X0306 4 2018-07-26 0 0001285819 OMEROS CORP OMER 0001472163 Kelbon Marcia S. 201 ELLIOTT AVENUE WEST SEATTLE WA 98119 0 1 0 0 VP Patent and General Counsel Common Stock 2018-07-26 4 M 0 35000 4.10 A 219645 D Common Stock 2018-07-26 4 S 0 35000 21.5339 D 184645 D Common Stock 2018-07-26 4 M 0 8000 6.05 A 192645 D Common Stock 2018-07-27 4 M 0 5723 4.10 A 198368 D Common Stock 2018-07-27 4 S 0 5723 21.7293 D 192645 D Stock Option (Right to Buy) 4.10 2018-07-26 4 M 0 35000 0.00 D 2022-01-07 Common Stock 35000 48252 D Stock Option (Right to Buy) 6.05 2018-07-26 4 M 0 8000 0.00 D 2020-03-28 Common Stock 8000 61996 D Stock Option (Right to Buy) 4.10 2018-07-27 4 M 0 5723 0.00 D 2022-01-07 Common Stock 35000 42529 D Open market sale pursuant to a Rule 10b5-1 trading plan previously adopted by the reporting person. The trading schedule, including sale periods, price and the number of shares to be sold, was established in accordance with Rule 10b5-1 under the Securities Exchange Act of 1934, as amended. The sale was planned in advance for purposes including funding ongoing home construction and the exercise and holding of certain Omeros options. This transaction was executed in multiple trades at prices ranging from $21.45 to $21.63; the price reported above reflects the weighted average sales price. The reporting person undertakes to provide full information regarding the number of shares and prices at which the transactions referenced in this footnote were effected upon request to the SEC staff, the issuer, or a security holder of the issuer. This transaction was executed in multiple trades at prices ranging from $21.48 to $21.90; the price reported above reflects the weighted average sales price. The reporting person undertakes to provide full information regarding the number of shares and prices at which the transactions referenced in this footnote were effected upon request to the SEC staff, the issuer, or a security holder of the issuer. The option vested and became exercisable over 48 equal monthly installments, with a vesting commencement date of April 1, 2011. On July 26, 2018, the reporting person paid the exercise price and exercised options to purchase 8,000 shares of the company's common stock. The shares have not been sold and are held for the account of the reporting person. The options previously vested and became exercisable in 48 equal monthly installments, with a vesting commencement date of April 1, 2010. /s/ Marcia S. Kelbon 2018-07-30