any amendment or supplement thereto,
(except aforesaid) did not contain any untrue statement of a material fact or
omit to state a material fact required to be stated therein or necessary to make
the statements therein, in light of the circumstances under which they were
made, not misleading. 

          (f)  You shall have received on the Closing Date and on any later date
on which Option Shares are purchased, as the case may be, the following opinion
of Buc Levitt & Beardsley, regulatory counsel for the Company, dated the Closing
Date or such later date on which Option Shares are purchased, addressed to the
Underwriters and with reproduced copies or signed counterparts thereof for each
of the Underwriters stating that such counsel is familiar with the technology
used by the Company, its business and the manner of its technology's use thereof
and has read the Registration Statement and the Prospectus including
particularly the portions of the Registration Statement and the Prospectus
referring to regulatory matters, and to the effect that:

               (i)  The information in the Registration Statement and the
Prospectus under the captions "Risk Factors--Government Regulation; No Assurance
of Regulatory Approval," and "Business--Government Regulation" (the "Regulatory
Information"), to the extent that it constitutes matters of law or legal
conclusions, has been reviewed by such counsel and is a fair and accurate
summary of such matters;

               (ii) In addition, such counsel shall state that such counsel has
participated in conferences with officials and other representatives of the
Company, at which such conferences the Regulatory Information and related
matters were discussed, and although they have not verified the 


                                      -19-
<PAGE>

accuracy or completeness of the statements contained in the Registration
Statement or the Prospectus, nothing has come to the attention of such counsel
which leads such counsel to believe that, at the time the Registration Statement
became effective and at all times subsequent thereto up to and on the Closing
Date and on any later date on which Option Shares are to be purchased, the
Regulatory Information in the Registration Statement and any amendment or
supplement thereto (other than financial statements including supporting
schedules and other financial and statistical information derived therefrom, as
to which such counsel need express no comment) did not contain any untrue
statement of a material fact or omit to state a material fact required to be
stated therein or necessary to make the statements therein not misleading, or at
the Closing Date or any later date on which Option Shares are to be purchased,
as the case may be, the Regulatory Information in the Prospectus, and any
amendment or supplement thereto, (except aforesaid) did not contain any untrue
statement of a material fact or omit to state a material fact required to be
stated therein or necessary to make the statements therein, in light of the
circumstances under which they were made, not misleading.

          (g)  You shall have received on the Closing Date and on any later date
on which Option Shares are to be purchased, as the case may be, an opinion of
Wilson Sonsini Goodrich & Rosati, in form and substance satisfactory to you,
with respect to the sufficiency of all such corporate proceedings and other
legal matters relating to this Agreement and the transactions contemplated
hereby as you may reasonably require, and the Company shall have furnished to
such counsel such documents as they may have requested for the purpose of
enabling them to pass upon such matters.

          (h)  You shall have received on the Closing Date and on any later date
on which Option Shares are to be purchased, as the case may be, a letter from
Ernst & Young LLP addressed to the Underwriters, dated the Closing Date or such
later date on which Option Shares are to be purchased, as the case may be,
confirming that they are independent certified public accountants with respect
to the Company within the meaning of the Act and the applicable published Rules
and Regulations and based upon the procedures described in such letter delivered
to you concurrently with the execution of this Agreement (herein called the
"Original Letter"), but carried out to a date not more than five (5) business
days prior to the Closing Date or such later date on which Option Shares are to
be purchased, as the case may be, (i) confirming, to the extent true, that the
statements and conclusions set forth in the Original Letter are accurate as of
the Closing Date or such later date on which Option Shares are to be purchased,
as the case may be, and (ii) setting forth any revisions and additions to the
statements and conclusions set forth in the Original Letter which are necessary
to reflect any changes in the facts described in the Original Letter since the
date of such letter, or to reflect the availability of more recent financial
statements, data or information.  The letter shall not disclose any change in
the condition (financial or otherwise), earnings, operations or business as
described in the Prospectus of the Company from that set forth in the
Registration Statement or Prospectus, which, in your sole judgment, is material
and adverse and that makes it, in your sole judgment, impracticable or
inadvisable to proceed with the public offering of the Shares as contemplated by
the Prospectus.  The Original Letter from Ernst & Young LLP shall be addressed
to or for the use of the Underwriters in form and substance satisfactory to the
Underwriters and shall (i) represent, to the extent true, that they are
independent certified public accountants with respect to the Company within the
meaning of the Act and the applicable published Rules and Regulations, (ii) set
forth their opinion with respect to their examination of the balance sheet of
the Company as of December 31, 1995 and related statements of operations,
shareholders' equity, and cash flows for the twelve (12) months ended
December 31, 1995, and(iii) state that Ernst & Young, LLP has performed the
procedure set out in Statement on Auditing Standards No. 71 ("SAS 71") for a
review of interim financial information and providing the report of Ernst &
Young LLP as described in SAS 71 in the financial statements for each of the
quarters in the three month period ending March 31, 1996


                                      -20-
<PAGE>

and 1995 (the "Quarterly Financial Statements"), (iv) state that in the course
of such review, nothing came to their attention that leads them to believe that
any material modifications need be made to any of the Quarterly Financial
Statements in order for them to be in compliance with generally accepted
accounting principles consistently applied across the periods presented and
(v) address other matters agreed upon by Ernst & Young, LLP and you.  In
addition, you shall have received from Ernst & Young LLP, a letter addressed to
the Company and made available to you for the use of the Underwriters stating
that their review of the Company's system of internal accounting controls, to
the extent they deemed necessary in establishing the scope of their examination
of the Company's financial statements as of December 31, 1995, did not disclose
any weaknesses in internal controls that they considered to be material
weaknesses.

          (i)  You shall have received on the Closing Date and on any later
date on which Option Shares are to be purchased, as the case may be, a
certificate of the Company, dated the Closing Date or such later date on which
Option Shares are to be purchased, as the case may be, signed by the Chief
Executive Officer and Chief Financial Officer of the Company, to the effect
that, and you shall be satisfied that:

               (i) The representations and warranties of the Company in this
Agreement are true and correct, as if made on and as of the Closing Date or any
later date on which Option Shares are to be purchased, as the case may be, and
the Company has complied with all the agreements and satisfied all the
conditions on its part to be performed or satisfied at or prior to the Closing
Date or any later date on which Option Shares are to be purchased, as the case
may be;

               (ii) No stop order suspending the effectiveness of the
Registration Statement has been issued and no proceedings for that purpose have
been instituted or are pending or threatened under the Act;

               (iii)  When the Registration Statement became effective and at 
all times subsequent thereto up to the delivery of such certificate, the
Registration Statement and the Prospectus, and any amendments or supplements
thereto, contained all material information required to be included therein by
the Act and the Rules and Regulations and in all material respects conformed to
the requirements of the Act and the Rules and Regulations, the Registration
Statement, and any amendment or supplement thereto, did not and does not include
any untrue statement of a material fact or omit to state a material fact
required to be stated therein or necessary to make the statements therein not
misleading, the Prospectus, and any amendment or supplement thereto, did not and
does not include any untrue statement of a material fact or omit to state a
material fact necessary to make the statements therein, in the light of the
circumstances under which they were made, not misleading, and, since the
effective date of the Registration Statement, there has occurred no event
required to be set forth in an amended or supplemented Prospectus which has not
been so set forth; and

                 (iv)  Subsequent to the respective dates as of which
information is given in the Registration Statement and Prospectus, there has not
been (a) any material adverse change in the condition (financial or otherwise),
earnings, operations or business as described in the Prospectus of the Company,
(b) any transaction that is material to the Company, except transactions entered
into in the ordinary course of business, (c) any obligation, direct or
contingent, that is material to the Company incurred by the Company, except
obligations incurred in the ordinary course of business, (d) any change in the
capital stock or outstanding indebtedness of the Company that is material to the
Company, (e) any dividend or distribution of any kind declared, paid or made on
the capital stock of the Company, or (f) 


                                      -21-
<PAGE>

any loss or damage (whether or not insured) to the property of the Company which
has been sustained or will have been sustained which has a material adverse
effect on the condition (financial or otherwise), earnings, operations or
business as described in the Prospectus of the Company.

          (j)  The Company shall have obtained and delivered to you an agreement
from each officer and director of the Company, and each beneficial owner
of one percent or more of the Company's outstanding shares of capital stock
as of the date of this Agreement in writing prior to the date hereof that such
person will not, during the Lock-up Period, effect the Disposition of any
Securities now owned or hereafter acquired directly by such person or with
respect to which such person has or hereafter acquires the power of disposition,
otherwise than (i) as a bona fide gift or gifts, provided the donee or donees
thereof agree in writing to be bound by this restriction, (ii) as a distribution
to partners or shareholders of such person, provided that the distributees
thereof agree in writing to be bound by the terms of this restriction, or
(iii) with the prior written consent of Robertson, Stephens & Company LLC.  The
foregoing restriction shall have been expressly agreed to preclude the holder of
the Securities from engaging in any hedging or other transaction which is
designed to or reasonably expected to lead to or result in a Disposition of
Securities during the Lock-up Period, even if such Securities would be disposed
of by someone other than the such holder.  Such prohibited hedging or other
transactions would including, without limitation, any short sale (whether or not
against the box) or any purchase, sale or grant of any right (including, without
limitation, any put or call option) with respect to any Securities or with
respect to any security (other than a broad-based market basket or index) that
includes, relates to or derives any significant part of its value from
Securities. Furthermore, such person will have also agreed and consented to the
entry of stop transfer instructions with the Company's transfer agent against
the transfer of the Securities held by such person except in compliance with
this restriction.

          (k)  The Company shall have furnished to you such further certificates
and documents as you shall reasonably request (including certificates of
officers) of the Company as to the accuracy of the representations and
warranties of the Company herein, as to the performance by the Company of its
obligations hereunder and as to the other conditions concurrent and precedent to
the obligations of the Underwriters hereunder.

          All such opinions, certificates, letters and documents will be in
compliance with the provisions hereof only if they are reasonably satisfactory
to Underwriters' Counsel.  The Company will furnish you with such number of
conformed copies of such opinions, certificates, letters and documents as you
shall reasonably request.

     7.   OPTION SHARES.

          (a)  On the basis of the representations, warranties and agreements
herein contained, but subject to the terms and conditions herein set forth, the
Company hereby grants to the several Underwriters, for the purpose of covering
over-allotments in connection with the distribution and sale of the Firm Shares
only, a nontransferable option to purchase up to an aggregate of  750,000 Option
Shares at the purchase price per share of $_______.  Such option may be
exercised by the Representatives on behalf of the several Underwriters on one
(1) occasion in whole or in part during the period of thirty (30) days after the
date on which the Firm Shares are initially offered to the public, by giving
written notice to the Company.  The number of Option Shares to be purchased by
each Underwriter upon the exercise of such option shall be the same proportion
of the total number of Option Shares to be purchased by the several Underwriters
pursuant to the exercise of such option as the number of Firm Shares purchased
by such Underwriter (set forth in Schedule A hereto) bears to the total number


                                      -22-
<PAGE>

of Firm Shares purchased by the several Underwriters (set forth in Schedule A
hereto), adjusted by the Representatives in such manner as to avoid fractional
shares.

               Delivery of definitive certificates for the Option Shares to be
purchased by the several Underwriters pursuant to the exercise of the option
granted by this Section 7 shall be made against payment of the purchase price
therefor by the several Underwriters by wire transfer of same-day funds paid to
an account designated by the Company in writing.  Such delivery and payment
shall take place at the offices of Heller Ehrman White & McAuliffe, 525
University Avenue, Palo Alto, California 94301-1908, or at such other place as
may be agreed upon among the Representatives and the Company (i) on the Closing
Date, if written notice of the exercise of such option is received by the
Company at least two (2) full business days prior to the Closing Date, or
(ii) on a date which shall not be later than the third (3rd) full business day
following the date the Company receives written notice of the exercise of such
option, if such notice is received by the Company less than two (2) full
business days prior to the Closing Date.  

               The certificates for the Option Shares to be so delivered will be
made available to you at such office or such other location including, without
limitation, in New York City, as you may reasonably request for checking at
least one (1) full business day prior to the date of payment and delivery and
will be in such names and denominations as you may request, such request to be
made at least two (2) full business days prior to such date of payment and
delivery.  If the Representatives so elect, delivery of the Option Shares may be
made by credit through full fast transfer to the accounts at The Depository
Trust Company designated by the Representatives.

               It is understood that you, individually, and not as the
Representatives of the several Underwriters, may (but shall not be obligated to)
make payment of the purchase price on behalf of any Underwriter or Underwriters
whose check or checks (or wire transfers as the case may be) shall not have been
received by you prior to the date of payment and delivery for the Option Shares
to be purchased by such Underwriter or Underwriters.  Any such payment by you
shall not relieve any such Underwriter or Underwriters of any of its or their
obligations hereunder.

          (b)  Upon exercise of any option provided for in Section 7(a) hereof,
the obligations of the several Underwriters to purchase such Option Shares will
be subject (as of the date hereof and as of the date of payment and delivery for
such Option Shares) to the accuracy of and compliance with the representations,
warranties and agreements of the Company herein, to the accuracy of the
statements of the Company and officers of the Company made pursuant to the
provisions hereof, to the performance by the Company of its obligations
hereunder, to the conditions set forth in Section 6 hereof, and to the condition
that all proceedings taken at or prior to the payment date in connection with
the sale and transfer of such Option Shares shall be satisfactory in form and
substance to you and to Underwriters' Counsel, and you shall have been furnished
with all such documents, certificates and opinions as you may request in order
to evidence the accuracy and completeness of any of the representations,
warranties or statements, the performance of any of the covenants or agreements
of the Company or the satisfaction of any of the conditions herein contained.

     8.   INDEMNIFICATION AND CONTRIBUTION.

          (a)  The Company agrees to indemnify and hold harmless each
Underwriter against any losses, claims, damages or liabilities, joint or
several, to which such Underwriter may become subject (including, without
limitation, in its capacity as an Underwriter or as a "qualified independent


                                      -23-
<PAGE>

underwriter" within the meaning of Schedule E of the Bylaws of the NASD), under
the Act, the Exchange Act or otherwise, specifically including, but not limited
to, losses, claims, damages or liabilities (or actions in respect thereof)
arising out of or based upon (i) any breach of any representation, warranty,
agreement or covenant of the Company herein contained, (ii) any untrue statement
or alleged untrue statement of any material fact contained in the Registration
Statement or any amendment or supplement thereto, or the omission or alleged
omission to state therein a material fact required to be stated therein or
necessary to make the statements therein not misleading, or (iii) any untrue
statement or alleged untrue statement of any material fact contained in any
Preliminary Prospectus or the Prospectus or any amendment or supplement thereto,
or the omission or alleged omission to state therein a material fact required to
be stated therein or necessary to make the statements therein, in the light of
the circumstances under which they were made, not misleading, and agrees to
reimburse each Underwriter for any legal or other expenses reasonably incurred
by it in connection with investigating or defending any such loss, claim,
damage, liability or action; PROVIDED, HOWEVER, that the Company shall not be
liable in any such case to the extent that any such loss, claim, damage,
liability or action arises out of or is based upon an untrue statement or
alleged untrue statement or omission or alleged omission made in the
Registration Statement, such Preliminary Prospectus or the Prospectus, or any
such amendment or supplement thereto, in reliance upon, and in conformity with,
written information relating to any Underwriter furnished to the Company by such
Underwriter, directly or through you, specifically for use in the preparation
thereof and, PROVIDED FURTHER, that the indemnity agreement provided in this
Section 8(a) with respect to any Preliminary Prospectus shall not inure to the
benefit of any Underwriter from whom the person asserting any losses, claims,
damages, liabilities or actions based upon any untrue statement or alleged
untrue statement of material fact or omission or alleged omission to state
therein a material fact purchased Shares, if a copy of the Prospectus in which
such untrue statement or alleged untrue statement or omission or alleged
omission was corrected had not been sent or given to such person within the time
required by the Act and the Rules and Regulations, unless such failure is the
result of noncompliance by the Company with Section 4(d) hereof.

               The indemnity agreement in this Section 8(a) shall extend upon
the same terms and conditions to, and shall inure to the benefit of, each
person, if any, who controls any Underwriter within the meaning of the Act or
the Exchange Act.  This indemnity agreement shall be in addition to any
liabilities which the Company may otherwise have.

          (b)  Each Underwriter, severally and not jointly, agrees to indemnify
and hold harmless the Company against any losses, claims, damages or
liabilities, joint or several, to which the Company may become subject under the
Act, the Exchange Act or otherwise, specifically including, but not limited to,
losses, claims, damages or liabilities (or actions in respect thereof) arising
out of or based upon (i) any breach of any representation, warranty, agreement
or covenant of such Underwriter herein contained, (ii) any untrue statement or
alleged untrue statement of any material fact contained in the Registration
Statement or any amendment or supplement thereto, or the omission or alleged
omission to state therein a material fact required to be stated therein or
necessary to make the statements therein not misleading, or (iii) any untrue
statement or alleged untrue statement of any material fact contained in any
Preliminary Prospectus or the Prospectus or any amendment or supplement thereto,
or the omission or alleged omission to state therein a material fact necessary
to make the statements therein, in the light of the circumstances under which
they were made, not misleading, in the case of subparagraphs (ii) and (iii) of
this Section 8(b) to the extent, but only to the extent, that such untrue
statement or alleged untrue statement or omission or alleged omission was made
in reliance upon and in conformity with written information furnished to the
Company by such Underwriter, directly or through you, specifically for use in
the preparation thereof, and agrees to reimburse the Company for


                                      -24-
<PAGE>

any legal or other expenses reasonably incurred by the Company in connection
with investigating or defending any such loss, claim, damage, liability or
action.

               The indemnity agreement in this Section 8(b) shall extend upon
the same terms and conditions to, and shall inure to the benefit of, each
officer of the Company who signed the Registration Statement and each director
of the Company, and each person, if any, who controls the Company within the
meaning of the Act or the Exchange Act.  This indemnity agreement shall be in
addition to any liabilities which each Underwriter may otherwise have.

          (c)  Promptly after receipt by an indemnified party under this
Section 8 of notice of the commencement of any action, such indemnified party
shall, if a claim in respect thereof is to be made against any indemnifying
party under this Section 8, notify the indemnifying party in writing of the
commencement thereof but the omission so to notify the indemnifying party will
not relieve it from any liability which it may have to any indemnified party
otherwise than under this Section 8.  In case any such action is brought against
any indemnified party, and it notified the indemnifying party of the
commencement thereof, the indemnifying party will be entitled to participate
therein and, to the extent that it shall elect by written notice delivered to
the indemnified party promptly after receiving the aforesaid notice from such
indemnified party, to assume the defense thereof, with counsel reasonably
satisfactory to such indemnified party; PROVIDED, HOWEVER, that if the
defendants in any such action include both the indemnified party and the
indemnifying party and the indemnified party shall have reasonably concluded
that there may be legal defenses available to it and/or other indemnified
parties which are different from or additional to those available to the
indemnifying party, the indemnified party or parties shall have the right to
select separate counsel to assume such legal defenses and to otherwise
participate in the defense of such action on behalf of such indemnified party or
parties.  Upon receipt of notice from the indemnifying party to such indemnified
party of the indemnifying party's election so to assume the defense of such
action and approval by the indemnified party of counsel, the indemnifying party
will not be liable to such indemnified party under this Section 8 for any legal
or other expenses subsequently incurred by such indemnified party in connection
with the defense thereof unless (i) the indemnified party shall have employed
separate counsel in accordance with the proviso to the next preceding sentence
(it being understood, however, that the indemnifying party shall not be liable
for the expenses of more than one separate counsel (together with appropriate
local counsel) approved by the indemnifying party representing all the
indemnified parties under Section 8(a) or 8(b) hereof who are parties to such
action), (ii) the indemnifying party shall not have employed counsel
satisfactory to the indemnified party to represent the indemnified party within
a reasonable time after notice of commencement of the action or (iii) the
indemnifying party has authorized the employment of counsel for the indemnified
party at the expense of the indemnifying party.  In no event shall any
indemnifying party be liable in respect of any amounts paid in settlement of any
action unless the indemnifying party shall have approved the terms of such
settlement; PROVIDED that such consent shall not be unreasonably withheld.  No
indemnifying party shall, without the prior written consent of the indemnified
party, effect any settlement of any pending or threatened proceeding in respect
of which any indemnified party is or could have been a party and indemnification
could have been sought hereunder by such indemnified party, unless such
settlement includes an unconditional release of such indemnified party from all
liability on all claims that are the subject matter of such proceeding.

          (d)  In order to provide for just and equitable contribution in any
action in which a claim for indemnification is made pursuant to this Section 8
but it is judicially determined (by the entry of a final judgment or decree by a
court of competent jurisdiction and the expiration of time to appeal or the
denial of the last right of appeal) that such indemnification may not be
enforced in such case 


                                    -25-

<PAGE>

notwithstanding the fact that this Section 8 provides for indemnification in 
such case, all the parties hereto shall contribute to the aggregate losses, 
claims, damages or liabilities to which they may be subject (after 
contribution from others) in such proportion so that the Underwriters 
severally and not jointly are responsible pro rata for the portion 
represented by the percentage that the underwriting discount bears to the 
initial public offering price, and the Company is responsible for the 
remaining portion, PROVIDED, HOWEVER, that (i) no Underwriter shall be 
required to contribute any amount in excess of the amount by which the 
underwriting discount applicable to the Shares purchased by such Underwriter 
exceeds the amount of damages which such Underwriter has otherwise required 
to pay and (ii) no person guilty of a fraudulent misrepresentation (within 
the meaning of Section 11(f) of the Act) shall be entitled to contribution 
from any person who is not guilty of such fraudulent misrepresentation.  The 
contribution agreement in this Section 8(d) shall extend upon the same terms 
and conditions to, and shall inure to the benefit of, each person, if any, 
who controls any Underwriter, the Company within the meaning of the Act or 
the Exchange Act and each officer of the Company who signed the Registration 
Statement and each director of the Company.


          (e)  The parties to this Agreement hereby acknowledge that they are
sophisticated business persons who were represented by counsel during the
negotiations regarding the provisions hereof including, without limitation, the
provisions of this Section 8, and are fully informed regarding said provisions. 
They further acknowledge that the provisions of this Section 8 fairly allocate
the risks in light of the ability of the parties to investigate the Company and
its business in order to assure that adequate disclosure is made in the
Registration Statement and Prospectus as required by the Act and the Exchange
Act.

     9.   REPRESENTATIONS, WARRANTIES, COVENANTS AND AGREEMENTS TO SURVIVE
DELIVERY.  All representations, warranties, covenants and agreements of the
Company and the Underwriters herein or in certificates delivered pursuant
hereto, and the indemnity and contribution agreements contained in Section 8
hereof shall remain operative and in full force and effect regardless of any
investigation made by or on behalf of any Underwriter or any person controlling
any Underwriter within the meaning of the Act or the Exchange Act, or by or on
behalf of the Company or any of its officers, directors or controlling persons
within the meaning of the Act or the Exchange Act, and shall survive the
delivery of the Shares to the several Underwriters hereunder or termination of
this Agreement.

     10.  SUBSTITUTION OF UNDERWRITERS.  If any Underwriter or Underwriters
shall fail to take up and pay for the number of Firm Shares agreed by such
Underwriter or Underwriters to be purchased hereunder upon tender of such Firm
Shares in accordance with the terms hereof, and if the aggregate number of Firm
Shares which such defaulting Underwriter or Underwriters so agreed but failed to
purchase does not exceed 10% of the Firm Shares, the remaining Underwriters
shall be obligated, severally in proportion to their respective commitments
hereunder, to take up and pay for the Firm Shares of such defaulting Underwriter
or Underwriters.

          If any Underwriter or Underwriters so defaults and the aggregate
number of Firm Shares which such defaulting Underwriter or Underwriters agreed
but failed to take up and pay for exceeds 10% of the Firm Shares, the remaining
Underwriters shall have the right, but shall not be obligated, to take up and
pay for (in such proportions as may be agreed upon among them) the Firm Shares
which the defaulting Underwriter or Underwriters so agreed but failed to
purchase.  If such remaining Underwriters do not, at the Closing Date, take up
and pay for the Firm Shares which the defaulting Underwriter or Underwriters so
agreed but failed to purchase, the Closing Date shall be postponed for twenty-
four (24) hours to allow the several Underwriters the privilege of substituting
within twenty-four (24) hours


                                      -26-
<PAGE>

(including non-business hours) another underwriter or underwriters (which may
include any nondefaulting Underwriter) satisfactory to the Company.  If no such
underwriter or underwriters shall have been substituted as aforesaid by such
postponed Closing Date, the Closing Date may, at the option of the Company, be
postponed for a further twenty-four (24) hours, if necessary, to allow the
Company the privilege of finding another underwriter or underwriters,
satisfactory to you, to purchase the Firm Shares which the defaulting
Underwriter or Underwriters so agreed but failed to purchase.  If it shall be
arranged for the remaining Underwriters or substituted underwriter or
underwriters to take up the Firm Shares of the defaulting Underwriter or
Underwriters as provided in this Section 10, (i) the Company shall have the
right to postpone the time of delivery for a period of not more than seven (7)
full business days, in order to effect whatever changes may thereby be made
necessary in the Registration Statement or the Prospectus, or in any other
documents or arrangements, and the Company agrees promptly to file any
amendments to the Registration Statement, supplements to the Prospectus or other
such documents which may thereby be made necessary, and (ii) the respective
number of Firm Shares to be purchased by the remaining Underwriters and
substituted underwriter or underwriters shall be taken as the basis of their
underwriting obligation.  If the remaining Underwriters shall not take up and
pay for all such Firm Shares so agreed to be purchased by the defaulting
Underwriter or Underwriters or substitute another underwriter or underwriters as
aforesaid and the Company shall not find or shall not elect to seek another
underwriter or underwriters for such Firm Shares as aforesaid, then this
Agreement shall terminate.

          In the event of any termination of this Agreement pursuant to the
preceding paragraph of this Section 10, neither the Company shall be liable to
any Underwriter (except as provided in Sections 5 and 8 hereof) nor shall any
Underwriter (other than an Underwriter who shall have failed, otherwise than for
some reason permitted under this Agreement, to purchase the number of Firm
Shares agreed by such Underwriter to be purchased hereunder, which Underwriter
shall remain liable to the Company and the other Underwriters for damages, if
any, resulting from such default) be liable to the Company (except to the extent
provided in Sections 5 and 8 hereof).

          The term "Underwriter" in this Agreement shall include any person
substituted for an Underwriter under this Section 10.

     11.  EFFECTIVE DATE OF THIS AGREEMENT AND TERMINATION.

          (a)  This Agreement shall become effective at the earlier of (i) 6:30
A.M., San Francisco time, on the first full business day following the effective
date of the Registration Statement, or (ii) the time of the initial public
offering of any of the Shares by the Underwriters after the Registration
Statement becomes effective.  The time of the initial public offering shall mean
the time of the release by you, for publication, of the first newspaper
advertisement relating to the Shares, or the time at which the Shares are first
generally offered by the Underwriters to the public by letter, telephone,
telegram or telecopy, whichever shall first occur.  By giving notice as set
forth in Section 12 before the time this Agreement becomes effective, you, as
Representatives of the several Underwriters, or the Company, may prevent this
Agreement from becoming effective without liability of any party to any other
party, except as provided in Sections 4(j), 5 and 8 hereof.

          (b)  You, as Representatives of the several Underwriters, shall have
the right to terminate this Agreement by giving notice as hereinafter specified
at any time on or prior to the Closing Date or on or prior to any later date on
which Option Shares are to be purchased, as the case may be, (i) if the Company
shall have failed, refused or been unable to perform any agreement on its part
to be performed, 


                                      -27-
<PAGE>

or because any other condition of the Underwriters' obligations hereunder
required to be fulfilled is not fulfilled, including, without limitation, any
change in the condition (financial or otherwise), earnings, operations or
business as described in the Prospectus of the Company from that set forth in
the Registration Statement or Prospectus, which, in your sole judgment, is
material and adverse, or (ii) if additional material governmental restrictions,
not in force and effect on the date hereof, shall have been imposed upon trading
in securities generally or minimum or maximum prices shall have been generally
established on the New York Stock Exchange or on the American Stock Exchange or
in the over the counter market by the NASD, or trading in securities generally
shall have been suspended on either such exchange or in the over the counter
market by the NASD, or if a banking moratorium shall have been declared by
federal, New York or California authorities, or (iii) if the Company shall have
sustained a loss by strike, fire, flood, earthquake, accident or other calamity
of such character as to interfere materially with the conduct of the business
and operations of the Company regardless of whether or not such loss shall have
been insured, or (iv) if there shall have been a material adverse change in the
general political or economic conditions or financial markets as in your
reasonable judgment makes it inadvisable or impracticable to proceed with the
offering, sale and delivery of the Shares, or (v) if there shall have been an
outbreak or escalation of hostilities or of any other insurrection or armed
conflict or the declaration by the United States of a national emergency which,
in the reasonable opinion of the Representatives, makes it impracticable or
inadvisable to proceed with the public offering of the Shares as contemplated by
the Prospectus.  In the event of termination pursuant to subparagraph (i) above,
the Company shall remain obligated to pay costs and expenses pursuant to
Sections 4(j), 5 and 8 hereof.  Any termination pursuant to any of subparagraphs
(ii) through (v) above shall be without liability of any party to any other
party except as provided in Sections 5 and 8 hereof.

          If you elect to prevent this Agreement from becoming effective or to
terminate this Agreement as provided in this Section 11, you shall promptly
notify the Company by telephone, telecopy or telegram, in each case confirmed by
letter.  If the Company shall elect to prevent this Agreement from becoming
effective, the Company shall promptly notify you by telephone, telecopy or
telegram, in each case, confirmed by letter.

     12.  NOTICES.  All notices or communications hereunder, except as herein
otherwise specifically provided, shall be in writing and if sent to you shall be
mailed, delivered, telegraphed (and confirmed by letter) or telecopied (and
confirmed by letter) to you c/o Robertson, Stephens & Company LLC,
555 California Street, Suite 2600, San Francisco, California 94104, telecopier
number (415) 781-0278, Attention:  General Counsel with a copy to Wilson Sonsini
Goodrich & Rosati, 650 Page Mill Road, Palo Alto, California 94304-1050,
telecopier number (415) 493-6811, Attention:  Alan K. Austin; if sent to the
Company, such notice shall be mailed, delivered, telegraphed (and confirmed by
letter) or telecopied (and confirmed by letter) to Affymetrix, Inc., 3380
Central Expressway, Santa Clara, California 95051, telecopier number (408) 481-
0920, Attention: John D. Diekman, Ph.D., Chief Executive Officer with a copy to
Heller Ehrman White & McAuliffe, 525 University Avenue, Palo Alto, California
94301-1908 , telecopier number (415) 324-0638, Attention:  Julian N. Stern.

     13.  PARTIES.  This Agreement shall inure to the benefit of and be binding
upon the several Underwriters and the Company and its executors, administrators,
successors and assigns.  Nothing expressed or mentioned in this Agreement is
intended or shall be construed to give any person or entity, other than the
parties hereto and their respective executors, administrators, successors and
assigns, and the controlling persons within the meaning of the Act or the
Exchange Act, officers and directors referred to in Section 8 hereof, any legal
or equitable right, remedy or claim in respect of this Agreement or any
provisions herein contained, this Agreement and all conditions and provisions
hereof being 


                                      -28-
<PAGE>

intended to be and being for the sole and exclusive benefit of the parties
hereto and their respective executors, administrators, successors and assigns
and said controlling persons and said officers and directors, and for the
benefit of no other person or entity.  No purchaser of any of the Shares from
any Underwriter shall be construed a successor or assign by reason merely of
such purchase.

          In all dealings with the Company under this Agreement, you shall act
on behalf of each of the several Underwriters, and the Company shall be entitled
to act and rely upon any statement, request, notice or agreement made or given
by you jointly or by Robertson, Stephens & Company LLC, on behalf of you.

     14.  APPLICABLE LAW.  This Agreement shall be governed by, and construed in
accordance with, the laws of the State of California.

     15.  COUNTERPARTS.  This Agreement may be signed in several counterparts,
each of which will constitute an original.


                                      -29-
<PAGE>

          If the foregoing correctly sets forth the understanding among the
Company and the several Underwriters, please so indicate in the space provided
below for that purpose, whereupon this letter shall constitute a binding
agreement among the Company and the several Underwriters.

                              Very truly yours,

                              AFFYMETRIX, INC.


                              By:                            
                                  ---------------------------
                              Name:                          
                                    -------------------------
                              Title:                         
                                     ------------------------



Accepted as of the date first above written:

ROBERTSON, STEPHENS & COMPANY LLC
CS FIRST BOSTON CORPORATION
MONTGOMERY SECURITIES
On their behalf and on behalf of each of the
several Underwriters named in Schedule A hereto.


By  ROBERTSON, STEPHENS & COMPANY LLC

By  ROBERTSON, STEPHENS & COMPANY GROUP, L.L.C.


By
   ---------------------------------------
          Authorized Signatory




                                      -30-
<PAGE>

                                   SCHEDULE A




                                                                Number of Firm 
                                                                 shares To Be 
Underwriters                                                         Purchased
------------                                                    ---------------

ROBERTSON, STEPHENS & COMPANY LLC. . . . . . . . . . . . . . . . .             
CS FIRST BOSTON CORPORATION. . . . . . . . . . . . . . . . . . . .             
MONTGOMERY SECURITIES. . . . . . . . . . . . . . . . . . . . . . .             




                                                                      ---------
     Total . . . . . . . . . . . . . . . . . . . . . . . . . . . .    5,000,000
                                                                      ---------
                                                                      ---------



<PAGE>

                     AMERICAN INDUSTRIAL REAL ESTATE ASSOCIATION

              STANDARD INDUSTRIAL/COMMERCIAL SINGLE-TENANT LEASE -- NET


1.  Basic Provisions ("Basic Provisions")

    1.1    Parties:  This Lease ("Lease"), dated for reference purposes only,
December 5, 1994, is made by and between Harry Locklin ("Lessor") and
Affymetrix, a California Corporation ("Lessee"), (collectively the "Parties," or
individually a "Party").

    1.2    Premises:  That certain real property, including all improvements
therein or to be provided by Lessor under the terms of this Lease, and commonly
known by the street address of 1145 Sonora Court, Sunnyvale, located in the
County of Santa Clara, State of California and generally described as (describe
briefly the nature of the property) approximately 19,900 square feet of an
office/R&D building together with parking areas and landscaping (if any)
appurtenant thereto.

    1.3    Term:  Five (5) years and 0 months ("Original Term") commencing
three (3) months after the date of delivery ("Commencement Date") and ending
April 30, 2000 ("Expiration Date"). (See Paragraph 3 for further provisions).

    1.4    Early Possession:  February 1, 1995, ("Early Possession Date")
however if National Semiconductor vacates building at an earlier date, access
shall be granted.  (See Paragraphs 3.2 and 3.3 for further provisions.)

    1.5    Base Rent:  $14,992.50 per month ("Base Rent"), payable on the first
day of each month commencing three (3) months after access is granted.  (See
Paragraph 4 for further provisions.)

/X/ If this box is checked, there are provisions in this Lease for the Base Rent
to be adjusted.

    1.6    Base Rent Paid Upon Execution: $14,992.50 as Base Rent for the first
full calendar month of the term.

    1.7    Security Deposit: $15,000.00 ("Security Deposit").  (See Paragraph 5
for further provisions.)

    1.8    Permitted Use:  Administrative offices, laboratory, research and
development facility, manufacturing and clean room areas.  (See Paragraph 6 for
further provisions.)

    1.9    Insuring Party:  Lessor is the "Insuring Party" unless otherwise
stated herein.  (See Paragraph 8 for further provisions.)

    1.10   Real Estate Brokers:  The following real estate brokers
(collectively, the "Brokers") and brokerage relationships exist in this
transaction and are consented to by the Parties (check applicable boxes):
Cornish & Carey Commercial Oncor International represents Lessor exclusively
("Lessor's Broker"), and Cornish & Carey Commercial Oncor International and
Catalyst Real Estate Group represents Lessee exclusively ("Lessee's Broker").

    1.11   Guarantor.  The obligations of the Lessee under this Lease are to be
guaranteed by ___________________ ("Guarantor").  (See Paragraph 37 for further
provisions.)

    1.12   Addenda.  Attached hereto is an Addendum or Addenda consisting of
Paragraphs 1 through 13 and Exhibits A and B, all of which constitute a part of
this Lease.

<PAGE>

2.  Premises.

    2.1    Letting.  Lessor hereby leases to Lessee, and Lessee hereby leases
from Lessor, the Premises, for the term, at the rental, and upon all of the
terms, covenants and conditions set forth in this Lease.  Unless otherwise
provided herein, any statement of square footage set forth in this Lease, or
that may have been used in calculating rental, is an approximation which Lessor
and Lessee agree is reasonable and the rental based thereon is not subject to
revision whether or not the actual square footage is more or less.

    2.2    Deleted.

    2.3    Deleted.

    2.4    Acceptance of Premises.  Lessee hereby acknowledges:  (a) that it
has been advised by the Brokers to satisfy itself with respect to the condition
of the Premises (including but not limited to the electrical and fire sprinkler
systems, security, environmental aspects, compliance with Applicable Law, as
defined in Paragraph 6.3) and the present and future suitability of the Premises
for Lessee's intended use and (c) that neither Lessor, nor any of Lessor's
agents, has made any oral or written representations or warranties with respect
to the said matters other than as set forth in this Lease.

    2.5    Lessee Prior Owner/Occupant.  The warranties made by Lessor in this
Paragraph 2 shall be of no force or effect if immediately prior to the date set
forth in Paragraph 1.1 Lessee was the owner or occupant of the Premises.  In
such event, Lessee shall, at Lessee's sole cost and expense, correct any
non-compliance of the Premises with said warranties.

3.  Term.

    3.1    Term.  The Commencement Date, Expiration Date and Original Term of
this Lease are as specified in Paragraph 13.

    3.2    Early Possession.  If Lessee totally or partially occupies the
Premises prior to the Commencement Date, the obligation to pay Base Rent shall
be abated for the period of such early possession.  All other terms of this
Lease, however, (including but not limited to the obligations to pay Real
Property Taxes and insurance premiums and to maintain the Premises) shall be in
effect during such period.  Any such early possession shall not affect nor
advance the Expiration Date of the Original Term.

    3.3    Delay in Possession.  If for any reason Lessor cannot deliver
possession of the Premises to Lessee as agreed herein by the Early Possession
Date if one is specified in Paragraph 1.4, or, if no Early Possession Date is
specified. by the Commencement Date, Lessor shall not be subject to any
liability therefor, nor shall such failure affect the validity of this Lease, or
the obligations of Lessee hereunder, or extend the term hereof, but in such
case, Lessee shall not, except as otherwise provided herein, be obligated to pay
rent or perform any other obligation of Lessee under the terms of the Lease
until Lessor delivers possession of the Premises to Lessee, if possession of the
Premises is not delivered to Lessee within sixty (60) days after the
Commencement Date, Lessee may, at its option, by notice in writing to Lessor
within ten (10) days thereafter, cancel this Lease, in which event the Parties
shall be discharged from all obligations hereunder; provided, however, that if
such written notice by Lessee is not received by Lessor within said ten (10) day
period, Lessee's right to cancel this Lease shall terminate and be of no further
force or effect.  Except as may be otherwise provided, and regardless of when
the term actually commences, if possession is not tendered to Lessee when
required by this Lease and Lessee does not terminate this Lease as aforesaid,
the period free of the obligation to pay Base Rent, if any, that Lessee would
otherwise have enjoyed shall run from the date of delivery


                                         -2-


<PAGE>

of possession and continue for a period equal to what Lessee would otherwise
have enjoyed under the terms hereof, but minus any days of delay caused by the
acts, changes or omissions of Lessee.

4.  Rent.

    4.1    Base Rent.  Lessee shall cause payment of Base Rent and other rent
or charges, as the same may be adjusted from time to time, to be received by
Lessor in lawful money of the United States, without offset or deduction, on or
before the day on which it is due under the terms of this Lease.  Base Rent and
all other rent and charges for any period during the term hereof which is for
less than one (1) full calendar month shall be prorated based upon the actual
number of days of the calendar month involved.  Payment of Base Rent and other
charges shall be made to Lessor at its address stated herein or to such other
persons or at such other addresses as Lessor may from time to time designate in
writing to Lessee.

5.  Security Deposit.  Lessee shall deposit with Lessor upon execution hereof
the Security Deposit set forth in Paragraph 1.7 as security for Lessee's
faithful performance of Lessee's obligations under this Lease.  If Lessee fails
to pay Base Rent or other rent or charges due hereunder, or otherwise Defaults
under this Lease (as defined in Paragraph 13.1), Lessor may use, apply or retain
all or any portion of said Security Deposit for the payment of any amount due
Lessor or to reimburse or compensate Lessor for any liability, cost, expense,
loss or damage (including attorneys' fees) which Lessor may suffer or incur by
reason thereof.  If Lessor uses or applies all or any portion of said Security
Deposit, Lessee shall within ten (10) days after written request therefor
deposit moneys with Lessor sufficient to restor said Security Deposit to the
full amount required by this Lease.  Any time the Base Rent increases during the
term of this Lease, Lessee shall, upon written request from Lessor, deposit
additional moneys with Lessor sufficient to maintain the same ratio between the
Security Deposit and the Base Rent as those amounts are specified in the Basic
Provisions.  Lessor shall not be required to keep all or any part of the
Security Deposit separate from its general accounts.  Lessor shall, at the
expiration or earlier termination of the term hereof and after Lessee has
vacated the Premises, return to Lessee (or, at Lessor's option, to the last
assignee, if any, of Lessee's interest herein), that portion of the Security
Deposit not used or applied by Lessor.  Unless otherwise expressly agreed in
writing by Lessor, no part of the Security Deposit shall be considered to be
held in trust, to bear interest or other increment for its use, or to be
prepayment for any moneys to be paid by Lessee under this Lease.

6.  Use.

    6.1    Use.  Lessee shall use and occupy the Premises only for the purposes
set forth in Paragraph 1.8, or any other use which is comparable thereto, and
for no other purpose.  Lessee shall not use or permit the use of the Premises in
a manner that creates waste or a nuisance, or that disturbs owners and/or
occupants of, or causes damage to, neighboring premises or properties.  Lessor
hereby agrees to no unreasonably withhold or delay its consent to any written
request by Lessee, Lessees assignees or subtenants, and by prospective assignees
and subtenants of the Lessee, its assignees and subtenants, for a modification
of said permitted purpose for which the premises may be used or occupied, so
long as the same will not impair the structural integrity of the improvements on
the Premises, the mechanical or electrical systems therein, is not significantly
more burdensome to the Premises and the improvements thereon, and is otherwise
permissible pursuant to this Paragraph 6.  If Lessor elects to withhold such
consent, Lessor shall within five (5) business days give a written notification
of same, which notice shall include an explanation of Lessor's reasonable
objections to the change in use.


                                         -3-


<PAGE>

    6.2    Hazardous Substances.

           (a)    Reportable Uses Require Consent.  Hazardous Substance shall
include, but not be limited to, hydrocarbons, petroleum, gasoline, crude oil or
any products, by-products or factions thereof.  Lessee shall not engage in any
activity in, on or about the Premises which constitutes a Reportable Use (as
hereinafter defined) of Hazardous Substances without the express prior written
consent of Lessor and compliance in a timely manner (at Lessee's sole cost and
expense) with all Applicable Law (as defined in Paragraph 6.3).  "Reportable
Use" shall mean (i) the installation or use of any above or below ground storage
tank, (ii) the generation, possession, storage, use, transportation, or disposal
of a Hazardous Substance that requires a permit from, or with respect to which a
report, notice, registration or business plan is required to be filed with, any
governmental authority.  Reportable Use shall also include Lessee's being
responsible for the presence in, on or about the Premises of a Hazardous
Substance with respect to which any Applicable Law requires that a notice be
given to persons entering or occupying the Premises or neighboring properties.
Notwithstanding the foregoing, Lessee may, without Lessor's prior consent, but
in compliance with all Applicable Law, use any ordinary and customary materials
reasonably required to be used by Lessee in the normal course of Lessee's
business permitted on the Premises, so long as such use is not a Reportable Use
and does not expose the Premises or neighboring properties to any meaningful
risk of contamination or damage or expose Lessor to any liability therefor.  In
addition, Lessor may (but without any obligation to do so) condition its consent
to the use or presence of any Hazardous Substance, activity or storage tank by
Lessee upon Lessee's giving Lessor such additional assurances as Lessor, in its
reasonable discretion, deems necessary to protect itself, the public, the
Premises and the environment against damage, contamination or injury and/or
liability therefrom or therefor, including, but not limited to, the installation
(and removal on or before Lease expiration or earlier termination) of reasonably
necessary protective modifications to the Premises (such as concrete
encasements) and/or the deposit of an additional Security Deposit under
paragraph 5 hereof.

           (b)    Duty to Inform Lessor.  If Lessee knows, or has reasonable
cause to believe, that a Hazardous Substance, or a condition involving or
resulting from same, has come to be located in, on, under or about the Premises,
other than as previously consented to be Lessor, Lessee shall immediately give
written notice of such fact to Lessor.  Lessee shall also immediately give
Lessor a copy of any statement, report, notice, registration, application,
permit, business plan, license, claim, action or proceeding given to, or
received from, any governmental authority or private party, or persons entering
or occupying the Premises, concerning the Presence, spill, release, discharge
of, or exposure to, any Hazardous Substance or contamination in, on, or about
the Premises, including but not limited to all such documents as may be involved
in any Reportable Uses involving the Premises.

           (c)    Indemnification.  Lessee shall indemnify, protect, defend and
hold Lessor, its agents, employees, lenders and ground Lessor, if any, and the
Premises, harmless from and against any and all loss of rents and/or damages,
liabilities, judgments, costs, claims, liens, expenses, penalties, permits and
attorney's and consultant's fees arising out of or involving any Hazardous
Substance or storage tank brought onto the Premises by or for Lessee or under
Lessee's control.  Lessee's obligations under this Paragraph 6 shall include,
but not be limited to, the effects of any contamination or injury to person,
property or the environment created or suffered by Lessee, and the cost of
investigation (including consultant's and attorney's fees and testing), removal,
remediation, restoration and/or abatement thereof, or of any contamination
therein involved, and shall survive the expiration or earlier termination of
this Lease.  No termination, cancellation or release agreement entered into by


                                         -4-


<PAGE>
Lessor and Lessee shall release Lessee from its obligations under this Lease
with respect to Hazardous Substances or storage tanks, unless specifically so
agreed by Lessor in writing at the time of such agreement.

    6.3    Lessee's Compliance with Law.  Except as otherwise provided in this
Lease, Lessee, shall, at Lessee's sole cost and expense, fully, diligently and
in a timely manner, comply with all "Applicable Law," which term is used in this
Lease to include all laws, rules, regulations, ordinances, directives,
covenants, easements and restrictions of record, permits, the requirements of
any applicable fire insurance underwriter or rating bureau, and the
recommendations of Lessor's engineers and/or consultants, relating in any manner
to the Premises (including but not limited to matters pertaining to
(i) industrial hygiene, (ii) environmental conditions on, in, under or about the
Premises, including soil and groundwater conditions, and (iii) the use,
generation, manufacture, production, installation, maintenance, removal,
transportation, storage, soil or release of any Hazardous Substance or storage
tank), now in effect or which may hereafter come into effect, and whether or not
reflecting a change in policy from any previously existing policy, Lessee shall,
within five (5) days after the receipt of Lessor's written request, provide
Lessor with copies of all documents and information, including, but not limited
to, permits, registrations, manifests, applications, reports and certificates,
evidencing Lessee's compliance with any Applicable Law specified by Lessor, and
shall immediately, upon receipt notify Lessor in writing (with copies of any
documents involved) of any threatened or actual claim notice citation, warning,
complaint or report pertaining to or involving failure by Lessee or the Premises
to comply with any Applicable Law.

    6.4    Inspection; Compliance.  Lessor and Lessor's Lender(s) (as defined
in Paragraph 8.3(a)) shall have the right to enter the Premises at any time, in
the case of an emergency, and otherwise at reasonable times, for the purpose of
inspecting the condition of the Premises and for verifying compliance by Lessee
with this Lease and all Applicable Laws (as defined in Paragraph 6.3), and to
employ experts and/or consultants in connection therewith and/or to advise
Lessor with respect to Lessee's activities, including but not limited to the
installation, operation, use, monitoring, maintenance, or removal of any
Hazardous Substance or storage tank on or from the Premises.  The costs and
expenses of any such inspections shall be paid by the party requesting same
unless a Default or breach of this Lease, violation of Applicable Law, or a
contamination, caused or materially contributed to by Lessee is found to exist
or be imminent, or unless the inspection is requested or ordered by a
governmental authority as the result of any such existing or imminent violation
or contamination.  In any such case, Lessee shall upon request reimburse Lessor
or Lessor's Lender, as the case may be, for the costs and expenses of such
inspections.

7.  Maintenance; Repairs, Utility Installations; Trade Fixtures and
    Alternations.

    7.1    Lessee's Obligations.

           (a)    Subject to the provisions of Paragraphs 2.2 (Lessor's
warranty as to condition), 2.3 (Lessor's warranty as to compliance with
covenants, etc.), 7.2 (Lessors obligations to repair), 9 (damage and
destruction), and 14 (condemnation).  Lessee shall at Lessee's sole cost and
expense and at all times keep the Premises and every part thereof in good order
condition and repair structural and non-structural (whether or not such portion
of the Premises requiring repairs or the means of repairing the same, are
reasonably or readily accessible to Lessee, and whether or not the need for such
repairs occurs as a result of Lessee's use any prior use, the elements or the
age of such portion of the Premises), including without limiting the generality
of the foregoing all equipment or facilities serving the Premises, such as
plumbing, heating, air conditioning,


                                         -5-

<PAGE>

ventilating, electrical, lighting facilities, boiler, fired or unfired pressure
vessels, fire sprinkler and/or standpipe and hose or other automatic fire
extinguishing system, including fire alarm and/or smoke detection systems and
equipment, fire hydrants, fixtures, walls (interior and exterior), foundations,
ceilings, roofs, floors, windows, doors, plate glass, skylights, landscaping,
driveways, parking lots, fences, retaining walls, signs, sidewalks and parkways
located in, on, about, or adjacent to the Premises Lessee shall not cause or
permit any Hazardous Substance to be spilled or released in, on, under or about
the Premises (including through the plumbing or sanitary sewer system) and shall
promptly, at Lessee's expense, take all investigatory and/or remedial action
reasonably recommended, whether or not formally ordered or required, for the
cleanup of any contamination of, and for the maintenance, security and/or
monitoring of the Premises, the elements surrounding same, or neighboring
properties, that was caused or materially contributed to by Lessee, or
pertaining to or involving any Hazardous Substance and/or storage tank brought
onto the Premises by or for Lessee or under its control.  Lessee, in keeping the
Premises in good order, condition and repair, shall exercise and perform good
maintenance practices Lessee's obligations shall include restorations,
replacements or renewals when necessary to keep the Premises and all
improvements thereon or a part thereof in good order, condition and state of
repair.

           (b)    Lessee shall, at Lessee's sole cost and expense, procure and
maintain contracts, with copies to Lessor, in customary form and substance for,
and with contractors specializing and experienced in, the inspection,
maintenance and service of the following equipment and improvements, if any,
located on the Premises:  (i) heating, air conditioning and ventilation
equipment, (ii) boiler, fired or unfired pressure vessels, (iii) fire sprinkler
and/or standpipe and hose or other automatic fire extinguishing systems,
including fire alarm and/or smoke detection, (iv) landscaping and irrigation
systems, (v) roof covering and drain maintenance and (vi) asphalt and parking
lot maintenance.

    7.2    Lessor's Obligations.  Except for the warranties and agreements of
Lessor contained in Paragraphs 2.2 (relating to condition of the Premises), 2.3
(relating to compliance with covenants, restrictions and building code), 9
(relating to destruction of the Premises) and 14 (relating to condemnation of
the Premises), it is intended by the Parties hereto that Lessor have no
obligation, in any manner whatsoever, to repair and maintain the Premises, the
improvements located thereon, or the equipment therein, whether structural or
nonstructural, all of which obligations are intended to be that of the Lessee
under Paragraph 7.1 hereof.  It is the intention of the Parties that the terms
of this Lease govern the respective obligations of the Parties as to maintenance
and repair of the Premises.  Lessee and Lessor expressly waive the benefit of
any statute now or hereafter in effect to the extent it is inconsistent with the
terms of this Lease with respect to, or which affords Lessee the right to make
repairs at the expense of Lessor or to terminate this Lease by reason of any
needed repairs.

    7.3    Utility Installations; Trade Fixtures; Alterations.

           (a)    Definitions; Consent Required.  The term "Utility
Installations" is used in this Lease to refer to all carpeting, window
coverings, air lines, power panels, electrical distribution, security, fire
protection systems, communication systems, lighting fixtures, heating,
ventilating, and air conditioning equipment, plumbing, and fencing in, on or
about the Premises.  The term "Trade Fixture" shall mean Lessee's machinery and
equipment that can be removed without doing material damage to the Premises.
The term "Alterations" shall mean any modification of the improvements on the
Premises from that which are provided by Lessor under the terms of this Lease,
other than Utility Installations or Trade Fixtures, whether by addition or
deletion.  "Lessee Owned Alterations and/or Utility



                                         -6-

<PAGE>

Installations" are defined as Alterations and/or Utility Installations made by
Lessee that are not yet owned by Lessor as defined in Paragraph 7.4(a).  Lessee
shall not make any Alterations or Utility Installations in, on, under or about
the Premises without Lessor's prior written consent.

           (b)    Consent.  Any Alterations or Utility Installations that
Lessee shall desire to make and which require the consent of the Lessor shall be
presented to Lessor in written form with proposed detailed plans.  All consents
given by Lessor, whether by virtue of Paragraph 7.3(a) or by subsequent specific
consent, shall be deemed conditioned upon A: (i) Lessee's acquiring all
applicable permits required by governmental authorities, (ii) the furnishing of
copies of such permits together with a copy of the plans and specifications for
the Alteration or Utility Installation to Lessor prior to commencement of the
work thereon, and (iii) the compliance by Lessee with all conditions of said
permits in a prompt and expeditious manner.  Any Alterations or Utility
Installations by Lessee during the term of this Lease shall be done in a good
and workmanlike manner, with good and sufficient materials, and in compliance
with all Applicable Law.  Lessee shall promptly upon completion thereof furnish
Lessor with as-built plans and specifications therefor.

           (c)    Indemnification.  Lessee shall pay, when due, all claims for
labor or materials furnished or alleged to have been furnished to or for Lessee
at or for use on the Premises, which claims are or may be secured by any
mechanics' or materialmen's lien against the Premises or any interest therein.
Lessee shall give Lessor not less than ten (10) days' notice prior to the
commencement of any work in, on or about the Premises, and Lessor shall have the
right to post notices of non-responsibility in or on the Premises as provided by
law.  If Lessee shall, in good faith, contest the validity of any such lien,
claim or demand, then Lessee shall at its sole expense defend and protect
itself, Lessor and the Premises against the same and shall pay and satisfy any
such adverse judgment that may be rendered thereon before the enforcement
thereof against the Lessor or the Premises.  If Lessor shall require, Lessee
shall furnish to Lessor a surety bond satisfactory to Lessor in an amount equal
to one and one-half times the amount of such contested lien claim or demand,
indemnifying Lessor against liability for he same, as required by law for the
holding of the Premises free from the effect of such lien or claim.  In
addition, Lessor may require Lessee to pay Lessor's attorney's fees and costs in
participating in such action if Lessor shall decide it is to its best interest
to do so.

    7.4    Ownership; Removal; and Restoration.

           (a)    Ownership.  Subject to Lessor's right to require their
removal or become the owner thereof as hereinafter provided in this Paragraph
7.4, all Alterations and Utility Additions made to the Premises by Lessee shall
be the property of and owned by Lessee, but considered a part of the Premises.
Lessor may, at any time and at its option, elect in writing to Lessee to be the
owner of all or any specified part of the Lessee Owned Alterations and Utility
Installations.  Unless otherwise instructed per subparagraph 7.4(b) hereof, all
Lessee Owned Alterations and Utility Installations shall, at the expiration or
earlier termination of this Lease, become the property of Lessor and remain upon
and be surrendered by Lessee with the Premises.

           (b)    Removal.  Unless otherwise agreed in writing, Lessor may
require that any or all Lessee Owned Alterations or Utility Installations be
removed by the expiration or earlier termination of the Lease, notwithstanding
their installation may have been consented to by Lessor.  Lessor may require the
removal at any time of all or any part of any Lessee Owned Alterations or
Utility Installations made without the required consent of Lessor.


                                         -7-

<PAGE>

           (c)    Surrender/Restoration.  Lessee shall surrender the Premises
by the end of the last day of the Lease term or any earlier termination date,
with all of the improvements, parts and surfaces thereof clean and free of
debris and in good operating order, condition and state of repair, ordinary wear
and tear excepted.  "Ordinary wear and tear" shall not include any damage or
deterioration that would have been prevented by good maintenance practice or by
Lessee performing all of its obligations under this Lease.  Except as otherwise
agreed or specified in writing by Lessor, the Premises, as surrendered, shall
include the Utility Installations.  The obligation of Lessee shall include the
repair of any damage occasioned by the installation, maintenance or removal of
Lessee's Trade Fixtures, furnishings, equipment, and Alterations and/or Utility
Installations, as well as the removal of any storage tank installed by or for
Lessee, and the removal, replacement, or remediation of any soil, material or
ground water contaminated by Lessee, all as may then be required by Applicable
Law and/or good service practice.  Lessee's Trade Fixtures shall remain the
property of Lessee and shall be removed by Lessee subject to its obligation to
repair and restore the Premises per this Lease.

8.  Insurance; Indemnity.

    8.1    Payment For Insurance.  Regardless of whether the Lessor or Lessee
is the Insuring Party, Lessee shall pay for all insurance required under this
Paragraph 8.  Premiums for policy periods commencing prior to or extending
beyond the Lease term shall be prorated to correspond to the Lease term.
Payment shall be made by Lessee to Lessor within ten (10) days following receipt
of an invoice for any amount due.

    8.2    Liability Insurance.

           (a)    Carried by Lessee.  Lessee shall obtain and keep in force
during the term of this Lease a Commercial General Liability policy of insurance
protecting Lessee and Lessor (as an additional insured) against claims for
bodily injury, personal injury and property damage based upon, involving or
arising out of the ownership, use, occupancy or maintenance of the Premises and
all areas appurtenant thereto.  Such insurance shall be on an occurrence basis
providing single limit coverage in an amount not less than $1,000,000 per
occurrence with an "Additional Insured-Managers or Lessors of Premises"
Endorsement and contain the "Amendment of the Pollution Exclusion" for damage
caused by heat, smoke, or fumes from  a hostile fire.  The policy shall not
contain any intra-insured exclusions as between insured persons or
organizations, but shall include coverage for liability assumed under this Lease
as an "insured contract" for the performance of Lessee's indemnity obligations
under this Lease.  The limits of said insurance required by this Lease or as
carried by Lessee shall not, however, limit the liability of Lessee nor relieve
Lessee of any obligation hereunder.  All insurance to be carried by Lessee shall
be primary to and not contributory with any similar insurance carried by Lessor,
whose insurance shall be considered excess insurance only.

           (b)    Carried By Lessor.  In the event Lessor is in the Insuring
Party, Lessor shall also maintain liability insurance described in Paragraph
8.2(a), above.  In addition to, and not in lieu of, the insurance required to be
maintained by Lessee.  Lessee shall not be named as an additional insured
therein

    8.3    Property Insurance - Building, Improvements and Rental Value.

           (a)    Building and Improvements.  The Insuring Party shall obtain
and keep in force during the term of this Lease a policy or policies in the name
of Lessor, with loss payable to Lessor and to the holders of any mortgages,
deeds of trust or ground leases on the Premises ("Leader(s)"), insuring loss or
damage to the Premises.  The amount of such insurance shall be equal to the full
replacement cost of the Premises, as the same


                                         -8-

<PAGE>

shall exist from time to time, or the amount required by the Lenders, but in no
event more than the commercially reasonable and available insurable value
thereof if by reason of the unique nature or age of the improvements involved,
such latter amount is less than full replacement cost.  If Lessor is the
Insuring Party, however, Lessee Owned Alterations and Utility Installations
shall be insured by Lessee under Paragraph 8.4 rather than by Lessor if the
coverage is available and commercially appropriate such policy or policies shall
insure against all risks of direct physical loss or damage (except the perils of
flood unless required by a Lender), including coverage for any additional costs
resulting from debris removal and reasonable amounts of coverage for the
enforcement of any ordinance or law regulating the reconstruction or replacement
of any undamaged sections of the Premises required to be demolished or removed
by reason of the enforcement of any building, zoning, safety or land use laws as
the result of a covered cause of loss.  Said policy or policies shall also
contain an agreed valuation provision in lieu of any coinsurance clause, waiver
of subrogation, and inflation guard protection causing an increase in the annual
property insurance coverage amount by a factor of not less than the adjusted
U.S. Department of Labor Consumer Price Index for All Urban Consumers for the
city nearest to where the Premises are located.  If such insurance coverage has
a deductible clause, the deductible amount shall not exceed $1,000 per
occurrence, and Lessee shall be liable for such deductible amount in the event
of an Insured Loss, as defined in Paragraph 9.1(c).

           (b)    Rental Value.  The Insuring Party shall, in addition, obtain
and keep in force during the term of this Lease a policy or policies in the name
of Lessor with loss payable to Lessor and Lender(s), insuring the loss of the
full rental and other charges payable by Lessee to Lessor under this Lease for
one (1) year (including all real estate taxes, insurance costs, and any
scheduled rental increases).  Said insurance shall provide that in the event the
Lease is terminated by reason of an insured loss, the period of indemnity for
such coverage shall be extended beyond the date of the completion of repairs or
replacement of the Premises, to provide for one full year's loss of rental
revenues from the date of any such loss.  Said insurance shall contain an agreed
valuation provision in lieu of any coinsurance clause, and the amount of
coverage shall be adjusted annually to reflect the projected rental income
property taxes, insurance premium costs and other expenses, if any, otherwise
payable by Lessee, for the next twelve (12) month period.  Lessee shall be
liable for any deductible amount in the event of such loss.

           (c)    Adjacent Premises.  If the Premises are part of a larger
building, or if the Premises are part of a group of buildings owned by Lessor
which are adjacent to the Premises, the Lessee shall pay for any increase in the
premiums for the property insurance of such building or buildings if said
increase is caused by Lessee's acts, omissions, use or occupancy of the
Premises.

           (d)    Tenant's Improvements.  If the Lessor is the Insuring Party,
the Lessor shall not be required to insure Lessee Owned Alterations and Utility
Installations unless the item in question has become the property of Lessor
under the terms of this Lease.  If Lessee is the Insuring Party, the policy
carried by Lessee under this Paragraph 8.3 shall insure Lessee Owned Alterations
and Utility Installations.

    8.4    Lessee's Property Insurance.  Subject to the requirements of
Paragraph 8.5, Lessee at its cost shall either by separate policy or, at
Lessor's option, by endorsement to a policy already carried, maintain insurance
coverage on all of Lessee's personal property, Lessee Owned Alterations and
Utility Installations in, on, or about the Premises similar in coverage to that
carried by the Insuring Party under Paragraph 8.3.  SUCH INSURANCE SHALL BE FULL
REPLACEMENT COST COVERAGE WITH A



                                         -9-

<PAGE>


DEDUCTIBLE OF NOT TO EXCEED $1,000 PER OCCURRENCE.  The proceeds from any such
insurance shall be used by Lessee for the replacement of personal property or
the restoration of Lessee Owned Alterations and Utility Installations.  Lessee
shall be the Insuring Party with respect to the insurance required by this
Paragraph 8.4 and shall provide Lessor with written evidence that such Insurance
is in force.

    8.5    Insurance Policies.  Insurance required hereunder shall be in
companies duly licensed to transact business in the state where the Premises are
located and maintaining during the policy term a "General Policyholders Rating"
of at least B+, V, or such other rating as may be required by a Lender having a
lien on the Premises, as set forth in the most current issue of "Best's
Insurance Guide." Lessee shall not do or permit to be done anything which shall
invalidate the insurance policies referred to in this Paragraph 8.  If Lessee is
the Insuring Party, Lessee shall cause to be delivered to Lessor certified
copies of policies of such insurance or certificate evidencing the existence and
amounts of such Insurance with the insureds and loss payable clauses as required
by this Lease.  No such policy shall be cancelable or subject to modification
except after thirty (30) days prior written notice to Lessor.  Lessee shall at
least thirty (30) days prior to the expiration of such policies, furnish Lessor
with evidence of renewals or "insurance binders" evidencing renewal thereof, or
Lessor may order such insurance and charge the cost thereof to Lessee, which
amount shall be payable by Lessee to Lessor upon demand.  If the Insuring Party
shall fail to procure and maintain the insurance required to be carried by the
Insuring Party under this Paragraph 8, the other Party may, but shall not be
required to, procure and maintain the same, but at Lessee's expense.

    8.6    Waiver of Subrogation.  Without affecting any other rights or
remedies, Lessee and Lessor ("Waiving Party") each hereby release and relieve
the other, and waive their entire right to recover damages (whether in contract
or in tort) against the other, for loss of or damage to the Waiving Party's
property arising out of or incident to the perils required to be insured against
under Paragraph 8.  The effect of such releases and waivers of the right to
recover damages shall not be limited by the amount of insurance carried or
required, or by any deductibles applicable thereto.

    8.7    Indemnity.  Except for Lessor's negligence and/or breach of express
warranties, Lessee shall indemnify, protect, defend and hold harmless the
Premises.  Lessor and its agents, Lessor's master or ground lessor, partners and
Lenders, from and against any and all claims, loss of rents and/or damages,
costs, liens, judgments, penalties, permits, attorney's and consultant's fees,
expenses and/or liabilities arising out of, involving, or in dealing with, the
occupancy of the Premises by Lessee, the conduct of Lessee's business, any act,
omission or neglect of Lessee, its agents, contractors, employees or invitees,
and out of any Default or Breach by Lessee in the performance in a timely manner
of any obligation on Lessee's part to be performed under this Lease.  The
foregoing shall include, but not be limited to, the defense or pursuit of any
claim or any action or proceeding involved therein, and whether or not (in the
case of claims made against Lessor) litigated and/or reduced to judgment, and
whether well founded or not.  In case any action or proceeding be brought
against Lessor by reason of any of the foregoing matters, Lessee upon notice
from Lessor shall defend the same at Lessee's expense by counsel reasonably
satisfactory to Lessor and Lessor shall cooperate with Lessee in such defense.
Lessor need not have first paid any such claim in order to be so indemnified.

    8.8    Exemption of Lessor from Liability.  Lessor shall not be liable for
injury or damage to the person or goods, wares, merchandise or other property of
Lessee.  Lessee's employees, contractors, invitees, customers, or any other
person in or about the Premises, whether such damage or injury is caused by or
results from fire, steam, electricity, gas, water or rain, or


                                         -10-

<PAGE>

from the breakage, leakage, obstruction or other defects of pipes, fire
sprinklers, wires, appliances, plumbing, air conditioning or lighting fixtures,
or from any other cause, whether the said injury or damage results from
conditions arising upon the Premises or upon other portions of the building of
which the Premises are a part, or from other sources or places, and regardless
of whether the cause of such damage or injury or the means of repairing the same
is accessible or not.  Lessor shall not be liable for any damages arising from
any act or neglect of any other tenant of Lessor.  Notwithstanding Lessor's
negligence or breach of this Lease, Lessor shall under no circumstances be
liable for injury to Lessee's business or for any loss of income or profit
therefrom.

9.  DAMAGE OR DESTRUCTION.

    9.1    Definitions.

           (a)    "Premises Partial Damage" shall mean damage or destruction to
the improvements on the Premises, other than Lessee Owned Alterations and
Utility Installations, the repair cost of which damage or destruction is less
than 50% of the then Replacement Cost of the Premises immediately prior to such
damage or destruction, excluding from such calculation the value of the land and
Lessee Owned Alterations and Utility Installations.

           (b)    "Premises Total Destruction" shall mean damage or destruction
to the Premises, other than Lessee Owned Alterations and Utility Installations
the repair cost of which damage or destruction is 50% or more of the then
Replacement Cost of the Premises immediately prior to such damage or
destruction, excluding from such calculation the value of the land and Lessee
Owned Alterations and Utility Installations.

           (c)    "Insured Loss" shall mean damage or destruction to
improvements on the Premises, other than Lessee Owned Alterations and Utility
Installations, which was caused by an event required to be covered by the
insurance described in Paragraph 8.3(a), irrespective of any deductible amounts
of coverage limits involved.

           (d)    "Replacement Cost" shall mean the cost to repair or rebuild
the improvements owned by Lessor at the time of the occurrence to their
condition existing immediately prior thereto, including demolition, debris
removal and upgrading required by the operation of applicable building codes,
ordinances or laws, and without deduction for depreciation.

           (e)    "Hazardous Substance Condition" shall mean the occurrence or
discovery of a condition involving the presence of, or a contamination by, a
Hazardous Substance as defined in Paragraph 6.2(a), in, or, under the Premises.

    9.2    Partial Damage - Insured Loss.  If a Premises Partial Damage that is
an Insured Loss occurs, then Lessor shall, at Lessor's expense, repair such
damage (but not Lessee's Trade Fixtures or Lessee Owned Alterations and Utility
Installations) as soon as reasonably possible and this Lease shall continue in
full force and effect; provided, however, that Lessee shall, at Lessor's
election, make the repair of any damage or destruction the total cost to repair
of which is $10,000 or less, and, in such event, Lessor shall make the insurance
proceeds available to Lessee on a reasonable basis for that purpose.
Notwithstanding the foregoing, if the required insurance was not in force or the
insurance proceeds are not sufficient to effect such repair the Insuring Party
shall promptly contribute the shortage in proceeds (except as to the deductible
which is Lessee's responsibility) as and when required to complete said repairs.

    9.3    Partial Damage - Uninsured Loss.  If a Premises Partial Damage that
is not an Insured Loss occurs, unless caused by a negligent or wilful act of
Lessee (in which event Lessee shall make the repairs at Lessee's expense and
this Lease shall


                                         -11-

<PAGE>

continue in full force and effect, but subject to Lessor's rights under
Paragraph 13), Lessor may at Lessor's option, either (i) repair such damage as
soon as reasonably possible at Lessor's expense, in which event this Lease shall
continue in full force and effect, or (ii) give written notice to Lessee within
thirty (30) days after receipt by Lessor of knowledge of the occurrence of such
damage of Lessor's desire to terminate this Lease as of the date sixty (60) days
following the giving of such notice.  In the event Lessor elects to give such
notice of Lessor's intention to terminate this Lease, Lessee shall have the
right within ten (10) days after the receipt of such notice to give written
notice to Lessor of Lessee's commitment to pay for the repair of such damage
totally at Lessee's expense and without reimbursement from Lessor.  Lessee shall
provide Lessor with the required funds or satisfactory assurance thereof within
thirty (30) days following Lessee's said commitment.  In such event this Lease
shall continue in full force and effect, and Lessor shall proceed to make such
repairs as soon as reasonably possible and the required funds are available.  If
Lessee does not give such notice and provide the funds or assurance thereof
within the times specified above, this Lease shall terminate as of the date
specified in Lessor's notice of termination.

    9.4    Total Destruction.  Notwithstanding any other provision hereof, if a
Premises Total Destruction occurs (including any destruction required by any
authorized public authority), this Lease shall terminate sixty (60) days
following the date of such Premises Total Destruction, whether or not the damage
or destruction is an Insured Loss or was caused by a negligent or willful act of
Lessee.  In the event, however, that the damage or destruction was caused by
Lessee, Lessor shall have the right to recover Lessor's damages from Lessee
except as released and waived in Paragraph 8.6.

    9.5    Damage Near End of Term.  If at any time during the last six (6)
months of the term of this Lease there is damage for which the cost to repair
exceeds one (1) month's Base Rent, whether or not an Insured Loss, Lessor may,
at Lessor's option, terminate this Lease effective sixty (60) days following the
date of occurrence of such damage by giving written notice to Lessee of Lessor's
election to do so within thirty (30) days after the date of occurrence of such
damage.  Provided, however, if Lessee at that time has an exercisable option to
extend this Lease or to purchase the Premises, then Lessee may preserve this
Lease by, within twenty (20) days following the occurrence of the damage, or
before the expiration of the time provided in such option for its exercise,
whichever is earlier ("Exercise Period"), (i) exercising such option and (ii)
providing Lessor with any shortage in insurance proceeds (or adequate assurance
thereof) needed to make the repairs.  If Lessee duly exercises such option
during said Exercise Period and provides Lessor with funds (or adequate
assurance thereof) to cover any shortage in insurance proceeds, Lessor shall, at
Lessor's expense repair such damage as soon as reasonably possible and this
Lease shall continue in full force and effect.  If Lessee fails to exercise such
option and provide such funds or assurance during said Exercise Period, then
Lessor may at Lessor's option terminate this Lease as of the expiration of said
sixty (60) day period following the occurrence of such damage by giving written
notice to Lessee of Lessor's election to do so within ten (10) days after the
expiration of the Exercise Period, notwithstanding any term or provision in the
grant of option to the contrary.

    9.6    Abatement of Rent; Lessee's Remedies.

           (a)    In the event of damage described in Paragraph 9.2 (Partial
Damage - Insured), whether or not Lessor or Lessee repairs or restores the
Premises, the Base Rent, Real Property Taxes, insurance premiums, and other
charges, if any, payable by Lessee hereunder for the period during which such
damage, its repair or the restoration continues (not to exceed the period for
which rental value insurance is required under Paragraph 8.3(b)), shall be
abated in proportion to the degree to which Lessee's use


                                         -12-

<PAGE>

of the Premises is impaired.  Except for abatement of Base Rent, Real Property
Taxes, insurance premiums, and other charges, if any, as aforesaid, all other
obligations of Lessee hereunder shall be performed by Lessee, and Lessee shall
have no claim against Lessor for any damage suffered by reason of any such
repair or restoration.

           (b)    If Lessor shall be obligated to repair or restore the
Premises under the provisions of this Paragraph 9 and shall not commence, in a
substantial and meaningful way, the repair or restoration of the Premises within
ninety (90) days after such obligation shall accrue, Lessee may, at any time
prior to the commencement of such repair or restoration, give written notice to
Lessor and to any Lenders of which Lessee has actual notice of Lessee's election
to terminate this Lease on a date not less than sixty (60) days following the
giving of such notice.  If Lessee gives such notice to Lessor and such Lenders
and such repair or restoration is not commenced within thirty (30) days after
receipt of such notice, this Lease shall terminate as of the date specified in
said notice.  If Lessor or a Lender commences the repair or restoration of the
Premises within thirty (30) days after receipt of such notice, this Lease shall
continue in full force and effect.  "Commence" as used in this Paragraph shall
mean either the unconditional authorization of the preparation of the required
plans, or the beginning of the actual work on the Premises, whichever first
occurs.

    9.7    Hazardous Substance Conditions.  If a Hazardous Substance Condition
occurs, unless Lessee is legally responsible therefor (in which case Lessee
shall make the investigation and remediation thereof required by Applicable Law
and this Lease shall continue in full force and effect, but subject to Lessor's
rights under Paragraph 13), Lessor may at Lessor's option either (i) investigate
and remediate such Hazardous Substance Condition, if required, as soon as
reasonably possible at Lessor's expense, in which event this Lease shall
continue in full force and effect, or (ii) if the estimated cost to investigate
and remediate such condition exceeds twelve (12) times the then monthly Base
Rent or $100,000, whichever is greater, give written notice to Lessee within
thirty (30) days after receipt by Lessor of knowledge of the occurrence of such
Hazardous Substance Condition of Lessor's desire to terminate this Lease as of
the date sixty (60) days following the giving of such notice.  In the event
Lessor elects to give such notice of Lessor's intention to terminate this Lease,
Lessee shall have the right within ten (10) days after the receipt of such
notice to give written notice to Lessor of Lessee's commitment to pay for the
investigation and remediation of such Hazardous Substance Condition totally at
Lessee's expense and without reimbursement from Lessor except tot he extent of
an amount equal to twelve (12) times the then monthly Base Rent or $100,000,
whichever is greater.  Lessee shall provide Lessor with the funds required of
Lessee or satisfactory assurance thereof within thirty (30) days following
Lessee's said commitment.  In such event this Lease shall continue in full force
and effect, and Lessor shall proceed to make such investigation and remediation
as soon as reasonably possible and the required funds are available.  If Lessee
does not give such notice and provide the required funds or assurance thereof
within the times specified above, this Lease shall terminate as of the date
specified in Lessor's notice of termination.  If a Hazardous Substance Condition
occurs for which Lessee is not legally responsible, there shall be abatement of
Lessee's obligations under this Lease to the same extent as provided in
Paragraph 9.6(a) for a period of not to exceed twelve (12) months.

    9.8    Termination - Advance Payments.  Upon termination of this Lease
pursuant to this Paragraph 9, an equitable adjustment shall be made concerning
advance Base Rent and any other advance payments made by Lessee to Lessor.
Lessor shall, in addition, return to Lessee so much of Lessee's Security Deposit
as has not been, or is not then required to be used by Lessor under the terms of
this Lease.


                                         -13-

<PAGE>

    9.9    Waive Statutes.  Lessor and Lessee agree that the terms of this
Lease shall govern the effect of any damage to or destruction of the Premises
with respect to the termination of this Lease and hereby waive the provisions of
any present or future statute to the extent inconsistent herewith.

10. Real Property Taxes.

    10.1   (a)    Payment of Taxes.  Lessee shall pay the Real Property Taxes,
as defined in Paragraph 10.2, applicable to the Premises during the term of this
Lease.  Subject to Paragraph 10.1(b), all such payments shall be made at least
ten (10) days prior to the delinquency date of the applicable installment.
Lessee shall promptly furnish Lessor with satisfactory evidence that such taxes
have been paid.  If any such taxes to be paid by Lessee shall cover any period
of time prior to or after the expiration or earlier termination of the term
hereof, Lessee's share of such taxes shall be equitably prorated to cover only
the period of time within the tax fiscal year this Lease is in effect, and
Lessor shall reimburse Lessee for any over payment after such proration.  If
Lessee shall fail to pay any Real Property Taxes required by this Lease to be
paid by Lessee, Lessor shall have the right to pay the same, and Lessee shall
reimburse Lessor therefor upon demand.

           (b)    Advance Payment.  In order to insure payment when due and
before delinquency of any or all Real Property Taxes, Lessor reserves the right,
at Lessor's option, to estimate the current Real Property Taxes applicable to
the Premises, and to require such current year's Real Property Taxes to be paid
in advance to Lessor by Lessee, either: (i) in a lump sum amount equal to the
installment due, at least twenty (20) days prior to the applicable delinquency
date, or (ii) monthly in advance with the payment of the Base Rent.  If Lessor
elects to require payment monthly in advance, the monthly payment shall be that
equal monthly amount which, over the number of months remaining before the month
in which the applicable tax installment would become delinquent (and without
interest thereon), would provide a fund large enough to fully discharge before
delinquency the estimated installment of taxes to be paid.  When the actual
amount of the applicable tax bill is known, the amount of such equal monthly
advance payment shall be adjusted as required to provide the fund needed to pay
the applicable taxes before delinquency.  If the amounts paid to Lessor by
Lessee under the provisions of this Paragraph are insufficient to discharge the
obligations of Lessee to pay such Real Property Taxes as the same become due,
Lessee shall pay to Lessor, upon Lessor's demand, such additional sums as are
necessary to pay such obligations.  All moneys paid to Lessor under this
Paragraph may be intermingled with other moneys of Lessor and shall not bear
interest.  In the event of a Breach by Lessee in the performance of the
obligations of Lessee under this Lease, then any balance of funds paid to Lessor
under the provisions of this Paragraph may, subject to proration as provided in
Paragraph 10.1(a), at the option of Lessor, be treated as an additional Security
Deposit under Paragraph 5.

    10.2   Definition of "Real Property Taxes."  As used herein, the term "Real
Property Taxes" shall include any form of real estate tax or assessment general,
special, ordinary or extraordinary, and any license fee, commercial rental tax,
improvement bond or bonds, levy or tax (other than inheritance, personal income
or estate taxes) imposed upon the Premises by any authority having the direct or
indirect power to tax, including any city, state or federal government, or any
school, agricultural, sanitary, fire, street, drainage or other improvement
district thereof, levied against any legal or equitable interest of Lessor in
the Premises or in the real property of which the Premises are a part, Lessor's
right to rent or other income therefrom, and/or Lessor's business of leasing the
Premises.  The term "Real Property Taxes" shall also include any tax, fee, levy,
assessment or charge, or any increase therein, imposed by reason of events
occurring, or changes in


                                         -14-

<PAGE>

applicable law taking effect, during the term of this Lease, including but not
limited to a change in the ownership of the Premises or in the improvements
thereon, the execution of this Lease, or any modification, amendment or transfer
thereof, and whether or not contemplated by the Parties.

    10.3   Joint Assessment.  If the Premises are not separately assessed,
Lessee's liability shall be an equitable proportion of the Real Property Taxes
for all of the land and improvements included within the tax parcel assessed,
such proportion to be determined by Lessor from the respective valuations
assigned in the Lessor's work sheets or such other information as may be
reasonably available Lessor's reasonable determination thereof, in good faith,
shall be conclusive.

    10.4   Personal Property Taxes.  Lessee shall pay prior to delinquency all
taxes assessed against and levied upon Lessee Owned Alternations, Utility
Installations, Trade Fixtures, furnishings, equipment and all personal property
of Lessee contained in the Premises or elsewhere.  When possible, Lessee shall
cause its Trade Fixtures, furnishings, equipment and all other personal property
to be assessed and billed separately from the real property of Lessor if any of
Lessee's said personal property shall be assessed with Lessor's real property.
Lessee shall pay Lessor the taxes attributable to Lessee within ten (10) days
after receipt of a written statement setting forth the taxes applicable to
Lessee's property or, at Lessor's option, as provided in Paragraph 10.1(b).

11. Utilities.  Lessee shall pay for all water, gas, heat, light, power,
telephone, trash disposal and other utilities and services supplied to the
Premises, together with any taxes thereon.  If any such services are not
separately metered to Lessee, Lessee shall pay a reasonable proportion, to be
determined by Lessor, of all charges jointly metered with other premises.

12. Assignment and Subletting.

    12.1   Lessor's Consent Required.

           (a)    Lessee shall not voluntarily or by operation of law assign,
transfer, mortgage or otherwise transfer or encumber (collectively,
"assignment") or sublet all or any part of Lessee's interest in this Lease or in
the Premises without Lessor's prior written consent given under the subject to
the terms of Paragraph 36.

           (b)    Deleted.

           (c)    Deleted.

           (d)    Deleted.

           (e)    Lessee's remedy for any breach of this Paragraph 12.1 by
Lessor shall be limited to compensatory damages and injunctive relief.

    12.2   Terms and Conditions Applicable to Assignment and Subletting.

           (a)    Regardless of Lessor's consent, any assignment or subletting
shall not:  (i) be effective without the express written assumption by such
assignee or sublessee of the obligations of Lessee under this Lease,
(ii) release Lessee of any obligations hereunder, or (iii) alter the primary
liability of Lessee for the payment of Base Rent and other sums due Lessor
hereunder or for the performance of any other obligations to be performed by
Lessee under this Lease.

           (b)    Lessor may accept any rent or performance of Lessee's
obligations from any person other than Lessee pending approval or disapproval of
an assignment.  Neither a delay in the


                                         -15-

<PAGE>

approval or disapproval of such assignment nor the acceptance of any rent or
performance shall constitute a waiver or estoppel of Lessor's right to exercise
its remedies for the Default or Breach by Lessee of any of the terms, covenants
or conditions of this Lease.

           (c)    The consent of Lessor to any assignment or subletting shall
not constitute a consent to any subsequent assignment or subletting by Lessee or
to any subsequent or successive assignment or subletting by the sublessee.
However, Lessor may consent to subsequent sublettings and assignments of the
sublease or any amendments or modifications thereto without notifying Lessee or
anyone else liable on the Lease or sublease and without obtaining their consent,
and such action shall not relieve such persons from liability under this Lease
or sublease.

           (d)    In the event of any Default or Breach of Lessee's obligations
under this Lease, Lessor may proceed directly against Lessee, any Guarantors or
any one else responsible for the performance of the Lessee's obligations under
this Lease, including the sublessee, without first exhausting Lessor's remedies
against any other person or entity responsible therefor to Lessor, or any
security held by Lessor or Lessee.

           (e)    Each request for consent to an assignment or subletting shall
be in writing, accompanied by information relevant to Lessor's determination as
to the financial and operational responsibility and appropriateness of the
proposed assignee or sublessee, including but not limited to the intended use
and/or required modification of the Premises, if any.  Lessee agrees to provide
Lessor with such other or additional information and/or documentation as may be
reasonably requested by Lessor.

           (f)    Any assignee of, or sublessee under, this Lease shall, by
reason of accepting such assignment or entering into such sublease, be deemed
for the benefit of Lessor, to have assumed and agreed to conform and comply with
each and every term, covenant, condition and obligation herein to be observed or
performed by Lessee during the term of said assignment or sublease, other than
such obligations as are contrary to or inconsistent with provisions of an
assignment or sublease to which Lessor has specifically consented in writing.

           (g)    Deleted.

           (h)    Deleted.

    12.3   Additional Terms and Conditions Applicable to Subletting.  The
following terms and conditions shall apply to any subletting by Lessee of all or
any part of the Premises and shall be deemed included in all subleases under
this Lease whether or not expressly incorporated therein:

           (a)    Lessee hereby assigns and transfers to Lessor all of Lessee's
interest in all rentals and income arising from any sublease of all or a portion
of the Premises heretofore or hereafter made by Lessee, and Lessor may collect
such rent and income and apply same toward Lessee's obligations under this
lease; provided, however, that until a Breach (as defined in Paragraph 13.1)
shall occur in the performance of Lessee's obligations under this Lease.  Lessee
may, except as otherwise provided in this Lease, receive, collect and enjoy the
rents accruing under such sublease.  Lessor shall not, by reason for any failure
of Lessee to perform and comply with any of Lessee's obligations to such
sublessee under such sublease.  Lessee hereby irrevocably authorizes and directs
any such sublessee, upon receipt of a written notice from Lessor stating that a
Breach exists in the performance of Lessee's obligations under this Lease, to
pay to Lessor the rents and other charges due and to become due under the
sublease.  Sublessee shall rely upon any such statement and request from Lessor
and shall pay such rents and other charges to Lessor without any obligation or
right to


                                         -16-

<PAGE>

inquire as to whether such Breach exists and notwithstanding any notice from or
claim from Lessee to the contrary.  Lessee shall have no right or claim against
said sublessee or, until the Breach has been cured, against Lessor, for any such
rents and other charges so paid by said sublessee to Lessor.

           (b)    In the event of a Breach by Lessee in the performance of its
obligations under this Lease, Lessor, at its option and without any obligation
to do so, may require any sublessee to attorn to Lessor, in which event Lessor
shall undertake the obligations of the sublessor under such sublease from the
time of the exercise of said option to the expiration of such sublease;
provided, however, Lessor shall not be liable for any prepaid rents or security
deposit paid by such sublessee to such sublessor or for any other prior Defaults
or Breaches or such sublessor under such sublease.

           (c)    Any matter or thing requiring the consent of the sublessor
under a sublease shall also require the consent of Lessor herein.

           (d)    No sublessee shall further assign or sublet all or any part
of the Premises without Lessor's prior written consent.

           (e)    Lessor shall deliver a copy of any notice of Default or
Breach by Lessee to the sublessee, who shall have the right to cure the Default
of Lessee within the grace period, if any, specified in such notice.  The
sublessee shall have a right or reimbursement and offset from and against Lessee
for any such Defaults cured by the sublessee.

13. Default; Breach; Remedies.

    13.1   Default; Breach.  A "Default" is defined as a failure by the Lessee
to observe comply with or perform any of the terms, covenants, conditions or
rules applicable to Lessee under this Lease.  A "Breach" is defined as the
occurrence of any one or more of the following Defaults and where a grace period
for cure after notice is specified herein the failure by Lessee to cure such
Default prior to the expiration of the applicable grace period shall entitle
Lessor to pursue the remedies set forth in Paragraphs 13.2 and/or 13.3.

           (a)    The vacating of the Premises without the intention to
reoccupy same, or the abandonment of the Premises.

           (b)    Except as expressly otherwise provided in this Lease, the
failure by Lessee to make any payment of Base Rent or any other monetary payment
required to be made by Lessee hereunder, whether to Lessor or to a third party,
as and when due, the failure by Lessee to provide Lessor with reasonable
evidence of insurance or surety bond required under this Lease, or the failure
of Lessee to fulfill any obligation under this Lease which endangers or
threatens life or property, where such failure continues for a period of three
(3) days following written notice thereof by or on behalf of Lessor to Lessee.

           (c)    Except as expressly otherwise provided in this Lease, the
failure by Lessee to provide Lessor with reasonable written evidence (in duly
executed original form, if applicable) of (i) compliance with Applicable Law per
Paragraph 6.3, (ii) the inspection, maintenance and service contracts required
under Paragraph 7.1(b), (iii) the recession of an unauthorized assignment or
subletting per Paragraph 12.1(b), (iv) a Tenancy Statement per Paragraph 16 or
37, (v) the subordination or non-subordination of this Lease per Paragraph 30,
(vi) the guaranty of the performance of Lessee's obligations under this Lease if
required under Paragraphs 1.11 and 37, (vii) the execution of any document
requested under Paragraph 42 (easements), or (viii) any other documentation or
information which Lessor may reasonably required of Lessee under the terms of
this Lease, where any such failure continues for a period of ten


                                         -17-

<PAGE>

(10) days following written notice by or on behalf of Lessor to Lessee.

           (d)    A Default by Lessee as to the terms, covenants, conditions or
provisions of this Lease, or of the rules adopted under Paragraph 40 hereof,
that are to be observed, complied with or performed by Lessee, other than those
described in subparagraphs (a), (b) or (c), above, where such Default continues
for a period of thirty (30) days after written notice thereof by or on behalf of
Lessor to Lessee; provided, however, that if the nature of Lessee's Default is
such that more than thirty (30) days are reasonably required for its cure, then
it shall not be deemed to be a Breach of this Lease by Lessee if Lessee
commences such cure within said thirty (30) days period and thereafter
diligently prosecutes such cure to completion.

           (e)    The occurrence of any of the following events:  (i) The
making by Lessee of any general arrangement or assignment for the benefit of
creditors, (ii) Lessee's becoming a "debtor" as defined in 11 U.S.C. Section 101
or any successor statute thereto (unless, in the case of a petition filed
against Lessee, the same is dismissed within sixty (60) days); (iii) the
appointment of a trustee or receiver to take possession of substantially all of
Lessee's assets located at the Premises or of Lessee's interest in this Lease,
where possession is not restored to Lessee within thirty (30) days; or (iv) the
attachment, execution or other judicial seizure of substantially all of Lessee's
assets located at the Premises or of Lessee's interest in this Lease, where such
seizure is not discharged within thirty (30) days; provided, however, in the
event that any provision of this subparagraph (e) is contrary to any applicable
law, such provision shall be of no force or effect, and not affect the validity
of the remaining provisions.

           (f)    The discovery by Lessor that any financial statement given to
Lessor by Lessee or any Guarantor of Lessee's obligations hereunder was
materially false.

           (g)    If the performance of Lessee's obligations under this Lease
is guaranteed:  (i) the death of a guarantor, (ii) the termination of a
guarantor's liability with respect to this Lease other than in accordance with
the terms of such guaranty, (iii) a guarantor's becoming insolvent or the
subject of a bankruptcy filing, (iv) a guarantor's refusal to honor the
guaranty, or (v) a guarantor's breach of its guaranty obligation on an
anticipatory breach basis, and Lessee's failure, within sixty (60) days
following written notice by or on behalf of Lessor to Lessee of any such event,
to provide Lessor with written alternative assurance or security, which, when
coupled with the then existing resources of Lessee, equals or exceeds the
combined financial resources of Lessee and the guarantors that existed at the
time of execution of this Lease.

    13.2   Remedies.  If Lessee fails to perform any affirmative duty or
obligation of Lessee under this Lease, within ten (10) days after written notice
to Lessee (or in case of an emergency, without notice), Lessor may at its option
(but without obligation to do so), perform such duty or obligation on Lessee's
behalf, including but not limited to the obtaining of reasonably required bonds,
insurance policies, or governmental licenses, permits or approvals.  The costs
and expenses of any such performance by Lessor shall be due and payable by
Lessee to Lessor upon invoice therefor.  If any check given to Lessor by Lessee
shall not be honored by the bank upon which it is drawn, Lessor, at its option,
may require all future payments to be made under this Lease by Lessee to be made
only by cashier's check.  In the event of a Breach of this Lease by Lessee, as
defined in Paragraph 13.1, with or without further notice or demand, and without
limiting Lessor in the exercise of any right or remedy which Lessor may have by
reason of such Breach, Lessor may:

           (a)    Terminate Lessee's right to possession of the Premises by any
lawful means, in which case this Lease and the


                                         -18-

<PAGE>

term hereof shall terminate and Lessee shall immediately surrender possession of
the Premises to Lessor.  In such event Lessor shall be entitled to recover from
Lessee: (i) the worth at the time of the award of the unpaid rent which had been
earned at the time of termination; (ii) the worth at the time of award of the
amount by which the unpaid rent which would have been earned after termination
until the time of award exceeds the amount of such rental loss that the Lessee
proves could have been reasonably avoided; (iii) the worth at the time of award
of the amount by which the unpaid rent for the balance of the term after the
time of award exceeds the amount of such rental loss that the Lessee proves
could be reasonably avoided; and (iv) any other amount necessary to compensate
Lessor for all the detriment proximately caused by the Lessee's failure to
perform its obligations under this Lease or which in the ordinary course of
things would be likely to result therefrom, including but not limited to the
cost of recovering possession of the Premises, expenses of reletting, including
necessary renovation and alteration of the Premises, reasonable attorneys' fees,
and that portion of the leasing commission paid by Lessor applicable to the
unexpired term of this Lease.  The worth at the time of award of the amount
referred to in provision (iii) of the prior sentence shall be computed by
discounting such amount at the discount rate of the Federal Reserve Bank of San
Francisco at the time of award plus one percent (1%).  Efforts by Lessor to
mitigate damages caused by Lessee's Default or Breach of this Lease shall not
waive Lessor's right to recover damages under this Paragraph.  If termination of
this Lease is obtained through the provisional remedy of unlawful detainer,
Lessor shall have the right to recover in such proceeding the unpaid rent and
damages as are recoverable therein, or Lessor may reserve therein the right to
recover all or any part thereof in a separate suit for such rent and/or damages.
If a notice and grace period required under subparagraphs 13.1(b), (c) or (d)
was not previously given, a notice to pay rent or quit, or to perform or quit,
as the case may be, given to Lessee under any statute authorizing the forfeiture
of leases for unlawful detainer shall also constitute the applicable notice for
grace period purposes required by subparagraphs 13.1(b), (c) or (d).  In such
case, the applicable grace period under subparagraphs 13.1(b), (c) or (d) and
under the unlawful detainer statute shall run concurrently after the one such
statutory notice, and the failure of Lessee to cure the Default within the
greater of the two such grace periods shall constitute both an unlawful detainer
and a Breach of this Lease entitling Lessor to the remedies provided for in this
Lease and/or by said statute.

           (b)    Continue the Lease and Lessee's right to possession in effect
(in California under California Civil Code Section 1951.4) after Lessee's Breach
and abandonment and recover the rent as it becomes due, provided Lessee has the
right to sublet or assign, subject only to reasonable limitations.  See
Paragraphs 12 and 36 for the limitations on assignment and subletting which
limitations Lessee and Lessor agree are reasonable.  Acts of maintenance or
preservation, efforts to relet the Premises, or the appointment of a receiver to
protect the Lessor's interest under the Lease, shall not constitute a
termination of the Lessee's right to possession.

           (c)    Pursue any other remedy now or hereafter available to Lessor
under the laws or judicial decisions of the state wherein the Premises are
located.

           (d)    The expiration or termination of this Lease and/or the
termination of Lessee's right to possession shall not relieve Lessee from
liability under any indemnity provisions of this Lease as to matters occurring
or accruing during the term hereof or by reason of Lessee's occupancy of the
Premises.

    13.3   Late Charges.  Lessee hereby acknowledges that late payment by
Lessee or Lessor of rent and other sums due hereunder will cause Lessor to incur
costs not contemplated by this Lease, the exact amount of which will be
extremely difficult to


                                         -19-

<PAGE>

ascertain.  Such costs include, but are not limited to processing and accounting
charges, and late charges which may be imposed upon Lessor by the terms of any
ground lease, mortgage or trust deed covering the Premises.  Accordingly, if any
installment of rent or any other sum due from Lessee shall not be received by
Lessor or Lessor's designee within five (5) days after such amount shall be due,
then, without any requirement for notice to Lessee, Lessee shall pay to Lessor a
late charge equal to six percent (6%) of such overdue amount.  The parties
hereby agree that such later charge represents a fair and reasonable estimate of
the costs Lessor will incur by reason of late payment by Lessee.  Acceptance of
such late charge by Lessor shall in no event constitute a waiver of Lessee's
Default or Breach with respect to such overdue amount, not prevent Lessor from
exercising any of the other rights and remedies granted hereunder.  In the event
that a late charge is payable hereunder, whether or not collected, for three (3)
consecutive installments of Base Rent, then notwithstanding Paragraph 4.1 or any
other provision of this Lease to the contrary.  Base Rent Shall, at Lessor's
option, become due and payable quarterly in advance.

    13.4   Breach by Lessor.  Lessor shall not be deemed in breach of this
Lease unless Lessor fails within a reasonable time to perform an obligation
required to be performed by Lessor.  For purposes of this Paragraph 13.5, a
reasonable time shall in no event be less than thirty (30) days after receipt by
Lessor, and by the holders of any ground lease, mortgage or deed of trust
covering the Premises whose name and address shall have been furnished Lessee in
writing for such purpose, of written notice specifying wherein such obligation
of Lessor has not been performed; provided, however, that if the nature of
Lessor's obligation is such that more than thirty (30) days after such notice
are reasonably required for its performance, then Lessor shall not be in breach
of this Lease if performance is commenced within such thirty (30) day period and
thereafter diligently pursued to completion.

14. Condemnation.  If the Premises or any portion thereof are taken under the
power of eminent domain or sold under the threat of the exercise of said power
(all of which are herein called "condemnation"), this Lease shall terminate as
to the part so taken as of the date the condemning authority takes title or
possession, whichever first occurs.  If more than ten percent (10%) of the floor
area of the Premises, or more than twenty-five percent (25%) of the land area
not occupied by any building, is taken by condemnation, Lessee may, at Lessee's
option, to be exercised in writing within ten (10) days after Lessor shall have
given Lessee written notice of such taking (or in the absence of such notice,
within ten (10) days after the condemning authority shall have taken possession)
terminate this Lease as of the date the condemning authority takes such
possession.  If Lessee does not terminate this Lease in accordance with the
foregoing, this Lease shall remain in full force and effect as to the portion of
the Premises remaining, except that the Base Rent shall be reduced in the same
proportion as the rentable floor area of the Premises taken bears to the total
rentable floor area of the building located on the Premises.  No reduction of
Base Rent shall occur if the only portion of the Premises taken is land on which
there is no building.  Any award for the taking of all or any part of the
Premises under the power of eminent domain or any payment made under threat of
the exercise of such power shall be the property of Lessor, whether such award
shall be made as compensation for diminution in value of the leasehold or for
the taking of the fee, or as severance damages; provided, however, that Lessee
shall be entitled to any compensation separately awarded to Lessee for Lessee's
relocation expenses and/or loss of Lessee's Trade Fixtures in the event that the
Lese is not terminated by reason of such condemnation.  Lessor shall to the
extent of its net severance damages received over and above the legal and other
expenses incurred by Lessor in the condemnation matter, repair any damage to the
premises caused by such condemnation, except to the extent that Lessee has been
reimbursed therefor by the condemning authority.  Lessee shall be


                                         -20-

<PAGE>

responsible for the payment of any amount in excess of such net severance
damages required to complete such repair.

15. Broker's Fee

    15.1   The Brokers named in Paragraph 1.10 are the procuring causes of this
Lease.

    15.2   Upon execution of this Lease by both Parties, Lessor shall pay to
said Brokers jointly, or in such separate shares as they may mutually designate
in writing, a fee as set forth in a separate written agreement between Lessor
and said Brokers (or in the event there is no separate written agreement between
Lessor and said Brokers, the sum of $125% of Sched) for brokerage services
rendered by said Brokers to Lessor in this transaction.

    15.3   Lessee and Lessor each represent and warrant to the other that it
has had no dealings with any person, firm, broker or finder (other than the
Brokers, if any named in Paragraph 1.10) in connection with the negotiation of
this Lease and/or the consummation of the transaction contemplated hereby, and
that no broker or other person, firm or entity other than said named Brokers is
entitled to any commission or finder's fee in connection with said transaction.
Lessee and Lessor do each hereby agree to indemnify, protect, defend and hold
the other harmless from and against liability for compensation or charges which
may be claimed by any such unnamed broker, finder or other similar party by
reason by any dealings or actions of the indemnifying Party, including any
costs, expenses, attorneys' fees reasonably incurred with respect thereto.

    15.4   Lessor and Lessee hereby consent to and approve all agency
relationships, including any dual agencies, indicated in Paragraph 1.10.

16. Tenancy Statement

    16.1   Each Party (as "Responding Party") shall within ten (10) days after
written notice from the other Party (the "Requesting Party") execute,
acknowledge and deliver to the Requesting Party a statement in writing in form
similar to the most current "Tenancy Statement" form published by the American
Industrial Real Estate Association, plus such additional information,
confirmation and/or statements as may be reasonably requested by the Requesting
Party.

    16.2   Lessor desires to finance, refinance, or sell the Premises, any part
thereof, or the building of which the Premises are a part, Lessee and all
Guarantors of Lessee's performance hereunder shall deliver to any potential
lender or purchase designated by Lessor such financial statements of Lessee and
such Guarantors as may be reasonably required by such lender or purchaser,
including but not limited to Lessee's financial statements for the past three
(3) years.  All such financial statements shall be received by Lessor and such
lender or purchaser in confidence and shall be used only for the purposes herein
set forth.

17. Lessor's Liability.  The term "Lessor" as used herein shall mean the owner
or owners at the time in question of the fee title to the Premises, or, if this
is a sublease, of the Lessee's interest in the prior lease.  In the event of a
transfer of Lessor's title or interest in the Premises or in this Lease, Lessor
shall deliver to the transferee or assignee (in cash or by credit) any unused
Security Deposit held by Lessor at the time of such transfer or assignment.
Except as provided in Paragraph 15, upon such transfer or assignment and
delivery of the Security Deposit, as aforesaid, the prior Lessor shall be
relieved of all liability with respect to the obligations and/or covenants under
this Lease thereafter to be performed by the lessor.  Subject to the foregoing,
the obligations and/or covenants in this Lease to be performed by the lessor
shall be binding only upon the Lessor as hereinabove defined.


                                         -21-

<PAGE>

18. Severability.  The invalidity of any provision of this Lease, as determined
by a court of competent jurisdiction, shall in no way affect the validity of any
other provision hereof.

19. Interest on Past-Due Obligations.  Any monetary payment due Lessor
hereunder, other than late charges, not received by lessor within thirty (30)
days following the date on which it was due, shall bear interest from the
thirty-first (31st) day after it was due at the rate of 12% per annum, but not
exceeding the maximum rate allowed by law, in addition to the late charge
provided for in Paragraph 13.4

20. Time of Essence.  Time is of the essence with respect to the performance of
all obligations to be performed or observed by the Parties under this Lease.

21. Rent Defined.  All monetary obligations of Lessee to Lessor under the terms
of this Lease are deemed to be rent.

22. No Prior or Other Agreements; Broker Disclaimer.  This Lease contains all
agreements between the Parties with respect to any matter mentioned herein, and
no other prior or contemporaneous agreement or understanding shall be effective.
Lessor and Lessee each represents and warrants to the Brokers that it has made,
and is relying solely upon, its own investigation as to the nature, quality,
character and financial responsibility of the other Party to this Lease and as
to the nature, quality and character of the Premises.  Brokers have no
responsibility with respect thereto or with respect to any default or breach
hereof by either Party.

23. Notices.

    23.1   All notices required or permitted by this Lease shall be in writing
and may be delivered in person (by hand or by messenger or courier service) or
may be sent by regular, certified or registered mail or U.S. Postal Service
Express Mail, with postage prepaid, or by facsimile transmission, and shall be
deemed sufficiently given if served in a manner specified in this Paragraph 23.
The addresses noted adjacent to a Party's signature on this Lease shall be that
Party's address for delivery or mailing of notice purposes.  Either Party may by
written notice to the other specify a different address for notice purposes,
except that upon Lessee's taking possession of the Premises, the Premises shall
constitute Lessee's address for the purpose of mailing or delivering notices to
Lessee.  A copy of all notices required or permitted to be given to Lessor
hereunder shall be concurrently transmitted to such party or parties at such
addresses as Lessor may from time to time hereafter designate by written notice
to Lessee.

    23.2   Any notice sent by registered or certified mail, return receipt
requested, shall be deemed given on the date of delivery shown on the receipt
card, or if no delivery date is shown, the postmark thereon.  If sent by regular
mail the notice shall be deemed given forty-eight (48) hours after the same is
addressed as required herein and mailed with postage prepaid.  Notices delivered
by United States Express Mail or overnight courier that guarantees next day
delivery shall be deemed given twenty-four (24) hours after delivery of the same
to the United States Postal Service or courier.  If any notice is transmitted by
facsimile transmission or similar means, the same shall be deemed served or
delivered upon telephone confirmation of receipt of the transmission thereof,
provided a copy is also delivered via delivery or mail.  If notice is received
on a Sunday or legal holiday, it shall be deemed received on the next business
day.

24. Waivers.  No waiver by Lessor of the Default or Breach of any term,
covenant or condition hereof by Lessee, shall be deemed a waiver of any other
term, covenant or condition hereof, or of any subsequent Default or Breach by
Lessee of the same or of any other term, covenant or condition hereof.  Lessor's
consent to, or approval of, any act shall not be deemed to render unnecessary


                                         -22-

<PAGE>

the obtaining of Lessor's consent to, or approval of, any subsequent or similar
act by Lessee, or be construed as the basis of an estoppel to enforce the
provision or provisions of this Lease requiring such consent.  Regardless of
Lessor's knowledge of a Default or Breach at the time of accepting rent, the
acceptance of rent by Lessor shall not be a waiver of any preceding Default or
Breach by Lessee of any provision hereof, other than the failure of Lessee to
pay the particular rent so accepted.  any payment given Lessor by Lessee may be
accepted by Lessor on account of moneys or damages due Lessor, notwithstanding
any qualifying statements or conditions made by Lessee in connection therewith,
which such statements and/or conditions shall be of no force or effect
whatsoever unless specifically agreed to in writing by Lessor at or before the
time of deposit of such payment.

25. Recording.  Either Lessor or Lessee shall, upon request of the other,
execute, acknowledge and deliver to the other a short form memorandum of this
Lease for recording purposes.  The Party requesting recordation shall be
responsible for payment of any fees or taxes applicable thereto.

26. No Right To Holdover.  Lessee has no right to retain possession of the
Premises or any part thereof beyond the expiration or earlier termination of
this Lease.

27. Cumulative Remedies.  No remedy or election hereunder shall be deemed
exclusive but shall, wherever possible be cumulative with all other remedies at
or in equity.

28. Covenants and Conditions.  All provisions of this Lease to be observed or
performed by Lessee are both covenants and conditions.

29. Binding Effect; Choice of Law.  This Lease shall be binding upon the
parties, their personal representatives, successors and assigns and be governed
by the laws of the state in which the Premises are located.  Any litigation
between the Parties hereto concerning this Lease shall be initiated in the
county in which the Premises are located.

30. Subordination; Attornment; Non-Disturbance.

    30.1   Subordination.  This Lease and any Option granted hereby shall be
subject and subordinate to any ground lease, mortgage, deed of trust, or other
hypothecation or security device (collectively, "Security Device"), now or
hereafter placed by Lessor upon the real property of which the Premises are a
part, to any and all advances made on the security thereof, and to all renewals,
modifications, consolidations, replacements and extensions thereof Lessee agrees
that the lenders holding any such Security Device shall have no duty, liability
or obligation to perform any of the obligations of Lessor under this Lease, but
that in the event of Lessor's default with respect to any such obligation,
Lessee will give any Lender whose name and address have been furnished Lessee in
writing for such purpose notice of Lessor's default and allow such Lender thirty
(30) days following receipt of such notice for the cure of said default before
invoking any remedies Lessee may have by reason thereof.  If any Lender shall
elect to have this Lease and/or any Option granted hereby superior to the lien
of its Security Device and shall give written notice thereof to lessee, this
Lease and such Options hslal be deemed prior to such Security Device,
notwithstanding the relative dates of the documentation or recordation thereof.

    30.2   Attornment.  Subject to the non-disturbance provisions of
Paragraph 30.3, Lessee agrees to attorn to a Lender or any other party who
acquires ownership of the Premises by reason of a foreclosure of a Security
Device, and that in the event of such foreclosure, such new owner shall not: (i)
be liable for any act or omission of any prior lessor or with respect to events
occurring prior to acquisition of ownership, (ii) be subject to any offsets or
defenses which Lessee might have against any prior


                                         -23-

<PAGE>

lessor, or (iii) be bound by prepayment of more than one (1) month's rent.

    30.3   Non-Disturbance.  With respect to Security Devices entered into by
Lessor after the execution of this Lease, Lessee's subordination of this Lease
shall be subject to receiving assurance (a "non-disturbance agreement") from the
Lender that Lessee's possession and this Lease, including any options to extend
the term hereof, will not be disturbed so long as Lessee is not in Breach hereof
and attorns to the record owner of the Premises.

    30.4   Self-Executing.  The agreements contained in this Paragraph 30 shall
be effective without the execution of any further documents; provided, however,
that, upon written request from Lessor or a Lender in connection with a sale,
financing or refinancing of the Premises, Lessee and Lessor shall execute such
further writings as may be reasonably required to separately document any such
subordination or non-subordination, attornment and/or non-disturbance agreement
as is provided for herein.

31. Attorney's Fees.  If any Party or Broker brings an action or proceeding to
enforce the terms hereof or declare rights hereunder, the Prevailing Party (as
hereafter defined) or Broker in any such proceeding action, or appeal thereon,
shall be entitled to reasonable attorney's fees.  Such fees may be awarded in
the same suit or recovered in a separate suit, whether or not such action or
proceeding is pursued to decision or judgment.  The term, "Prevailing Party"
shall include, without limitation, a Party or Broker who substantially obtains
or defeats the relief south, as the case may be, whether by compromise,
settlement, judgment, or the abandonment by the other Party or Broker of its
claim or defense.  The attorney's fees award shall not be computed in accordance
with any court fee schedule, but shall be such as to fully reimburse all
attorney's fees reasonably incurred.  Lessor shall be entitled to attorney's
fees, costs and expenses incurred in the preparation and service of notices of
Default and consultations in connection therewith, whether or not a legal action
is subsequently commenced in connection with such Default or resulting Breach.

32. Lessor's Access; Showing Premises; Repairs.  Lessor and Lessor's agents
shall have the right to enter the Premises at any time, in the case of an
emergency, and otherwise at reasonable times for the purpose of showing the same
to prospective purchasers, lenders, or lessees, and making such alterations,
repairs, improvements or additions to the Premises or to the building of which
they are a part, as Lessor may reasonably deem necessary.  Lessor may at any
time place on or about the premises or building any ordinary "For Sale" signs
and Lessor may at any time during the last one hundred twenty (120) days of the
term hereof place on or about the Premises any ordinary "For Lease" signs.  All
such activities of Lessor shall be without abatement of rent or liability to
Lessee.

33. Auctions. Lessee shall not conduct, nor permit to be conducted, either
voluntarily or involuntarily, any auction upon the Premises without first having
obtained Lessor's prior written consent.  Notwithstanding anything to the
contrary in this Lease, Lessor shall not be obligated to exercise any standard
of reasonableness in determining whether to grant such consent.

34. Signs.  Lessee shall not place any sign upon the Premises, except that
Lessee may, with Lessor's prior written consent, install (but not on the roof)
such signs as are reasonably required to advertise Lessee's own business.  The
installation of any sign on the Premises by or for Lessee shall be subject to
the provisions of Paragraph 7 (Maintenance, Repairs, Utility Installations,
Trade Fixtures and Alterations).  Unless otherwise expressly agreed herein.
Lessor reserves all rights to the use of the roof and the right to install, and
all revenues from the installation, of such advertising signs on the Premises
including


                                         -24-

<PAGE>

the roof, as do not unreasonably interfere with the conduct of Lessee's
business.

35. Termination; Merger.  Unless specifically stated otherwise in writing by
Lessor, the voluntary or other surrender of this Lease by Lessee, the mutual
termination or cancellation hereof, or a termination hereof by Lessor for Breach
by Lessee, shall automatically terminate any sublease or lesser estate in the
Premises; provided, however, Lessor shall, in the event of any such surrender,
termination or cancellation, have the option to continue any one or all of any
existing substances.  Lessor's failure within ten (10) days following any such
event to make a written election to the contrary by written notice of any
existing subtenancies.  Lessor's failure within ten (10) days following any such
event to make a written election to the contrary by written notice to the holder
of any such lesser interest, shall constitute Lessor's election to have such
event constitute the termination of such interest.

36. Consents.

           (a)    Except for Paragraph 33 hereof (Auctions) or as otherwise
provided herein, wherever in this Lease the consent of a Party is required to an
act by or for the other Party, such consent shall not be unreasonably withheld
or delayed.  Lessor's actual reasonable costs and expenses (including but not
limited to architects', attorneys', engineers' or other consultants' fees)
incurred in the consideration of, or response to, a request by Lessee for any
Lessor consent pertaining to this Lease or the Premises, including but not
limited to consents to an assignment, a subletting or the presence or use of a
Hazardous Substance, practice or storage tank, shall be paid by Lessee to Lessor
upon receipt of an invoice and supporting documentation therefor.  Subject to
Paragraph 12.2(e) (applicable to assignment or subletting), Lessor may, as a
condition to considering any such request by Lessee, require that Lessee deposit
with Lessor an amount of money (in addition to the Security Deposit held under
Paragraph 5) reasonably calculated by Lessor to represent the cost Lessor will
incur in considering and responding to Lessee's request.  Except as otherwise
provided, any unused portion of said deposit shall be refunded to Lessee without
interest.  Lessor's consent to any act, assignment of this Lease or subletting
of the Premises by Lessee shall not constitute an acknowledgement that no
Default or Breach by lessee of this Lease exists, nor shall such consent be
deemed a waiver of any then existing Default or Breach, except as may be
otherwise specifically stated in writing by Lessor at the time of such consent.

           (b)    All conditions to Lessor's consent authorized by this Lease
are acknowledged by Lessee as being reasonable.  The failure to specify herein
any particular condition to Lessor's consent shall not preclude the imposition
by Lessor at the time of consent of such further or other conditions as are then
reasonable with reference to the particular matter for which consent is being
given.

37. Guarantor.

    37.1   If there are to be any Guarantors of this Lease per Paragraph 1.11,
the form of the guaranty to be executed by each such Guarantor shall be in the
form most recently published by the American Industrial Real Estate Association,
and each said Guarantor shall have the same obligations as Lessee under this
Lease, including but not limited to the obligation to provide the Tenancy
Statement and information called for by Paragraph 16.

    37.2   It shall constitute a Default of the Lessee under this Lease if any
such Guarantor fails or refuses, upon reasonable request by Lessor to give, (a)
evidence of the due execution of the guaranty called for by this Lease,
including the authority of the Guarantor (and of the party signing on
Guarantor's behalf) to obligate such Guarantor on said guaranty, and including
in the


                                         -25-

<PAGE>

case of a corporate Guarantor, a certified copy of a resolution of its board of
directors authorizing the making of such guaranty, together with a certificate
of incumbency showing the signature of the persons authorized to sign on its
behalf, (b) current financial statements of Guarantor as may from time to time
be requested by Lessor, (c) a Tenancy Statement or a written confirmation that
the guaranty is still in effect.

38. Quiet Possession.  Upon payment by Lessee of the rent for the Premises and
the observance and performance of all of the covenants, conditions and
provisions on Lessee's part to be observed and performed under this Lease,
Lessee shall have quiet possession of the Premises for the entire term hereof
subject to all of the provisions of this Lease.

39. Options.

    39.1          Deleted.

    39.2          Deleted.

    39.3          Deleted

    39.4          Effect of Default on Options.

           (a)    Lessee shall have no right to exercise an Option,
notwithstanding any provision in the grant of Option to the contrary; (i) during
the period commencing with the giving of any notice of Default under Paragraph
13.1 and continuing until the noticed Default is cured, or (ii) during the
period of time any monetary obligation due Lessor from Lessee is unpaid (without
regard to whether notice thereof is given Lessee), or (iii) during the time
Lessee is in Breach of this Lease, or (iv) in the event that Lessor has given to
Lessee three (3) or more notices of Default under Paragraph 13.1, whether or not
the Defaults are cured, during the twelve (12) month period immediately
preceding the exercise of the Option.

           (b)    The period of time within which an Option may be exercised
shall not be extended or enlarged by reason of Lessee's inability to exercise an
Option because of the provisions of Paragraph 39.4(a).

           (c)    All rights of Lessee under the provisions of an Option shall
terminate and be of no further force or effect, notwithstanding Lessee's due and
timely exercise of the Option, if, after such exercise and during the term of
this Lease, (i) Lessee fails to pay to Lessor a monetary obligation of Lessee
for a period of thirty (30) days after such obligation becomes due (without any
necessity of Lessor to give notice thereof to Lessee), or (ii) Lessor gives to
Lessee three (3) or more notices of Default under Paragraph 13.1 during any
twelve (12) month period, whether or not the Defaults are cured, or (iii) if
Lessee commits a Breach of this Lease.

40. Multiple Buildings.  If the Premises are part of a group of buildings
controlled by Lessor, Lessee agrees that it will abide by, keep and observe all
reasonable rules and regulations which Lessor may make from time to time for the
management, safety, care, and cleanliness of the grounds, the parking and
unloading of vehicles and the preservation of good order, as well as for the
convenience of other occupants or tenants of such other buildings and their
invitees, and that Lessee will pay its fair share of common expenses incurred in
connection therewith.

41. Security Measures.  Lessee hereby acknowledges that the rental payable to
Lessor hereunder does not include the cost of guard service or other security
measures, and that Lessor shall have no obligation whatsoever to provide same.
Lessee assumes all responsibility for the protection of the Premises, Lessee,
its agents and invitees and their property from the acts of third parties.


                                         -26-

<PAGE>

42. Reservations.  Lessor reserves to itself the right, from time to time, to
grant, without the consent or joinder of Lessee, such easements, rights and
dedications that Lessor deems necessary, and to cause the recordation of parcel
maps and restrictions, so long as such easements, rights, dedications, maps and
restrictions do not unreasonably interfere with the use of the Premises by
Lessee.  Lessee agrees to sign any documents reasonably requested by Lessor to
effectuate any such easement rights, dedication, map or restrictions.

43. Performance Under Protest.  If at any time a dispute shall arise as to any
amount or sum of money to be paid by one Party to the other under the provisions
hereof, the Party against whom the obligation to pay the money is asserted shall
have the right to make payment "under protest" and such payment shall not be
regarded as a voluntary payment and there shall survive the right on the part of
said Party to institute suit for recovery of such sum.  If it shall be adjudged
that there was no legal obligation on the part of said Party to pay such sum or
any part thereof, said Party shall be entitled to recover such sum or so much
thereof as it was not legally required to pay under the provisions of this
Lease.

44. Authority.  If either Party hereto is a corporation, trust, or general or
limited partnership, each individual executing this Lease on behalf of such
entity represents and warrants that he or she is duly authorized to execute and
deliver this Lease on its behalf.  If Lessee is a corporation, trust or
partnership, Lessee shall, within thirty (30) days after request by Lessor,
deliver to Lessor evidence satisfactory to Lessor of such authority.

45. Conflict.  Any conflict between the printed provisions of this Lease and
the typewritten or handwritten provisions shall be controlled by the typewritten
or handwritten provisions.

46. Offer.  Preparation of this Lease by Lessor or Lessor's agent and
submission of same to Lessee shall not be deemed an offer to lease to Lessee.
This Lease is not intended to be binding until executed by all Parties hereto.

47. Amendments.  This Lease may be modified only in writing, signed by the
Parties in interest at the time of the modification.  The parties shall amend
this Lease from time to time to reflect any adjustments that are made to the
Base Rent or other rent payable under this Lease.  As long as they do not
materially change Lessee's obligations hereunder, Lessee agrees to make such
reasonable non-monetary modifications to this Lease as may be reasonably
required by an institutional, insurance company, or pension plan Lender in
connection with the obtaining of normal financing or refinancing of the property
of which the Premises are a part.

48. Multiple Parties.  Except as otherwise expressly provided herein, if more
than one person or entity is named herein as either Lessor or Lessee, the
obligations of such Multiple Parties shall be the joint and several
responsibility of all persons or entities named herein as such Lessor or Lessee.



LESSOR AND LESSEE HAVE CAREFULLY READ AND REVIEWED THIS LEASE AND EACH TERM AND
PROVISION CONTAINED HEREIN, AND BY THE EXECUTION OF THIS LEASE SHOW THEIR
INFORMED AND VOLUNTARY CONSENT THERETO.  THE PARTIES HEREBY AGREE THAT, AT THE
TIME THIS LEASE IS EXECUTED, THE TERMS OF THIS LEASE ARE COMMERCIALLY REASONABLE
AND EFFECTUATE THE INTENT AND PURPOSE OF LESSOR AND LESSEE WITH RESPECT TO THE
PREMISES.

    IF THIS LEASE HAS BEEN FILLED IN, IT HAS BEEN PREPARED FOR SUBMISSION
    TO YOUR ATTORNEY FOR HIS APPROVAL. FURTHER, EXPERTS SHOULD BE
    CONSULTED TO EVALUATE THE CONDITION OF THE PROPERTY AS TO THE POSSIBLE
    PRESENCE OF ASBESTOS, STORAGE TANKS OR HAZARDOUS SUBSTANCES.  NO


                                         -27-

<PAGE>

    REPRESENTATION OR RECOMMENDATION IS MADE BY THE AMERICAN INDUSTRIAL REAL
    ESTATE ASSOCIATION OR BY THE REAL ESTATE BROKER(S) OR THEIR AGENTS OR
    EMPLOYEES AS TO THE LEGAL SUFFICIENCY, LEGAL EFFECT, OR TAX CONSEQUENCES OF
    THIS LEASE OR THE TRANSACTION TO WHICH IT RELATES; THE PARTIES SHALL RELY
    SOLELY UPON THE ADVICE OF THEIR OWN COUNSEL AS TO THE LEGAL AND TAX
    CONSEQUENCES OF THIS LEASE.  IF THE SUBJECT PROPERTY IS LOCATED IN A STATE
    OTHER THAN CALIFORNIA, AN ATTORNEY FROM THE STATE WHERE THE PROPERTY IS
    LOCATED SHOULD BE CONSULTED.

The parties hereto have executed this Lease at the place on the dates specified
above to their respective signatures.

Executed at Lafayette, CA by LESSOR:  /s/ Harry Locklin

By
Name Printed
Title

Address:   956 Reliez Station Lane
           Lafayette, CA  94949
Tel. No. (510) 939-5666 Fax No. (510) 935-7678

by LESSEE:  Affymetrix, a California Corporation

By:  /s/ David B. Singer
Name Printed:  David B. Singer
Title:  President & Chief Executive Officer

By:  /s/ Stephen P. A. Fodor
Name Printed:     Stephen P. A. Fodor
                  3380 Central Expressway
                  Santa Clara, CA  95051

Tel No. (408) 522-6030  Fax No. (408) 481-0422



                                         -28-

<PAGE>

National Semiconductor


September 13, 1994




Mr. Harry Locklin
956 Reliez Station Lane
Lafayette, CA  94949

Dear Harry,

In follow up to our conversation of September 12, 1994, I am confirming National
Semiconductor Corporation's (NSC) position on the physical condition of the
property upon termination of the lease November 31, 1994.

1.  NSC will require a minimum of one (1) additional month to effectively
    vacate.  This will make the lease termination date December 31, 1994.

2.  Recognizing the requirements of Building Departments and Government
    Planning Agencies don't always coincide with private industry planning
    criteria.  I would like the flexibility of an additional month (January
    1995) for a holdover if we cannot meet current schedules.  I would give you
    forty-five (45) days notice if I needed this flexibility.

3.  Referencing letter of September 9, 1994 forwarded by Affymetrix (Dan
    Lazare), NSC agrees to all provisions of the letter except the following
    points - A to E.

    OFFICE AREAS

    A.     All Projection Screens - NSC may remove one or two screens in the
           reception area conference rooms.

    B.     NSC reserves the right to remove their conference room furniture in
           the reception area rooms.

    C.     Other - NSC would prefer this work to be the responsibility of the
           Owner or Affymetrix.  NSC will perform the work, however, if an
           alternate solution is not agreed upon between Owner and Affymetrix.

A.  PLANS.

    1.     PRELIMINARY PLANS.  Within thirty (30) days after execution of this
lease, Lessee shall, through an architect approved by Lessor, prepare plans and
specifications (the "Preliminary Plans") which shall indicate fully the specific
requirements of Lessee's space and the Tenant Improvements, as hereinafter
defined, required by Lessee, all adequate in scope to obtain a building permit
for construction of the Tenant Improvements.  "Tenant Improvements" shall mean
all improvements to the reality which constitutes the Premises, including,
without any limitation, interior portions of the Leased Premises such as
interior partitions, the floor coverings, reflected ceiling plan, interior
painting, types of materials and colors to be used within the Leased Premises,
signs (if any), plumbing fixtures, electrical requirements and mechanical
requirements including the heating, ventilating and air conditioning
requirements of Lessee, modifications to increase sprinkler system capacities
and communications systems wiring plans, among other things.

           The Preliminary Plans shall be subject to Lessor's prior written
approval (not to be unreasonably withheld), and


                                         -29-

<PAGE>

within ten (10) business days after receipt of the Preliminary Plans, Lessor
shall notify Lessee of its approval or disapproval.  Lessee's architect shall,
at Lessee's expense, revise the Preliminary Plans in accordance with Lessor's
objections and comments and resubmit them to Lessor within ten (10) days after
receipt of any disapproval by Lessor, in conformity with Lessor's comments.

    2.     FINAL PLANS.  The Preliminary Plans, approved or as modified
pursuant to paragraph 1, are hereinafter referred to as the "Final Plans."
Collectively, the Preliminary Plans, Final Plans and all changes thereto are
hereinafter referred to as the "Plans."

B.  CONSTRUCTION.  Lessor, at its own cost and expense, as soon as practicable
after the Final Plans have been adopted and approved and all other conditions to
Lessor's Work (if any) have been fulfilled, and unless prevented or delayed by
conditions over which it has no control, will arrange for the performance of
Lessor's Work (if any) either by Lessor or by contract with a contractor of its
choice.  If there is no Lessor's Work to be performed, Lessee will accept the
Premises in accordance with Paragraph D hereof and proceed with Lessee's Work
accordingly.

    1.     LESSOR'S WORK.  Lessor's Work shall be limited to that described in
Schedule 1 attached hereto.

    2.     LESSEE'S WORK.  Lessee's Work is described in Schedule 1 attached
hereto and shall be performed by Lessee at Lessee's sole cost and expense,
unless otherwise specifically provided in Schedule 2, if attached hereto.

C.  CHANGE ORDERS.  Any changes, modifications or alterations ("Change Orders")
requested by Lessee after approval of the Final Plans, shall be processed by the
Lessee's architect at Lessee's expense, and be subject to Lessor's prior written
approval.

    Upon revision of the Plans to accommodate any requested Change Order,
Lessor shall proceed with Lessor's Work, if any, as changed, provided any
additional Construction Costs resulting therefrom shall be paid in full by
Lessee to Lessor prior to adoption of such change, modification or alteration.
No such changes, modifications or alterations in the Plans and no changes in the
construction required by the Plans shall be made without the written consent of
Lessor after written request therefor by Lessee.  In the event Lessee rescinds
its request for a Change Order, Lessee shall remain liable for all increased
Construction Costs resulting from Lessor's processing of the requested Change
Order and any subsequent processing necessary to eliminate the Change Order from
Plans.

D.  ACCEPTANCE OF LEASED PREMISES.  Lessee agrees that upon substantial
completion of the Lessor's Work, if any, Lessee will accept the Premises.  After
acceptance of the Premises by Lessee, Lessee shall save and hold Lessor harmless
from liability as provided in the Lease.

    Upon acceptance of the Premises by Lessee, Lessee shall forthwith proceed
to perform all of Lessee's Work at its sole cost and expense as Lessee may
desire in order to prepare the Premises for Lessee's use thereof, provided any
such work to be performed by Lessee shall be performed in accordance with the
provisions set forth in the Lease regarding Alterations and only after receipt
of the approvals required by this Lease.

E.  RULES IN RESPECT OF ALTERATIONS. All work performed by the Lessee shall be
subject to compliance with the provisions of that Article of the Lease dealing
with Alterations, except where expressly in conflict with the Exhibit B.

F.  INSURANCE.  Prior to the commencement of Lessee's Work and until completion
thereof, or commencement of the Lease Term, whichever is the last to occur,
Lessee shall effect and maintain


                                         -30-

<PAGE>

Builder's Risk Insurance covering Lessor, Lessee and Lessee's contractors, as
their interest may appear, against loss or damage by fire, vandalism and
malicious mischief and such other risks as are customarily covered by a standard
"All Risk" policy of insurance protecting against all risk of physical loss or
damage to Lessee's Work in place and all materials stored at the site of
Lessee's Work, and all materials, equipment, supplies and temporary structures
of all kinds of incidental to Lessee's Work, and equipment, all while forming a
part of or contained in such improvements or temporary structures, or while on
the premises all to the actual replacement cost thereof at all times on a
completed value basis.  Lessee shall provide Lessor with certificates, or at
Lessor's request, a copy of the policy, evidencing that such insurance is in
full force and effect and stating the term thereof.  In addition, Lessee agrees
to indemnify and hold Lessor harmless against any and all claims for injury to
persons or damage to property by reason of the use of the Premises for the
performance of Lessee' Work, and claims, fines and penalties arising out of any
failure of Lessee or its agents, contractors and employees to comply with any
law, ordinance, code requirements, regulations or other requirements applicable
to Lessee's Work.  Lessee agrees to require all contractors and subcontractors
engaged in the performance of Lessee's Work to effect and maintain and deliver
to Lessee and Lessor certificates evidencing the existence of, and covering
Lessor, Lessee and Lessee's contractors, prior to commencement of Lessee's Work
and until completion thereof, the following insurance coverages:

    1.     Worker's Compensation and Occupational Disease Insurance in
accordance with the laws of the State in which the work is performed, including
Employer's Insurance to the limit of ONE HUNDRED THOUSAND DOLLARS ($100,000.00).

    2.     Commercial General Liability Insurance (excluding "Automobile
Liability") with independent contractors, contractual liability and completed
operations endorsements, covering personal injury, including death, with a limit
of THREE MILLION DOLLARS ($3,000,000.00) for any one (1) occurrence and property
damage with a limit of ONE MILLION DOLLARS ($1,000,000.00) for any one (1)
occurrence or a combined single limit policy of THREE MILLION DOLLARS
($3,000,000.00) per occurrence.

    3.     Comprehensive Automobile Insurance, including "nonowned"
automobiles, against bodily injury, including death resulting therefrom, with
limits of ONE MILLION DOLLARS ($1,000,000.00) for any one occurrence and TWO
HUNDRED FIFTY THOUSAND DOLLARS ($250,000) property damage or a combined single
limit of ONE MILLION DOLLARS ($1,000,000.00).

    4.     Owner's protective liability coverage for an amount not less than
THREE MILLION DOLLARS ($3,000,000.00).


                                         -31-

<PAGE>

                                  ADDENDUM TO LEASE


           This is an Addendum to that certain Standard Industrial/Commercial
Single-Tenant Lease (the "Form Lease") by and between Harry Locklin, as Lessor,
and Affymetrix, Inc., a California corporation, as Lessee, dated December 5,
1994.  Should there be any conflict between the provisions of this Addendum and
the provisions of the Form Lease, the provisions of this Addendum shall control.


1.  LESSEE'S INSPECTION:

    a.     INSPECTION:  Subsequent to vacation of the Premises by NSC, but
within forty-five (45) days of the Early Possession Date  Lessee may, at its own
risk and expense, upon reasonable notice to Lessor, and subject to such
conditions as Lessor may impose, conduct such reasonable soils and other
investigations on the Premises as Lessee may require.  Lessee shall rely upon
its own inspections and its own professional advisors in its examinations of the
property and all improvements thereon.  Lessee shall repair all damage to the
Premises resulting from Lessee's or Lessee's representatives coming upon the
Premises to perform such inspections, tests or analyses. Lessee shall indemnify,
defend by counsel acceptable to Lessor, and hold Lessor harmless from and
against any cost, claims, damages or liabilities, including but not limited to,
attorneys' fees and court costs that may arise in connection with any testing
done on the Premises.  Lessee's obligations under this Paragraph 1 shall survive
termination of this Lease.

    b.     NOTICE:  Within forty-five (45) days of the Early Possession Date,
Lessee shall notify Lessor in writing of any repair, replacements, and/or
alterations reasonably necessary to cause compliance with Paragraph 2 hereof.

2.  CONDITION OF PREMISES:

    a.     Lessor will replace and/or repair all floor damage resulting from
equipment removal wear and tear from the previous Lessee.  The cost of such
repair will not be deducted from the Allowance referenced in Schedule 2 of
Exhibit B hereof.  Upon occupancy of the Premises by Lessee, the roof and all
building systems, including but not limited to HVAC, electrical and plumbing
systems, and the NSC Equipment described in this Addendum, shall be in good
condition.  The Premises shall be delivered to Lessee in accordance with all
local and state codes and ordinances and comply with the Americans With
Disabilities Act ("ADA") requirements.  In the event that the upgrades that
Lessee proposes causes increased requirements for ADA, that cost shall be the
sole responsibility of the Lessee.  After Lessor has completed any items which
Lessee has identified as requiring repair, replacement or alteration in
accordance with Paragraph 1, or after forty-five (45) days from the Early
Possession Date without any notice from Lessee, Lessor shall have no further
obligation with respect thereto except as otherwise expressly

<PAGE>

provided in the Lease as amended by this Addendum.  If at any time during the
term of the Lease the HVAC units need to be replaced, the Lessee shall only be
responsible for its prorata share of the unit's useful life (the term of the
Lease remaining divided by the expected life of the units).

    b.     ROOF:  Lessor shall maintain the structural portions of the roof
and, provided Lessee has maintained the roof membrane as herein required, be
responsible for roof membrane replacement as and when required.  Lessor shall
effect such repairs as are noted on Lessee's notice delivered pursuant to
Paragraph 1 hereof and thereafter Lessee shall maintain the roof membrane in
good condition, reasonable wear and tear and damage by fire and other casualty
excepted but shall not be required to replace the same unless replacement
becomes required as a result of improper maintenance.  Lessee shall have access
to all appropriate past inspection records in Lessor's possession.


3.  INSURANCE:  Property insurance maintained by Lessor shall include
earthquake coverage but with respect to such earthquake coverage, Lessee shall
only be obligated to reimburse Lessor for 50% of that portion of the premium
applicable thereto.  Lessee shall have the right to review and reasonably
approve the property insurance maintained by Lessor for compliance with the
terms of this Lease and with respect to the amount of the deductible provided
therein.

4.  OPERATING EXPENSES:  Except to the extent that the Form Lease or this
Addendum expressly provides that Lessor shall pay such expenses, Lessee shall be
responsible for all operating expenses of the Premises.

5.  RENT SCHEDULE:

    MONTHS        LEASE RATE/MONTH          PER SQ. FT.
    ------        ----------------          -----------

    01-30         $14,992.50           $.75 NNN
    31-60         $15,992.00           $.80 NNN

6.  OPTION TO EXTEND THE TERM:

    a.     NOTICE OF EXERCISE.  Provided that Lessee is not in Breach of this
Lease at the time of exercise, Lessee shall have two options to extend the
initial term hereof for additional and consecutive periods of three (3) years
each upon the same terms and conditions as stated herein, except for Minimum
Monthly Rent.  The number of additional periods shall be reduced by one for each
option that is exercised.  Each such extension is herein referred to as an
"Extended Term."  Failure to timely exercise the first option hereunder shall
cause both options to become immediately null and void.  Lessee must exercise
its right, if at all, by written notification (the "Notice of Exercise") to
Lessor not less than six (6) months prior to the expiration of the initial term
hereof, or the then current Extended Term, if any.


                                         -2-

<PAGE>

    b.     OPTIONS ARE NOT PERSONAL.    In the event that Lessee assigns its
interest under the Lease as permitted hereunder, Lessee shall have the right to
assign the Option to such assignee and in the event Lessee sublets all or part
of the Premises as permitted hereunder, Lessee shall continue to have the right
to exercise its Option.

    c.     STRICT COMPLIANCE. Lessor grants the rights contained herein to
Lessee in consideration of Lessee's strict compliance with the provisions
hereof, including, without limitation, the manner of exercise of this option.

    d.     FAIR MARKET RENTAL.  If Lessee exercises the right to extend the
term then the Minimum Monthly Rent shall be adjusted to equal the Fair Market
Rental for the premises as of the date of the commencement of each such Extended
Term, pursuant to the procedures hereinafter set forth.  In determining the
"Fair Market Rental" for the Leased Premises the following factors applicable to
the Leased Premises or any comparable premises shall be considered:

           i.     Rental rates being charged for comparable premises in the
                  same geographical location.

           ii.    The relative locations of the comparable premises.

           iii.   The fact that Lessor will be providing no improvement
                  allowance.

           iv.    Rental adjustments, if any, or rental concessions.

           v.     Services and utilities provided or to be provided.

           vi.    Use limitations or restrictions.

           vii.   Any other relevant Lease terms or conditions.

           viii.  The fact that Lessor will not be paying a
                  commission.

           The Minimum Monthly Rent payable during the pendency of any
appraisal period shall continue to be the Minimum Monthly Rent payable at the
end of the previous Term.

    e.     DETERMINATION OF FAIR MARKET RENTAL.  Upon exercise of the right to
extend the term, and included within the Notice of Exercise, Lessee shall notify
Lessor of its opinion of Fair Market Rental as above defined for the Extended
Term.  If Lessor disagrees with Lessee's opinion of the Fair Market Rental, it
shall so notify Lessee ("Lessor's Value Notice") within thirty (30) days after
receipt of Lessee's Notice of Exercise.

    f.     APPRAISAL.  If the parties cannot resolve any disagreement regarding
the Fair Market Rent within ten (10) days after receipt by Lessee of Lessor's
Value Notice, then, within


                                         -3-

<PAGE>

twenty (20) days after Lessee's receipt of Lessor's Value Notice, Lessor and
Lessee each, and by giving notice to the other party, shall appoint a real
estate appraiser with at least five (5) years' full-time appraisal experience in
the geographical area of the Premises and with the leasing of properties of a
similar use as the Premises (i.e. research, development and production) to
appraise and set the Fair Market Rental for the Extended Term.  If either Lessor
or Lessee does not appoint an appraiser within twenty (20) days after the other
party has given notice of the name of its appraiser, the single appraiser
appointed shall be the sole appraiser and shall set the Fair Market Rental for
the Extended Term.  If two (2) appraisers are appointed by Lessor and Lessee
they shall meet promptly and attempt to set the Fair Market Rental for the
Extended Term.  If the two (2) appraisers are unable to agree within thirty (30)
days after the second appraiser has been appointed, they shall select a third
appraiser meeting the qualifications stated hereinabove within ten (10) days
after the last day the two (2) appraisers are given to set the Fair Market
Rental.  The third appraiser shall be a person who has not previously acted in
any capacity for either Lessor or Lessee.  The cost of appointing all of the
appraisers shall be shared equally by the parties.  Within thirty (30) days
after the selection of the third appraiser, a majority of the appraisers shall
set the Fair Market Rental for the Extended Term.  If a majority of the
appraisers is unable to set the Fair Market Rental within the stipulated period
of time, the three (3) appraisals shall be added together and their total
divided by three (3); the resulting quotient shall be the Fair Market Rental for
the Premises during the Extended Term.  However, if the low appraisal is more
than ten percent (10%) lower than the middle appraisal, the low appraisal shall
be disregarded; if the high appraisal is more than ten percent (10%) higher than
the middle appraisal, the high appraisal shall be disregarded.  If only one (1)
appraisal is disregarded, the remaining two (2) appraisals shall be added
together and their total divided by two (2); the resulting quotient shall be the
Fair Market Rental for the Premises during the Extended Term.  If both the low
appraisal and the high appraisal are disregarded as stated hereinabove, the
middle appraisal shall be the Fair Market Rental for the Premises during the
Extended Term.  After the Fair Market Rental for the Extended Term has been set,
the appraisers immediately shall notify Lessor and Lessee, and Lessor and Lessee
immediately shall execute an amendment to the Lease stating the Fair Market
Rental.

7.  EXISTING EQUIPMENT TO REMAIN IN FACILITY:  Lessor has received, in the form
of Exhibit A attached (see letters of September 9, 1994 and September 13, 1994),
a commitment from National Semiconductor Corporation ("NSC") that, on their
departure from the Premises, they will leave all mechanical and electrical
equipment in place and operating.  Such equipment shall include an air
compressor(s), vacuum pump(s), process cooling water equipment ("NSC
Equipment"), deionized water system, acid waste treatment system, all roof top
equipment, 50 Herz generator & panel, all standard laboratory chemical benches
and fume hoods.  Lessor shall request NSC to leave one half of


                                         -4-

<PAGE>

the office cubicles and furniture in the facility.  Lessor shall request that
all disconnections from NSC Equipment be made in a neat, workmanlike manner with
no loose or dangling wires and no hacksawed, cut or hammered pipes.

    In the event that NSC does not abide by its commitment to leave all
mechanical and electrical equipment in place and operating, Lessee shall have
the right, as its sole remedy, exercisable within thirty (30) days after the
Early Possession Date, to terminate the Lease without any liability to Lessor.

8.  INFORMATION AND REQUEST FROM PRIOR LESSEE:  Lessor shall request that NSC
provide Affymetrix with the following information:

    a.     Operating and maintenance manuals for all equipment left in the
           building.

    b.     Written preventive maintenance and repair records and identity of
           contractors, if any, who performed such work.

    c.     Copies of building permits and inspections and copies of
           decommissioning documents.

9.  SIGNAGE/GRAPHICS:  Lessee will have the right to display its corporate name
and logo on the face of the structure and at various locations surrounding the
building as long as Lessee is in compliance with ordinances of the City of
Sunnyvale.  Lessee shall repair any damages made to the Premises due to the
installation, maintenance and/or removal of such signs.

10. RIGHTS TO ASSIGN OR SUBLEASE:  Lessee shall have the right to assign all or
any portion of its interest under this Lease or sublet the entire Premises
without Lessor's consent to any parent, wholly-owned, subsidiary or affiliate of
Lessee, any party which results from any merger, consolidation or other business
organization of Lessee, and/or any party which acquires all or substantially all
the assets or stock of Lessee; provided, however, that Lessee shall give Lessor
at least thirty (30) days' prior written notice thereof; that Lessee shall not
be released from its obligations under the lease by reason of any such
assignment; that the Transferee have a net worth at least equal to that of
Affymetrix at lease execution; and that the Transferee has sufficient working
capital to meet all lease obligations as they accrue.

11. NO REPRESENTATIONS:  Lessee acknowledges that Lessor's Broker has not made
any independent investigation of the Premises or determination with respect to
the physical and environmental condition of the Premises including without
limitation the existence of any underground tanks, pumps, piping, toxic or
hazardous substances on the Premises.


                                         -5-

<PAGE>

    Likewise, no investigation has been made to ensure compliance with the
"American With Disabilities Act" (ADA). This Act may require a variety of
changes to a facility, including potential removal of barriers to access by
disabled persons and provision of auxiliary aids and services for hearing,
vision or speech impaired persons.  Lessee is advised to obtain independent
legal and technical advise with respect to the physical and environmental
condition and ADA compliance of the Premises.  Lessee agrees that it will rely
solely on its own investigations and/or that of a licensed professional
specializing in such matters and not on Lessor's Broker.  Lessor's Broker does
not represent or warrant the accuracy or completeness of any documents or
information reviewed or received by any of the parties in connection with this
transaction, including reports, structural, geological or engineering studies,
and plans and specifications.  Except as expressly provided herein, Lessor makes
no representation or warranty as to the Premises or the condition thereof, or
the suitability for Lessee's use or compliance with governmental regulations.

12. CONTINGENCY:  Lessee's improvement of the Premises in accordance with plans
approved by Lessor is subject to the receipt of permits from the City of
Sunnyvale.  Promptly after approval of its plans by Lessor, Lessee shall apply
for such permits and diligently pursue such application.  If such permits are
not received by February 28, 1995, Lessee may thereafter terminate this Lease
upon notice to the Lessor given not later than March 31, 1995.

13. EXPIRATION DATE:  Notwithstanding Section 1.3 of the Form Lease to the
contrary, if the Commencement Date occurs after May 1, 1995, the Expiration Date
shall occur five (5) years and zero (0) months after the Commencement Date.
(Therefore, for example, if the Commencement Date does not occur until June 1,
1995, then the Expiration Date shall be May 31, 2000.)

14. NOTICE OF DELIVERY OF EARLY POSSESSION; COMMENCEMENT DATE MEMORANDUM:
Lessor shall provide ten (10) business days prior written notice to Lessee in
the event that Lessor desires to deliver possession of the Premises to Lessee
prior to February 1, 1995.  Further, within ten (10) days after delivery the
parties shall execute a memorandum setting forth the Commencement Date and
Expiration Date of the Lease.

15. REAL ESTATE BROKERS:  The following information is specified to clarify
Section 1.10 of the Form Lease:

           Lessor has dealt exclusively with Jim Binsacca at Cornish & Carey
Commercial Oncor International.  Lessee has dealt exclusively with R. Randolph
Scott at Cornish & Carey Commercial Oncor International and Mark Pearson at
Catalyst Real Estate Group.

16. DELAY IN POSSESSION:  Notwithstanding Section 3.3 of the Form Lease to the
contrary, and in addition to any termination


                                         -6-

<PAGE>

rights Lessee may have thereunder, if possession of the Premises is not
delivered to Lessee by March 1, 1995, Lessee shall have the right, as its sole
remedy, to terminate this Lease.

17. HAZARDOUS SUBSTANCE:  For the purposes of the Lease "Hazardous Substance"
shall mean and include any hazardous or toxic substance, material or waste which
is or becomes regulated by any local governmental or regulatory authority, the
state of California or the United States government.  Lessor makes the following
representations and warranties to Lessee as of the date of the Lease (which
representations and warranties will survive the termination of the Lease) with
respect to Hazardous Substances:  (i) except as disclosed in the letter of
Advanced Safety Applications, Inc. dated September 13, 1983 addressed to James
Schlosser of Printed Circuits International, Inc. which was delivered to Lessee
by Lessor, to Lessor's actual knowledge without inquiry there is no
contamination from any Hazardous Substances on the Premises; (ii) to Lessor's
actual knowledge without inquiry, the Premises is in compliance with all laws
relating to Hazardous Substances including, but not limited to, those relating
to soil and groundwater conditions; (iii) there are no claims or actions pending
or threatened against Lessor or any portion of the Premises by any governmental
entity or agency or any other person or entity relating to Hazardous Substances
or pursuant to laws concerning Hazardous Substances; (iv) there is to Lessor's
actual knowledge without inquiry no occurrence or condition on any other real
property that could cause the Premises or any part thereof to be otherwise
subject to any restrictions on ownership, occupancy, transferability or use
which would interfere with Lessee's intended use thereof as proposed in this
Lease under any laws concerning Hazardous Substances.

    a.     Lessor shall indemnify, protect, defend and hold harmless Lessee,
its directors, officers, employees, and agents, and any assignees, subtenants,
or successors to Lessee's interest in the Premises and their directors,
officers, employees, and agents, from and against any and all damages,
liabilities, judgments, costs, claims, liens, expenses and penalties including
reasonable attorneys' fees arising out of or attributable to the use,
generation, production, maintenance, storage, disposal, discharge, release, or
transportation of Hazardous Substances on the Premises prior to the date of
delivery of the Premises; and from and against the cost of any investigation,
removal, remediation, restoration or abatement thereof.  Nothing herein
contained shall make Lessor responsible for Lessee's business interruption or
loss of profits under the provisions of this indemnity.

    b.     If any such investigation, removal, remediation, restoration or
abatement or similar action is required by any governmental authority ("Remedial
Activity"), and such action requires that Lessee be closed for business or
access be denied in whole or in part for greater than a twenty-four (24) hour
period, then:


                                         -7-

<PAGE>

           i.      If the Remedial Activity materially interferes with Lessee's
production, such as the loss of the use of the production floor and systems that
support production activity ("Essential Activities") all payments due under the
Lease, including Base Rent, shall be abated entirely during the period beyond
twenty-four (24) hours and if the closure or denial of access persists in excess
of sixty (60) days then Lessee shall have the right to terminate the Lease.

           ii.    If the Remedial Activity materially interferes with  Lessee's
use which is not an Essential Activity all payments due under the Lease,
including Base Rent, shall be abated (on a square footage basis) only to the
extent that Lessee is deprived of the use of a portion of the Premises during
the period beyond twenty-four (24) hours and if the closure or denial of access
persists in excess of one hundred twenty (120) days then Lessee shall have the
right to terminate the Lease.

    c.     Notwithstanding any provision of the Lease to the contrary, Lessee
shall have no obligation whatsoever, including no financial obligations, with
respect to or otherwise attributable to the use, generation, production,
maintenance, storage, disposal, discharge, release or transportation of
Hazardous Substances on neighboring properties unless caused by Lessee.

18. CAPITAL IMPROVEMENTS:  Notwithstanding Section 7.1 of the Form Lease to the
contrary, the cost of each capital expenditure made for reasonably necessary (as
opposed to elective) repairs and/or replacements to the parking lot or the HVAC
systems made by Lessee shall be amortized over the period of its useful life and
Lessor shall be responsible to pay upon demand by Lessee the amortized portion
attributable to any period after expiration of the Term.  For the purposes of
calculating Lessor's obligations hereinabove the Term shall not be deemed to
include any then unexercised Option terms.  In the event that Lessee exercises
an Option to extend the Term after any payment by Lessor hereunder has already
taken place, the parties shall recalculate Lessor's obligation and the
appropriate amount shall be returned to Lessor, upon the exercise of such Option
to extend.

19. ALTERATIONS:  Notwithstanding Section 7.3 of the Form Lease to the
contrary, Lessee may make any Alterations in, on, under or about the Premises
without Lessor's prior written consent provided that the cumulative cost thereof
in any calendar year does not exceed $50,000 and provided further that such
Alterations are not Utility Installations, do not affect the structural portions
of the Premises or the exterior of the building.

20. REMOVAL OF TENANT IMPROVEMENT WORK:  Notwithstanding any provision of
Section 7.4 of the Form Lease to the contrary, Lessee shall not be obligated to
remove from the Premises at the expiration of the Term any part of its initial
improvements approved by Lessor, including the Tenant Improvement Work


                                         -8-

<PAGE>

identified in Schedules 1 and 2 to the Addendum.  As to any alterations or
additions during the Term of the Lease, Lessee shall be obligated to remove the
same only if Lessor has specified such removal at the time that required consent
of the Lessor to such alterations or additions is sought and obtained.

21. EXEMPTION OF LESSOR FROM LIABILITY:  Lessor's exemption from liability in
Section 8.8 of the Form Lease shall not extend to any injury or damage to the
extent attributable to the negligence or wilful misconduct of Lessor or its
breach of the Lease.

22. REPAIR OF PARTIAL DAMAGE TO PREMISES:

    a.     Notwithstanding Section 9.6 of the Form Lease to the contrary,
Lessor's repair of Premises Partial Damage pursuant to Section 9.2 of the Form
Lease shall be completed no later than one hundred fifty (150) days after the
date of occurrence of the damage subject to delays beyond the reasonable control
of Lessor including strikes, acts of God, extraordinary weather conditions and
the like.   If within thirty (30) days after the occurrence of the damage Lessee
reasonably estimates that the repair of the damage will take more than 150 days
to repair, Lessee shall have the right to terminate this Lease as of the date of
the damage by notice in writing to Lessor delivered within such thirty (30) day
period.

    b.     The provisions of Section 9.2 are limited to the extent that Lessee
shall not be required to contribute more than 50% of the deductible amount of
the property insurance policy toward the cost of repair or restoration, and
Lessor shall contribute the balance.

23. LESSOR'S OBLIGATION OF REMEDIATION:  Notwithstanding provision (ii) of
Section 9.7 of the Form Lease to the contrary, Lessor shall bear the full cost
of investigation and remediation of any Hazardous Substance condition, and
Lessor shall have no right to terminate the Lease in connection therewith, if
such Hazardous Substance condition is attributable to, in whole or in part,
Hazardous Substances which were in existence in, on or under the Premises on or
prior to the date of delivery thereof.

24. PAYMENT OF TAXES:  Lessor and Lessee agree that during the Term Lessee
shall make advance payments of Real Property Taxes along with payments of Base
Rent as provided in Section 10.1(b) of the Form Lease.

25. CURE PERIOD FOR CERTAIN DEFAULTS:  The ten (10) day cure period for certain
defaults specified in the final line of Section 13.1(c) of the Form Lease shall
be replaced with the number fifteen (15).

26. MORTGAGEE NON-DISTURBANCE:  Within Thirty (30) days following the full
execution of the Lease by both parties thereto, Lessor shall use its best
efforts to obtain a non-disturbance and recognition agreement from each present
mortgagee


                                         -9-

<PAGE>

of Lessor having rights in the Premises appear to those of Lessee under this
Lease which agreement shall be reasonably acceptable to Lessee.  Said agreement
shall provide, at a minimum, that Lessee's use and enjoyment of the Premises
shall not be disturbed so long as Lessee is not in Breach of the Lease.  Lessee
shall have the right to terminate this lease if the non-disturbance agreement
has not been obtained within sixty (60) days of the execution of this lease.

27. NO GROUND LEASE:  Lessor warrants that there is no ground lease in effect
with respect to the Premises.

28. LESSOR ACCESS:  Notwithstanding any provision of Section 32 of the Form
Lease to the contrary, except in an emergency  Lessor must provide reasonable
advance notice to Lessee of its desire to enter the Premises.  Such entry (other
than in emergencies) may occur only during reasonable business hours as
determined by Lessee in its sole discretion.  Any entry shall be for a
reasonable period of time only and shall cause as little interference to Lessee
and its business as reasonably necessary.  Lessor acknowledges that Lessee may
impose reasonable security measures on or otherwise limit or restrict Lessor's
access to certain portions of the Premises in order to protect proprietary or
confidential information used by Lessee and its business provided however,
Lessor may obtain access to such restricted areas for legitimate business
purposes for persons who are not competitors of Lessee provided such non
competitors shall sign a confidentiality agreement in form and substance
reasonably satisfactory to Lessee.

29. RETURN OF DEPOSITS:  Should this lease be terminated by either party as
permitted herein, Lessor promptly shall return to Lessee all payments and
deposits theretofore made by Lessee to Lessor.


LESSOR:    HARRY LOCKLIN               LESSEE:  AFFYMETRIX


By: /S/ HARRY P. LOCKLIN          By:  /S/ DAVID B. SINGER
    --------------------               -------------------

Date:  12/11/94                   Its:     PRESIDENT
    ----------                         -------------


                                  By:  /S/ STEPHEN P. A. FODOR
                                      --------------------------

                                  Its:     PRESIDENT
                                      --------------------------

                                       Date:    12/6/94
                                            -----------


                                         -10-

<PAGE>

                                      SCHEDULE 1


LESSOR'S WORK:    Except as to any work which is required to place the Premises
                  in the condition required for delivery as set forth in the
                  Lease, Lessor shall not be responsible for any work
                  whatsoever with respect to the Leased Premises.  Lessee
                  agrees that, subject to the provisions of the Lease and
                  Addendum thereto, (i) it shall accept the Leased Premises in
                  AS-IS condition as of the date Lessee takes possession of the
                  Leased Premises with Lessor's consent; (ii) Lessor shall have
                  no responsibility to make any Tenant Improvements which may
                  be required to prepare the Leased Premises for Lessee's use;
                  (iii) Lessee, at its sole cost and expense, shall complete
                  any Tenant Improvements which may be required upon the Leased
                  Premises prior to Lessee's initial opening for business; and
                  (iv) all such Tenant Improvements shall be completed in
                  accordance with all applicable City, County, and State laws,
                  ordinances, rules and regulations relating thereto.

LESSEE'S WORK:    Lessee shall cause to be prepared and submitted to Lessor for
                  its approval plans for Lessee's improvements to the Premises
                  ("Tenant Improvements").  Lessor shall promptly approve or
                  disapprove such plans and Lessee shall make all changes which
                  may reasonably be requested by Lessor.  When such plans have
                  been approved by Lessor they shall be referred to herein as
                  the Final Plans.   Lessee's Work shall consist of all work
                  described in the Final Plans and any other work which is
                  approved by the Lessor or which may be required by Lessee or
                  governmental authority, or which may be necessary to ready
                  the Leased Premises for Lessee's occupancy.


                                         -1-

<PAGE>

                                      SCHEDULE 2

    Lessor shall reimburse Lessee for all Construction Costs incurred by Lessee
in the construction of the Tenant Improvements, but not in any event to exceed
the sum of Ninety Thousand Dollars ($90,000), hereinafter referred to as the
"Improvement Allowance."  The term "Construction Costs" shall mean building
permit fees and the amount of the contract for labor and materials paid to third
party contractors or subcontractors in the building trades for Tenant
Improvements.  Construction Costs shall exclude all other costs and, further,
shall exclude costs that might otherwise be considered to be Construction Costs
but which are for professional services, insurance or bonds, licenses,
inspection, soils reports, signs, equipment, trade fixtures, interior
decorations, other improvements which are not of a permanent nature or which are
unique to Lessee's use and not readily usable by another tenant, nor utility
hook-up fees.

    Upon Lessor's approval of Final Plans and following issuance of necessary
building permits, Lessor shall pay to Lessee the sum of Forty-Five Thousand
Dollars ($45,000) on account of the Improvement Allowance.  The balance of the
Improvement Allowance shall be paid within thirty (30) days thereafter.

    a.     Following completion of the Tenant Improvements Lessee shall do the
following:

           i.     Certify to Lessor that the total cost of Lessee's Work equals
or exceeds the Improvement Allowance and deliver such evidence thereof as Lessor
shall reasonably request.

           ii.    Cause the Leased Premises to be discharged and released from
any and all claims or liens that may have accrued from the performance of
Lessee's Work.

           iii.   Deliver to Lessor or its designee copies of all guarantees
and warranties relating to the work performed.

           iv.    Deliver a written guaranty to Lessor from Lessee, and
certificate from Lessee's architect, that all work has been substantially
performed in accordance with the Final Plans, as amended by approved change
orders, if any.

           v.     Deliver to Lessor a copy of the certificate of Occupancy
issued by the appropriate governmental agency, if any.

           vi.    Furnish Lessor with one (1) set of as-built plans which
incorporate all changes in the Final Plans made during the course of
construction, and which accurately describe the work as in fact built.

    b.     If at any time during the progress of the work or before the final
payment is made any lien or claim of lien is filed or notification to withhold
money for labor or material


                                         -2-

<PAGE>

furnished by Lessee or the contractor is served on Lessor, Lessor shall have the
right to withhold from any payment otherwise due Lessee an amount sufficient to
discharge any and all such liens or claims.  Documentation in form satisfactory
to Lessor that such liens or claims have been released must be furnished to
Lessor by Lessee or Lessee's contractor before the retained money will be paid
to Lessee, or if Lessee or its contractor have not settled the liens or claims
within a reasonable time, not to exceed ten (10) business days, from and after
the date on which such lien or claim is made, Lessor shall have the right, but
not the obligation, to discharge any or all such liens or claims out of the
withheld money.


                                         -3-


<PAGE>
                                                                    EXHIBIT 11.1
 
                                AFFYMETRIX, INC.
 
                 STATEMENT OF COMPUTATION OF NET LOSS PER SHARE
                    (IN THOUSANDS, EXCEPT PER SHARE AMOUNTS)
 
<TABLE>
<CAPTION>
                                                                 YEAR ENDED DECEMBER 31,       THREE MONTHS ENDED
                                                             -------------------------------       MARCH 31,
                                                               1993       1994       1995       1995       1996
                                                             ---------  ---------  ---------  ---------  ---------
<S>                                                          <C>        <C>        <C>        <C>        <C>
Net loss...................................................  $  (5,592) $  (9,680) $ (10,747) $  (2,174) $  (3,921)
                                                             ---------  ---------  ---------  ---------  ---------
                                                             ---------  ---------  ---------  ---------  ---------
Historical primary and fully diluted number of shares:
  Weighted average common shares...........................         19        398        409        408        409
  Shares related to SAB Topic 4D:
    Common shares..........................................        201        201        201        201        201
    Stock options and warrants.............................      1,424      1,424      1,424      1,424      1,424
    Preferred shares.......................................      5,778      5,778      5,778      5,778      5,778
                                                             ---------  ---------  ---------  ---------  ---------
Shares used in computing net loss per share................      7,422      7,801      7,812      7,811      7,812
                                                             ---------  ---------  ---------  ---------  ---------
                                                             ---------  ---------  ---------  ---------  ---------
Net loss per share.........................................  $   (0.75) $   (1.24) $   (1.38) $   (0.28) $   (0.50)
                                                             ---------  ---------  ---------  ---------  ---------
                                                             ---------  ---------  ---------  ---------  ---------
Pro forma number of shares:
  Weighted average common shares...........................         19        398        409        408        409
  Shares related to SAB Topic 4D:
    Common shares..........................................        201        201        201        201        201
    Stock options and warrants.............................      1,424      1,424      1,424      1,424      1,424
    Preferred shares.......................................      5,778      5,778      5,778      5,778      5,778
  Convertible preferred shares, as if converted............      3,293      9,852      9,852      9,852      9,852
                                                             ---------  ---------  ---------  ---------  ---------
Shares used in computing pro forma net loss per share......     10,715     17,653     17,664     17,663     17,664
                                                             ---------  ---------  ---------  ---------  ---------
                                                             ---------  ---------  ---------  ---------  ---------
Pro forma net loss per share...............................  $   (0.52) $   (0.55) $   (0.61) $   (0.12) $   (0.22)
                                                             ---------  ---------  ---------  ---------  ---------
                                                             ---------  ---------  ---------  ---------  ---------
</TABLE>

<PAGE>
                                                                    EXHIBIT 23.1
 
               CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS
 
   
    We  consent  to  the reference  to  our  firm under  the  captions "Selected
Financial Data" and "Experts"  and to the  use of our  report dated February  9,
1996  (except  for the  first  paragraph of  Note  9, as  to  which the  date is
           , 1996), in Amendment No. 2  to the Registration Statement (Form  S-1
No. 333-3648) and related Prospectus of Affymetrix, Inc. for the registration of
5,750,000 shares of its common stock.
    
 
                                          ERNST & YOUNG LLP
Palo Alto, California
         , 1996
 
--------------------------------------------------------------------------------
The  foregoing consent is in the form that will be signed upon the completion of
the reverse stock split described in Note 9 to the financial statements.
 
                                          /s/ Ernst & Young LLP
   
Palo Alto, California
May 20, 1996
    

<PAGE>

                                                                   EXHIBIT 23.3

                  CONSENT OF TOWNSEND AND TOWNSEND AND CREW LLP


     We consent to the reference to our firm under the caption "Experts" in 
the Registration Statement (Form S-1) and related Prospectus of Affymetrix, 
Inc. for the registraion of 5,750,000 shares of its common stock.


                                       TOWNSEND AND TOWNSEND AND CREW LLP


                                       By: /s/ Paul C. Haughey
                                          ------------------------------------
                                          Paul C. Haughey
                                          Partner


Palo Alto, California
May 20, 1996



<PAGE>
                                                                    EXHIBIT 24.3
 
                               POWER OF ATTORNEY
 
    KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears
below constitutes and appoints John D. Diekman, Ph.D. and Kenneth J. Nussbacher,
or either of them, each with the power of substitution, his attorney-in-fact, to
sign  any amendments  to this  Registration Statement  (including post-effective
amendments), and to file the same, with exhibits thereto and other documents  in
connection  therewith,  with  the  Securities  and  Exchange  Commission, hereby
ratifying and  confirming  all  that  each of  said  attorneys-in-fact,  or  his
substitute or substitutes, may do or cause to be done by virtue hereof.
 
    Pursuant   to  the  requirements  of  the   Securities  Act  of  1933,  this
Registration Statement on Form S-1 has  been signed by the following persons  in
the capacities and on the dates indicated.
 
<TABLE>
<C>                                                    <S>                                         <C>
                      SIGNATURE                                         CAPACITY                        DATE
-----------------------------------------------------  ------------------------------------------  ---------------
 
                                                       Director, and Chief Executive
     ------------------------------------------         Officer (Principal Executive Officer)        May  , 1996
               John D. Diekman, Ph.D.
 
     ------------------------------------------        Director and President                        May  , 1996
              Stephen P.A. Fodor, Ph.D.
 
     ------------------------------------------        Director                                      May  , 1996
                  Paul Berg, Ph.D.
 
     ------------------------------------------        Director                                      May  , 1996
                   Douglas M. Hurt
 
     ------------------------------------------        Director                                      May  , 1996
                Vernon R. Loucks, Jr.
 
                   /s/ BARRY C. ROSS, PH.D.
     ------------------------------------------        Director                                     May 10, 1996
                Barry C. Ross, Ph.D.
 
     ------------------------------------------        Director                                      May  , 1996
                   David B. Singer
 
     ------------------------------------------        Director                                      May  , 1996
                    John A. Young
 
     ------------------------------------------        Director                                      May  , 1996
            Alejandro C. Zaffaroni, Ph.D.
 
                                                       Chief Financial Officer
     ------------------------------------------         (Principal Financial and                     May  , 1996
                Kenneth J. Nussbacher                   Accounting Officer)
</TABLE>


© 2022 IncJournal is not affiliated with or endorsed by the U.S. Securities and Exchange Commission