X0306 4 2018-02-21 0 0000073020 NORTHWEST NATURAL GAS CO NWN 0001661934 Burkhartsmeyer Frank 220 NW SECOND AVENUE PORTLAND OR 97209 0 1 0 0 SVP & Chief Financial Officer Common Stock 2018-02-21 4 A 0 375 0 A 6391 D Shares are issuable as a result of satisfaction of the performance threshold for 2017 under restricted stock unit awards. Organization and Executive Compensation Committee certification of the satisfaction of the performance threshold occurred on the transaction date. Includes 6,016 time-based restricted stock units (RSUs) granted under issuer's Long Term Incentive Plan. The RSUs vest in four equal installments: 1,504 shares on each March 1, 2018, 2019, 2020 and 2021. Shawn M. Filippi, Attorney-in-Fact 2018-02-23