X0306 4 2017-02-28 0 0000073020 NORTHWEST NATURAL GAS CO NWN 0001629792 Filippi Shawn M 220 NW SECOND AVE PORTLAND OR 97209 0 1 0 0 VP, CCO & Corporate Secretary Common Stock 2017-02-28 4 M 0 600 44.48 A 1429.663 D Common Stock 2017-02-28 4 S 0 600 59.95 D 829.663 D Common Stock 2017-03-01 4 F 0 105 60.10 D 724.663 D Common Stock 775.8182 I See Footnote Employee Stock Option to Buy 44.48 2017-02-28 4 M 0 600 0 D 2017-02-28 Common Stock 600 0 D 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. Shares held in reporting person's account in issuer's Retirement K Savings Plan as of February 28, 2017. The option vested in four equal installments on each of February 21, 2008, and January 1, 2009, 2010 and 2011. Option was granted as part of compensation for services. The option was exercised as a cashless exercise. Shawn M. Filippi 2017-03-01