X0306 4 2017-03-01 0 0000073020 NORTHWEST NATURAL GAS CO NWN 0001605072 Imeson Thomas J 220 NW SECOND AVENUE PORTLAND OR 97209 0 1 0 0 VP, Public Affairs Common Stock 2017-03-01 4 F 0 70 60.10 D 3683 D Common Stock 2202.217 I See Footnote Common Stock 64.3807 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 24, 2017. Includes 3,453 restricted stock units (RSUs) granted under issuer's Long Term Incentive Plan. The RSUs vest in three equal installments of shares on March 31, 2017, 2018 and 2019. 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, 2017. Shawn M. Filippi, Attorney-in-Fact 2017-03-03