X0306 4 2018-03-01 0 0000073020 NORTHWEST NATURAL GAS CO NWN 0001571275 WILSON BRODY J 220 NW SECOND AVENUE PORTLAND OR 97209 0 1 0 0 VP, Treas., CAO & Controller Common Stock 2018-03-01 4 F 0 165 52.15 D 3754 D Common Stock 2018-03-01 4 F 0 281 52.15 D 3473 D Common Stock 440.578 I See Footnote Common Stock 153.162 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 23, 2018. 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 23, 2018. Shares have been credited to reporting person's account under issuer's Deferred Compensation Plan for Directors and Executives. Shares held in the reporting person's account under issuer's Retirement K Savings Plan as of February 28, 2018. Shawn M. Filippi, Attorney-in-Fact 2018-03-05