Rain Enhancement Technologies Holdco Inc-A美股招股说明书(2026-04-14版)

Rain Enhancement Technologies Holdco, Inc. 5,000,000 Shares of Class A Common Stock Underlying Warrants(For Issuance) 5,914,057 Shares of Class A Common Stock(For Resale) This prospectus supplement No. 9 (this “Supplement”) supplements, updates and amends the information contained in the prospectusdated April 25, 2025 (the “Prospectus”) relating to the issuance of shares of Class A common stock, par value $0.0001 per share (the“Class A Common Stock”), of Rain Enhancement Technologies Holdco, Inc. (the “Company”) upon the exercise of warrants of theCompany (“Warrants”) and the resale from time to time of shares of Class A Common Stock by the selling shareholders (includingtheirtransferees,donees,pledgees and other successors-in-interest)named in the Prospectus. This Supplement updates andsupplements the Prospectus. This Supplement is being filed to update and supplement the information previously included in the Prospectus with the informationcontained in the Company’s Current Reports on Form 8-K filed with the SEC on April 6, 2026 and April 14, 2026 (collectively, the“Form 8-Ks”). Accordingly, we have attached the Form 8-Ks to this Supplement. You should read this Supplement in conjunction withthe Prospectus. This Supplement is not complete without, and may not be delivered or used except in conjunction with, the Prospectus,including any amendments or supplements thereto. This Supplement is qualified by reference to the Prospectus, except to the extentthat the information provided by this Supplement supersedes information contained in the Prospectus. Capitalized terms used in thisSupplement have the meanings given to them in the Prospectus. Our shares of Class A Common Stock and Warrants are listed on the Nasdaq Stock Market LLC (“Nasdaq”) under the symbols“RAIN” and “RAINW,” respectively. On April 13, 2026, the closing price of our Class A Common Stock was $2.22 per share and theclosing price for our Warrants was $0.22 per Warrant. We are an “emerging growth company” as defined under the federal securities laws, and, as such, may elect to comply with certainreduced public company reporting requirements for this and future filings. INVESTING IN OUR SECURITIES INVOLVES RISKS. YOU SHOULD CAREFULLY CONSIDER THE RISK FACTORSSET FORTH UNDER THE SECTION ENTITLED “RISK FACTORS” ON PAGE 12 OF THE PROSPECTUS, BEFOREMAKING ANY DECISION WHETHER TO INVEST IN OUR SECURITIES. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of thesesecurities or passed upon the adequacy or accuracy of this Supplement or the accompanying Prospectus. Any representation tothe contrary is a criminal offense. The date of this prospectus supplement is April 14, 2026. UNITED STATESSECURITIES AND EXCHANGE COMMISSIONWASHINGTON, 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 (Date of earliest event reported): March 31, 2026 RAIN ENHANCEMENT TECHNOLOGIES HOLDCO, INC.(Exact name of registrant as specified in its charter) Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrantunder 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)) 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 forcomplying 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. Effective as of March 31, 2026, Rain Enhancement Technologies Holdco, Inc. (the “Company”) and RHY Management LLC, anaffiliate of Harry You, the Company’s chairman and a beneficial owner of more than 10% of the Company’s Class A common stockand Class B common stock, (“RHY”) entered into an amendment (the “Loan Agreement Amendment”) to that certain Loan Agreementbetween RHY and the Company, dated as of December 30, 2024 (the “Loan Agreement”), increasing the amount that could beborrowed by the Company under the line of credit (the “LOC”) pursuant to the Loan Agreement from $7,000,000 to $10,000,000. The foregoing description does not purport to be complete and is qualified in its entirety by reference to the full text of the LoanAgreement Amendment. A copy of the Loan Agreement Am