X0306 4 2017-03-01 0 0000073020 NORTHWEST NATURAL GAS CO NWN 0001668229 Murandu Ngoni 220 NW SECOND AVENUE PORTLAND OR 97209 0 1 0 0 VP & CIO Common Stock 2017-03-01 4 F 0 181 60.10 D 973 D Common Stock 35.5039 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 the satisfaction of the performance threshold and vesting for these restricted stock units was reported on Form 4 filed on February 24, 2017. Includes 330 restricted stock units granted under issuer's Long Term Incentive Plan, which shall vest on March 31, 2017. Shares held in reporting person's account under the issuer's Retirement K Savings Plan as of February 28, 2017. Shawn M. Filippi, Attorney-in-Fact 2017-03-03