ARROW FINANCIAL CORP

proxy statement of Adirondack, which also constitutes a prospectus of Arrow, that will be sent to shareholders of Adirondack seeking certain approvals related to the proposed transaction. Arrow may file with the SEC other relevant documents concerning the proposed transaction. This communication does not constitute an offer to sell or a solicitation of an offer to buy any securities or a solicitation of any vote or approval, nor shall there be any offer or sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No offer of securities shall be made except by means of a prospectus meeting the requirements of the Securities Act of 1933, as amended. INVESTORS AND SHAREHOLDERS ARE URGED TO READ, WHEN AVAILABLE, THE REGISTRATION STATEMENT ON FORM S-4, THE PROXY STATEMENT/PROSPECTUS TO BE INCLUDED WITHIN THE REGISTRATION STATEMENT ON FORM S-4 AND ANY OTHER RELEVANT DOCUMENTS FILED OR TO BE FILED WITH THE SEC IN CONNECTION WITH THE PROPOSED TRANSACTION, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THOSE DOCUMENTS, BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT ARROW, ADIRONDACK, AND THE PROPOSED TRANSACTION. Investors and shareholders will be able to obtain a free copy of the registration statement, including the proxy statement/prospectus, as well as other relevant documents filed with the SEC containing information about Arrow, without charge, at the SEC’s website www.sec.gov. Copies of documents filed with the SEC by Arrow will be made available free of charge in the “Documents” section of Arrow’s website, www.arrowfinancial.com, under the heading “Filings.” The information on Arrow’s website is not, and shall not be deemed to be, a part of this communication or incorporated into other filings Arrow makes with the SEC. Participants in Solicitation Adirondack, Arrow, and certain of their respective directors and executive officers may be deemed to be participants in the solicitation of proxies from shareholders of Adirondack in respect of the proposed transaction under the rules of the SEC. Information regarding Arrow’s directors and executive officers is available in its definitive proxy statement, which was filed with the SEC on April 24, 2025 and certain other documents filed by Arrow with the SEC. Other information regarding the participants in the solicitation of proxies in respect of the proposed transaction and a description of their direct and indirect interests, by security holdings or otherwise, will be contained in the proxy statement/prospectus and other relevant materials to be filed with the SEC. INVESTOR RELATIONS CONTACT: Penko Ivanov Senior EVP, Chief Financial Officer & Treasurer Arrow Financial Corporation (518) 415-4512 penko.ivanov@arrowbank.com MEDIA CONTACTS: Rachael Murray Corporate Communications Professional Arrow Financial Corporation (518) 415-4313 rachael.murray@arrowbank.com Anna Jolly Duval VP, Communications Manager Arrow Financial Corporation (518) 338-6270 anna.duval@arrowbank.com