HMH

SEC source: 0001628280-26-060781 · wk-form4_1788559026.xml · nonDerivative · entry 2

Skogerbo Pal · CIK 0002035218 · Chief Technology Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 62,031

F2 · shares: Represents shares of Class A common stock, par value $0.01 per share of the Issuer withheld to satisfy tax withholding obligations upon the vesting of performance-based restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001628280-26-060781 · wk-form4_1788559026.xml · nonDerivative · entry 1

Skogerbo Pal · CIK 0002035218 · Chief Technology Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 67,211

F1 · shares: On April 2, 2026, the reporting person was granted 10,927 performance-based restricted stock units, each of which represented a contingent right to receive one share of Class A common stock, par value $0.01 per share, of HMH Holding Inc. (the "Issuer"). The restricted stock units could be earned up to 200% of target depending on the Issuer's EBITDA growth as compared to the EBITDA growth of a set of peer companies over the three-year period from September 1, 2023 through August 31, 2026 and subject to the reporting person's continued service throughout such three-year period. On September 3, 2026, the Compensation Committee of the Board of Directors of the Issuer certified achievement of the performance condition at 50%, resulting in the restricted stock units originally granted becoming earned at 100% of the target amount granted.

SEC source: 0001628280-26-060780 · wk-form4_1788558970.xml · nonDerivative · entry 2

RETTIG DWIGHT W · CIK 0001228420 · Chf Admn Officer, GC, Corp Sec

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 104,995

F2 · shares: Represents shares of Class A common stock, par value $0.01 per share of the Issuer withheld to satisfy tax withholding obligations upon the vesting performance-based restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001628280-26-060780 · wk-form4_1788558970.xml · nonDerivative · entry 1

RETTIG DWIGHT W · CIK 0001228420 · Chf Admn Officer, GC, Corp Sec

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 109,295

F1 · shares: On April 2, 2026, the reporting person was granted 10,927 performance-based restricted stock units, each of which represented a contingent right to receive one share of Class A common stock, par value $0.01 per share, of HMH Holding Inc. (the "Issuer"). The restricted stock units could be earned up to 200% of target depending on the Issuer's EBITDA growth as compared to the EBITDA growth of a set of peer companies over the three-year period from September 1, 2023 through August 31, 2026 and subject to the reporting person's continued service throughout such three-year period. On September 3, 2026, the Compensation Committee of the Board of Directors of the Issuer certified achievement of the performance condition at 50%, resulting in the restricted stock units originally granted becoming earned at 100% of the target amount granted.

SEC source: 0001628280-26-060778 · wk-form4_1788558910.xml · nonDerivative · entry 2

Qureshi Hunain · CIK 0002035763 · Chief Accounting Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 25,789

F2 · shares: Represents shares of Class A common stock, par value $0.01 per share of the Issuer withheld to satisfy tax withholding obligations upon the vesting of performance-based restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001628280-26-060778 · wk-form4_1788558910.xml · nonDerivative · entry 1

Qureshi Hunain · CIK 0002035763 · Chief Accounting Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 26,994

F1 · shares: On April 2, 2026, the reporting person was granted 3,060 performance-based restricted stock units, each of which represented a contingent right to receive one share of Class A common stock, par value $0.01 per share, of HMH Holding Inc. (the "Issuer"). The restricted stock units could be earned up to 200% of target depending on the Issuer's EBITDA growth as compared to the EBITDA growth of a set of peer companies over the three-year period from September 1, 2023 through August 31, 2026 and subject to the reporting person's continued service throughout such three-year period. On September 3, 2026, the Compensation Committee of the Board of Directors of the Issuer certified achievement of the performance condition at 50%, resulting in the restricted stock units originally granted becoming earned at 100% of the target amount granted.

SEC source: 0001628280-26-060777 · wk-form4_1788558857.xml · nonDerivative · entry 2

McGee Thomas W. · CIK 0002035200 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 154,995

F2 · shares: Represents shares of Class A common stock, par value $0.01 per share of the Issuer withheld to satisfy tax withholding obligations upon the vesting of performance-based restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001628280-26-060777 · wk-form4_1788558857.xml · nonDerivative · entry 1

McGee Thomas W. · CIK 0002035200 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 159,295

F1 · shares: On April 2, 2026, the reporting person was granted 10,927 performance-based restricted stock units, each of which represented a contingent right to receive one share of Class A common stock, par value $0.01 per share, of HMH Holding Inc. (the "Issuer"). The restricted stock units could be earned up to 200% of target depending on the Issuer's EBITDA growth as compared to the EBITDA growth of a set of peer companies over the three-year period from September 1, 2023 through August 31, 2026 and subject to the reporting person's continued service throughout such three-year period. On September 3, 2026, the Compensation Committee of the Board of Directors of the Issuer certified achievement of the performance condition at 50%, resulting in the restricted stock units originally granted becoming earned at 100% of the target amount granted.

SEC source: 0001628280-26-060774 · wk-form4_1788558750.xml · nonDerivative · entry 2

Dyrseth Roy A. · CIK 0002035162 · Chief Commercial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 74,390

F2 · shares: Represents shares of Class A common stock, par value $0.01 per share of the Issuer withheld to satisfy tax withholding obligations upon the vesting of performance-based restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001628280-26-060774 · wk-form4_1788558750.xml · nonDerivative · entry 1

Dyrseth Roy A. · CIK 0002035162 · Chief Commercial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 79,570

F1 · shares: On April 2, 2026, the reporting person was granted 10,927 performance-based restricted stock units, each of which represented a contingent right to receive one share of Class A common stock, par value $0.01 per share, of HMH Holding Inc. (the "Issuer"). The restricted stock units could be earned up to 200% of target depending on the Issuer's EBITDA growth as compared to the EBITDA growth of a set of peer companies over the three-year period from September 1, 2023 through August 31, 2026 and subject to the reporting person's continued service throughout such three-year period. On September 3, 2026, the Compensation Committee of the Board of Directors of the Issuer certified achievement of the performance condition at 50%, resulting in the restricted stock units originally granted becoming earned at 100% of the target amount granted.

SEC source: 0001628280-26-060773 · wk-form4_1788558701.xml · nonDerivative · entry 2

CHAUVIERE E CHARLS · CIK 0001240953 · Chief Operations Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 92,294

F2 · shares: Represents shares of Class A common stock, par value $0.01 per share of the Issuer withheld to satisfy tax withholding obligations upon the vesting of performance-based restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001628280-26-060773 · wk-form4_1788558701.xml · nonDerivative · entry 1

CHAUVIERE E CHARLS · CIK 0001240953 · Chief Operations Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 96,594

F1 · shares: On April 2, 2026, the reporting person was granted 10,927 performance-based restricted stock units, each of which represented a contingent right to receive one share of Class A common stock, par value $0.01 per share, of HMH Holding Inc. (the "Issuer"). The restricted stock units could be earned up to 200% of target depending on the Issuer's EBITDA growth as compared to the EBITDA growth of a set of peer companies over the three-year period from September 1, 2023 through August 31, 2026 and subject to the reporting person's continued service throughout such three-year period. On September 3, 2026, the Compensation Committee of the Board of Directors of the Issuer certified achievement of the performance condition at 50%, resulting in the restricted stock units originally granted becoming earned at 100% of the target amount granted.

SEC source: 0001628280-26-060772 · wk-form4_1788558621.xml · nonDerivative · entry 2

Bergsvik Eirik · CIK 0002035158 · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 144,234

F2 · shares: Represents shares of Class A common stock, par value $0.01 per share of the Issuer withheld to satisfy tax withholding obligations upon the vesting of performance-based restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001628280-26-060772 · wk-form4_1788558621.xml · nonDerivative · entry 1

Bergsvik Eirik · CIK 0002035158 · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 152,521

F1 · shares: On April 2, 2026, the reporting person was granted 17,483 performance-based restricted stock units, each of which represented a contingent right to receive one share of Class A common stock, par value $0.01 per share, of HMH Holding Inc. (the "Issuer"). The restricted stock units could be earned up to 200% of target depending on the Issuer's EBITDA growth as compared to the EBITDA growth of a set of peer companies over the three-year period from September 1, 2023 through August 31, 2026 and subject to the reporting person's continued service throughout such three-year period. On September 3, 2026, the Compensation Committee of the Board of Directors of the Issuer certified achievement of the performance condition at 50%, resulting in the restricted stock units originally granted becoming earned at 100% of the target amount granted.

SEC source: 0001628280-26-060325 · wk-form4_1788459588.xml · nonDerivative · entry 1

RETTIG DWIGHT W · CIK 0001228420 · Chf Admn Officer, GC, Corp Sec

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 98,368

F1 · shares: Represents shares of Class A common stock, par value $0.01 per share of the Issuer withheld to satisfy tax withholding obligations upon the vesting of restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001628280-26-060324 · wk-form4_1788459519.xml · nonDerivative · entry 1

Skogerbo Pal · CIK 0002035218 · Chief Technology Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 56,284

F1 · shares: Represents shares of Class A common stock, par value $0.01 per share of the Issuer withheld to satisfy tax withholding obligations upon the vesting of restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001628280-26-060323 · wk-form4_1788459482.xml · nonDerivative · entry 1

Qureshi Hunain · CIK 0002035763 · Chief Accounting Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 23,934

F1 · shares: Represents shares of Class A common stock, par value $0.01 per share of the Issuer withheld to satisfy tax withholding obligations upon the vesting of restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001628280-26-060322 · wk-form4_1788459447.xml · nonDerivative · entry 1

McGee Thomas W. · CIK 0002035200 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 148,368

F1 · shares: Represents shares of Class A common stock, par value $0.01 per share of the Issuer withheld to satisfy tax withholding obligations upon the vesting of restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001628280-26-060321 · wk-form4_1788459408.xml · nonDerivative · entry 1

Dyrseth Roy A. · CIK 0002035162 · Chief Commercial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 68,643

F1 · shares: Represents shares of Class A common stock, par value $0.01 per share of the Issuer withheld to satisfy tax withholding obligations upon the vesting of restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001628280-26-060320 · wk-form4_1788459367.xml · nonDerivative · entry 1

CHAUVIERE E CHARLS · CIK 0001240953 · Chief Operations Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 85,667

F1 · shares: Represents shares of Class A common stock, par value $0.01 per share of the Issuer withheld to satisfy tax withholding obligations upon the vesting of restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001628280-26-060319 · wk-form4_1788459302.xml · nonDerivative · entry 1

Bergsvik Eirik · CIK 0002035158 · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 135,038

F1 · shares: Represents shares of Class A common stock, par value $0.01 per share of the Issuer withheld to satisfy tax withholding obligations upon the vesting of restricted stock units. This settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001193125-26-279926 · ownership.xml · nonDerivative · entry 2

Skogerbo Pal · CIK 0002035218 · Chief Technology Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 60,429

F2 · shares: Represents restricted stock units granted to the reporting person under the HMH Holding Inc. 2026 Long-Term Incentive Plan on June 19, 2026. Each restricted stock unit represents a contingent right to receive one share of Class A Common Stock. The restricted stock units vest in three equal installments on September 19, 2027, June 19, 2028 and June 19, 2029.

SEC source: 0001193125-26-279918 · ownership.xml · nonDerivative · entry 2

Bergsvik Eirik · CIK 0002035158 · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 141,669

F2 · shares: Represents restricted stock units granted to the reporting person under the HMH Holding Inc. 2026 Long-Term Incentive Plan on June 19, 2026. Each restricted stock unit represents a contingent right to receive one share of Class A Common Stock. The restricted stock units vest in three equal installments on September 19, 2027, June 19, 2028 and June 19, 2029.

SEC source: 0001193125-26-279913 · ownership.xml · nonDerivative · entry 2

CHAUVIERE E CHARLS · CIK 0001240953 · Chief Operations Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 89,109

F2 · shares: Represents restricted stock units granted to the reporting person under the HMH Holding Inc. 2026 Long-Term Incentive Plan on June 19, 2026. Each restricted stock unit represents a contingent right to receive one share of Class A Common Stock. The restricted stock units vest in three equal installments on September 19, 2027, June 19, 2028 and June 19, 2029.

SEC source: 0001193125-26-279905 · ownership.xml · nonDerivative · entry 2

McGee Thomas W. · CIK 0002035200 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 151,810

F2 · shares: Represents restricted stock units granted to the reporting person under the HMH Holding Inc. 2026 Long-Term Incentive Plan on June 19, 2026. Each restricted stock unit represents a contingent right to receive one share of Class A Common Stock. The restricted stock units vest in three equal installments on September 19, 2027, June 19, 2028 and June 19, 2029.

SEC source: 0001193125-26-279899 · ownership.xml · nonDerivative · entry 2

Qureshi Hunain · CIK 0002035763 · Chief Accounting Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 25,904

F2 · shares: Represents restricted stock units granted to the reporting person under the HMH Holding Inc. 2026 Long-Term Incentive Plan on June 19, 2026. Each restricted stock unit represents a contingent right to receive one share of Class A Common Stock. The restricted stock units vest in three equal installments on September 19, 2027, June 19, 2028 and June 19, 2029.

SEC source: 0001193125-26-279903 · ownership.xml · nonDerivative · entry 2

RETTIG DWIGHT W · CIK 0001228420 · Chf Admn Officer, GC, Corp Sec

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 101,810

F2 · shares: Represents restricted stock units granted to the reporting person under the HMH Holding Inc. 2026 Long-Term Incentive Plan on June 19, 2026. Each restricted stock unit represents a contingent right to receive one share of Class A Common Stock. The restricted stock units vest in three equal installments on September 19, 2027, June 19, 2028 and June 19, 2029.

SEC source: 0001193125-26-279898 · ownership.xml · nonDerivative · entry 2

Dyrseth Roy A. · CIK 0002035162 · Chief Commercial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 72,788

F2 · shares: Represents restricted stock units granted to the reporting person under the HMH Holding Inc. 2026 Long-Term Incentive Plan on June 19, 2026. Each restricted stock unit represents a contingent right to receive one share of Class A Common Stock. The restricted stock units vest in three equal installments on September 19, 2027, June 19, 2028 and June 19, 2029.

SEC source: 0001193125-26-279926 · ownership.xml · nonDerivative · entry 1

Skogerbo Pal · CIK 0002035218 · Chief Technology Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 47,031

F1 · shares: Represents shares of Class A common stock, par value $0.01 per share ("Class A Common Stock"), of HMH Holding Inc. (the "Issuer") withheld to satisfy tax withholding obligations upon the vesting of restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001193125-26-279918 · ownership.xml · nonDerivative · entry 1

Bergsvik Eirik · CIK 0002035158 · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 93,437

F1 · shares: Represents shares of Class A common stock, par value $0.01 per share ("Class A Common Stock"), of HMH Holding Inc. (the "Issuer") withheld to satisfy tax withholding obligations upon the vesting of restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001193125-26-279913 · ownership.xml · nonDerivative · entry 1

CHAUVIERE E CHARLS · CIK 0001240953 · Chief Operations Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 69,013

F1 · shares: Represents shares of Class A common stock, par value $0.01 per share ("Class A Common Stock"), of HMH Holding Inc. (the "Issuer") withheld to satisfy tax withholding obligations upon the vesting of restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001193125-26-279905 · ownership.xml · nonDerivative · entry 1

McGee Thomas W. · CIK 0002035200 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 127,694

F1 · shares: Represents shares of Class A common stock, par value $0.01 per share ("Class A Common Stock"), of HMH Holding Inc. (the "Issuer") withheld to satisfy tax withholding obligations upon the vesting of restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001193125-26-279899 · ownership.xml · nonDerivative · entry 1

Qureshi Hunain · CIK 0002035763 · Chief Accounting Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 21,885

F1 · shares: Represents shares of Class A common stock, par value $0.01 per share ("Class A Common Stock"), of HMH Holding Inc. (the "Issuer") withheld to satisfy tax withholding obligations upon the vesting of restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001193125-26-279903 · ownership.xml · nonDerivative · entry 1

RETTIG DWIGHT W · CIK 0001228420 · Chf Admn Officer, GC, Corp Sec

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 77,694

F1 · shares: Represents shares of Class A common stock, par value $0.01 per share ("Class A Common Stock"), of HMH Holding Inc. (the "Issuer") withheld to satisfy tax withholding obligations upon the vesting of restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001193125-26-279898 · ownership.xml · nonDerivative · entry 1

Dyrseth Roy A. · CIK 0002035162 · Chief Commercial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 54,031

F1 · shares: Represents shares of Class A common stock, par value $0.01 per share ("Class A Common Stock"), of HMH Holding Inc. (the "Issuer") withheld to satisfy tax withholding obligations upon the vesting of restricted stock units. This net settlement was approved by the board of directors of the Issuer pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended.

SEC source: 0001193125-26-211626 · ownership.xml · nonDerivative · entry 1

RETTIG DWIGHT W · CIK 0001228420 · Chf Admn Officer, GC, Corp Sec

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 117,473

F1 · shares: Represents restricted stock units granted to the reporting person under the HMH Holding Inc. 2026 Long-Term Incentive Plan on May 5, 2026. Each restricted stock unit represents a contingent right to receive one share of Class A common stock, par value $0.01 per share, of HMH Holding Inc. (the "Issuer"). Due to an administrative error in the calculation of equity awards granted on April 2, 2026, fewer restricted stock units were granted to the reporting person than were approved by the Board of Directors of the Issuer to be granted on that date. This grant represents a true-up award to align the number of restricted stock units granted with the amounts originally approved.

F2 · shares: (Continued from footnote 1) The restricted stock units include 17,326 restricted stock units that vested immediately upon grant, 624 restricted stock units that vest on September 1, 2026, 874 restricted stock units that vest in two equal annual installments on September 1, 2026 and September 1, 2027 and 1,311 restricted stock units that vest in three equal annual installments on September 1, 2026, September 1, 2027 and September 1, 2028.

SEC source: 0001193125-26-211590 · ownership.xml · nonDerivative · entry 1

CHAUVIERE E CHARLS · CIK 0001240953 · Chief Operations Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 103,160

F1 · shares: Represents restricted stock units granted to the reporting person under the HMH Holding Inc. 2026 Long-Term Incentive Plan on May 5, 2026. Each restricted stock unit represents a contingent right to receive one share of Class A common stock, par value $0.01 per share, of HMH Holding Inc. (the "Issuer"). Due to an administrative error in the calculation of equity awards granted on April 2, 2026, fewer restricted stock units were granted to the reporting person than were approved by the Board of Directors of the Issuer to be granted on that date. This grant represents a true-up award to align the number of restricted stock units granted with the amounts originally approved.

F2 · shares: (Continued from footnote 1) The restricted stock units include 14,873 restricted stock units that vested immediately upon grant, 624 restricted stock units that vest on September 1, 2026, 874 restricted stock units that vest in two equal annual installments on September 1, 2026 and September 1, 2027 and 1,311 restricted stock units that vest in three equal annual installments on September 1, 2026, September 1, 2027 and September 1, 2028.

SEC source: 0002035763-26-000001 · ownership.xml · nonDerivative · entry 1

Qureshi Hunain · CIK 0002035763 · Chief Accounting Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 29,683

F1 · shares: Represents restricted stock units granted to the reporting person under the HMH Holding Inc. 2026 Long-Term Incentive Plan on May 5, 2026. Each restricted stock unit represents a contingent right to receive one share of Class A common stock, par value $0.01 per share, of HMH Holding Inc. (the "Issuer"). Due to an administrative error in the calculation of equity awards granted on April 2, 2026, fewer restricted stock units were granted to the reporting person than were approved by the Board of Directors of the Issuer to be granted on that date. This grant represents a true-up award to align the number of restricted stock units granted with the amounts originally approved.

F2 · shares: (Continued from footnote 1) The restricted stock units include 3,396 restricted stock units that vested immediately upon grant, 175 restricted stock units that vest on September 1, 2026, 1,063 restricted stock units that vest in two equal annual installments on September 1, 2026 and September 1, 2027 and 455 restricted stock units that vest in three equal annual installments on September 1, 2026, September 1, 2027 and September 1, 2028.

SEC source: 0001193125-26-211577 · ownership.xml · nonDerivative · entry 1

Bergsvik Eirik · CIK 0002035158 · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 144,996

F1 · shares: Represents restricted stock units granted to the reporting person under the HMH Holding Inc. 2026 Long-Term Incentive Plan on May 5, 2026. Each restricted stock unit represents a contingent right to receive one share of Class A common stock, par value $0.01 per share, of HMH Holding Inc. (the "Issuer"). Due to an administrative error in the calculation of equity awards granted on April 2, 2026, fewer restricted stock units were granted to the reporting person than were approved by the Board of Directors of the Issuer to be granted on that date. This grant represents a true-up award to align the number of restricted stock units granted with the amounts originally approved.

F2 · shares: (Continued from footnote 1) The restricted stock units include 18,644 restricted stock units that vested immediately upon grant, 999 restricted stock units that vest on September 1, 2026, 1,398 restricted stock units that vest in two equal annual installments on September 1, 2026 and September 1, 2027 and 2,097 restricted stock units that vest in three equal annual installments on September 1, 2026, September 1, 2027 and September 1, 2028.

SEC source: 0001193125-26-211554 · ownership.xml · nonDerivative · entry 1

Skogerbo Pal · CIK 0002035218 · Chief Technology Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 73,744

F1 · shares: Represents restricted stock units granted to the reporting person under the HMH Holding Inc. 2026 Long-Term Incentive Plan on May 5, 2026. Each restricted stock unit represents a contingent right to receive one share of Class A common stock, par value $0.01 per share, of HMH Holding Inc. (the "Issuer"). Due to an administrative error in the calculation of equity awards granted on April 2, 2026, fewer restricted stock units were granted to the reporting person than were approved by the Board of Directors of the Issuer to be granted on that date. This grant represents a true-up award to align the number of restricted stock units granted with the amounts originally approved.

F2 · shares: (Continued from footnote 1) The restricted stock units include 9,659 restricted stock units that vested immediately upon grant, 624 restricted stock units that vest on September 1, 2026, 874 restricted stock units that vest in two equal annual installments on September 1, 2026 and September 1, 2027 and 1,311 restricted stock units that vest in three equal annual installments on September 1, 2026, September 1, 2027 and September 1, 2028.

SEC source: 0001193125-26-211538 · ownership.xml · nonDerivative · entry 1

McGee Thomas W. · CIK 0002035200 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 167,473

F1 · shares: Represents restricted stock units granted to the reporting person under the HMH Holding Inc. 2026 Long-Term Incentive Plan on May 5, 2026. Each restricted stock unit represents a contingent right to receive one share of Class A common stock, par value $0.01 per share, of HMH Holding Inc. (the "Issuer"). Due to an administrative error in the calculation of equity awards granted on April 2, 2026, fewer restricted stock units were granted to the reporting person than were approved by the Board of Directors of the Issuer to be granted on that date. This grant represents a true-up award to align the number of restricted stock units granted with the amounts originally approved.

F2 · shares: (Continued from footnote 1) The restricted stock units include 17,326 restricted stock units that vested immediately upon grant, 624 restricted stock units that vest on September 1, 2026, 874 restricted stock units that vest in two equal annual installments on September 1, 2026 and September 1, 2027 and 1,311 restricted stock units that vest in three equal annual installments on September 1, 2026, September 1, 2027 and September 1, 2028.

SEC source: 0001193125-26-211531 · ownership.xml · nonDerivative · entry 1

Dyrseth Roy A. · CIK 0002035162 · Chief Commercial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 80,744

F1 · shares: Represents restricted stock units granted to the reporting person under the HMH Holding Inc. 2026 Long-Term Incentive Plan on May 5, 2026. Each restricted stock unit represents a contingent right to receive one share of Class A common stock, par value $0.01 per share, of HMH Holding Inc. (the "Issuer"). Due to an administrative error in the calculation of equity awards granted on April 2, 2026, fewer restricted stock units were granted to the reporting person than were approved by the Board of Directors of the Issuer to be granted on that date. This grant represents a true-up award to align the number of restricted stock units granted with the amounts originally approved.

F2 · shares: (Continued from footnote 1) The restricted stock units include 9,659 restricted stock units that vested immediately upon grant, 624 restricted stock units that vest on September 1, 2026, 874 restricted stock units that vest in two equal annual installments on September 1, 2026 and September 1, 2027 and 1,311 restricted stock units that vest in three equal annual installments on September 1, 2026, September 1, 2027 and September 1, 2028.

SEC source: 0001193125-26-204656 · ownership.xml · derivative · entry 3

Baker Hughes Co · CIK 0001701605 · Director · 10% owner · Director by Deputization

Baker Hughes Holdings LLC · CIK 0000808362 · Director · 10% owner · Director by Deputization

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · Baker Hughes Holdings LLC See footnotes

Disclosed balance after: 15,945,826

Underlying: Class A common stock · 342,922 shares

Expires not disclosed

F1 · derivative.exercise_price: On April 30, 2026, the underwriters of the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Baker Hughes (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"),

F2 · derivative.exercise_price: (Continued from footnote 1) non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. With regards to Baker Hughes, HMH B.V. will purchase the following securities for a purchase price of $6,446,933.60 to be paid to Baker Hughes: (i) 342,922 Issuer Class B Shares, (ii) 342,922 B.V. Non-Voting Class A Shares in exchange for $2,773,200.59 and (iii) 342,922 B.V. Non-Voting Class B Shares in exchange for $3,673,733.01.

F4 · derivative.exercise_price: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · kind: On April 30, 2026, the underwriters of the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Baker Hughes (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"),

F2 · kind: (Continued from footnote 1) non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. With regards to Baker Hughes, HMH B.V. will purchase the following securities for a purchase price of $6,446,933.60 to be paid to Baker Hughes: (i) 342,922 Issuer Class B Shares, (ii) 342,922 B.V. Non-Voting Class A Shares in exchange for $2,773,200.59 and (iii) 342,922 B.V. Non-Voting Class B Shares in exchange for $3,673,733.01.

F4 · kind: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · shares: On April 30, 2026, the underwriters of the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Baker Hughes (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"),

F2 · shares: (Continued from footnote 1) non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. With regards to Baker Hughes, HMH B.V. will purchase the following securities for a purchase price of $6,446,933.60 to be paid to Baker Hughes: (i) 342,922 Issuer Class B Shares, (ii) 342,922 B.V. Non-Voting Class A Shares in exchange for $2,773,200.59 and (iii) 342,922 B.V. Non-Voting Class B Shares in exchange for $3,673,733.01.

F4 · shares: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · derivative.exercise_date: On April 30, 2026, the underwriters of the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Baker Hughes (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"),

F2 · derivative.exercise_date: (Continued from footnote 1) non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. With regards to Baker Hughes, HMH B.V. will purchase the following securities for a purchase price of $6,446,933.60 to be paid to Baker Hughes: (i) 342,922 Issuer Class B Shares, (ii) 342,922 B.V. Non-Voting Class A Shares in exchange for $2,773,200.59 and (iii) 342,922 B.V. Non-Voting Class B Shares in exchange for $3,673,733.01.

F4 · derivative.exercise_date: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · derivative.expiration_date: On April 30, 2026, the underwriters of the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Baker Hughes (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"),

F2 · derivative.expiration_date: (Continued from footnote 1) non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. With regards to Baker Hughes, HMH B.V. will purchase the following securities for a purchase price of $6,446,933.60 to be paid to Baker Hughes: (i) 342,922 Issuer Class B Shares, (ii) 342,922 B.V. Non-Voting Class A Shares in exchange for $2,773,200.59 and (iii) 342,922 B.V. Non-Voting Class B Shares in exchange for $3,673,733.01.

F4 · derivative.expiration_date: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · ownership.nature: On April 30, 2026, the underwriters of the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Baker Hughes (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"),

F2 · ownership.nature: (Continued from footnote 1) non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. With regards to Baker Hughes, HMH B.V. will purchase the following securities for a purchase price of $6,446,933.60 to be paid to Baker Hughes: (i) 342,922 Issuer Class B Shares, (ii) 342,922 B.V. Non-Voting Class A Shares in exchange for $2,773,200.59 and (iii) 342,922 B.V. Non-Voting Class B Shares in exchange for $3,673,733.01.

F3 · ownership.nature: In this filing, Baker Hughes Company and Baker Hughes Holdings LLC are collectively referred to as "Baker Hughes". Baker Hughes Company has an indirect pecuniary interest in the securities held by Baker Hughes Holdings LLC. Consequently, Baker Hughes Company may be deemed to share beneficial ownership in the securities held directly by Baker Hughes Holdings LLC. The board of directors and officers of Baker Hughes Company disclaim beneficial ownership with respect to such securities.

F4 · ownership.nature: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F5 · ownership.nature: Judson E. Bailey and M. Georgia Magno are directors of the Issuer and were nominated for such roles by Baker Hughes Holdings LLC. By virtue of their service on the Board of Directors of the Issuer, for purposes of Section 16, Baker Hughes Holdings LLC may be deemed to be a "director by deputization" of the Issuer.

SEC source: 0001193125-26-204656 · ownership.xml · derivative · entry 2

Baker Hughes Co · CIK 0001701605 · Director · 10% owner · Director by Deputization

Baker Hughes Holdings LLC · CIK 0000808362 · Director · 10% owner · Director by Deputization

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · Baker Hughes Holdings LLC See footnotes

Disclosed balance after: 15,945,826

Underlying: Class A common stock · 342,922 shares

Expires not disclosed

F1 · derivative.exercise_price: On April 30, 2026, the underwriters of the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Baker Hughes (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"),

F2 · derivative.exercise_price: (Continued from footnote 1) non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. With regards to Baker Hughes, HMH B.V. will purchase the following securities for a purchase price of $6,446,933.60 to be paid to Baker Hughes: (i) 342,922 Issuer Class B Shares, (ii) 342,922 B.V. Non-Voting Class A Shares in exchange for $2,773,200.59 and (iii) 342,922 B.V. Non-Voting Class B Shares in exchange for $3,673,733.01.

F4 · derivative.exercise_price: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · kind: On April 30, 2026, the underwriters of the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Baker Hughes (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"),

F2 · kind: (Continued from footnote 1) non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. With regards to Baker Hughes, HMH B.V. will purchase the following securities for a purchase price of $6,446,933.60 to be paid to Baker Hughes: (i) 342,922 Issuer Class B Shares, (ii) 342,922 B.V. Non-Voting Class A Shares in exchange for $2,773,200.59 and (iii) 342,922 B.V. Non-Voting Class B Shares in exchange for $3,673,733.01.

F4 · kind: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · shares: On April 30, 2026, the underwriters of the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Baker Hughes (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"),

F2 · shares: (Continued from footnote 1) non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. With regards to Baker Hughes, HMH B.V. will purchase the following securities for a purchase price of $6,446,933.60 to be paid to Baker Hughes: (i) 342,922 Issuer Class B Shares, (ii) 342,922 B.V. Non-Voting Class A Shares in exchange for $2,773,200.59 and (iii) 342,922 B.V. Non-Voting Class B Shares in exchange for $3,673,733.01.

F4 · shares: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · derivative.exercise_date: On April 30, 2026, the underwriters of the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Baker Hughes (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"),

F2 · derivative.exercise_date: (Continued from footnote 1) non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. With regards to Baker Hughes, HMH B.V. will purchase the following securities for a purchase price of $6,446,933.60 to be paid to Baker Hughes: (i) 342,922 Issuer Class B Shares, (ii) 342,922 B.V. Non-Voting Class A Shares in exchange for $2,773,200.59 and (iii) 342,922 B.V. Non-Voting Class B Shares in exchange for $3,673,733.01.

F4 · derivative.exercise_date: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · derivative.expiration_date: On April 30, 2026, the underwriters of the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Baker Hughes (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"),

F2 · derivative.expiration_date: (Continued from footnote 1) non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. With regards to Baker Hughes, HMH B.V. will purchase the following securities for a purchase price of $6,446,933.60 to be paid to Baker Hughes: (i) 342,922 Issuer Class B Shares, (ii) 342,922 B.V. Non-Voting Class A Shares in exchange for $2,773,200.59 and (iii) 342,922 B.V. Non-Voting Class B Shares in exchange for $3,673,733.01.

F4 · derivative.expiration_date: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · ownership.nature: On April 30, 2026, the underwriters of the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Baker Hughes (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"),

F2 · ownership.nature: (Continued from footnote 1) non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. With regards to Baker Hughes, HMH B.V. will purchase the following securities for a purchase price of $6,446,933.60 to be paid to Baker Hughes: (i) 342,922 Issuer Class B Shares, (ii) 342,922 B.V. Non-Voting Class A Shares in exchange for $2,773,200.59 and (iii) 342,922 B.V. Non-Voting Class B Shares in exchange for $3,673,733.01.

F3 · ownership.nature: In this filing, Baker Hughes Company and Baker Hughes Holdings LLC are collectively referred to as "Baker Hughes". Baker Hughes Company has an indirect pecuniary interest in the securities held by Baker Hughes Holdings LLC. Consequently, Baker Hughes Company may be deemed to share beneficial ownership in the securities held directly by Baker Hughes Holdings LLC. The board of directors and officers of Baker Hughes Company disclaim beneficial ownership with respect to such securities.

F4 · ownership.nature: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F5 · ownership.nature: Judson E. Bailey and M. Georgia Magno are directors of the Issuer and were nominated for such roles by Baker Hughes Holdings LLC. By virtue of their service on the Board of Directors of the Issuer, for purposes of Section 16, Baker Hughes Holdings LLC may be deemed to be a "director by deputization" of the Issuer.

SEC source: 0001193125-26-204656 · ownership.xml · nonDerivative · entry 1

Baker Hughes Co · CIK 0001701605 · Director · 10% owner · Director by Deputization

Baker Hughes Holdings LLC · CIK 0000808362 · Director · 10% owner · Director by Deputization

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · Baker Hughes Holdings LLC See footnotes

Disclosed balance after: 15,945,826

F1 · kind: On April 30, 2026, the underwriters of the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Baker Hughes (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"),

F2 · kind: (Continued from footnote 1) non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. With regards to Baker Hughes, HMH B.V. will purchase the following securities for a purchase price of $6,446,933.60 to be paid to Baker Hughes: (i) 342,922 Issuer Class B Shares, (ii) 342,922 B.V. Non-Voting Class A Shares in exchange for $2,773,200.59 and (iii) 342,922 B.V. Non-Voting Class B Shares in exchange for $3,673,733.01.

F4 · kind: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · ownership.nature: On April 30, 2026, the underwriters of the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Baker Hughes (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"),

F2 · ownership.nature: (Continued from footnote 1) non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. With regards to Baker Hughes, HMH B.V. will purchase the following securities for a purchase price of $6,446,933.60 to be paid to Baker Hughes: (i) 342,922 Issuer Class B Shares, (ii) 342,922 B.V. Non-Voting Class A Shares in exchange for $2,773,200.59 and (iii) 342,922 B.V. Non-Voting Class B Shares in exchange for $3,673,733.01.

F3 · ownership.nature: In this filing, Baker Hughes Company and Baker Hughes Holdings LLC are collectively referred to as "Baker Hughes". Baker Hughes Company has an indirect pecuniary interest in the securities held by Baker Hughes Holdings LLC. Consequently, Baker Hughes Company may be deemed to share beneficial ownership in the securities held directly by Baker Hughes Holdings LLC. The board of directors and officers of Baker Hughes Company disclaim beneficial ownership with respect to such securities.

F4 · ownership.nature: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F5 · ownership.nature: Judson E. Bailey and M. Georgia Magno are directors of the Issuer and were nominated for such roles by Baker Hughes Holdings LLC. By virtue of their service on the Board of Directors of the Issuer, for purposes of Section 16, Baker Hughes Holdings LLC may be deemed to be a "director by deputization" of the Issuer.

SEC source: 0000950157-26-000570 · form4.xml · derivative · entry 4

Akastor ASA · CIK 0002037057 · 10% owner

Akastor AS · CIK 0002124921 · Director · 10% owner · Director by Deputization

Mercury HoldCo AS · CIK 0002124920 · 10% owner

Mercury HoldCo Inc. · CIK 0002124922 · Director · 10% owner · Director by Deputization

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · Akastor AS See footnotes

Disclosed balance after: 15,945,826

Underlying: Class A common stock · 342,922 shares

Expires not disclosed

F1 · derivative.exercise_price: On April 30, 2026, the underwriters of the initial public offering of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. (cont'd in fn 2)

F2 · derivative.exercise_price: (cont'd from fn 1) The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Akastor (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"), non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. (cont'd in fn 3)

F3 · derivative.exercise_price: (cont'd from fn 2) With regards to Akastor, HMH B.V. will purchase the following securities for a cumulative purchase price of $6,446,933.60 to be paid to Akastor: (i) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class A Shares from Mercury HoldCo Inc. in exchange for $2,773,200.59 and (ii) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class B Shares from Akastor AS in exchange for $3,673,733.01.

F5 · derivative.exercise_price: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Akastor has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · kind: On April 30, 2026, the underwriters of the initial public offering of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. (cont'd in fn 2)

F2 · kind: (cont'd from fn 1) The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Akastor (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"), non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. (cont'd in fn 3)

F3 · kind: (cont'd from fn 2) With regards to Akastor, HMH B.V. will purchase the following securities for a cumulative purchase price of $6,446,933.60 to be paid to Akastor: (i) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class A Shares from Mercury HoldCo Inc. in exchange for $2,773,200.59 and (ii) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class B Shares from Akastor AS in exchange for $3,673,733.01.

F5 · kind: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Akastor has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · shares: On April 30, 2026, the underwriters of the initial public offering of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. (cont'd in fn 2)

F2 · shares: (cont'd from fn 1) The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Akastor (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"), non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. (cont'd in fn 3)

F3 · shares: (cont'd from fn 2) With regards to Akastor, HMH B.V. will purchase the following securities for a cumulative purchase price of $6,446,933.60 to be paid to Akastor: (i) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class A Shares from Mercury HoldCo Inc. in exchange for $2,773,200.59 and (ii) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class B Shares from Akastor AS in exchange for $3,673,733.01.

F5 · shares: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Akastor has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · derivative.exercise_date: On April 30, 2026, the underwriters of the initial public offering of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. (cont'd in fn 2)

F2 · derivative.exercise_date: (cont'd from fn 1) The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Akastor (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"), non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. (cont'd in fn 3)

F3 · derivative.exercise_date: (cont'd from fn 2) With regards to Akastor, HMH B.V. will purchase the following securities for a cumulative purchase price of $6,446,933.60 to be paid to Akastor: (i) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class A Shares from Mercury HoldCo Inc. in exchange for $2,773,200.59 and (ii) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class B Shares from Akastor AS in exchange for $3,673,733.01.

F5 · derivative.exercise_date: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Akastor has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · derivative.expiration_date: On April 30, 2026, the underwriters of the initial public offering of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. (cont'd in fn 2)

F2 · derivative.expiration_date: (cont'd from fn 1) The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Akastor (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"), non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. (cont'd in fn 3)

F3 · derivative.expiration_date: (cont'd from fn 2) With regards to Akastor, HMH B.V. will purchase the following securities for a cumulative purchase price of $6,446,933.60 to be paid to Akastor: (i) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class A Shares from Mercury HoldCo Inc. in exchange for $2,773,200.59 and (ii) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class B Shares from Akastor AS in exchange for $3,673,733.01.

F5 · derivative.expiration_date: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Akastor has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · ownership.nature: On April 30, 2026, the underwriters of the initial public offering of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. (cont'd in fn 2)

F2 · ownership.nature: (cont'd from fn 1) The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Akastor (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"), non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. (cont'd in fn 3)

F3 · ownership.nature: (cont'd from fn 2) With regards to Akastor, HMH B.V. will purchase the following securities for a cumulative purchase price of $6,446,933.60 to be paid to Akastor: (i) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class A Shares from Mercury HoldCo Inc. in exchange for $2,773,200.59 and (ii) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class B Shares from Akastor AS in exchange for $3,673,733.01.

F4 · ownership.nature: In this filing, Akastor ASA, Akastor AS, Mercury HoldCo AS and Mercury HoldCo Inc. are collectively referred to as "Akastor". Akastor ASA has an indirect pecuniary interest in the securities held by each of Akastor AS and Mercury HoldCo Inc. Mercury HoldCo AS has an indirect pecuniary interest in the securities held by Mercury HoldCo Inc. Consequently, Akastor ASA may be deemed to share beneficial ownership in the securities held directly by Akastor AS, and Akastor ASA and Mercury HoldCo AS may be deemed to share beneficial ownership in the securities held directly by Mercury HoldCo Inc. The board of directors and officers of Akastor ASA, Mercury HoldCo Inc., Akastor AS and Mercury HoldCo AS disclaim beneficial ownership with respect to such securities.

F5 · ownership.nature: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Akastor has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F6 · ownership.nature: Karl Erik Kjelstad and Svein Oskar Stoknes are directors of the Issuer and were nominated for such roles by Akastor AS and Mercury HoldCo Inc. By virtue of their service on the Board of Directors of the Issuer, for purposes of Section 16, Akastor AS and Mercury HoldCo Inc. may be deemed to be a "director by deputization" of the Issuer.

SEC source: 0000950157-26-000570 · form4.xml · derivative · entry 3

Akastor ASA · CIK 0002037057 · 10% owner

Akastor AS · CIK 0002124921 · Director · 10% owner · Director by Deputization

Mercury HoldCo AS · CIK 0002124920 · 10% owner

Mercury HoldCo Inc. · CIK 0002124922 · Director · 10% owner · Director by Deputization

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · Mercury HoldCo Inc. See footnotes

Disclosed balance after: 15,945,826

Underlying: Class A common stock · 342,922 shares

Expires not disclosed

F1 · derivative.exercise_price: On April 30, 2026, the underwriters of the initial public offering of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. (cont'd in fn 2)

F2 · derivative.exercise_price: (cont'd from fn 1) The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Akastor (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"), non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. (cont'd in fn 3)

F3 · derivative.exercise_price: (cont'd from fn 2) With regards to Akastor, HMH B.V. will purchase the following securities for a cumulative purchase price of $6,446,933.60 to be paid to Akastor: (i) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class A Shares from Mercury HoldCo Inc. in exchange for $2,773,200.59 and (ii) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class B Shares from Akastor AS in exchange for $3,673,733.01.

F5 · derivative.exercise_price: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Akastor has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · kind: On April 30, 2026, the underwriters of the initial public offering of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. (cont'd in fn 2)

F2 · kind: (cont'd from fn 1) The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Akastor (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"), non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. (cont'd in fn 3)

F3 · kind: (cont'd from fn 2) With regards to Akastor, HMH B.V. will purchase the following securities for a cumulative purchase price of $6,446,933.60 to be paid to Akastor: (i) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class A Shares from Mercury HoldCo Inc. in exchange for $2,773,200.59 and (ii) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class B Shares from Akastor AS in exchange for $3,673,733.01.

F5 · kind: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Akastor has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · shares: On April 30, 2026, the underwriters of the initial public offering of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. (cont'd in fn 2)

F2 · shares: (cont'd from fn 1) The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Akastor (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"), non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. (cont'd in fn 3)

F3 · shares: (cont'd from fn 2) With regards to Akastor, HMH B.V. will purchase the following securities for a cumulative purchase price of $6,446,933.60 to be paid to Akastor: (i) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class A Shares from Mercury HoldCo Inc. in exchange for $2,773,200.59 and (ii) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class B Shares from Akastor AS in exchange for $3,673,733.01.

F5 · shares: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Akastor has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · derivative.exercise_date: On April 30, 2026, the underwriters of the initial public offering of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. (cont'd in fn 2)

F2 · derivative.exercise_date: (cont'd from fn 1) The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Akastor (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"), non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. (cont'd in fn 3)

F3 · derivative.exercise_date: (cont'd from fn 2) With regards to Akastor, HMH B.V. will purchase the following securities for a cumulative purchase price of $6,446,933.60 to be paid to Akastor: (i) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class A Shares from Mercury HoldCo Inc. in exchange for $2,773,200.59 and (ii) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class B Shares from Akastor AS in exchange for $3,673,733.01.

F5 · derivative.exercise_date: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Akastor has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · derivative.expiration_date: On April 30, 2026, the underwriters of the initial public offering of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. (cont'd in fn 2)

F2 · derivative.expiration_date: (cont'd from fn 1) The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Akastor (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"), non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. (cont'd in fn 3)

F3 · derivative.expiration_date: (cont'd from fn 2) With regards to Akastor, HMH B.V. will purchase the following securities for a cumulative purchase price of $6,446,933.60 to be paid to Akastor: (i) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class A Shares from Mercury HoldCo Inc. in exchange for $2,773,200.59 and (ii) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class B Shares from Akastor AS in exchange for $3,673,733.01.

F5 · derivative.expiration_date: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Akastor has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · ownership.nature: On April 30, 2026, the underwriters of the initial public offering of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. (cont'd in fn 2)

F2 · ownership.nature: (cont'd from fn 1) The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Akastor (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"), non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. (cont'd in fn 3)

F3 · ownership.nature: (cont'd from fn 2) With regards to Akastor, HMH B.V. will purchase the following securities for a cumulative purchase price of $6,446,933.60 to be paid to Akastor: (i) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class A Shares from Mercury HoldCo Inc. in exchange for $2,773,200.59 and (ii) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class B Shares from Akastor AS in exchange for $3,673,733.01.

F4 · ownership.nature: In this filing, Akastor ASA, Akastor AS, Mercury HoldCo AS and Mercury HoldCo Inc. are collectively referred to as "Akastor". Akastor ASA has an indirect pecuniary interest in the securities held by each of Akastor AS and Mercury HoldCo Inc. Mercury HoldCo AS has an indirect pecuniary interest in the securities held by Mercury HoldCo Inc. Consequently, Akastor ASA may be deemed to share beneficial ownership in the securities held directly by Akastor AS, and Akastor ASA and Mercury HoldCo AS may be deemed to share beneficial ownership in the securities held directly by Mercury HoldCo Inc. The board of directors and officers of Akastor ASA, Mercury HoldCo Inc., Akastor AS and Mercury HoldCo AS disclaim beneficial ownership with respect to such securities.

F5 · ownership.nature: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Akastor has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F6 · ownership.nature: Karl Erik Kjelstad and Svein Oskar Stoknes are directors of the Issuer and were nominated for such roles by Akastor AS and Mercury HoldCo Inc. By virtue of their service on the Board of Directors of the Issuer, for purposes of Section 16, Akastor AS and Mercury HoldCo Inc. may be deemed to be a "director by deputization" of the Issuer.

SEC source: 0000950157-26-000570 · form4.xml · nonDerivative · entry 2

Akastor ASA · CIK 0002037057 · 10% owner

Akastor AS · CIK 0002124921 · Director · 10% owner · Director by Deputization

Mercury HoldCo AS · CIK 0002124920 · 10% owner

Mercury HoldCo Inc. · CIK 0002124922 · Director · 10% owner · Director by Deputization

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · Akastor AS See footnotes

Disclosed balance after: 15,945,826

F1 · kind: On April 30, 2026, the underwriters of the initial public offering of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. (cont'd in fn 2)

F2 · kind: (cont'd from fn 1) The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Akastor (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"), non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. (cont'd in fn 3)

F3 · kind: (cont'd from fn 2) With regards to Akastor, HMH B.V. will purchase the following securities for a cumulative purchase price of $6,446,933.60 to be paid to Akastor: (i) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class A Shares from Mercury HoldCo Inc. in exchange for $2,773,200.59 and (ii) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class B Shares from Akastor AS in exchange for $3,673,733.01.

F5 · kind: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Akastor has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · ownership.nature: On April 30, 2026, the underwriters of the initial public offering of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. (cont'd in fn 2)

F2 · ownership.nature: (cont'd from fn 1) The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Akastor (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"), non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. (cont'd in fn 3)

F3 · ownership.nature: (cont'd from fn 2) With regards to Akastor, HMH B.V. will purchase the following securities for a cumulative purchase price of $6,446,933.60 to be paid to Akastor: (i) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class A Shares from Mercury HoldCo Inc. in exchange for $2,773,200.59 and (ii) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class B Shares from Akastor AS in exchange for $3,673,733.01.

F4 · ownership.nature: In this filing, Akastor ASA, Akastor AS, Mercury HoldCo AS and Mercury HoldCo Inc. are collectively referred to as "Akastor". Akastor ASA has an indirect pecuniary interest in the securities held by each of Akastor AS and Mercury HoldCo Inc. Mercury HoldCo AS has an indirect pecuniary interest in the securities held by Mercury HoldCo Inc. Consequently, Akastor ASA may be deemed to share beneficial ownership in the securities held directly by Akastor AS, and Akastor ASA and Mercury HoldCo AS may be deemed to share beneficial ownership in the securities held directly by Mercury HoldCo Inc. The board of directors and officers of Akastor ASA, Mercury HoldCo Inc., Akastor AS and Mercury HoldCo AS disclaim beneficial ownership with respect to such securities.

F5 · ownership.nature: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Akastor has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F6 · ownership.nature: Karl Erik Kjelstad and Svein Oskar Stoknes are directors of the Issuer and were nominated for such roles by Akastor AS and Mercury HoldCo Inc. By virtue of their service on the Board of Directors of the Issuer, for purposes of Section 16, Akastor AS and Mercury HoldCo Inc. may be deemed to be a "director by deputization" of the Issuer.

SEC source: 0000950157-26-000570 · form4.xml · nonDerivative · entry 1

Akastor ASA · CIK 0002037057 · 10% owner

Akastor AS · CIK 0002124921 · Director · 10% owner · Director by Deputization

Mercury HoldCo AS · CIK 0002124920 · 10% owner

Mercury HoldCo Inc. · CIK 0002124922 · Director · 10% owner · Director by Deputization

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · Mercury HoldCo Inc. See footnotes

Disclosed balance after: 16,117,287

F1 · kind: On April 30, 2026, the underwriters of the initial public offering of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. (cont'd in fn 2)

F2 · kind: (cont'd from fn 1) The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Akastor (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"), non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. (cont'd in fn 3)

F3 · kind: (cont'd from fn 2) With regards to Akastor, HMH B.V. will purchase the following securities for a cumulative purchase price of $6,446,933.60 to be paid to Akastor: (i) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class A Shares from Mercury HoldCo Inc. in exchange for $2,773,200.59 and (ii) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class B Shares from Akastor AS in exchange for $3,673,733.01.

F5 · kind: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Akastor has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · ownership.nature: On April 30, 2026, the underwriters of the initial public offering of HMH Holding Inc. (the "Issuer") partially exercised their option to purchase (the "Over Allotment") additional shares of the Issuer's Class A Common Stock, par value $0.01 per share (the "Class A Common Stock"). In connection with the Over Allotment, the underwriters will purchase 685,844 shares of Class A Common Stock, and the transaction is anticipated to close on May 5, 2026. (cont'd in fn 2)

F2 · ownership.nature: (cont'd from fn 1) The Issuer will contribute the net proceeds from the Over Allotment, which will amount to $12,893,867.20, to HMH Holding B.V. ("HMH B.V."), and HMH B.V. will use such net proceeds to purchase in equal proportion from Akastor (as defined below) and another stockholder of HMH B.V., respectively, an aggregate number of shares of Class B common stock of the Issuer (the "Issuer Class B Shares"), non-voting Class A ordinary shares in HMH B.V. (the "B.V. Non-Voting Class A Shares") and non-voting Class B shares in HMH B.V. (the "B.V. Non-Voting Class B Shares"), respectively, equal to the number of shares of Class A Common Stock to be purchased by the underwriters pursuant to the Over Allotment. (cont'd in fn 3)

F3 · ownership.nature: (cont'd from fn 2) With regards to Akastor, HMH B.V. will purchase the following securities for a cumulative purchase price of $6,446,933.60 to be paid to Akastor: (i) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class A Shares from Mercury HoldCo Inc. in exchange for $2,773,200.59 and (ii) 171,461 Issuer Class B Shares and 342,922 B.V. Non-Voting Class B Shares from Akastor AS in exchange for $3,673,733.01.

F4 · ownership.nature: In this filing, Akastor ASA, Akastor AS, Mercury HoldCo AS and Mercury HoldCo Inc. are collectively referred to as "Akastor". Akastor ASA has an indirect pecuniary interest in the securities held by each of Akastor AS and Mercury HoldCo Inc. Mercury HoldCo AS has an indirect pecuniary interest in the securities held by Mercury HoldCo Inc. Consequently, Akastor ASA may be deemed to share beneficial ownership in the securities held directly by Akastor AS, and Akastor ASA and Mercury HoldCo AS may be deemed to share beneficial ownership in the securities held directly by Mercury HoldCo Inc. The board of directors and officers of Akastor ASA, Mercury HoldCo Inc., Akastor AS and Mercury HoldCo AS disclaim beneficial ownership with respect to such securities.

F5 · ownership.nature: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Akastor has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Class A Common Stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F6 · ownership.nature: Karl Erik Kjelstad and Svein Oskar Stoknes are directors of the Issuer and were nominated for such roles by Akastor AS and Mercury HoldCo Inc. By virtue of their service on the Board of Directors of the Issuer, for purposes of Section 16, Akastor AS and Mercury HoldCo Inc. may be deemed to be a "director by deputization" of the Issuer.

SEC source: 0001193125-26-140142 · ownership.xml · derivative · entry 7

Baker Hughes Co · CIK 0001701605 · Director · 10% owner · Director by Deputization

Baker Hughes Holdings LLC · CIK 0000808362 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · Baker Hughes Holdings LLC

Disclosed balance after: 16,288,748

Underlying: Class A common stock · 16,288,748 shares

Expires not disclosed

F1 · derivative.exercise_price: Prior to the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer"), Baker Hughes Holdings LLC, a wholly owned subsidiary of Baker Hughes Company, held 50 Class B ordinary shares (the "B.V. Voting Class B Shares") of HMH Holding B.V. ("HMH B.V.") and 50 Class A ordinary shares (the "B.V. Voting Class A Shares") of HMH B.V. In this filing, Baker Hughes Company and Baker Hughes Holdings LLC are collectively referred to as "Baker Hughes". In connection with the corporate reorganization and Baker Hughes' participation in the synthetic secondary as described in the Issuer's Registration Statement on Form S-1 (Registration No. 333-281497), the following transactions have occurred: first, HMH B.V., the predecessor entity to the Issuer, underwent a 346,774.96 for 1 stock split, after which Baker Hughes Company held 17,338,748 B.V. Voting Class B Shares and 17,338,748 B.V. Voting Class A Shares (through Baker Hughes Holdings LLC);

F2 · derivative.exercise_price: (Continued from footnote 1) second, HMH B.V. recapitalized to convert (i) Baker Hughes Holdings LLC's 16,288,748 B.V. Voting Class A Shares to non-voting Class A ordinary shares (the "B.V. Non-Voting Class A Shares") and (ii) its 16,288,748 B.V. Voting Class B Shares to non-voting Class B ordinary shares (the "B.V. Non-Voting Class B Shares"); third, (i) Baker Hughes Holdings LLC sold 1,050,000 B.V. Voting Class B Shares and 1,050,000 B.V. Voting Class A Shares, in each case, to the Issuer in exchange cumulatively for $19,740,000 and (ii) Baker Hughes Holdings LLC received 16,288,748 shares of Class B common stock of the Issuer (the "Issuer Class B Shares") in exchange for relinquishing voting rights on its remaining 16,288,748 B.V. Voting Class B Shares and 16,288,748 B.V. Voting Class A Shares that were recapitalized into 16,288,748 B.V. Non-Voting Class B Shares and 16,288,748 B.V. Non-Voting Class A Shares, respectively.

F4 · derivative.exercise_price: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Issuer's Class A common stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · kind: Prior to the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer"), Baker Hughes Holdings LLC, a wholly owned subsidiary of Baker Hughes Company, held 50 Class B ordinary shares (the "B.V. Voting Class B Shares") of HMH Holding B.V. ("HMH B.V.") and 50 Class A ordinary shares (the "B.V. Voting Class A Shares") of HMH B.V. In this filing, Baker Hughes Company and Baker Hughes Holdings LLC are collectively referred to as "Baker Hughes". In connection with the corporate reorganization and Baker Hughes' participation in the synthetic secondary as described in the Issuer's Registration Statement on Form S-1 (Registration No. 333-281497), the following transactions have occurred: first, HMH B.V., the predecessor entity to the Issuer, underwent a 346,774.96 for 1 stock split, after which Baker Hughes Company held 17,338,748 B.V. Voting Class B Shares and 17,338,748 B.V. Voting Class A Shares (through Baker Hughes Holdings LLC);

F2 · kind: (Continued from footnote 1) second, HMH B.V. recapitalized to convert (i) Baker Hughes Holdings LLC's 16,288,748 B.V. Voting Class A Shares to non-voting Class A ordinary shares (the "B.V. Non-Voting Class A Shares") and (ii) its 16,288,748 B.V. Voting Class B Shares to non-voting Class B ordinary shares (the "B.V. Non-Voting Class B Shares"); third, (i) Baker Hughes Holdings LLC sold 1,050,000 B.V. Voting Class B Shares and 1,050,000 B.V. Voting Class A Shares, in each case, to the Issuer in exchange cumulatively for $19,740,000 and (ii) Baker Hughes Holdings LLC received 16,288,748 shares of Class B common stock of the Issuer (the "Issuer Class B Shares") in exchange for relinquishing voting rights on its remaining 16,288,748 B.V. Voting Class B Shares and 16,288,748 B.V. Voting Class A Shares that were recapitalized into 16,288,748 B.V. Non-Voting Class B Shares and 16,288,748 B.V. Non-Voting Class A Shares, respectively.

F4 · kind: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Issuer's Class A common stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · derivative.exercise_date: Prior to the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer"), Baker Hughes Holdings LLC, a wholly owned subsidiary of Baker Hughes Company, held 50 Class B ordinary shares (the "B.V. Voting Class B Shares") of HMH Holding B.V. ("HMH B.V.") and 50 Class A ordinary shares (the "B.V. Voting Class A Shares") of HMH B.V. In this filing, Baker Hughes Company and Baker Hughes Holdings LLC are collectively referred to as "Baker Hughes". In connection with the corporate reorganization and Baker Hughes' participation in the synthetic secondary as described in the Issuer's Registration Statement on Form S-1 (Registration No. 333-281497), the following transactions have occurred: first, HMH B.V., the predecessor entity to the Issuer, underwent a 346,774.96 for 1 stock split, after which Baker Hughes Company held 17,338,748 B.V. Voting Class B Shares and 17,338,748 B.V. Voting Class A Shares (through Baker Hughes Holdings LLC);

F2 · derivative.exercise_date: (Continued from footnote 1) second, HMH B.V. recapitalized to convert (i) Baker Hughes Holdings LLC's 16,288,748 B.V. Voting Class A Shares to non-voting Class A ordinary shares (the "B.V. Non-Voting Class A Shares") and (ii) its 16,288,748 B.V. Voting Class B Shares to non-voting Class B ordinary shares (the "B.V. Non-Voting Class B Shares"); third, (i) Baker Hughes Holdings LLC sold 1,050,000 B.V. Voting Class B Shares and 1,050,000 B.V. Voting Class A Shares, in each case, to the Issuer in exchange cumulatively for $19,740,000 and (ii) Baker Hughes Holdings LLC received 16,288,748 shares of Class B common stock of the Issuer (the "Issuer Class B Shares") in exchange for relinquishing voting rights on its remaining 16,288,748 B.V. Voting Class B Shares and 16,288,748 B.V. Voting Class A Shares that were recapitalized into 16,288,748 B.V. Non-Voting Class B Shares and 16,288,748 B.V. Non-Voting Class A Shares, respectively.

F4 · derivative.exercise_date: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Issuer's Class A common stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · derivative.expiration_date: Prior to the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer"), Baker Hughes Holdings LLC, a wholly owned subsidiary of Baker Hughes Company, held 50 Class B ordinary shares (the "B.V. Voting Class B Shares") of HMH Holding B.V. ("HMH B.V.") and 50 Class A ordinary shares (the "B.V. Voting Class A Shares") of HMH B.V. In this filing, Baker Hughes Company and Baker Hughes Holdings LLC are collectively referred to as "Baker Hughes". In connection with the corporate reorganization and Baker Hughes' participation in the synthetic secondary as described in the Issuer's Registration Statement on Form S-1 (Registration No. 333-281497), the following transactions have occurred: first, HMH B.V., the predecessor entity to the Issuer, underwent a 346,774.96 for 1 stock split, after which Baker Hughes Company held 17,338,748 B.V. Voting Class B Shares and 17,338,748 B.V. Voting Class A Shares (through Baker Hughes Holdings LLC);

F2 · derivative.expiration_date: (Continued from footnote 1) second, HMH B.V. recapitalized to convert (i) Baker Hughes Holdings LLC's 16,288,748 B.V. Voting Class A Shares to non-voting Class A ordinary shares (the "B.V. Non-Voting Class A Shares") and (ii) its 16,288,748 B.V. Voting Class B Shares to non-voting Class B ordinary shares (the "B.V. Non-Voting Class B Shares"); third, (i) Baker Hughes Holdings LLC sold 1,050,000 B.V. Voting Class B Shares and 1,050,000 B.V. Voting Class A Shares, in each case, to the Issuer in exchange cumulatively for $19,740,000 and (ii) Baker Hughes Holdings LLC received 16,288,748 shares of Class B common stock of the Issuer (the "Issuer Class B Shares") in exchange for relinquishing voting rights on its remaining 16,288,748 B.V. Voting Class B Shares and 16,288,748 B.V. Voting Class A Shares that were recapitalized into 16,288,748 B.V. Non-Voting Class B Shares and 16,288,748 B.V. Non-Voting Class A Shares, respectively.

F4 · derivative.expiration_date: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Issuer's Class A common stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F1 · ownership.nature: Prior to the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer"), Baker Hughes Holdings LLC, a wholly owned subsidiary of Baker Hughes Company, held 50 Class B ordinary shares (the "B.V. Voting Class B Shares") of HMH Holding B.V. ("HMH B.V.") and 50 Class A ordinary shares (the "B.V. Voting Class A Shares") of HMH B.V. In this filing, Baker Hughes Company and Baker Hughes Holdings LLC are collectively referred to as "Baker Hughes". In connection with the corporate reorganization and Baker Hughes' participation in the synthetic secondary as described in the Issuer's Registration Statement on Form S-1 (Registration No. 333-281497), the following transactions have occurred: first, HMH B.V., the predecessor entity to the Issuer, underwent a 346,774.96 for 1 stock split, after which Baker Hughes Company held 17,338,748 B.V. Voting Class B Shares and 17,338,748 B.V. Voting Class A Shares (through Baker Hughes Holdings LLC);

F2 · ownership.nature: (Continued from footnote 1) second, HMH B.V. recapitalized to convert (i) Baker Hughes Holdings LLC's 16,288,748 B.V. Voting Class A Shares to non-voting Class A ordinary shares (the "B.V. Non-Voting Class A Shares") and (ii) its 16,288,748 B.V. Voting Class B Shares to non-voting Class B ordinary shares (the "B.V. Non-Voting Class B Shares"); third, (i) Baker Hughes Holdings LLC sold 1,050,000 B.V. Voting Class B Shares and 1,050,000 B.V. Voting Class A Shares, in each case, to the Issuer in exchange cumulatively for $19,740,000 and (ii) Baker Hughes Holdings LLC received 16,288,748 shares of Class B common stock of the Issuer (the "Issuer Class B Shares") in exchange for relinquishing voting rights on its remaining 16,288,748 B.V. Voting Class B Shares and 16,288,748 B.V. Voting Class A Shares that were recapitalized into 16,288,748 B.V. Non-Voting Class B Shares and 16,288,748 B.V. Non-Voting Class A Shares, respectively.

F3 · ownership.nature: Baker Hughes Company has an indirect pecuniary interest in the securities held by each of Baker Hughes Holdings LLC. Consequently, Baker Hughes Company may be deemed to share beneficial ownership in the securities held directly by Baker Hughes Holdings LLC. The board of directors and officers of Baker Hughes Company disclaim beneficial ownership with respect to such securities.

F4 · ownership.nature: Pursuant to the Exchange Agreement, dated as of April 2, 2026, by and among the Issuer, HMH B.V. and the other parties thereto, Baker Hughes has the right to exchange one Issuer Class B Share, one B.V. Non-Voting Class A Share and one B.V. Non-Voting Class B Share for cash or shares of the Issuer's Class A common stock on a one-for-one basis, subject to customary conversion rate adjustments (e.g. for stock splits, stock dividends and reclassifications). These rights are exercisable at any time after the conclusion of the Issuer's IPO lock-up period (i.e., September 27, 2026, unless the IPO lock-up is earlier released or waived by the underwriters of the Issuer's IPO) and do not expire.

F5 · ownership.nature: Judson E. Bailey and M. Georgia Magno are directors of the Issuer and were nominated for such roles by Baker Hughes Holdings LLC. By virtue of their service on the Board of Directors of the Issuer, for purposes of Section 16, Baker Hughes Holdings LLC may be deemed to be a "director by deputization" of the Issuer.