X0306 4 2012-12-31 0 0000913077 AFFYMETRIX INC AFFX 0001455312 Witney Frank C/O AFFYMETRIX, INC. 3420 CENTRAL EXPRESSWAY SANTA CLARA CA 95051 1 1 0 0 President and CEO Comon Stock 2012-12-31 4 F 0 22009 3.17 D 214236 D Represents the number of shares withheld by Affymetrix, Inc. to cover the tax liability resulting from the scheduled vesting of 60,000 performance stock units determined to be earned on January 31, 2012 with respect to Dr. Witney's 2011 performance. When they are earned, Dr. Witney's performance stock units vest one year after the end of the applicable performance period. /s/ Siang H. Chin, Attorney-in-Fact for Frank Witney 2013-01-02