X0306 4 2021-05-21 0 0001402829 Orion Group Holdings Inc ORN 0001476693 Buchler Peter R. 12000 AEROSPACE AVENUE SUITE 300 HOUSTON TX 77034 0 1 0 0 EVP and General Counsel Common Stock 2021-05-21 4 F 0 2491 6.21 D 297921 D Common Stock 2021-05-24 4 F 0 4478 6.27 D 293443 D Reflects a reduction of shares of restricted stock withheld to cover taxes payable by the reporting person due to the vesting of a restricted stock grant on May 21, 2021. Reflects a reduction of shares of restricted stock withheld to cover taxes payable by the reporting person due to the vesting of restricted stock grants on May 24, 2021. Peter R. Buchler 2021-05-25