OMEROS CORP

(a)None.

(b)None.

(c) Our directors and Section 16 reporting officers may from time to time enter into plans or other arrangements for the purchase or sale of our shares that are intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act (a “10b5-1 Plan”). On February 10, 2026, David J. Borges, our Vice President, Finance, Chief Accounting Officer and Treasurer, adopted a 10b5-1 Plan providing for the potential exercise of vested stock options and the associated sale of up to 50,000 shares of our common stock under certain conditions. Mr. Borges’ 10b5-1 Plan will remain in effect until the earliest of (i) December 1, 2026, (ii) the date of which all of the shares of common stock covered by the 10b5-1 Plan have been sold, and (iii) such time as Mr. Borges’ 10b5-1 Plan is otherwise terminated or expires according to its terms.

During the three months ended March 31, 2026, none of our directors and no other Section 16 reporting officers adopted or terminated any contract, instruction or written plan for the purchase or sale of our securities that was intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act or any “non-Rule 10b5-1 trading arrangement” (as defined in Item 408(c) of Regulation S-K).