Arrow Financial (NASDAQ: AROW) boosts New York footprint with Adirondack Bancorp acquisition

Rhea-AI Filing Summary

Arrow Financial Corporation agreed to acquire Adirondack Bancorp, Inc. in a stock-and-cash merger that expands Arrow’s community banking footprint across upstate New York, including the Mohawk Valley and additional Adirondack markets.

Each Adirondack share will be converted into 1.8610 Arrow shares plus $18.72 in cash, implying total consideration of about $89.1 million based on Arrow’s share price on February 25, 2026. The combined company is projected to have about $5.4 billion in assets, $4.8 billion in deposits and $4.1 billion in gross loans, with management targeting roughly 18% cash EPS accretion in 2027, a 20% internal rate of return and a tangible book value per share earnback period of 2.9 years. Adirondack’s CEO, Rocco Arcuri Sr., will become Regional President and join Arrow’s and Arrow Bank’s boards, while voting and lock-up agreements from key Adirondack shareholders are designed to support deal approval and manage post-closing share sales. Closing is contingent on Adirondack shareholder approval and customary banking regulatory approvals.

Positive

• Meaningful earnings accretion and returns: Management projects approximately 12.8%–18.1% 2027 EPS accretion, a roughly 20% internal rate of return and a 2.9‑year tangible book value per share earnback, indicating a financially attractive acquisition on the disclosed assumptions.
• Stronger regional franchise and scale: The merger creates a roughly $5.4 billion‑asset community bank with expanded reach across upstate New York, including the Mohawk Valley and additional Adirondack counties, enhancing Arrow’s competitive position and lending capacity.
• Solid pro forma capital and credit profile: After purchase accounting marks, management expects tangible common equity near 8.0%, CET1 about 11.9%, total risk‑based capital around 13.8%, and allowance coverage above 1.00%, alongside historically low net charge‑offs and controlled nonperforming assets.

Negative

• None.

Insights

Bank M&A and Capital Markets Analyst

Arrow’s Adirondack deal is strategically logical, EPS-accretive and capital-supportive, though integration and execution risks remain.

Arrow Financial is using a mixed stock-and-cash structure to buy Adirondack Bancorp, adding roughly $942 million of assets and deepening its position in upstate New York. Management highlights complementary markets, especially in the Mohawk Valley and Adirondack region, and the ability to cross-sell wealth management and insurance products into Adirondack’s customer base.

The pro forma outlook is financially strong on disclosed assumptions: projected 2027 cash EPS accretion around 12.8%–18.1%, internal rate of return near 20%, and an estimated tangible book value per share earnback of 2.9 years. Cost saves are sizable, targeting 45% of Adirondack’s noninterest expense, with most benefits expected after integration and purchase‑accounting accretion from loan and securities marks.

Capital and credit metrics remain conservative, with pro forma tangible common equity around 8.0%, CET1 roughly 11.9%, total risk‑based capital about 13.8%, and allowance coverage above 1.00%. Due diligence covered nearly 400 credit files, and both banks show historically low net charge‑offs and manageable nonperforming assets. Execution risk centers on realizing forecast cost saves, integrating systems and culture, and securing required regulatory and Adirondack shareholder approvals by the targeted late Q2 or early Q3 2026 close.

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report: February 25, 2026

(Date of earliest event reported)

ARROW FINANCIAL CORPORATION

(Exact name of registrant as specified in its charter)

New York			0-12507			22-2448962
(State or other jurisdiction of incorporation)			(Commission File Number)			(IRS Employer Identification No.)

250 Glen Street

Glens Falls

New York

12801

(Address of principal executive offices)

(Zip Code)

Registrant’s telephone number, including area code:

518

745-1000

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:
☒			Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
☐			Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
☐			Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
☐			Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of Each Class			Trading Symbol			Name of each exchange on which registered
Common Stock, Par Value $1.00 per share			AROW			NASDAQ Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).
Emerging growth company						☐
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act						☐

Item 1.01 Entry into a Material Definitive Agreement.

On February 25, 2026, Arrow Financial Corporation, a New York corporation ("Arrow") entered into an Agreement and Plan of Merger (the “Agreement”) with Adirondack Bancorp, Inc., a New York corporation (“Adirondack”) and Arrow Merger Sub, Inc. (“Merger Sub”), a Maryland corporation and wholly owned subsidiary of Arrow. Subject to the terms and conditions of the Agreement, which has been approved by the boards of directors of each party, Adirondack will merge with and into Merger Sub, with Adirondack as the surviving corporation and immediately thereafter, Adirondack will merge with and into Arrow, with Arrow as the surviving corporation (collectively the “Merger”). Following the Merger, Adirondack Bank, the wholly-owned New York chartered commercial bank subsidiary of Adirondack, will merge with and into Arrow Bank National Association and a wholly-owned subsidiary of Arrow (“Arrow Bank”), with Arrow Bank as the surviving bank (the “Bank Merger” and, together with the Merger, the “Transaction”).

Merger Consideration

Upon the terms and subject to the conditions of the Agreement, at the effective time of the Merger (the “Effective Time”), each share of common stock, par value $5.00 per share, of Adirondack outstanding immediately prior to the Effective Time will be converted into the right to receive (i) 1.8610 shares of Arrow common stock, par value $1.00 per share, and (ii) $18.72 in cash. Holders of Adirondack common stock will receive cash in lieu of fractional shares. The Merger is intended to be a tax-free reorganization under Section 368(a) of the Internal Revenue Code.

Certain Governance Matters

At the Effective Time, Arrow and Arrow Bank will take all actions necessary to appoint to each respective board of directors, Rocco Arcuri, Sr., current President and Chief Executive Officer of Adirondack. In addition, Mr. Arcuri will be appointed Regional President at the Effective Time.

Terms and Conditions of the Agreement

The Agreement contains customary representations and warranties from both Adirondack and Arrow, and each party has agreed to customary covenants, including, among others, covenants relating to (i) the conduct of its business during the interim period between the execution of the Agreement and the Effective Time, (ii) the obligation of Adirondack to call a meeting of its shareholders to approve the Agreement and, subject to certain exceptions, the obligation of Adirondack’s board of directors to recommend that its shareholders approve the Agreement, and (iii) Adirondack’s non-solicitation obligations related to alternative acquisition proposals. Adirondack and Arrow have also agreed to use their reasonable best efforts to prepare and file all applications, notices and other documents to obtain all necessary consents and approvals for consummation of the transactions contemplated by the Agreement.

The completion of the Merger is subject to customary conditions, including (i) approval of the Agreement by the requisite vote of the shareholders of Adirondack, (ii) authorization for listing on Nasdaq of the shares of Arrow common stock to be issued in the Merger, (iii) receipt of required regulatory approvals, including the approval of the Board of Governors of the Federal Reserve System, the Office of the Comptroller of the Currency and the New York State Department of Financial Services, without the imposition of any condition or restriction that would be reasonably expected to have a material adverse effect on the continuing corporation and its subsidiaries, taken as a whole, after giving effect to the Merger and the Bank Merger, (iv) effectiveness of the registration statement on Form S-4 for the Arrow common stock to be issued in the Merger and (v) the absence of any order, injunction, decree or other legal restraint preventing the completion of the Merger, the Bank Merger or any of the other transactions contemplated by the Agreement or making the completion of the Merger, the Bank Merger or any of the other transactions contemplated by the Agreement illegal. Each party’s obligation to complete the Merger is also subject to certain additional customary conditions, including (a) subject to certain exceptions, the accuracy of the representations and warranties of the other party, (b) performance in all material respects by the other party of its obligations under the Agreement, and (c) receipt by such party of an opinion from its counsel to the effect that the Merger will qualify as a “reorganization” within the meaning of Section 368(a) of the Internal Revenue Code of 1986, as amended. In addition, Arrow’s obligation to complete the Merger is also subject to holders of fewer than 5% of the outstanding shares of Adirondack common stock perfecting their appraisal rights under applicable New York law.

The Agreement provides certain termination rights for both Adirondack and Arrow and further provides that a termination fee of $3.62 million will be payable by Adirondack upon termination of the Agreement under certain circumstances.

The representations, warranties and covenants of each party set forth in the Agreement have been made only for purposes of, and were and are solely for the benefit of the parties to the Agreement; may be subject to limitations agreed upon by the contracting parties, including being qualified by confidential disclosures made for the purposes

of allocating contractual risk between the parties to the Agreement instead of establishing these matters as facts; and, may be subject to standards of materiality applicable to the contracting parties that differ from those applicable to investors. Accordingly, the representations and warranties may not describe the actual state of affairs at the date they were made or at any other time, and investors should not rely on them as statements of fact. In addition, such representations and warranties (i) will not survive consummation of the Merger and (ii) were made only as of the date of the Agreement or such other date as is specified in the Agreement. Moreover, information concerning the subject matter of the representations and warranties may change after the date of the Agreement, which subsequent information may or may not be fully reflected in the parties’ public disclosures. Accordingly, the Agreement is included with this filing only to provide investors with information regarding the terms of the Agreement, and not to provide investors with any other information regarding Adirondack or Arrow, their respective affiliates or their respective businesses. The Agreement should not be read alone, but should instead be read in conjunction with the other information regarding Adirondack, Arrow, their respective affiliates or their respective businesses, the Agreement, the Merger, and the Bank Merger that will be contained in, or incorporated by reference into, the Registration Statement on Form S-4 that will include a proxy statement of Adirondack and a prospectus of Arrow, and as may be amended from time-to-time, as well as in the Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and other filings that Arrow makes with the Securities and Exchange Commission (“SEC”).

The foregoing description of the Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Agreement, which is attached hereto as Exhibit 2.1 and incorporated herein by reference.

Voting Agreements

Simultaneously with the execution of the Agreement, Arrow entered into a voting agreement (a “Voting Agreement”) with each of the directors on the board of directors of Adirondack and certain Adirondack shareholders. Such Adirondack shareholders and each Adirondack director, as a shareholder party to a Voting Agreement, has agreed, among other things, to vote shares of Adirondack common stock owned by such shareholder, and over which such shareholder has the right to dispose of and has voting power, in favor of the Agreement and the other transactions contemplated by the Agreement, and against any competing acquisition proposal, any action, agreement transaction or proposal which could reasonably be expected to result in a breach of any representation, warranty, covenant, agreement or other obligation of Adirondack in the Agreement, or other action that is intended or would reasonably be expected to prevent, impede, interfere with, delay, postpone or discourage any of the transactions contemplated by the Agreement. The Voting Agreements will terminate in certain circumstances, including upon consummation of the Merger or the termination of the Agreement in accordance with its terms.

The foregoing description of the Voting Agreements do not purport to be complete and are qualified in their entirety by reference to the full text of the Voting Agreements, the form of which is attached as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated by reference herein.

Lock Up Agreements

Simultaneously with the execution of the Agreement, Arrow entered into a lock-up agreement (a “Lock-Up Agreement”) with certain shareholders of Adirondack. Pursuant to the Lock-Up Agreement, such shareholder has agreed, among other things, to (i) not sell or dispose of any shares of Arrow common stock received by or to be received by the shareholder pursuant to the Agreement for 180 days following the Effective Time; and (ii) not sell or dispose of more than 10,000 shares of Arrow common stock on any single trading day of shares of Arrow common stock received by or to be received by the shareholder pursuant to the Agreement between 181 days and 365 days following the Effective Time.

The foregoing description of the Lock-Up Agreements do not purport to be complete and are qualified in their entirety by reference to the full text of the Lock-Up Agreements, the form of which is attached as Exhibit 99.2 to this Current Report on Form 8-K and is incorporated by reference herein.

Item 7.01. Regulation FD Disclosure.

On February 26, 2026, Arrow made available certain presentation materials related to its proposed acquisition of Adirondack. A copy of the presentation material is included as Exhibit 99.3 to this current report on Form 8-K.

The information furnished under this Report, including Exhibit 99.3 shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or subject to the liabilities of that section. The information shall not be deemed incorporated by reference into any other filing with the Securities and Exchange Commission made by Arrow, regardless of any general incorporation language in such filing.

Item 8.01. Other Events.

A copy of the joint press release announcing the Transaction is attached hereto as Exhibit 99.4, and the information contained therein is incorporated herein by reference.

Item 9.01. Financial Statements and Exhibits

Exhibit No						Description
Exhibit 2.1						Agreement and Plan of Merger, dated as of February 25, 2026, by and among Arrow Financial Corporation, Adirondack Bancorp, Inc. and Arrow Merger Sub, Inc. *
Exhibit 99.1						Form of Adirondack Voting Agreement, dated as of February 25, 2026, by and among Arrow Financial Corporation and certain shareholders of Adirondack Bancorp, Inc.
Exhibit 99.2						Form of Lock-Up Agreement, dated as of February 25, 2026, by and among Arrow Financial Corporation and certain shareholders of Adirondack Bancorp, Inc.
Exhibit 99.3						Investor Presentation dated February 26, 2026
Exhibit 99.4						Joint Press Release issued by Arrow Financial Corporation and Adirondack Bancorp, Inc. dated February 26, 2026
Exhibit 104						Cover Page Interactive Data File (embedded within the Inline XBRL document)
						* The schedules and certain exhibits have been omitted pursuant to Item 601(b)(2) of Regulation S-K. Arrow Financial Corporation agrees to furnish a copy of such schedules and exhibits, or any section thereof, to the SEC upon request.

Cautionary Notes on Forward Looking Statements

This Current Report on Form 8-K includes “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, including with respect to (or based on) the beliefs, goals, intentions, and expectations of Arrow and Adirondack regarding the proposed Transaction, revenues, earnings, earnings per share, loan production, asset quality, and capital levels, among other matters; our estimates of future costs and benefits of the actions we may take; our assessments of expected losses on loans; our assessments of interest rate and other market risks; our ability to achieve our financial and other strategic goals; the expected timing of completion of the proposed Transaction; the expected cost savings, synergies, returns and other anticipated benefits from the proposed Transaction; and other statements that are not historical facts.

Forward–looking statements are typically identified by such words as “believe,” “expect,” “anticipate,” “intend,” “outlook,” “estimate,” “forecast,” “project,” “will,” “should,” and other similar words and expressions, and are subject to numerous assumptions, risks, and uncertainties, which change over time. Forward-looking statements include, without limitation, those relating to the terms, timing and closing of the proposed Transaction.

Additionally, forward-looking statements speak only as of the date they are made; Arrow and Adirondack do not assume any duty, and do not undertake, to update such forward-looking statements, whether written or oral, that may be made from time to time, whether as a result of new information, future events, or otherwise. Furthermore, because forward-looking statements are subject to assumptions and uncertainties, actual results or future events could differ, possibly materially, from those indicated in or implied by such forward-looking statements as a result of a variety of factors, many of which are beyond the control of Arrow and Adirondack. Such statements are based upon the current beliefs and expectations of the management of Adirondack and Arrow and are subject to significant risks and uncertainties outside of the control of the parties. Caution should be exercised against placing undue reliance on forward-looking statements. The factors that could cause actual results to differ materially include the following: the occurrence of any event, change or other circumstances that could give rise to the right of one or both of the parties to terminate the definitive Agreement between Arrow and Adirondack; the outcome of any legal proceedings that may be instituted against Arrow and Adirondack; the possibility that the proposed Transaction will not close when expected or at all because required regulatory, shareholder or other approvals are not received or other conditions to the closing are not satisfied on a timely basis or at all, or are obtained subject to conditions that are not anticipated (and the risk that required regulatory approvals may result in the imposition of conditions that could adversely affect the combined company or the expected benefits of the proposed Transaction); the ability of Arrow and Adirondack to meet expectations regarding the timing, completion and accounting and tax treatments of the proposed Transaction; the risk that any announcements relating to the proposed Transaction could have adverse effects on the market price of the common stock of either or both parties to the proposed Transaction; the possibility that the anticipated benefits of the proposed Transaction will not be realized when expected or at all, including as a result of the impact of, or problems arising from, the integration of the two companies or as a result of

the strength of the economy and competitive factors in the areas where Arrow and Adirondack do business; certain restrictions during the pendency of the proposed Transaction that may impact the parties’ ability to pursue certain business opportunities or strategic transactions; the possibility that the Transaction may be more expensive to complete than anticipated, including as a result of unexpected factors or events; diversion of management’s attention from ongoing business operations and opportunities; the possibility that the parties may be unable to achieve expected synergies and operating efficiencies in the Merger within the expected timeframes or at all and to successfully integrate Adirondack’s operations and those of Arrow; such integration may be more difficult, time-consuming or costly than expected; revenues following the proposed Transaction may be lower than expected; Arrow’s and Adirondack’s success in executing their respective business plans and strategies and managing the risks involved in the foregoing; the dilution caused by Arrow’s issuance of additional shares of its capital stock in connection with the proposed Transaction; effects of the announcement, pendency or completion of the proposed Transaction on the ability of Arrow and Adirondack to retain customers and retain and hire key personnel and maintain relationships with their suppliers, and on their operating results and businesses generally; and risks related to the potential impact of general economic, political and market factors on the companies or the proposed Transaction and other factors that may affect future results of Arrow and Adirondack; and the other factors discussed in the “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” sections of Arrow’s Annual Report on Form 10-K for the year ended December 31, 2024 and its Quarterly Reports on Form 10–Q for the quarters ended March 31, 2025, June 30, 2025, and September 30, 2025, and other reports Arrow files with the SEC.

Additional Information and Where to Find It

In connection with the proposed Transaction, Arrow will file a registration statement on Form S-4 with the SEC to register the shares of Arrow common stock to be issued in connection with the proposed transaction. The registration statement will include a 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.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

						ARROW FINANCIAL CORPORATION
Date:			February 26, 2026			/s/ Penko Ivanov
						Penko Ivanov Chief Financial Officer

1 FORM OF ADIRONDACK BANCORP, INC. VOTING AGREEMENT This Voting Agreement (this “Agreement”), dated as of February 25, 2026, is entered into by and between Arrow Financial Corporation, a New York corporation (“Arrow”), Arrow Merger Sub, Inc., a Maryland corporation and a direct, wholly-owned subsidiary of Arrow (“Merger Sub”), and the undersigned (the “Shareholder”), a shareholder of Adirondack Bancorp, Inc., a New York corporation (“Adirondack”). WHEREAS, subject to the terms and conditions of the Agreement and Plan of Merger (as the same may be amended, supplemented or modified, the “Merger Agreement”), dated as of the date hereof, by and between Arrow, Merger Sub, and Adirondack, Merger Sub will be merged with and into Adirondack (the “Merger”), with Adirondack as the interim surviving corporation (the “Interim Surviving Corporation”), and as soon as reasonably practicable following the Merger and as part of a single integrated transaction for purposes of the Internal Revenue Code of 1986, as amended, the Interim Surviving Corporation will be merged with and into Arrow (the “Holdco Merger”), with Arrow as the surviving corporation (the “Surviving Corporation”); WHEREAS, as of the date of this Agreement, the Shareholder owns beneficially or of record, and has the power to vote or direct the voting of, certain shares of common stock, $5.00 value per share, of Adirondack (“Common Stock”) (all such shares of Common Stock owned beneficially or of record by Shareholder, the “Existing Shares”); and WHEREAS, as a condition and inducement for Arrow to enter into the Merger Agreement, Arrow has required that the Shareholder, in his or her capacity as a shareholder of Adirondack, enter into this Agreement, and the Shareholder has agreed to enter into this Agreement. NOW THEREFORE, in consideration of the foregoing, the mutual covenants and agreements set forth herein, and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto agree as follows: 1. Definitions. Capitalized terms not defined in this Agreement have the meaning assigned to those terms in the Merger Agreement. The following definition also applies to this Agreement: a. Beneficial Ownership. For purposes of this Agreement, the terms “beneficial owner” and “beneficially own” shall have the meaning set forth in Rule 13d-3 promulgated by the Securities and Exchange Commission under the Securities Exchange Act of 1934, as amended (the “Exchange Act”). 2. Effectiveness; Termination. This Agreement shall be effective upon signing. If the Merger Agreement is terminated for any reason in accordance with its terms, this Agreement shall automatically terminate and be null and void and of no effect as of the date of the termination of the Merger Agreement; provided that (i) this Section 2 and Sections 8 through 13 hereof shall survive any such termination and (ii) such termination shall not relieve any party of any liability or damages resulting from any willful or material

2 breach of any of his or her representations, warranties, covenants or other agreements set forth herein. 3. Voting Agreement. From the date hereof until the earlier of (a) the final adjournment of the Adirondack Shareholder Meeting or (b) the termination of this Agreement in accordance with its terms (the “Support Period”), the Shareholder irrevocably and unconditionally hereby agrees, that at any meeting (whether annual or special and each adjourned or postponed meeting) of Adirondack’s shareholders, however called, or in connection with any written consent of Adirondack’s shareholders, the Shareholder shall (i) appear at such meeting or otherwise cause all of his or her Existing Shares and all other shares of Common Stock or voting securities of Adirondack over which such Shareholder has acquired beneficial or record ownership after the date hereof and has the power to vote or direct the voting of (including any shares of Common Stock acquired by means of purchase, dividend or distribution, or issued upon the exercise of any stock options to acquire Common Stock or the conversion of any convertible securities, or pursuant to any other equity awards or derivative securities or otherwise) (together with the Existing Shares, the “Shares”), which such Shareholder owns or controls as of the applicable record date, to be counted as present thereat for purposes of calculating a quorum, and (ii) vote or cause to be voted (including by proxy or written consent, if applicable) all such Shares (A) in favor of the approval of the Merger Agreement and the approval of the transactions contemplated thereby, including the Merger and Holdco Merger, (B) in favor of any proposal to adjourn or postpone such meeting of Adirondack’s shareholders to a later date if there are not sufficient votes to approve the Merger Agreement, (C) against any action or proposal in favor of an Acquisition Proposal, without regard to the terms of such Acquisition Proposal, and (D) against any action, proposal, transaction or agreement that would reasonably be likely to (1) result in a breach of any covenant, representation or warranty or any other obligation or agreement of Adirondack contained in the Merger Agreement, or of the Shareholder contained in this Agreement, or (2) prevent, impede, interfere with, delay, postpone, discourage or frustrate the purposes of or adversely affect the consummation of the transactions contemplated by the Merger Agreement, including the Merger and Holdco Merger; provided, that the foregoing applies solely to the Shareholder in his or her capacity as a shareholder and Shareholder makes no agreement or understanding in this Agreement in Shareholder’s capacity as a director or officer of Adirondack or any of its subsidiaries (if Shareholder holds such office), and nothing in this Agreement: (a) will limit or affect any actions or omissions taken by Shareholder in Shareholder’s capacity as such a director or officer, including in exercising rights under the Merger Agreement, and no such actions or omissions shall be deemed a breach of this Agreement; or (b) will be construed to prohibit, limit or restrict Shareholder from exercising Shareholder’s fiduciary duties as a director or officer to Adirondack or its shareholders. For the avoidance of doubt, the foregoing commitments apply to any Shares held by any trust, limited partnership or other entity holding Shares for which the Shareholder serves in any partner, shareholder or trustee capacity. To the extent the Shareholder does not control, by himself or herself, the determinations of such shareholder entity, the Shareholder agrees to exercise all voting or other determination rights such Shareholder has in such shareholder entity to carry out the intent and purposes of his, her or its support and voting obligations in this paragraph and otherwise set forth in this

3 Agreement. The Shareholder covenants and agrees that, except for this Agreement, such Shareholder (x) has not entered into, and shall not enter into during the Support Period, any other voting agreement or voting trust with respect to the Shares and (y) has not granted, and shall not grant during the Support Period, a proxy, consent or power of attorney with respect to the Shares except any proxy to carry out the intent of this Agreement and any proxy granted for ordinary course proposals at an annual meeting. The Shareholder agrees not to enter into any agreement or commitment with any person the effect of which would be inconsistent with or otherwise violate the provisions and agreements set forth herein. 4. Transfer Restrictions. The Shareholder hereby agrees that such Shareholder will not, during the Support Period, without the prior written consent of Arrow, directly or indirectly, offer for sale, sell, transfer, assign, give, tender in any tender or exchange offer, pledge, encumber, hypothecate or similarly dispose of (by merger, by testamentary disposition, by operation of law or otherwise), either voluntarily or involuntarily, enter into any swap or other arrangements that transfers to another, in whole or in part, any of the economic consequences of ownership of, enter into any contract, option or other arrangement or understanding with respect to the sale, transfer, assignment, pledge, encumbrance, hypothecation or other disposition of (by merger, by testamentary disposition, by operation of law or otherwise) or otherwise convey or dispose of, any of the Shares, or any interest therein, including the right to vote any Shares, as applicable (a “Transfer”); provided, that the Shareholder may (i) Transfer Shares pursuant to any currently existing pledge agreement or for estate planning or philanthropic purposes so long as the transferee, prior to the date of Transfer, agrees in a signed writing to be bound by and comply with the provisions of this Agreement and the Shareholder provides at least two (2) days’ prior written notice (which shall include the written consent of the transferee agreeing to be bound by and comply with the provisions of this Agreement), in which case the Shareholder shall remain jointly and severally liable for any breach of this Agreement by such transferee, (ii) bequeath Shares by will or operation of law, in which case this Agreement shall bind the transferee, (iii) surrender Shares to Adirondack in connection with the vesting, settlement or exercise of Adirondack equity awards to satisfy any withholding for the payment of taxes incurred in connection with such vesting, settlement or exercise, or, in respect of Adirondack equity awards, the exercise price thereon, or (iv) Transfer Shares as is otherwise permitted by Arrow in its sole discretion. 5. Representations of the Shareholder. The Shareholder represents and warrants to Arrow as follows:(a) if it is not a natural person, that it is duly organized or formed, validly existing and in good standing under the laws of its jurisdiction of organization or formation and has the power and authority to execute and deliver this Agreement and to consummate the transactions contemplated hereby, and has taken all necessary action to authorize the execution, delivery and performance of this Agreement; (b) the Shareholder has full legal right, capacity and authority to execute and deliver this Agreement, to perform the Shareholder’s obligations hereunder and to consummate the transactions contemplated hereby; (c) this Agreement has been duly and validly executed and delivered by the Shareholder and, assuming the due authorization, execution and delivery of this Agreement by Arrow, constitutes a valid and legally binding agreement of the Shareholder, enforceable against the Shareholder in accordance with its terms, and no other action is

4 necessary to authorize the execution and delivery of this Agreement by the Shareholder or the performance of his or her obligations hereunder; (d) the execution and delivery of this Agreement by the Shareholder does not, and the consummation of the transactions contemplated hereby and the compliance with the provisions hereof will not, conflict with or violate any law or result in any breach of or violation of, or constitute a default (or an event that with notice or lapse of time or both would become a default) under, or give to others any rights of termination, amendment, acceleration or cancellation of, or result in the creation of a lien on any of the Shares pursuant to, any agreement or other instrument or obligation binding upon the Shareholder or the Shares (including under the certificate of incorporation and bylaws of Adirondack), nor require any authorization, consent or approval of, or filing with, any Governmental Entity; (e) the Shareholder beneficially owns (as such term is used in Rule 13d-3 of the Exchange Act) and has the power to vote or direct the voting of the Shares, and the number of such Shares as of the date of this Agreement is identified on the signature page hereto; (f) the Shareholder beneficially owns the Shares free and clear of any proxy, voting restriction, adverse claim or other lien (other than any restrictions created by this Agreement or under applicable federal or state securities laws); and (g) the Shareholder has read and is familiar with the terms of the Merger Agreement. The Shareholder agrees that the Shareholder shall not take any action that would make any representation or warranty of the Shareholder contained herein untrue or incorrect or have the effect of preventing, impairing, delaying or adversely affecting the performance by the Shareholder of his or her obligations under this Agreement. The Shareholder agrees, without further consideration, to execute and deliver such additional documents and to take such further actions as are necessary or reasonably requested by Arrow to confirm and assure the rights and obligations set forth in this Agreement. 6. Publicity. The Shareholder hereby authorizes Arrow and Adirondack to publish and disclose in any announcement or disclosure in connection with the Merger and Holdco Merger, including in the S-4, the Proxy Statement or any other filing with any Governmental Entity made in connection with the Merger and Holdco Merger, the Shareholder’s identity and ownership of the Shares and the nature of the Shareholder’s obligations under this Agreement. The Shareholder agrees to notify Arrow as promptly as practicable of any inaccuracies or omissions in any information relating to the Shareholder that is so published or disclosed. 7. Entire Agreement; Assignment. The recitals are incorporated as a part of this Agreement. This Agreement and the Merger Agreement constitute the entire agreement among the parties with respect to the subject matter hereof and supersedes all other prior agreements and understandings, both written and oral, among the parties with respect to the subject matter hereof, other than, if the Shareholder is a director or officer of Adirondack, with respect to any employment, non-competition, non-solicit or consulting agreement between the Shareholder and either Arrow or Adirondack, or its affiliates. Nothing in this Agreement, express or implied, is intended to or shall confer upon any person not a party to this Agreement any right, benefit or remedy of any nature whatsoever under or by reason of this Agreement. This Agreement shall not be assigned by operation of law or otherwise and shall be binding upon and inure solely to the benefit of each party hereto; provided, however, that the rights under this Agreement are assignable by Arrow to a majority-owned

5 affiliate or any successor-in-interest of Arrow, but no such assignment shall relieve Arrow of its obligations hereunder. 8. Remedies/Specific Enforcement. Each of the parties hereto agrees that this Agreement is intended to be legally binding and specifically enforceable pursuant to its terms and that Arrow would be irreparably harmed if any of the provisions of this Agreement are not performed in accordance with its specific terms and that monetary damages would not provide adequate remedy in such event. Accordingly, in the event of any breach or threatened breach by the Shareholder of any covenant or obligation contained in this Agreement, in addition to any other remedy to which Arrow may be entitled (including monetary damages), Arrow shall be entitled to seek injunctive relief to prevent breaches or threatened breaches of this Agreement and to specifically enforce the terms and provisions hereof, and the Shareholder hereby waives any defense in any action for specific performance or an injunction or other equitable relief that a remedy at law would be adequate. The Shareholder further agrees that neither Arrow nor any other person or entity shall be required to obtain, furnish or post any bond or similar instrument in connection with or as a condition to obtaining any remedy referred to in this paragraph, and the Shareholder irrevocably waives any right he or she may have to require the obtaining, furnishing or posting of any such bond or similar instrument. 9. Governing Law. This Agreement is governed by, and shall be interpreted in accordance with, the laws of the State of New York, without regard to any applicable conflict of law principles. 10. Notice. All notices and other communications hereunder shall be in writing and shall be deemed given if delivered personally, telecopied (with confirmation), mailed by registered or certified mail (return receipt requested) or delivered by an express courier (with confirmation) if to the Shareholder, to the address or e-mail address, as applicable, set forth in Schedule A hereto, and if to Arrow, all notices hereunder shall be delivered to the addresses set forth below, or pursuant to such other instructions as may be designated in writing by the party to receive such notice: (a) if to Arrow or Merger Sub, to: Arrow Financial Corporation 250 Glen Street Glens Falls, NY 12801 Attention: David S. DeMarco President and Chief Executive Officer Email: dave.demarco@arrowbank.com (b) With copies (which shall not constitute notice) to: Spierer, Woodward, Corbalis & Goldberg 5050 South Syracuse Street, Suite 900 Denver, CO 80237

6 Attention: Ernie Panasci Email: epanasci@practicallawyer.com 11. Severability. Whenever possible, each provision or portion of any provision of this Agreement shall be interpreted in such manner as to be effective and valid under applicable law, but if any provision or portion of any provision of this Agreement is held to be invalid, illegal or unenforceable in any respect under any applicable law or rule in any jurisdiction, such invalidity, illegality or unenforceability shall not affect any other provision or portion of any provision in such jurisdiction, and this Agreement shall be reformed, construed and enforced in such jurisdiction such that the invalid, illegal or unenforceable provision or portion thereof shall be interpreted to be only so broad as is enforceable. 12. Amendments; Waivers. Any provision of this Agreement may be amended or waived if, and only if, such amendment or waiver is in writing and signed (a) in the case of an amendment, by Arrow and the Shareholder, and (b) in the case of a waiver, by the party against whom the waiver is to be effective. No failure or delay by any party in exercising any right, power or privilege hereunder shall operate as a waiver thereof, nor shall any single or partial exercise thereof preclude any other or further exercise thereof or the exercise of any other right, power or privilege. 13. Waiver of Jury Trial. EACH PARTY ACKNOWLEDGES AND AGREES THAT ANY CONTROVERSY THAT MAY ARISE UNDER THIS AGREEMENT IS LIKELY TO INVOLVE COMPLICATED AND DIFFICULT ISSUES, AND THEREFORE EACH SUCH PARTY HEREBY IRREVOCABLY AND UNCONDITIONALLY WAIVES, TO THE EXTENT PERMITTED BY LAW AT THE TIME OF INSTITUTION OF THE APPLICABLE LITIGATION, ANY RIGHT SUCH PARTY MAY HAVE TO A TRIAL BY JURY IN RESPECT OF ANY LITIGATION DIRECTLY OR INDIRECTLY ARISING OUT OF OR RELATING TO THIS AGREEMENT. EACH PARTY CERTIFIES AND ACKNOWLEDGES THAT: (I) NO REPRESENTATIVE, AGENT OR ATTORNEY OF ANY OTHER PARTY HAS REPRESENTED, EXPRESSLY OR OTHERWISE, THAT SUCH OTHER PARTY WOULD NOT, IN THE EVENT OF LITIGATION, SEEK TO ENFORCE THE FOREGOING WAIVER; (II) THE PARTY UNDERSTANDS AND HAS CONSIDERED THE IMPLICATIONS OF THIS WAIVER; (III) THE PARTY MAKES THIS WAIVER VOLUNTARILY; AND (IV) THE PARTY HAS BEEN INDUCED TO ENTER INTO THIS AGREEMENT BY, AMONG OTHER THINGS, THE MUTUAL WAIVERS AND CERTIFICATIONS IN THIS SECTION 13. 14. Counterparts. The parties may execute this Agreement in one or more counterparts, including by facsimile or other electronic signature. All the counterparts will be construed together and will constitute one Agreement. [Signature pages follow]

IN WITNESS WHEREOF, the parties hereto have duly executed and delivered this Agreement as of the date first written above. ARROW FINANCIAL CORPORATION By: David S. DeMarco Title: President and Chief Executive Officer [Additional Signatures on Next Page]

SHAREHOLDER: Name Address _____________________________ Address Number of Shares: ___________________

SCHEDULE A Shareholder Information Name, Address and E-Mail Address for Notices

FORM OF LOCK-UP AGREEMENT THIS LOCK-UP AGREEMENT (this “Lock-Up Agreement”), dated as of February 25, 2026, is entered into by and between Arrow Financial Corporation, a New York corporation (“Arrow”), and the undersigned shareholder (the “Shareholder”) of Adirondack Bancorp, Inc., a New York corporation (the “Company”). WHEREAS, in connection with the proposed acquisition of the Company by Arrow, and in consideration of the Company, Arrow, and Merger Sub entering into that certain Agreement and Plan of Merger dated as of February 25, 2026, (the “Merger Agreement”), the receipt and sufficiency of such consideration being hereby acknowledged and accepted, and in order to induce Arrow to enter into the Merger Agreement, the Shareholder, who will receive [●] shares of Arrow Common Stock (the “Executive Arrow Shares”) in connection with the Merger, hereby agrees with Arrow as follows: 1. Lock-Up Periods. a. During the period commencing on the date on which the Effective Time occurs and ending at 5:00 p.m. Eastern Time on the date which is 180 days following the date on which the Effective Time occurs (the “180 Day Lock-Up Period”), the Shareholder will not directly or indirectly take any action to offer, sell, contract to sell, sell any option, warrant, or contract to purchase, purchase any option, warrant, or contract to sell, transfer, pledge, or otherwise dispose of, or enter into any transaction which is designed to, or might reasonably be expected to, result in the disposition (whether by actual disposition or effective economic disposition or otherwise) of any Executive Arrow Shares received by or to be received by the Shareholder pursuant to the Merger Agreement; b. During the period commencing on the date on which is 181 days following the date on which the Effective Time occurs and ending at 5:00 p.m. Eastern Time on the date which is 365 days following the date on which the Effective Time occurs (the “365 Day Lock-Up Period”), the Shareholder will not directly or indirectly take any action to offer, sell, contract to sell, sell any option, warrant, or contract to purchase, purchase any option, warrant, or contract to sell, transfer, pledge, or otherwise dispose of, or enter into any transaction which is designed to, or might reasonably be expected to, result in the disposition (whether by actual disposition or effective economic disposition or otherwise) of more than 10,000 shares of the Executive Arrow Shares on any single trading day received by or to be received by the Shareholder pursuant to the Merger Agreement; c. During the Lock-Up Period, the restrictions on disposition set forth in 1.a and b above shall apply to any swap or other derivative transaction that transfers to another, in whole or in part, any of the economic benefits or risks of ownership of Executive Arrow Shares, whether any such transaction is to be settled by delivery of Arrow Common Stock or other securities, in cash, or otherwise; or

d. publicly disclose an intention to effect any transaction contemplated by this Section 1. 2. Any attempted transfer of the Executive Arrow Shares in violation of this Lock-Up Agreement will be of no effect and null and void, regardless of whether the purported transferee has any actual or constructive knowledge of the transfer restrictions set forth in this Lock-Up Agreement, and will not be recorded on the stock transfer records of Arrow. 3. This Lock-Up Agreement shall not prohibit the Shareholder from making transfers of Executive Arrow Shares: a. (i) by will or operation of law as a result of the death of the Shareholder, in which case, this Agreement shall bind the transferee, and (ii) for bona fide estate planning purposes to the Shareholder’s (x) affiliates (as defined in the Merger Agreement) or (y) immediate family members (as defined below) (each, a “Permitted Transferee”), or (iii) upon the determination by Arrow that the Shareholder has suffered a Disability; provided that, in the case of the foregoing subclauses (i) and (ii) only, as a condition to such transfer, such Permitted Transferee shall be required to duly execute and deliver to Arrow a joinder to this Agreement (in form and substance reasonably satisfactory to Arrow); provided, further, that, in the case of the foregoing subclause (ii) only, the Shareholder shall remain jointly and severally liable for any breaches or violations by any such permitted transferee of the terms hereof. An immediate family member of Shareholder means any child, stepchild, parent, stepparent, spouse, sibling, mother- in-law, father-in-law, son-in-law, daughter-in-law, brother-in-law, or sister-in-law of Shareholder, and any person (other than a tenant or employee) sharing the household of Shareholder. 4. The Shareholder also agrees and consents to the entry of stop transfer instructions with Arrow and its transfer agent and registrar against the transfer of the Executive Arrow Shares, except in compliance with this Lock-Up Agreement. In furtherance of the foregoing, Arrow and its transfer agent are each hereby authorized to decline to make any transfer of securities if such transfer would constitute a violation or breach of this Lock-Up Agreement. Arrow may cause a legend in the form set forth below, or a legend substantially equivalent thereto, to be placed upon any certificates or other documents, ledgers, or instruments evidencing the Shareholder’s ownership of the Executive Arrow Shares: THE SHARES REPRESENTED BY THIS INSTRUMENT ARE SUBJECT TO AND MAY ONLY BE TRANSFERRED IN COMPLIANCE WITH A LOCK-UP AGREEMENT, A COPY OF WHICH IS ON FILE AT THE PRINCIPAL OFFICE OF ARROW FINANCIAL CORPORATION 5. If the Merger Agreement is terminated without the consummation of the Merger, this Lock-Up Agreement shall automatically terminate and shall be of no further force and effect. 6. Arrow agrees that upon the earlier of (i) the termination of the Merger Agreement or (ii) the expiration of the Lock-Up Period, it shall immediately and solely at Arrow’s own expense instruct Arrow’s transfer agent to remove any legend placed upon any

certificates or other documents, ledgers, or instruments evidencing the Shareholder’s ownership of Executive Arrow Shares pursuant to the terms of this Lock-Up Agreement. 7. The Shareholder hereby represents and warrants that the Shareholder has full power and authority and legal capacity to enter into this Lock-Up Agreement. The Shareholder may not assign or delegate this Lock-Up Agreement or any of the Shareholder’s rights, interests, duties, or obligations hereunder without the prior written consent of Arrow. Subject to the preceding sentence, this Lock-Up Agreement and any obligations of the Shareholder hereunder shall be binding upon the heirs, executors, administrators, personal representatives, successors, and permitted assigns of the Shareholder. 8. The Shareholder understands that Arrow will proceed with the Merger in reliance on this Lock-Up Agreement. Moreover, the Shareholder understands and agrees that Arrow and the Company are relying upon the accuracy, completeness, and truth of the Shareholder’s representations, warranties, agreements, and certifications contained in this Lock- Up Agreement. 9. Arrow and the Shareholder agree that irreparable damage would occur if this Lock-Up Agreement is not performed in accordance with the terms hereof and that Arrow shall be entitled to equitable relief, including injunctive relief or specific performance of the terms hereof, in addition to any other remedy to which it is entitled at law or in equity. Furthermore, each of Arrow and the Shareholder hereby further waives any requirement under any law to post security or a bond as a prerequisite to obtaining equitable relief. Additionally, if Arrow institutes any legal suit, action, or proceeding (a “Legal Proceeding”) against the Shareholder to enforce, or otherwise arising out of, this Lock-Up Agreement, Arrow shall be entitled to receive, in addition to all other damages to which it may be entitled, all costs Arrow incurs in connection with such Legal Proceeding, including attorneys’ fees and expenses and court costs, if the Shareholder is found by a court to be at fault and liable. 10. All notices, requests, consents, and other communications required or permitted under or related to this Lock-Up Agreement shall be in writing and shall be deemed given, delivered, and effective (i) when delivered, if delivered personally, or if by e-mail, upon confirmation of receipt, (ii) on the fifth Business Day after mailing, if mailed by first class United States Mail, postage prepaid and return receipt requested, or (iii) on the first Business Day after mailing, if sent by a nationally recognized overnight delivery service, in each case addressed to, in the case of the Shareholder, the Shareholder’s address set forth on the signature page hereto, and, in the case of Arrow or the Company, their respective addresses set forth in the Merger Agreement. 11. This Lock-Up Agreement shall be governed by, and construed, interpreted, and enforced in accordance with, the laws of the State of New York, without regard to conflict of laws principles. 12. Each party agrees that it will bring any action or proceeding in respect of any claim arising out of or related to this Lock-Up Agreement or the transactions contemplated

County, New York (the “Chosen Courts”), and, solely in connection with claims arising under this Lock-Up Agreement or the transactions that are the subject of this Lock-Up Agreement, (i) irrevocably submits to the exclusive jurisdiction of the Chosen Courts, (ii) waives any objection to laying venue in any such action or proceeding in the Chosen Courts, (iii) waives any objection that the Chosen Courts are an inconvenient forum or do not have jurisdiction over any party and (iv) agrees that service of process upon such party in any such action or proceeding will be effective if notice is given in accordance with Section 10. 13. This Lock-Up Agreement represents the entire understanding of Arrow and the Shareholder with respect to the subject matter hereof and supersedes any and all prior agreements, understandings, and arrangements, whether written or oral, between Arrow and the Shareholder with respect to such subject matter. 14. This Lock-Up Agreement may not be amended except by an instrument in writing signed on behalf of or by each of Arrow and the Shareholder. 15. Capitalized terms used and not otherwise defined in this Lock-Up Agreement shall have the meanings ascribed to such terms in the Merger Agreement. Whenever the words “include,” “includes,” and “including” are used in this Lock-Up Agreement, they shall be deemed to be followed by the words “without limitation,” whether or not actually followed by such words. Any singular term used in this Lock-Up Agreement shall be deemed to include the plural, and any plural term the singular. Any gender reference in this Lock-Up Agreement shall be deemed to include all genders. Arrow and the Shareholder have participated jointly in the negotiation and drafting of this Lock-Up Agreement, and, in the event an ambiguity or question of intent or interpretation arises, this Lock-Up Agreement shall be construed as if drafted jointly by Arrow and the Shareholder and no presumption or burden of proof shall arise favoring or disfavoring either Arrow or the Shareholder by virtue of the authorship of any of the provisions of this Lock-Up Agreement. 16. This Lock-Up Agreement may be executed in multiple counterparts, each of which shall be deemed to constitute an original, but all of which together shall constitute one and the same instrument. A facsimile or other electronic copy of a signature page to this Lock-Up Agreement shall be deemed to be, and shall have the same force and effect as, an original signature page. [signature page follows]

IN WITNESS WHEREOF, the undersigned have executed this Lock-Up Agreement effective as of the date first set forth above. ARROW FINANCIAL CORPORATION By: David S. DeMarco President and Chief Executive Officer SHAREHOLDER: Address:

Announcing the Strategic Acquisition of Adirondack Bancorp, Inc. February 26, 2026

2 Disclaimer Cautionary Notes on Forward Looking Statements This presentation includes “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, including with respect to (or based on) the beliefs, goals, intentions, and expectations of Arrow and Adirondack regarding the proposed transaction, revenues, earnings, earnings per share, loan production, asset quality, and capital levels, among other matters; our estimates of future costs and benefits of the actions we may take; our assessments of expected losses on loans; our assessments of interest rate and other market risks; our ability to achieve our financial and other strategic goals; the expected timing of completion of the proposed transaction; the expected cost savings, synergies, returns and other anticipated benefits from the proposed transaction; and other statements that are not historical facts. Forward–looking statements are typically identified by such words as “believe,” “expect,” “anticipate,” “intend,” “outlook,” “estimate,” “forecast,” “project,” “will,” “should,” and other similar words and expressions, and are subject to numerous assumptions, risks, and uncertainties, which change over time. Forward-looking statements include, without limitation, those relating to the terms, timing and closing of the proposed transaction. Additionally, forward-looking statements speak only as of the date they are made; Arrow and Adirondack do not assume any duty, and do not undertake, to update such forward-looking statements, whether written or oral, that may be made from time to time, whether as a result of new information, future events, or otherwise. Furthermore, because forward-looking statements are subject to assumptions and uncertainties, actual results or future events could differ, possibly materially, from those indicated in or implied by such forward-looking statements as a result of a variety of factors, many of which are beyond the control of Arrow and Adirondack. Such statements are based upon the current beliefs and expectations of the management of Adirondack and Arrow and are subject to significant risks and uncertainties outside of the control of the parties. Caution should be exercised against placing undue reliance on forward-looking statements. The factors that could cause actual results to differ materially include the following: the occurrence of any event, change or other circumstances that could give rise to the right of one or both of the parties to terminate the definitive Merger Agreement between Arrow and Adirondack; the outcome of any legal proceedings that may be instituted against Arrow and Adirondack; the possibility that the proposed transaction will not close when expected or at all because required regulatory, shareholder or other approvals are not received or other conditions to the closing are not satisfied on a timely basis or at all, or are obtained subject to conditions that are not anticipated (and the risk that required regulatory approvals may result in the imposition of conditions that could adversely affect the combined company or the expected benefits of the proposed transaction); the ability of Arrow and Adirondack to meet expectations regarding the timing, completion and accounting and tax treatments of the proposed transaction; the risk that any announcements relating to the proposed transaction could have adverse effects on the market price of the common stock of either or both parties to the proposed transaction; the possibility that the anticipated benefits of the proposed transaction will not be realized when expected or at all, including as a result of the impact of, or problems arising from, the integration of the two companies or as a result of the strength of the economy and competitive factors in the areas where Arrow and Adirondack do business; certain restrictions during the pendency of the proposed transaction that may impact the parties’ ability to pursue certain business opportunities or strategic transactions; the possibility that the transaction may be more expensive to complete than anticipated, including as a result of unexpected factors or events; diversion of management’s attention from ongoing business operations and opportunities; the possibility that the parties may be unable to achieve expected synergies and operating efficiencies in the Merger within the expected timeframes or at all and to successfully integrate Adirondack’s operations and those of Arrow; such integration may be more difficult, time-consuming or costly than expected; revenues following the proposed transaction may be lower than expected; Arrow’s and Adirondack’s success in executing their respective business plans and strategies and managing the risks involved in the foregoing; the dilution caused by Arrow’s issuance of additional shares of its capital stock in connection with the proposed transaction; effects of the announcement, pendency or completion of the proposed transaction on the ability of Arrow and Adirondack to retain customers and retain and hire key personnel and maintain relationships with their suppliers, and on their operating results and businesses generally; and risks related to the potential impact of general economic, political and market factors on the companies or the proposed transaction and other factors that may affect future results of Arrow and Adirondack; and the other factors discussed in the “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” sections of Arrow’s Annual Report on Form 10-K for the year ended December 31, 2024 and its Quarterly Reports on Form 10–Q for the quarters ended March 31, 2025, June 30, 2025, and September 30, 2025, and other reports Arrow files with the SEC.

3 Disclaimer Additional Information and Where to Find It In connection with the proposed transaction, Arrow will file a registration statement on Form S-4 with the SEC to register the shares of Arrow common stock to be issued in connection with the proposed transaction. The registration statement will include a 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.

4 Transaction Rationale (1) Based on non-NYC MSA NY headquartered publicly traded banks with less than $10 billion in assets Compelling Strategic Combination Low Risk Transaction Financially Attractive • Natural extension of our growth strategy • Market expansion with addition of high quality, low-cost deposit franchise • Creates the #4 community bank ranked by assets in Upstate New York(1) • Entry into the Utica and Syracuse MSAs as well as Franklin County – extending our reach in the “Tech Valley” of New York • Accelerates growth by immediately expanding lending capacity while adding complementary product offerings (Wealth Management, Insurance) • Solidifying our commitment to “Banking the Adirondacks” • Building scalable, more efficient and more profitable franchise • Substantial EPS accretion with and without purchase accounting marks • TBVPS earnback of 2.9 years (crossover method) • Significant back-office consolidation opportunity and identified branch optimization opportunities resulting in meaningful cost saves • Pro forma capital levels remain well in excess of internal minimum targets and significantly exceed regulatory “well-capitalized” levels • 20% internal rate of return • Adirondack’s strong risk management culture reduces execution and integration risk • Excellent credit discipline and asset quality • Thorough due diligence completed with nearly 400 files reviewed • 100% of classified / non-performing and 44% of CRE / C&I • Strong cultural alignment with shared community focus

5 Overview of Adirondack Bancorp, Inc. • Subsidiary: Adirondack Bank; Headquarters: Utica, NY • Operates 19 branches and 1 LPO across Upstate and Central New York • Chobani: Broke ground in April 2025 on a $1.2 billion plant in Oneida County expected to create over 1,000 new jobs • Micron: Building the largest U.S. semiconductor facility in New York • “This $100 billion investment will help cement Central New York as a global leader in advanced manufacturing.” – Micron Chairman, President & CEO Franchise & Market Highlights Financial Highlights(1) 1Q25 2Q25 3Q25 4Q25 2025Y Balance Sheet ($M) Total Assets $994 $960 $1,002 $942 $942 Gross Loans HFI 622 619 623 624 624 Deposits 911 874 913 848 848 Loans / Deposits (%) 68.3% 70.8% 68.2% 73.6% 73.6% Tangible Common Equity 67 68 70 73 73 Earnings & Profitability Net Income ($000s) $677 $1,139 $1,254 $1,280 $4,350 ROAA 0.28% 0.47% 0.52% 0.52% 0.45% ROAE 4.07% 6.58% 7.05% 6.97% 6.21% ROATCE 4.20% 6.78% 7.26% 7.17% 6.39% Net Interest Margin 3.65% 3.66% 3.77% 3.94% 3.75% Cost of Total Deposits 0.87% 0.86% 0.83% 0.80% 0.84% Asset Quality & Capital Ratios NPAs / Assets 0.98% 0.89% 0.61% 0.47% 0.47% TCE / TA 6.71% 7.08% 7.04% 7.72% 7.72% Tier 1 Leverage 8.47% 8.59% 8.55% 8.54% 8.54% CET1 16.52% 16.79% 16.57% 16.96% 16.96% Total Capital 17.49% 17.76% 17.53% 17.94% 17.94% County Deposit Market Share Note: Deposit data as of June 30, 2025 (1) Bank level financial information shown as of December 31, 2025 Source: S&P Capital IQ Pro; Chobani.com; governor.ny.gov; wbng.com County Market Rank Branches In-Market Deposits ($M) Market Share Oneida 5 9 $540 11.3% Herkimer 2 5 254 31.5% Franklin 4 2 39 5.4% Essex 5 2 32 3.5% Clinton 7 1 9 0.4%

6 Pro Forma Company Snapshot Geographic Footprint(1) Arrow Financial Corp. (38) Adirondack Bancorp, Inc. (20) Pro Forma Financial Highlights(2) Top 10 Upstate New York Community Banks(3) $5.5B Total Assets $4.9B Total Deposits $4.1B Gross Loans $431M Tangible Common Equity 8.0% TCE / TA 11.9% CET1 Ratio 8.8% Leverage Ratio 13.8% Total RBC Ratio (1) Adirondack branch count of 20 includes 1 LPO (2) Includes estimated impact from purchase accounting adjustments; assumes June 30, 2026 transaction closing date (3) Based on non-NYC MSA NY headquartered publicly traded banks with less than $10 billion in assets Source: S&P Capital IQ Pro Rank Company MRQ Assets ($M) 1 Tompkins Financial Corporation 8,668 2 TrustCo Bank Corp NY 6,441 3 Financial Institutions, Inc. 6,274 -- Pro Forma Franchise(2) 5,490 4 Canandaigua National Corporation 5,270 5 Arrow Financial Corporation 4,446 6 Greene County Bancorp, Inc. 3,147 7 Chemung Financial Corporation 2,710 8 Orange County Bancorp, Inc. 2,659 9 Pioneer Bancorp, Inc. 2,151 10 Lyons Bancorp Inc. 2,069 16 Adirondack Bancorp, Inc. 942

7 Pro Forma Loan & Deposit Composition L o a n C o m p o s it io n D e p o s it M ix Note: Financial data as of December 31, 2025; Loan and deposit compositions reflect Call Report information Note: Jumbo Time Deposits are time deposits with balances of more than $250,000 (1) Pro Forma compositions exclude purchase accounting adjustments; Pro Forma totals may not sum due to rounding Source: S&P Capital IQ Pro; Company Documents MRQ Cost of Deposits: 1.92% MRQ Cost of Deposits: 0.80% MRQ Cost of Deposits: 1.71% MRQ Yield on Loans: 5.47% MRQ Yield on Loans: 5.67% MRQ Yield on Loans: 5.50% Noninterest -Bearing 18.3% Retail Time 16.3% Jumbo Time 4.0% IB, MMDA, & Savings 61.4% Noninterest -Bearing 36.5% Retail Time 6.7% Jumbo Time 12.9% IB, MMDA, & Savings 43.9% Noninterest -Bearing 21.5% Retail Time 14.6% Jumbo Time 5.5% IB, MMDA, & Savings 58.3% Pro Forma(1) 1-4 Family 39.3% C&D 2.1% Multifa mily 4.9% NOO- CRE 11.2% OO- CRE 6.6% C&I 3.9% Consumer & Other 32.1% 1-4 Family 47.8% C&D 5.9% Multifa mily 5.8% NOO- CRE 13.7% OO- CRE 8.4% C&I 17.4% Consumer & Other 1.0% 1-4 Family 40.6%C&D 2.7% Multifa mily 5.0% NOO- CRE 11.6% OO- CRE 6.8% C&I 5.9% Consumer & Other 27.3%

8 Credit Quality and Due Diligence Review Diligence Focus AreasNet Charge-Offs / Average Loans (%) Non-Performing Assets / Total Assets (%)(1) 0.19% 0.01% 2016Y 2017Y 2018Y 2019Y 2020Y 2021Y 2022Y 2023Y 2024Y 2025Y AROW Adirondack 0.15% 0.47% 2016Y 2017Y 2018Y 2019Y 2020Y 2021Y 2022Y 2023Y 2024Y 2025Y AROW Adirondack Peak NCOs: 0.20% Peak NCOs: 0.19% Peak NPAs: 1.48% Peak NPAs: 0.50% Credit Review Financials, Accounting & Tax Interest Rate Management Securities Portfolio Human Resources IT and Operations Internal & External Audit Facilities Legal & Compliance Cyber Security Note: Financial data as of December 31, 2025 (1) Nonperforming assets include nonaccrual loans and leases, renegotiated loans and leases, and real estate owned Source: S&P Capital IQ Pro

9 Transaction Structure & Overview Acquiror / Target Implied Transaction Value(1) Consideration Pro Forma Ownership Approvals Due Diligence Anticipated Closing Arrow Financial Corporation (NASDAQ: AROW) / Adirondack Bancorp, Inc. $89.1 million or $82.79 per share 89.2% AROW / 10.8% Adirondack Bancorp, Inc. Adirondack Bancorp, Inc. shareholder approval; customary regulatory approvals Comprehensive financial, business, operation, loan and legal due diligence Late Q2 / Early Q3 2026 Pricing(1)(2) ▪ Price / Tangible Book Value: 138.2% ▪ Price / ’26E EPS + Cost Saves: 5.3x ▪ Core Deposit Premium: 3.5% (1) Based on AROW’s closing stock price of $34.43 as of February 25, 2026 (2) Based upon financial data as of December 31, 2025 Fixed exchange ratio of 1.8610 shares of AROW stock and $18.72 in cash per share of Adirondack Bancorp, Inc. common stock ▪ 77% stock consideration | 23% cash consideration(1)

10 Key Transaction Assumptions Merger Costs Cost Savings Earnings Projections Purchase Accounting Adjustments $29.8 million pre-tax; $23.0 million after-tax 45.0% of Adirondack Bancorp, Inc.’s non-interest expense base ▪ 75% realized in 2026 and 100% thereafter ▪ AROW assumes consensus analyst estimates for 2026 and 2027, with an assumed long-term growth rate of 6.0% ▪ Adirondack Bancorp, Inc. assumes internal estimate for 2026, with an assumed long-term growth rate of 6.0% Core Deposit Intangible 3.00%, or $20.5 million, amortized sum-of-the-years digits over 10 years ▪ $8.5 million or 1.36% gross credit mark (current ALLL of $4.7 million) ▪ $17.4 million loan interest rate mark, accreted straight-line (“SL”) over 3.5 years ▪ $0.2 million write-up on HTM securities, amortized SL over 2.1 years ▪ $3.3 million write-up on fixed assets; $1.8 million amortized SL over 15 years ▪ After-tax AOCI of $10.8 million, accreted SL over 4.2 years ▪ Additional identified DTA of $2.8 million

11 Pro Forma Financial Impact Note: Figures shown assumes June 30, 2026 transaction closing date (1) Excludes the impact of merger charges (2) Includes cost savings and opportunity cost of cash (3) Tangible book value earnback calculated using the crossover method (4) AROW 2027 standalone based on consensus analyst estimates Source: S&P Capital IQ Pro Financially Attractive 12.8% ’27E Cash EPS Accretion(1)(2) TBVPS Dilution TBVPS Earnback(3) (9.1%) 2.9 yrs ’27E GAAP EPS Accretion(1) 18.1% IRR 20% Well-Capitalized & Well-Reserved CET1TCE / TA Total RBC 8.0% Leverage LLR / Gross Loans 8.8% 11.9% 13.8% 1.05% 2027E ROAA(4) Desirable Earnings Profile 1.28% 1.40% Standalone Pro Forma 57.0% 55.1% Standalone Pro Forma 2027E Efficiency(4) 2027E NIM(4) 3.49% 3.77% Standalone Pro Forma

Appendix

13 EPS & Goodwill Reconciliation Note: See page 10 for transaction assumptions Source: S&P Capital IQ Pro Illustrative 2027 EPS Accretion Goodwill Reconciliation Projected at Closing (6/30/2026) $ in thousands Aggregate Deal Value $89,107 Adirondack Common Equity 68,804 Less: Adirondack Intangibles (2,023) Less: Deal Expenses (Net of Taxes) (23,000) Adirondack Adjusted TCE 43,781 Purchase Accounting Adjustments: Pre-Tax Net Credit Mark (3,778) Loan Interest Rate Mark (17,439) HTM Securities Interest Rate Mark 227 Fixed Asset Mark 3,268 Pre-Tax Net FMV Adjustments (17,722) Deferred Tax Asset / (Liability) - FV Marks 4,431 Additional DTA 2,829 Adirondack Adjusted TCE 33,318 Excess Over Adjusted TCE 55,789 Core Deposit Intangible: Core Deposit Intangible 20,451 Deferred Tax Asset / (Liability) (5,113) Goodwill Allocation $40,451 $ in thousands GAAP Cash AROW Net Income $59,900 $59,900 Adirondack Net Income $4,876 $4,876 Net Amortization of Intangibles $203 Combined Net Income $64,776 $64,979 After-Tax Adjustments: Cost Savings 12,404 12,404 CDI Amortization (2,649) Opportunity Cost of Cash (1,310) (1,310) Loan Interest Rate Mark Accretion 3,737 HTM Securities Amortization (82) AFS Securities (AOCI) Accretion 2,603 Fixed Asset Mark Amortization (88) Adjusted Net Income $79,391 $76,073 Pro Forma Average Diluted Shares 18,416 18,416 Pro Forma EPS $4.31 $4.13 AROW Standalone EPS $3.65 $3.66 Accretion / (Dilution) to AROW - $ $0.66 $0.47 Accretion / (Dilution) to AROW - % 18.1% 12.8%

FOR IMMEDIATE RELEASE Arrow Financial Corporation Announces Strategic Acquisition of Adirondack Bancorp, Inc. GLENS FALLS, N.Y. and UTICA, N.Y. (February 26, 2026) — Arrow Financial Corporation (NASDAQGS: AROW) (“Arrow” or "AROW"), the parent company of Arrow Bank National Association, and Adirondack Bancorp, Inc. (“Adirondack”), the parent company of Adirondack Bank, jointly announced today that both companies’ boards of directors have unanimously approved an agreement and plan of merger (the “Agreement”) pursuant to which Adirondack will merge with and into Arrow. This strategic acquisition extends Arrow’s eight-county footprint farther into the Adirondack region and into the Mohawk Valley to include Oneida, Herkimer and Franklin counties, while strengthening its commitment to Essex and Clinton counties. Based on the financial results as of December 31, 2025, the combined company would have pro-forma total assets of $5.4 billion, total deposits of $4.8 billion, and total gross loans of $4.1 billion.1 David S. DeMarco, Arrow President and CEO, stated, “Arrow Bank and Adirondack Bank are two deeply rooted and culturally aligned community banks that share a long-standing commitment to building strong relationships, understanding the important role we play in local economic growth and community support. As our company celebrates its 175th anniversary, this strategic acquisition shows Arrow’s commitment to accelerating our growth and expanding our market presence. Bringing together these two institutions allows us to complement Adirondack’s current product offerings with our wealth management and insurance services and deliver meaningful value for our shareholders.” Rocco F. Arcuri Sr., Adirondack President and CEO, will stay with Arrow as Regional President and will join the Arrow Board of Directors. “In Arrow, we have found a partner that shares our own culture and values and, like Adirondack, has a history of providing excellent customer service while supporting the communities it serves. Aligning our two community banks will create a more robust organization equipped for the future while benefitting our customers who will have the local support they expect with access to more products, services and locations. I’m excited to continue with Arrow to further align our mission and help ensure a smooth transition for all involved.” Established in 1898 and converted to a state charter in December 2003, Adirondack operates 19 branch locations spanning Oneida, Herkimer, Franklin, Essex and Clinton counties, and a loan production office in Onondaga County. As of December 31, 2025, Adirondack had total assets of $942 million, total deposits of $848 million, and total loans of $624 million.2 Transaction Details Pursuant to the terms of the Agreement, Adirondack shareholders will receive a combination of stock and cash upon closing of the merger with Arrow. Each outstanding share of Adirondack common stock will be converted into 1.8610 shares of Arrow common stock plus $18.72 in cash. Based on the closing stock price of AROW common stock of $34.43 as of February 25, 2026, the per share implied consideration value is $82.79 and the aggregate implied transaction value is approximately $89.1 million. Closing of the transaction is expected by the end of the second quarter of 2026 following receipt of approvals from regulatory authorities, the approval of Adirondack shareholders, and the satisfaction of other customary closing conditions.

Once the acquisition is completed, Arrow will have 58 offices in upstate New York offering a full range of financial products and services. Financial Benefits of the Merger The transaction is expected to be financially attractive with an estimated 2027 EPS accretion of approximately 18%, a strong internal rate of return of approximately 20% and a Tangible Book Value per Share earn-back period of 2.9 years. On a pro-forma basis, the business is expected to deliver compelling return metrics supported by a strong balance sheet, including: • Allowance Coverage Ratio of over 1.00% • Tangible Common Equity at closing of transaction of approximately 8% • Total Risk-Based-Capital at closing of approximately 14% Hovde Group, LLC is serving as financial advisor to Arrow and provided a fairness opinion, with Spierer, Woodward, Corbalis & Goldberg serving as legal advisor. Keefe, Bruyette & Woods, A Stifel Company is serving as financial advisor to Adirondack and provided a fairness opinion, with Luse Gorman serving as legal advisor. 1Includes estimated impact from purchase accounting adjustments as of December 31, 2025 2Source: S&P Capital IQ Pro About Arrow Financial Corporation Arrow Financial Corporation is a bank holding company headquartered in Glens Falls, New York, providing banking, insurance and wealth management services from Plattsburgh to Albany. Arrow’s full- service commercial bank Arrow Bank National Association was formerly named Glens Falls National Bank and Trust Company and Saratoga National Bank and Trust Company. The Bank, celebrating its 175th anniversary throughout 2026, provides a broad range of financial products, including online and mobile banking, mortgages, commercial loans, investments and more. Other subsidiaries include an insurance company, Upstate Agency, LLC. The Company’s common stock is traded through the Nasdaq Exchange under the symbol “AROW.” Visit arrowfinancial.com for more information. About Adirondack Bancorp, Inc. Adirondack Bancorp, Inc, is the bank holding company for Adirondack Bank. Adirondack Bank is a New York state-chartered financial institution headquartered in Utica, New York. On October 31, 1898, Adirondack Bank began serving the needs of Northern New York state as the Saranac Lake Co- Operative Savings and Loan Association. In 1990, the Bank was re-capitalized as a stock corporation and the change in ownership also saw a change in the Bank’s operation as a newly chartered Federal Savings Bank. Later in 1995, it was re-chartered as a National Bank and became Adirondack Bank, N.A. To better serve its customers, Adirondack converted to a state charter in December 2003. Adirondack Bank now serves Upstate New York, from the historic Mohawk Valley to the Canadian border. Visit adirondackbank.com for more information. Forward-Looking Statements This news release includes “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, including with respect to (or based on) the beliefs, goals, intentions, and expectations of Arrow and Adirondack regarding the proposed transaction, revenues, earnings, earnings per share, loan production, asset quality, and capital levels, among other matters; our estimates of future costs and benefits of the actions we may take; our assessments of expected losses on loans; our assessments of interest rate and other market risks; our ability to achieve our financial and other strategic goals; the expected timing of completion of the proposed transaction; the expected cost savings, synergies, returns and other anticipated benefits from the proposed transaction; and other statements that are not historical facts.

Forward–looking statements are typically identified by such words as “believe,” “expect,” “anticipate,” “intend,” “outlook,” “estimate,” “forecast,” “project,” “will,” “should,” and other similar words and expressions, and are subject to numerous assumptions, risks, and uncertainties, which change over time. Forward-looking statements include, without limitation, those relating to the terms, timing and closing of the proposed transaction. Additionally, forward-looking statements speak only as of the date they are made; Arrow and Adirondack do not assume any duty, and do not undertake, to update such forward-looking statements, whether written or oral, that may be made from time to time, whether as a result of new information, future events, or otherwise. Furthermore, because forward-looking statements are subject to assumptions and uncertainties, actual results or future events could differ, possibly materially, from those indicated in or implied by such forward-looking statements as a result of a variety of factors, many of which are beyond the control of Arrow and Adirondack. Such statements are based upon the current beliefs and expectations of the management of Adirondack and Arrow and are subject to significant risks and uncertainties outside of the control of the parties. Caution should be exercised against placing undue reliance on forward-looking statements. The factors that could cause actual results to differ materially include the following: the occurrence of any event, change or other circumstances that could give rise to the right of one or both of the parties to terminate the definitive Merger Agreement between Arrow and Adirondack; the outcome of any legal proceedings that may be instituted against Arrow and Adirondack; the possibility that the proposed transaction will not close when expected or at all because required regulatory, shareholder or other approvals are not received or other conditions to the closing are not satisfied on a timely basis or at all, or are obtained subject to conditions that are not anticipated (and the risk that required regulatory approvals may result in the imposition of conditions that could adversely affect the combined company or the expected benefits of the proposed transaction); the ability of Arrow and Adirondack to meet expectations regarding the timing, completion and accounting and tax treatments of the proposed transaction; the risk that any announcements relating to the proposed transaction could have adverse effects on the market price of the common stock of either or both parties to the proposed transaction; the possibility that the anticipated benefits of the proposed transaction will not be realized when expected or at all, including as a result of the impact of, or problems arising from, the integration of the two companies or as a result of the strength of the economy and competitive factors in the areas where Arrow and Adirondack do business; certain restrictions during the pendency of the proposed transaction that may impact the parties’ ability to pursue certain business opportunities or strategic transactions; the possibility that the transaction may be more expensive to complete than anticipated, including as a result of unexpected factors or events; diversion of management’s attention from ongoing business operations and opportunities; the possibility that the parties may be unable to achieve expected synergies and operating efficiencies in the Merger within the expected timeframes or at all and to successfully integrate Adirondack’s operations and those of Arrow; such integration may be more difficult, time-consuming or costly than expected; revenues following the proposed transaction may be lower than expected; Arrow’s and Adirondack’s success in executing their respective business plans and strategies and managing the risks involved in the foregoing; the dilution caused by Arrow’s issuance of additional shares of its capital stock in connection with the proposed transaction; effects of the announcement, pendency or completion of the proposed transaction on the ability of Arrow and Adirondack to retain customers and retain and hire key personnel and maintain relationships with their suppliers, and on their operating results and businesses generally; and risks related to the potential impact of general economic, political and market factors on the companies or the proposed transaction and other factors that may affect future results of Arrow and Adirondack; and the other factors discussed in the “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” sections of Arrow’s Annual Report on Form 10-K for the year ended December 31, 2024 and its Quarterly Reports on Form 10–Q for the quarters ended March 31, 2025, June 30, 2025, and September 30, 2025, and other reports Arrow files with the SEC. Additional Important Information and Where to Find It In connection with the proposed transaction, Arrow will file a registration statement on Form S-4 with the SEC to register the shares of Arrow common stock to be issued in connection with the proposed transaction. The registration statement will include a 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

FAQ

What did Arrow Financial Corporation (AROW) announce regarding Adirondack Bancorp, Inc.?

Arrow Financial Corporation agreed to acquire Adirondack Bancorp, Inc. in a stock-and-cash merger. Adirondack will merge into Arrow, and its bank subsidiary will combine with Arrow Bank National Association, expanding Arrow’s community banking footprint across upstate New York and the Adirondack region.

What consideration will Adirondack shareholders receive in the Arrow Financial (AROW) merger?

Each Adirondack share will be converted into 1.8610 shares of Arrow common stock plus $18.72 in cash. Based on Arrow’s February 25, 2026 share price, this implies per-share consideration of about $82.79 and an aggregate transaction value of roughly $89.1 million.

How will the Arrow Financial (AROW) and Adirondack Bancorp deal affect the combined company’s size?

Using December 31, 2025 figures and purchase accounting estimates, the combined company is projected to have about $5.4 billion in assets, $4.8 billion in deposits and $4.1 billion in gross loans, significantly increasing Arrow’s scale in its core New York markets.

What financial impact does Arrow Financial (AROW) expect from acquiring Adirondack Bancorp?

Arrow projects roughly 18% 2027 GAAP EPS accretion, about 12.8% cash EPS accretion, an internal rate of return near 20% and a tangible book value per share earnback period of 2.9 years, assuming targeted cost savings and purchase accounting accretion.

What regulatory and shareholder approvals are required for the Arrow Financial (AROW)–Adirondack merger?

The transaction requires approval by Adirondack’s shareholders and banking regulators, including the Federal Reserve, the Office of the Comptroller of the Currency and the New York State Department of Financial Services, along with satisfaction of customary merger closing conditions.

How will leadership and governance change after Arrow Financial (AROW) acquires Adirondack Bancorp?

Adirondack President and CEO Rocco F. Arcuri Sr. will become Regional President at Arrow and join the boards of Arrow and Arrow Bank. Voting and lock-up agreements with key Adirondack shareholders are designed to support approval and manage post-closing share sales.

How is the Arrow Financial (AROW) acquisition of Adirondack expected to affect capital and credit quality?

Pro forma estimates show tangible common equity near 8.0%, CET1 around 11.9%, total risk-based capital about 13.8% and allowance coverage above 1.00%. Both banks report historically low net charge-offs and manageable nonperforming assets, supporting the combined risk profile.

Filing Exhibits & Attachments

8 documents

Press Releases

• EX-99.1 EX-99.1 23.2 KB
• EX-99.2 EX-99.2 14.0 KB
• EX-99.3 EX-99.3 24.3 KB
• EX-99.4 EX-99.4 17.5 KB

Other Documents

• EX-2.1 EX-2.1 394.1 KB
• EX-101 XBRL TAXONOMY EXTENSION SCHEMA DOCUMENT 1.8 KB
• EX-101 XBRL TAXONOMY EXTENSION LABEL LINKBASE DOCUMENT 21.1 KB
• EX-101 XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE DOCUMENT 12.2 KB