X0306 4 2013-12-31 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 Common Stock 2013-12-31 4 F 0 9396 8.57 D 275747 D Represents the number of shares withheld by Affymetrix, Inc. to cover the tax liability resulting from the scheduled vesting of 25,000 performance stock units determined to be earned on February 12, 2013 with respect to Dr. Witney's 2012 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 2014-01-03