X0206 3 2014-03-01 0 0001049502 MKS INSTRUMENTS INC MKSI 0001600515 Quirk Brian Charles 2 TECH DRIVE, SUITE 201 ANDOVER MA 01810 1 Sr. VP, Global Operations Common Stock 3152.635 D Restricted Stock Unit Common Stock 17040.25 D Restricted Stock Unit Common Stock 14428.831 D The RSUs vest in equal annual installments over three years from the respective original grant date. The amount above comprises of: 2,113.136 which was granted on April 11, 2011; 4,938.407 which was granted on April 2, 2012; 3,962.536 which was granted on February 25, 2013; and 6,026.171 on February 10, 2014. Each restricted stock unit represents the contingent right to receive one share of common stock of MKS Instruments, Inc. These RSUs are subject to the achievement of performance criteria determined in the first year of the grant and thereafter vests in equal annual installments of over three years from the respective original grant date. The amount above comprises of 5,389.575 which was granted on on February 25, 2013 and 9,039.256 on February 10, 2014. /s/Renee M. Donlan POA 2014-03-06