爱国者国家银行美股招股说明书(2025-06-04版)

PATRIOT NATIONAL BANCORP, INC. 8,524,160 Shares of Common Stock We are offering 8,524,160 shares, referred to as the “Shares,” of our common stock, par value $0.01 per share, or“Common Stock,” directly to certain accredited investors, referred to as the “purchasers,” pursuant to this prospectus supplement Our Common Stock is listed on The Nasdaq Global Market, or “Nasdaq,” under the symbol “PNBK”. On June 3, 2025,the last reported sale price of our Common Stock, as reported on Nasdaq, was $1.17 per share. Investing in our securities involves a high degree of risk. Before buying any securities, you should carefully readthe discussion of the risks of investing in our securities in“Risk Factors”beginning on page S-3of this prospectus Neither the Securities and Exchange Commission nor any state securities commission has approved or disapprovedof these securities or passed upon the adequacy or accuracy of this prospectus supplement or the accompanying prospectus. The purchase price of each Share of Common Stock to the purchasers identified in the securities purchase agreement,dated as of June 3, 2025, by and among us and the purchasers listed on the signature pages thereto is $1.25 per Share. The Shares We anticipate that delivery of the Shares of Common Stock against payment will be made on or about June 5, 2025,subject to satisfaction of customary closing conditions. The date of this prospectus supplement is June 4, 2025 PROSPECTUS SUPPLEMENT ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement and the accompanying prospectus relate to the offering of our Common Stock. Before buyingany Shares of our Common Stock that we are offering, we urge you to carefully read this prospectus supplement and theaccompanying prospectus, together with the information incorporated by reference as described under the headings “Where You This prospectus supplement and the accompanying prospectus are part of the registration statement on Form S-3 (File No.333-287283) that we filed with the Securities and Exchange Commission, or the “SEC,” utilizing a shelf registration process, andthat was declared effective by the SEC on May 22, 2025. This document is in two parts. The first part is this prospectussupplement, which describes the terms of this offering of our Common Stock and also adds to, updates information contained inthe accompanying prospectus and the documents incorporated by reference. The second part is the accompanying prospectus, To the extent the information contained in this prospectus supplement differs from or conflicts with the informationcontained in the accompanying prospectus or any document incorporated by reference having an earlier date, the information inthis prospectus supplement will control. If any statement in one of these documents is inconsistent with a statement in anotherdocument having a later date—for example, a document incorporated by reference into this prospectus supplement and theaccompanying prospectus—the statement in the document having the later date modifies or supersedes the earlier statement. We You should assume that the information contained in this prospectus supplement is accurate as of the date on the frontcover of this prospectus supplement only and that any information we have incorporated by reference or included in theaccompanying prospectus is accurate only as of the date given in the document incorporated by reference or as of the date of theaccompanying prospectus, as applicable, regardless of the time of delivery of this prospectus supplement, the accompanying This prospectus supplement and the accompanying prospectus contain summaries of certain provisions contained in someof the documents described herein, but reference is made to the actual documents for complete information. All of the summariesare qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed asexhibits to the registration statement of which this prospectus is a part, or documents incorporated by reference, or will be filed asexhibits to documents incorporated by reference herein, and you may obtain copies of those documents as described below underthe headings “Where You Can Find More Information” and “Information Incorporated by Reference.” We further note that therepresentations, warranties and covenants made by us in any agreement that is filed as an exhibit to any document that is This prospectus supplement and the accompanying prospectus do not constitute an offer to sell, or a solicitation of anoffer to purchase, the securities offered by this prospectus supplement and the accompanying prospectus in any jurisdiction to anyperson to whom it is unlawful to make, or from whom it is unlawful to solicit, such an offer in such jurisdiction. Persons into This prospectus supplement and the accompanying prospectus incorporate by reference market data and industry statisticsand forecasts that are based on independent industry