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To the Shareholders of AMBASE CORPORATION,

The 2026 Annual Meeting of Shareholders of AMBASE CORPORATION will be held on May 27, 2026 for Shareholders of record as of April 07, 2026.

Your vote is important, so please vote at your earliest convenience.

If you are a registered holder, to vote your proxy you will need your account's unique 11-digit Control Number, which is located in your proxy e-mail or located beneath the company and account number on the upper-right side of your proxy material.

To vote online, please click Vote Your Online Proxy.

To vote by telephone, call toll - free 1 - 800 - PROXIES (1 - 800 - 776 - 9437) in the United States or 1 - 201 - 299 - 4446 from foreign countries and follow the instructions.

If you own shares through a broker, please follow the instructions that were provided to you by your broker/financial institution.

If you have any questions, please contact AST.

Thank You,

Equiniti Trust Company, LLC

Transfer Agent for AMBASE CORPORATION