Newbury Street II Acquisition Corp

Trading Arrangements

During the quarterly period ended June 30, 2025, none of our directors or officers (as defined in Rule 16a-1(f) promulgated under the Exchange Act)adopted orterminated any “Rule 10b5-1 trading arrangement” or any “non-Rule 10b5-1 trading arrangement,” as each term is defined in Item 408(a) of Regulation S-K.

Additional Information

On May 28, 2025, Matthew Hong notified the Board of his resignation as a member and chairman of the Board and a member and chair of the Audit Committee, effective as of the same day.

On May 28, 2025, the Board appointed Anthony James Vinciquerra and William Zachre Wyatt as directors of the Board. Effective as of May 28, 2025, Mr. Vinciquerra was appointed as chairman of the Board, Ted Seides, a director of our Company, was appointed as a member of the Audit Committee, and Josh Gold, a director and member of the Audit Committee, was appointed as chair of the Audit Committee. The New Directors will serve as Class III Directors of the Board, whose term will expire at our third annual general meeting.

In connection with the appointments, the New Directors signed a joinder to the Letter Agreement, pursuant to which, among other things, the signatories agreed to waive certain redemption rights and to vote any Ordinary Shares they hold in favor of an initial Business Combination. The New Directors also entered into a standard director indemnity agreement with our Company. Each of the New Directors will also receive membership interests in the Sponsor representing ownership of certain Class B Ordinary Shares solely upon consummation of the Business Combination with a target introduced by such director.