TMC the metals Co Inc.

10b5-1 Trading Arrangements

During the three months ended March 31, 2025, none of ourdirectors or officers (as defined in Section 16 of the Securities Exchange Act of 1934, as amended)adopted, modified orterminated anycontract, instruction or written plan for the purchase or sale of our securities that was intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) or any “non-Rule 10b5-1 trading arrangement,” as defined in Item 408(a) of Regulation S-K.

Board Observer Agreement

On May 12, 2025, we entered into a Board Observer Agreement with Zachary A. Wydra, the Chief Executive Officer of First Manhattan Co. LLC and related entities and portfolio manager of certain accounts managed by First Manhattan Co. LLC, a beneficial owner of more than five percent (5%) of our issued and outstanding common shares, under which Mr. Wydra will serve as a non-voting observer to our board of directors, whereby he may have access to certain information and attend and provide input at meetings of our board of directors, subject to certain limitations. Mr. Wydra will not receive any compensation for his role as a board observer. The foregoing description of the Board Observer Agreement does not purport to be a complete description of the rights and obligations of the parties thereunder and is qualified in its entirety by reference to the full text of the Board Observer Agreement which we expect to attach as an Exhibit to our Quarterly Report on Form 10-Q for the quarter ended June 30, 2025 and incorporated therein by reference.