X0306 4 2015-03-04 0 0000073020 NORTHWEST NATURAL GAS CO NWN 0001383981 Yoshihara Grant M 220 NW SECOND AVENUE PORTLAND OR 97209 0 1 0 0 VP Common Stock 2015-03-04 4 F 0 268 46.57 D 10898.967 D Common Stock 2015-03-04 4 F 0 190 46.57 D 10708.967 D Common Stock 2231.5824 I See Footnote Shares were withheld by the issuer to cover withholding taxes on issuance of shares due to vesting of restricted stock units. Organization and Executive Compensation Committee certification of satisfaction of the performance threshold and vesting for these restricted stock units was reported on Form 4 filed on February 27, 2015. Shares were withheld by the issuer to cover withholding taxes on issuance of performance shares. Organization and Executive Compensation Committee certification of the payout of these performance shares was reported on Form 4 filed on February 27, 2015. Shares held in reporting person's account under issuer's Retirement K Savings Plan as of February 28, 2015. Shawn M. Filippi, Attorney-in-Fact 2015-03-06