X0306 4 2015-03-25 0 0000913077 AFFYMETRIX INC AFFX 0001485088 Last Andrew J. C/O AFFYMETRIX, INC. 3420 CENTRAL EXPRESSWAY SANTA CLARA CA 95051 0 1 0 0 EVP, Chief Operating Officer Common Stock 2015-03-25 4 M 0 90000 5.29 A 260112 D Common Stock 2015-03-25 4 M 0 20000 4.22 A 280112 D Common Stock 2015-03-25 4 S 0 110000 12.79 D 170112 D Option to Purchase Common Stock 5.29 2015-03-25 4 M 0 90000 0 D 2016-12-17 Common Stock 90000 0 D Option to Purchase Common Stock 4.22 2015-03-25 4 M 0 20000 0 D 2017-08-19 Common Stock 20000 50000 D Sold pursuant to a 10b5-1 Trading Plan. These sales were executed in multiple trades at prices ranging from $12.685 to $12.99. The price reported above reflects the weighted average sales price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected. Stock option became exercisable in equal annual installments over four years from the grant date of December 17, 2009. Stock option became exercisable in equal annual installments over four years from the grant date of August 19, 2010. /s/ Siang H. Chin, Attorney-in-Fact for Andrew J. Last 2015-03-26