米德尔赛克斯水务公司美股招股说明书(2025-05-12版)

PROSPECTUS SUPPLEMENT(To Prospectus Dated May12, 2025) Up to $110,000,000 of Common Stock This prospectus supplement relates to shares of common stock, no par value (“Middlesex Common Stock”), of MiddlesexWater Company (“Middlesex” or the “Company”). Middlesex has entered into an ATM Equity Offering Sales Agreement with BofASecurities,Inc., Robert W. Baird& Co. Incorporated and Janney Montgomery Scott LLC as our sales agents (collectively, the“Agents”), under which we may offer and sell from time to time our common stock having an aggregate offering price of up to Middlesex Common Stock is listed on the NASDAQ Global Select Market under the symbol “MSEX.” On May9, 2025 theclosing price of Middlesex Common Stock on the NASDAQ Global Select Market was $60.09 per share. Sales, if any, of common stock under the ATM Equity Offering Sales Agreement may be made in ordinary brokers’transactions, to or through a market maker, on or through the Nasdaq Global Select Market or any other market venue where ourcommon stock may be traded, in the over-the-counter market, in privately negotiated transactions, in block trades, in transactions that We will designate the maximum amount of common stock to be sold through the sales agents on a daily basis or otherwise aswe and the sales agents agree and the minimum price per share at which such common stock may be sold. Subject to the terms andconditions of the ATM Equity Offering Sales Agreement, the sales agents will use their reasonable efforts consistent with their normalsales and trading practices to sell on our behalf all of the designated shares of common stock. We may instruct the sales agents not to We will pay each sales agent a commission of up to 2% of the gross sales price per share of common stock sold through suchagent under the ATM Equity Offering Sales Agreement. We have also agreed to reimburse the Agents for certain of their expenses. Inconnection with the sale of the shares of common stock on our behalf, each of the Agents may be deemed to be an “underwriter” Settlement of any sales of common stock will occur on the first business day following the date on which such sales weremade. There is no arrangement for funds to be received in an escrow, trust or similar arrangement. Sales of our common stock as Investing in Middlesex Common Stock involves a high degree of risk. Before making a decision to invest in MiddlesexCommon Stock, you should carefully consider the risks described in PartI,Item 1A of the Company’s most recent Annual Report onForm10-K (“Form10-K”) under the heading “Risk Factors,” and under the headings “Risk Factors” of this prospectus supplement Neitherthe Securities and Exchange Commission(“SEC”)nor any other regulatory body has approved ordisapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplement or the related No person has been authorized to give any information or to make any representations other than those contained inthis prospectus supplement. If any other information or representations are given or made, you must not rely on them ashaving been authorized. Prospectus Supplement ABOUT THIS PROSPECTUS SUPPLEMENT Unless otherwise mentioned or unless the context requires otherwise, all references in this prospectus supplement to“Middlesex,” “Company,” “we,” “us,” “our” or similar references mean Middlesex Water Company, and its subsidiaries, includingTidewater Utilities,Inc. (“Tidewater”) and Tidewater’s wholly-owned subsidiaries, Southern Shores Water Company, LLC (“SouthernShores”) and White Marsh Environmental Systems,Inc. (“White Marsh”). The Company’s other subsidiaries are Pinelands WaterCompany (“Pinelands Water”) and Pinelands Wastewater Company (“Pinelands Wastewater”) (collectively, “Pinelands”), UtilityService Affiliates,Inc. (“USA”) and Utility Service Affiliates (Perth Amboy) Inc. (“USA-PA”). In this prospectus supplement You should rely only on the information contained, or incorporated by reference, in this prospectus supplement and theaccompanying prospectus. Neither we nor any sales agent or underwriter has authorized anyone to provide you with differentinformation. If anyone provides you with different or inconsistent information, you should not rely on it. We are not, and the Agentsand any underwriters are not, making an offer to sell the securities in any jurisdiction where the offer or sale is not permitted or inwhich the person making such offer or solicitation is not qualified to do so or to any person to whom it is unlawful to make such offer This document is in two parts. The first part is this prospectus supplement, which describes the terms of this offering ofMiddlesex Common Stock and also adds to and updates information contained in the accompanying prospectus and the documentsincorporated by reference into this prospectus supplement and the accompanying prospectus. The second part, the accompanyingprospectus dated May12, 2025, including the documents in