X0306 4 2022-03-05 0 0001580156 Houghton Mifflin Harcourt Co HMHC 0001718775 ONeill James P. C/O HOUGHTON MIFFLIN HARCOURT 125 HIGH STREET BOSTON MA 02110 0 1 0 0 EVP, GM, Core Curriculum Common Stock 2022-03-05 4 M 0 12904 0.00 A 98342 D Common Stock 2022-03-05 4 F 0 4604 20.92 D 93738 D Common Stock 2022-03-05 4 A 0 37170 0.00 A 130908 D Common Stock 2022-03-05 4 F 0 13264 20.92 D 117644 D Restricted Stock Units 2022-03-05 4 M 0 12904 0.00 D Common Stock 12904 0 D 12,904 restricted stock units held by Mr. O'Neill vested on March 5, 2022 and were settled in exchange for a like amount of shares of Houghton Mifflin Harcourt Company's (the "Company") common stock, subject to the Company withholding of 4,604 shares of common stock to satisfy withholding obligations in connection with federal, state, local or other taxes required to be withheld or paid in connection with the settlement of the restricted stock units. 37,170 performance stock units held by Mr. O'Neill vested on March 5, 2022 and were settled in exchange for a like amount of shares of Company common stock, subject to the Company's withholding of 13,264 shares of common stock to satisfy withholding obligations in connection with federal, state, local or other taxes required to be withheld or paid in connection with the settlement of the performance stock units. Each restricted stock unit represents a contingent right to receive one share of the Company's common stock. William F. Bayers is the Executive Vice President, Secretary and General Counsel of the Company. s/ William F. Bayers, Attorney-in-Fact 2022-03-08