X0306 4 2015-02-27 0 0000909832 COSTCO WHOLESALE CORP /NEW COST 0001487207 McKay John D 999 LAKE DRIVE ISSAQUAH WA 98027 0 1 0 0 Executive Vice President Common Stock 2015-02-27 4 A 0 1599 146.96 A 64944 D Represents additional restricted stock units ("RSUs") resulting from the upward adjustment of outstanding unvested RSUs by a factor of 1.042 in connection with the $5.00 per share special cash dividend payable by the issuer to shareholders of record on February 27, 2015. The adjustment was required under the plan documents governing the grants. The RSUs reported are subject to the same vesting schedules as the original RSUs to which they relate. Deanna K. Nakashima, attorney-in-fact 2015-03-03