Rubico Inc美股招股说明书(2025-11-26版)

PROSPECTUS SUPPLEMENT NO. 3(TO PROSPECTUS DATED NOVEMBER 4, 2025) 12,315,270 Units,Each Unit Consisting of One Common Share or One Pre-funded Warrant to Purchase One Common Share and One Class A 615,763 Representative Warrants (and up to 12,315,270 Common Shares Underlying the Pre-funded Warrants, up to 49,261,080 Common Shares Underlying theClass A Warrants and up to 2,463,052 Common Shares Underlying the Representative Warrants) RUBICO INC. This is a supplement (the “Prospectus Supplement”) to the prospectus, dated November 4, 2025 (as supplemented or amendedfrom time to time, the “Prospectus”) of Rubico Inc. (the “Company”), which forms a part of the Company’s Registration Statement on This Prospectus Supplement is being filed to update and supplement the information included in the Prospectus with theinformation contained in the Company’s Report on Form 6-K, furnished to the U.S. Securities and Exchange Commission (the This Prospectus Supplement should be read in conjunction with, and delivered with, the Prospectus and is qualified byreference to the Prospectus except to the extent that the information in this Prospectus Supplement supersedes the information This Prospectus Supplement is not complete without, and may not be delivered or utilized except in connection with, theProspectus, 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 Prospectusfor a discussion 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 ordetermined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense. The date of this prospectus supplement is November 26, 2025. UNITED STATES SECURITIES AND EXCHANGE COMMISSIONWashington, D.C. 20549 FORM 6-K REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13A-16 OR 15D-16 UNDER THE SECURITIESEXCHANGE ACT OF 1934 For the month of November 2025 Commission File Number: 001-42684 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☒Form 40-F☐ On November 25, 2025, the Registrant issued a press release, a copy of which is attached hereto asExhibit 99.1. SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to besigned on its behalf by the undersigned hereunto duly authorized. Rubico Inc. Date: November 26, 2025 By: /s/ Nikolaos PapastratisNikolaos PapastratisChief Financial Officer Rubico Inc. Announces Time Charter Extensions and Contracted Revenue Backlog of $120.8 Million ATHENS, Greece, November 25, 2025 (GLOBE NEWSWIRE) -- Rubico Inc. (NASDAQ: RUBI) (the “Company”), an internationalowner and operator of modern, fuel efficient "ECO" tanker vessels, announced today that it entered into agreements with the time Specifically, both vessels will continue earning a gross daily hire rate of $32,850 until 11 January 2027 and thereafter, and for 4 years,they earn a gross daily hire rate of $29,990. All other terms will remain as per the current time charter contracts, including the charterer’s option to extend each time charter fortwo additional years at a gross daily rate of $34,750 for the first optional year and $36,750 for the second optional year. Following this About the Company Rubico Inc. is a global provider of shipping transportation services specializing in the ownership of vessels. The Company is aninternational owner and operator of two modern, fuel efficient, eco 157,000 dwt Suezmax tankers. The Company is incorporated under the laws of the Republic of the Marshall Islands and has executive offices in Athens, Greece. TheCompany's common shares trade on the Nasdaq Capital Market under the symbol “RUBI”. Please visit the Company’s website at:https://rubicoinc.com/ Forward-Looking Statements Matters discussed in this press release may constitute forward-looking statements. The Private Securities Litigation Reform Act of1995 provides safe harbor protections for forward-looking statements in order to encourage companies to provide prospectiveinformation about their business. Forward-looking statements include statements concerning plans, objectives, goals, strategies, future The Company desires to take advantage of the safe harbor provisions of the Private Securities Litigation Reform Act of 1995 and isincluding this cautionary statement in connection with this safe harbor legislation. The words “believe,” “anticipate,” “intends,”“estimate,” “forecast,” “project,” “plan,” “potential,” “may,” “should,” “expect” “pending” and similar expressions identify forward-looking statements. The forward-looking statements in this press release are based upon various assumptions, many of which arebased, in turn, upon furthe