X0306 4 2018-03-01 0 0000073020 NORTHWEST NATURAL GAS CO NWN 0001538965 Weber David A. 220 NW SECOND AVENUE PORTLAND OR 97209 0 1 0 0 Pres & CEO of Issuer's Sub. Common Stock 2018-03-01 4 F 0 134 52.15 D 291.154 D Common Stock 1635.49 I See Footnote Common Stock 10438.979 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 have been credited to reporting person's account under issuer's Deferred Compensation Plan for Directors and Executives. Shares held in 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