X0306 4 2017-03-31 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 2017-03-31 4 F 0 102 59.15 D 871 D Common Stock 2017-03-31 4 M 0 660 A 1531 D Common Stock 2017-03-31 4 D 0 660 59.15 D 871 D Common Stock 35.4954 I See Footnote Phantom Restricted Stock Units 2017-03-31 4 M 0 660 D 2017-03-31 2017-03-31 Common Stock 660 0 D Shares were withheld by the issuer to cover withholding taxes on issuance of shares due to vesting of restricted stock units. Each phantom restricted stock unit (Phantom RSU) is the economic equivalent of one share of issuer's common stock, plus accrued dividends, payable in cash. Shares held in reporting person's account under the issuer's Retirement K Savings Plan as of March 31, 2017. The Phantom RSUs fully vested on March 31, 2017. Shawn M. Filippi, Attorney-in-Fact 2017-04-04