Rubico Inc美股招股说明书(2026-06-24版)

PROSPECTUS SUPPLEMENT NO. 17(TO PROSPECTUS DATED SEPTEMBER 19, 2025) Up to 15,000,000 Common Shares RUBICO INC. This is a supplement (the “Prospectus Supplement”) to the prospectus, dated September 19, 2025 (as supplemented or amended fromtime to time, the “Prospectus”) of Rubico Inc. (the “Company”), which forms a part of the Company’s Registration Statement on Form F-1(Registration Nos. 333-288796, 333-291884, 333-293441 and 333-294944), as amended from time to time. This Prospectus Supplement is being filed to update and supplement the information included in the Prospectus with the informationcontained in the Company’s Reports on Form 6-K, furnished to the U.S. Securities and Exchange Commission (the “Commission”) on June 23,2026, June 23, 2026, June 12, 2026 and May 26, 2026 (the “Form 6-Ks”). Accordingly, the Form 6-Ks are attached to this ProspectusSupplement. This Prospectus Supplement should be read in conjunction with, and delivered with, the Prospectus and is qualified by reference to theProspectus except to the extent that the information in this Prospectus Supplement supersedes the information contained in the Prospectus. This Prospectus Supplement is not complete without, and may not be delivered or utilized except in connection with, the Prospectus,including any amendments or supplements to it. Investing in our securities involves a high degree of risk. See “Risk Factors” beginning on page 12 of the Prospectus for adiscussion of information that should be considered in connection with an investment in our securities. Neither the Commission nor any state securities commission has approved or disapproved of these securities or determined ifthis prospectus is truthful or complete. Any representation to the contrary is a criminal offense. The date of this prospectus supplement is June 23, 2026. UNITED STATESSECURITIES AND EXCHANGE COMMISSIONWashington, D.C. 20549 FORM 6-K REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR 15d-16 UNDER THE SECURITIES EXCHANGEACT OF 1934 For the month of June 2026 Commission File Number:001-42684 Rubico Inc.(Translation of registrant's name into English) 20 Iouliou Kaisara Str19002 PaianiaAthens, Greece(Address of principal executive office) Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.Form 20-F [X ]Form 40-F [] On June 23, 2026, the Registrant issued a press release, a copy of which is attached hereto as Exhibit 99.1 and is incorporated herein byreference. Attached hereto as Exhibit 1.1 is a copy of the Articles of Amendment to the Amended and Restated Articles of Incorporation of theRegistrant, filed with the Registrar of Corporations of the Republic of the Marshall Islands on June 23, 2026. Exhibit 1.1. Articles of Amendment to Amended and Restated Articles of Incorporation Exhibit 99.1. Press release dated June 23, 2026 SIGNATURE 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 theundersigned, thereunto duly authorized. Rubico Inc.(Registrant)/s/ Nikolaos PapastratisNikolaos PapastratisChief Financial Officer Date: June 23, 2026 Rubico Inc. Announces Reverse Stock Split ATHENS, Greece, June 23, 2026 (GLOBE NEWSWIRE)--Rubico Inc.(Nasdaq: RUBI) (the “Company” or “Rubico”), a global provider ofshipping transportation services specializing in the ownership of vessels, announced today that its board of directors (the “Board”) hasdetermined to effect a 1 for 25 reverse stock split (the “Reverse Stock Split”) of the Company’s issued common shares, par value $0.01 (the“Common Shares”), effective at the opening of trading on June 26, 2026. Reverse Stock SplitThe Reverse Stock Split will be effective, and the Common Shares will begin trading on a split-adjusted basis on the Nasdaq Capital Market (“Nasdaq”), at the opening of trading on June 26, 2026, under the existing trading symbol “RUBI.” The new CUSIP number for the CommonShares following the Reverse Stock Split will be Y1250N131. When the Reverse Stock Split becomes effective, every 25 issued and outstanding Common Shares will be automatically converted into 1 issuedand outstanding Common Share without any change in (i) the par value per share or (ii) the total number of Common Shares the Company isauthorized to issue. Details The Reverse Stock Split will not (i) affect any shareholder’s ownership percentage of Common Shares (except as a result of the cancellation offractional shares), (ii) have any direct impact on the market capitalization of the Company, or (iii) modify any voting rights or other terms of theCommon Shares. As of June 23, 2026, the Company had 15,126,008 outstanding Common Shares, which will be reduced to approximately605,040 Common Shares, to be adjusted for cancellation of any fractional shares. No fractional shares will be created or issued in connection with the Reverse Stock Split. Shareho