单元特公司美股招股说明书(2025-06-03版)

Filed Pursuant to Rule 424(b)(5)Registration No. 333-287753 PROSPECTUS SUPPLEMENT(To Prospectus dated June3, 2025) This prospectus supplement and the accompanying prospectus relate to the offer and sale from time to time of shares of our common stock, having an aggregate offeringprice of up to $50,000,000 through Janney Montgomery Scott LLC and Scotia Capital (USA) Inc. (collectively, the “sales agents” and each individually, a “sales agent”),as our agents under an “at the market offering” distribution agreement (the “distribution agreement”). The distribution agreement provides that, in addition to theissuance and sale of common stock by us through the sales agents acting as sales agents or directly to the sales agents acting as principals, we also may enter into forwardsale agreements, between us and affiliates of each sales agent. We refer to these affiliated entities, when acting in such capacity, as forward purchasers. In connectionwith each such forward sale agreement, and subject to the terms and conditions of the distribution agreement, the relevant forward purchaser will, at our request, borrowfrom third parties and, through the relevant sales agent, sell a number of shares of our common stock equal to the number of shares of our common stock that will We will not initially receive any proceeds from the sale of borrowed shares of our common stock by a forward seller. In the event of full physical settlement of eachforward sale agreement (by delivery of our common stock) with the relevant forward purchaser on one or more dates specified by us on or prior to the maturity date ofthe relevant forward sale agreement, we expect to receive aggregate cash proceeds equal to the product of the initial forward sale price under such forward saleagreement and the number of shares of our common stock underlying such forward sale agreement, subject to the price adjustment and other provisions of such forward The shares of our common stock will be offered at market prices prevailing at the time of sale in “at the market offerings,” as defined in Rule 415 of the Securities Act of1933, as amended (the “Securities Act”). We will submit orders to only one sales agent or one forward seller, as the case may be, relating to the sale of shares of ourcommon stock on any given day. Subject to the terms and conditions of the distribution agreement, the sales agents, forward sellers or forward purchasers have agreed to The distribution agreement also provides that we may sell shares of our common stock to a sales agent as principal for its own account at a price agreed upon at the timeof the sale. If we sell shares of our common stock to a sales agent as principal, then we will enter into a separate terms agreement with that sales agent setting forth the We have agreed to pay each sales agent a commission equal to up to 2% of the sales price of all shares of our common stock sold through it as our sales agent under thedistribution agreement. In connection with each forward sale agreement, the relevant forward seller will receive, reflected in a reduced initial forward sale price payableby the relevant forward purchaser under its forward sale agreement, a commission equal to up to 2% of the volume weighted average of the sales prices of all borrowed Our common stock is listed on the New York Stock Exchange (the “NYSE”) under the symbol “UTL”. The last reported sale price of our common stock on the NYSE onMay30, 2025 was $54.83 per share. Investing in our common stock involves significant risks. You should review carefully the “Risk Factors” on pageS-7of thisprospectus supplement, and in the documents incorporated by reference in this prospectus supplement and accompanying base Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon theadequacy or accuracy of this prospectus supplement. Any representation to the contrary is a criminal offense. Janney Montgomery Scott TABLE OF CONTENTS ABOUT THIS PROSPECTUS SUPPLEMENTCAUTIONARY STATEMENT ABOUT FORWARD-LOOKING INFORMATIONPROSPECTUS SUPPLEMENT SUMMARYTHE OFFERINGRISK FACTORSUSE OF PROCEEDSPLAN OF DISTRIBUTIONLEGAL MATTERSEXPERTSWHERE YOU CAN FIND MORE INFORMATIONINFORMATION INCORPORATED BY REFERENCE ge1234 ABOUT THIS PROSPECTUSWHERE YOU CAN FIND MORE INFORMATION ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement and the accompanying base prospectus are part of an automatic shelf registration statement on FormS-3that we filed withthe Securities and Exchange Commission (the “SEC”) utilizing a “shelf” registration process. Under this shelf registration process, we may from time totime offer shares of our common stock having an aggregate offering price of up to $50,000,000 under this prospectus supplement at prices and on terms This prospectus supplement is not complete without, and may not be utilized except in connection with, the accompanying base prospectus dated Jun