X0609 4 2026-04-30 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 2026-04-30 4 J 0 171461 0 D 16117287 I Mercury HoldCo Inc. See footnotes Class B Common Stock 2026-04-30 4 J 0 171461 0 D 15945826 I Akastor AS See footnotes B.V. Non-Voting Class A Shares 2026-04-30 4 J 0 342922 8.087 D Class A common stock 342922 15945826 I Mercury HoldCo Inc. See footnotes B.V. Non-Voting Class B Shares 2026-04-30 4 J 0 342922 10.713 D Class A common stock 342922 15945826 I Akastor AS See footnotes 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) (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) (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. 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. 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. 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 2026-05-04 /s/ Oyvind Paaske, Chair of Akastor AS 2026-05-04 /s/ Oyvind Paaske, Chair of Mercury HoldCo AS 2026-05-04 /s/ Askel Matre, Director of Mercury HoldCo Inc. 2026-05-04