INTERNATIONAL BANCSHARES CORP

The Board of Directors of International Bancshares Corporation, a Texas corporation, is soliciting proxies to be used at the Annual Meeting of Shareholders currently scheduled to be held on Monday, May 20, 2024 at 5:00 p.m., local time, at the IBC Annex Building, located at 2416 Jacaman Rd., Laredo, Texas 78041. The Company will pay for the cost of the proxy material preparation and solicitation, including the reasonable charges and expenses of brokerage firms, banks or other nominees for forwarding proxy materials to street name holders. International Bancshares Corporation is referred to in this Proxy Statement as “we,” “us,” “our,” or the “Company.”

It is expected that the solicitation of proxies will be primarily by mail. Proxies may also be solicited personally by regular employees of the Company for no additional compensation. Any shareholder giving a proxy has the power to revoke it at any time prior to the voting of the proxy by giving notice in person or in writing to the Company’s Secretary at 1200 San Bernardo Avenue, Laredo, Texas 78042, or by appearing at the Annual Meeting, giving notice of revocation of the proxy, and voting in person. The approximate date on which this Proxy Statement and the accompanying form of proxy are first sent or given to shareholders is April 22, 2024.