Platinum SpinCo, Inc.

Item 5.03 Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year. On September 29, 2026, Platinum SpinCo Inc. (the “Company”) filed a Certificate of Amendment (the “Certificate of Amendment”) to its Certificate of Incorporation with the Secretary of State of the State of Delaware. The Certificate of Amendment became effective upon filing. The Certificate of Amendment amended and restated Article IV of the Certificate of Incorporation. Prior to the amendment, Article IV authorized the Company to issue 5,000 shares of common stock, par value $0.001 per share (the “Common Stock”). As amended, Section 4.1 of Article IV authorizes the Company to issue 60,000,000 shares of Common Stock, par value $0.001 per share. New Section 4.2 of Article IV provides that, effective upon the effectiveness of the Certificate of Amendment, all shares of Common Stock issued and outstanding immediately prior to such time were automatically reclassified and converted into an aggregate number of shares of Common Stock equal to the number of shares of common stock of Modine Manufacturing Company (“Modine”), the Company’s sole stockholder, issued and outstanding as of the close of business on September 28, 2026, excluding shares held by Modine as treasury stock or held by any of Modine’s subsidiaries, less an adjustment for up to 2,000 shares of Common Stock issuable to Modine under the Equity Contribution Agreement, dated as of September 28, 2026, between the Company and Modine, to the extent not issued prior to such effectiveness. The foregoing description of the Certificate of Amendment does not purport to be complete and is qualified in its entirety by reference to the full text of the Certificate of Amendment, a copy of which is filed as Exhibit 3.1 to this Current Report on Form 8-K and is incorporated herein by reference.