X0609 4 2026-04-02 0002021880 HMH Holding Inc HMH 0002037057 Akastor ASA true OKSENOYVEIEN 10 LYSAKER Q8 1366 NORWAY true 0002124921 Akastor AS true OKSENOYVEIEN 10 LYSAKER Q8 1366 NORWAY true true true Director by Deputization 0002124920 Mercury HoldCo AS true OKSENOYVEIEN 10 LYSAKER Q8 1366 NORWAY true 0002124922 Mercury HoldCo Inc. false 3300 NORTH SAM HOUSTON PARKWAY EAST HOUSTON TX 77032 true true true Director by Deputization false Class B common stock 2026-04-02 4 J 0 8144374 0 A 8144374 I Mercury HoldCo Inc. See footnotes Class B common stock 2026-04-02 4 J 0 8144374 0 A 16288748 I Akastor AS See footnotes B.V. Voting Class A Shares 2026-04-02 4 J 0 1050000 9.4 D Class A common stock 1050000 16288748 I Mercury HoldCo Inc. B.V. Voting Class B Shares 2026-04-02 4 J 0 1050000 9.4 D Class A common stock 1050000 16288748 I Akastor AS B.V. Voting Class A Shares 2026-04-02 4 J 0 16288748 0 D Class A common stock 16288748 0 I Mercury HoldCo Inc. B.V. Voting Class B Shares 2026-04-02 4 J 0 16288748 0 D Class A common stock 16288748 0 I Akastor AS B.V. Non-Voting Class A Shares 2026-04-02 4 J 0 16288748 0 A 2026-09-27 Class A common stock 16288748 16288748 I Mercury HoldCo Inc. B.V. Non-Voting Class B Shares 2026-04-02 4 J 0 16288748 0 A 2026-09-27 Class A common stock 16288748 16288748 I Akastor AS Prior to the initial public offering ("IPO") of HMH Holding Inc. (the "Issuer"), (a) Akastor AS, a direct wholly owned subsidiary of Akastor ASA, held 50 Class B ordinary shares (the "B.V. Voting Class B Shares") of HMH Holding B.V. ("HMH B.V.") and (b) Mercury HoldCo Inc., an indirect wholly owned subsidiary of Akastor ASA (with Mercury HoldCo AS as an intermediary subsidiary between Akastor ASA and Mercury HoldCo Inc.) held 50 Class A ordinary shares (the "B.V. Voting Class A Shares") of HMH B.V. In this filing, Akastor ASA, Akastor AS, Mercury HoldCo AS and Mercury HoldCo Inc. are collectively referred to as "Akastor". (cont'd in fn 2) (cont'd from fn 1) In connection with the corporate reorganization and Akastor's 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 Akastor held 17,338,748 B.V. Voting Class B Shares (through Akastor AS) and 17,338,748 B.V. Voting Class A Shares (through Mercury HoldCo Inc.); second, HMH B.V. recapitalized to convert (i) 16,288,748 of Mercury HoldCo Inc.'s B.V. Voting Class A Shares to non-voting Class A ordinary shares (the "B.V. Non-Voting Class A Shares") and (ii) 16,288,748 of Akastor AS's B.V. Voting Class B Shares to non-voting Class B ordinary shares (the "B.V. Non-Voting Class B Shares"); (cont'd in fn 3) (cont'd from fn. 2) third, (i) Akastor AS sold 1,050,000 B.V. Voting Class B Shares, and Mercury HoldCo Inc. sold 1,050,000 B.V. Voting Class A Shares, in each case, to the Issuer in exchange cumulatively for $19,740,000 and (ii) each of Akastor AS and Mercury HoldCo Inc. received 8,144,374 shares of Class B common stock of the Issuer (the "Issuer Class B Shares") in exchange for relinquishing voting rights on their respective remaining 16,288,748 B.V. Voting Class B Shares (held by Akastor AS) and 16,288,748 B.V. Voting Class A Shares (held by Mercury HoldCo Inc.) that were recapitalized into 16,288,748 B.V. Non-Voting Class B Shares (held by Akastor AS) and 16,288,748 B.V. Non-Voting Class A Shares (held by Mercury HoldCo Inc.), respectively. 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. 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 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. 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. /s/ Karl Erik Kjelstad, as Chief Executive Officer of Akastor ASA 2026-04-02 /s/ Oyvind Paaske, Chair of Akastor AS 2026-04-02 /s/ Oyvind Paaske, Chair of Mercury HoldCo AS 2026-04-02 /s/ Askel Matre, Director of Mercury HoldCo Inc. 2026-04-02