| SC 13G/A | 2023-02-14 | ALLIANCEBERNSTEIN L.P. | Houghton Mifflin Harcourt Co | 0 | 0.0% | EDGAR |
| SC 13G | 2023-02-10 | Burgundy Asset Management Ltd. | Houghton Mifflin Harcourt Co | 0 | 0.0% | EDGAR |
| SC 13G | 2022-04-18 | GLAZER CAPITAL, LLC | Houghton Mifflin Harcourt Co | 0 | 0.0% | EDGAR |
| SC 13G/A | 2022-04-11 | WELLINGTON MANAGEMENT GROUP LLP | Houghton Mifflin Harcourt Co | 4,081,419 | 3.2% | EDGAR |
| SC 13G/A | 2022-02-14 | ALLIANCEBERNSTEIN L.P. | Houghton Mifflin Harcourt Co | 7,132,285 | 5.6% | EDGAR |
| SC 13G | 2022-02-14 | Burgundy Asset Management Ltd. | Houghton Mifflin Harcourt Co | 11,003,124 | 8.6% | EDGAR |
| SC 13G | 2022-02-10 | VANGUARD GROUP INC | Houghton Mifflin Harcourt Co | 6,642,286 | 5.2% | EDGAR |
| SC 13G/A | 2022-02-04 | WELLINGTON MANAGEMENT GROUP LLP | Houghton Mifflin Harcourt Co | 14,119,581 | 11.1% | EDGAR |
| SC 13G/A | 2022-02-03 | BlackRock Inc. | Houghton Mifflin Harcourt Co | 8,627,188 | 6.8% | EDGAR |
| SC 13G/A | 2021-02-12 | DIMENSIONAL FUND ADVISORS LP | Houghton Mifflin Harcourt Co | 3,926,933 | 3.1% | EDGAR |
| SC 13G | 2021-02-12 | Burgundy Asset Management Ltd. | Houghton Mifflin Harcourt Co | 10,632,055 | 8.4% | EDGAR |
| SC 13G/A | 2021-02-10 | VANGUARD GROUP INC | Houghton Mifflin Harcourt Co | 5,992,896 | 4.8% | EDGAR |
| SC 13G/A | 2021-02-08 | ALLIANCEBERNSTEIN L.P. | Houghton Mifflin Harcourt Co | 8,578,200 | 6.8% | EDGAR |
| SC 13G/A | 2021-02-04 | WELLINGTON MANAGEMENT GROUP LLP | Houghton Mifflin Harcourt Co | 16,016,561 | 12.7% | EDGAR |
| SC 13G/A | 2021-01-29 | BlackRock Inc. | Houghton Mifflin Harcourt Co | 7,963,164 | 6.3% | EDGAR |
| SC 13D/A | 2020-12-10 | Anchorage Capital Group, L.L.C. | Houghton Mifflin Harcourt Co | 0 | 0.0% | EDGAR |
| SC 13D/A | 2020-11-05 | Anchorage Capital Group, L.L.C. | Houghton Mifflin Harcourt Co | 19,889,174 | 15.8% | EDGAR |
| SC 13G/A | 2020-02-18 | ALLIANCEBERNSTEIN L.P. | Houghton Mifflin Harcourt Co | 8,627,697 | 6.9% | EDGAR |
| SC 13G | 2020-02-14 | Burgundy Asset Management Ltd. | Houghton Mifflin Harcourt Co | 7,359,647 | 5.9% | EDGAR |
| SC 13G/A | 2020-02-12 | VANGUARD GROUP INC | Houghton Mifflin Harcourt Co | 9,449,937 | 7.6% | EDGAR |