Material Agreement (Form 8-K)

As previously disclosed, on December 4, 2025, dMY Squared Technology Group, Inc., a Massachusetts corporation ("dMY"), Horizon Quantum Holdings Ltd. (formerly known as Horizon Quantum Holdings Pte. Ltd. and Rose Holdco Pte. Ltd.) (Company Registration No.: 202537774K), a Singapore public company limited by shares ("Holdco"), and Horizon Quantum Computing Pte. Ltd. (Company Registration No.: 201802755E), a Singapore private limited company by shares ("Horizon"), entered into Subscription Agreements (the "PIPE Subscription Agreements") with certain institutional and accredited investors, qualified institutional buyers and strategic investors (the "PIPE Investors"), whereby Holdco has agreed to issue and sell, and the PIPE Investors agreed to subscribe for and purchase, in a private placement (the "PIPE Investment"), an aggregate of approximately $110.4 million of Holdco's Class A ordinary shares (the "PIPE Shares"), at a per share price equal to the price at which dMY's public shares may be redeemed (the "Redemption Price") in connection with the previously-announced business combination among dMY, Holdco, and Horizon (the "Business Combination").

On March 6, 2026, dMY, Holdco, and Horizon entered into additional Subscription Agreements with additional PIPE Investors, pursuant to which Holdco has agreed to issue and sell, and the additional PIPE Investors agreed to subscribe for and purchase an additional $1,450,000 of PIPE Shares, at a per share price equal to the Redemption Price. The additional PIPE Investment includes a $1,000,000 investment by Penchant Family Holdings LLC, an entity controlled by Penchant Holdings, Inc., its Managing Member, of which Danielle Lambert serves as its President. Ms. Lambert is a director nominee of Holdco. As of the date of this Current Report on Form 8-K, the aggregate amount of the PIPE Investment is $111,862,500.

The foregoing description of the PIPE Subscription Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the form of the PIPE Subscription Agreement, a copy of which is included as Exhibit 10.1 to this Current Report on Form 8-K and is incorporated herein by reference

Additional Information about the Business Combination and Where to Find It

In connection with the Business Combination, Holdco and Horizon filed a registration statement on Form F-4 relating to the Business Combination and certain other matters (the "Registration Statement"), which includes a preliminary proxy statement of dMY and a preliminary prospectus of Holdco with respect to the securities to be offered in the Business Combination. The Registration Statement became effective on February 17, 2026. The same day, dMY filed and mailed a definitive proxy statement/prospectus (the "Proxy Statement") to its shareholders as of the record date established for voting on the Business Combination. The Proxy Statement contains important information about the Business Combination and the other matters to be voted upon at a special meeting of shareholders of dMY (the "Special Meeting"). This Current Report on Form 8-K does not contain all the information that should be considered concerning the Business Combination and other matters and is not intended to provide the basis for any investment decision or any other decision in respect of such matters. dMY, Holdco, and Horizon may also file other documents with the Securities and Exchange Commission (the "SEC") regarding the Business Combination. dMY's shareholders and other interested persons are advised to read the definitive proxy statement/prospectus and other documents filed in connection with the Business Combination, as these materials contain important information about dMY, Holdco, Horizon, and the Business Combination. The documents filed by dMY, Holdco, and Horizon with the SEC also may be obtained free of charge upon written request to dMY at dMY Squared Technology Group, Inc., 1180 North Town Center Drive, Suite 100, Las Vegas, Nevada 89144.

Participants in the Solicitation

dMY, Holdco, and Horizon and their respective directors, executive officers and other members of their management and employees, under SEC rules, may be deemed to be participants in the solicitation of proxies of dMY's shareholders in connection with the Business Combination. Investors and security holders may obtain more detailed information regarding the names, affiliations and interests of dMY's directors and officers in dMY's Annual Report on Form 10-K for the fiscal year ended December 31, 2024, filed with the SEC on April 3, 2025 (the "dMY Annual Report") or its subsequent quarterly reports. Information regarding the persons who may, under SEC rules, be deemed participants in the solicitation of proxies to dMY's shareholders in connection with the Business Combination is set forth in the Proxy Statement for the Business Combination. Information concerning the interests of Holdco's, Horizon's and dMY's participants in the solicitation, which may, in some cases, be different than those of their respective equityholders generally, is set forth in the Proxy Statement relating to the Business Combination.