Rubico Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 20-F

(Mark One)

OR

For the fiscal year ended December 31, 2025

OR

OR

Date of event requiring this shell company report: Not applicable

For the transition period from _____to _____

Commission file number:001-42684

Rubico Inc.

(Exact name of Registrant as specified in its charter)

(Translation of Registrant’s name into English)

Republic of the Marshall Islands

(Jurisdiction of incorporation or organization)

20 Iouliou Kaisara Str

19002 Paiania, Athens, Greece

(Address of principal executive offices)

Nikolaos Papastratis

Tel.+30 210 812 8107

Email: npapastratis@rubicoinc.com

20 Iouliou Kaisara Str

19002 Paiania, Athens, Greece

(Name, Telephone, E-mail and/or Facsimile number and Address of Company Contact Person)

Securities registered or to be registered pursuant to Section 12(b) of the Act:

Securities registered or to be registered pursuant to Section 12(g) of the Act: None

Securities for which there is a reporting obligation pursuant to Section 15(d) of the Act: None

Indicate the number of outstanding shares of each of the issuer’s classes of capital or common stock as of the close of the period covered by the annual report:

As of December 31, 2025,385,501 shares of common stock, par value $0.01 per share, and 100,000 Series D Preferred Shares, par value $0.01 per share, were outstanding.

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.☐Yes☒No

If this report is an annual or transition report, indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934.☐Yes☒No

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.☒Yes ☐No

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).☒Yes ☐No

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company that prepares its financial statements in accordance with U.S. GAAP, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards† provided pursuant to Section 13(a) of the Exchange Act.☒

† The term “new or revised financial accounting standard” refers to any update issued by the Financial Accounting Standards Board to its Accounting Standards Codification after April 5, 2012.

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report.☐

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements.☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b).☐

Indicate by check mark which basis of accounting the registrant has used to prepare the financial statements included in this filing:

If “Other” has been checked in response to the previous question, indicate by check mark which financial statement item the registrant has elected to follow.

If this is an annual report, indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

This annual report on Form 20-F (the “Annual Report”) and any other written or oral statements made by us or on our behalf may include forward-looking statements made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995, which reflect our current views with respect to future events and financial performance. Forward-looking statements include statements concerning plans, objectives, goals, strategies, future events or performance, and underlying assumptions and other statements, which are statements other than statements of historical facts. When used in this Annual Report, statements that are predictive in nature, that depend upon or refer to future events or conditions, or that include words such as “anticipate,” “believe,” “expect,” “intend,” “estimate,” “forecast,” “project,” “plan,” “potential,” “continue,” “possible,” “likely,” “may,” “should,” and similar words, phrases or expressions identify forward-looking statements, and the negatives of those words, phrases, or expressions, or statements that events, conditions, or results “can,” “will,” “may,” “must,” “would,” “could,” or “should” occur or be achieved and similar expressions in connection with any discussion, expectation, or projection of future operating or financial performance, costs, regulations, events, or trends identify forward-looking statements. The absence of these words does not mean that a statement is not forward-looking. Without limiting the generality of the foregoing, all statements in this Annual Report concerning or relating to estimated and projected earnings, margins, costs, expenses, expenditures, cash flows, growth rates, future financial results and liquidity are forward-looking statements. In addition, we, through our senior management, from time to time may make forward-looking public statements concerning our expected future operations and performance and other developments.

The forward-looking statements in this Annual Report are based upon various assumptions, many of which are based, in turn, upon further assumptions, including without limitation, management’s examination of historical operating trends, data contained in our records and other data available from third parties. Although we believe that these assumptions were reasonable when made, because these assumptions are inherently subject to significant risks, uncertainties and contingencies that are described more fully in “Item 3. Key Information—D. Risk Factors”, are difficult or impossible to predict and are beyond our control, we cannot assure you that we will achieve or accomplish these expectations, beliefs or projections.

In addition to these assumptions and matters discussed elsewhere herein and in the documents incorporated by reference herein, important factors that, in our view, could cause actual results to differ materially from those discussed in the forward-looking statements include the following:

Should one or more of the foregoing risks or uncertainties materialize, or should any of our assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements. Consequently, there can be no assurance that actual results or developments anticipated by us will be realized or, even if substantially realized, that they will have the expected consequences to, or effects on, us. Given these uncertainties, prospective investors are cautioned not to place undue reliance on such forward-looking statements. All forward-looking statements in this Annual Report are qualified in their entirety by the cautionary statements contained in this Annual Report.

Any forward-looking statements contained herein are made only as of the date of this Annual Report, and except to the extent required by applicable law or regulation we undertake no obligation to publicly update or revise any forward-looking statement or statements to reflect events or circumstances after the date on which such statement is made or to reflect the occurrence of unanticipated events. If one or more forward-looking statements are updated, no inference should be drawn that additional updates will be made with respect to those or other forward-looking statements. New factors emerge from time to time, and it is not possible for us to predict all or any of these factors. Further, we cannot assess the impact of each such factor on our business or the extent to which any factor, or combination of factors, may cause actual results to be materially different from those contained in any forward-looking statement.