[6-K] Rubico Inc. Current Report (Foreign Issuer)

Rhea-AI Filing Summary

Rubico Inc. furnished a Form 6-K noting a press release and updating its capital structure. The company reported 40,827,280 Common Shares issued and outstanding as of November 13, 2025, reflecting issuances from its recent public offering and warrant exercises.

The filing also outlines conditional share issuance tied to warrants: if all remaining Class A Warrants are exercised on a zero cash basis after the second warrant reset date on November 18, 2025, 15,674,560 additional Common Shares would be issued. If all remaining Representative Warrants are exercised on the same basis after that date, a further 1,863,052 Common Shares would be issued.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13A-16 OR 15D-16 UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of November 2025

Commission File Number: 001-42684

RUBICO INC.

(Translation of registrant’s name into English)

20 Iouliou Kaisara Str
19002 Paiania

Athens, 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 ☒ Form 40-F ☐

INFORMATION CONTAINED IN THIS FORM 6-K REPORT

On November 12, 2025, the Registrant issued a press release, a copy of which is attached hereto as Exhibit 99.1.

As of November 13, 2025, Rubico Inc. (the “Company”) had 40,827,280 common shares, par value $0.01 per share (the “Common Shares”), issued and outstanding, which included Common Shares issued upon the exercise of the Class A Warrants to purchase one Common Share (the “Class A Warrants”) and warrants issued to Maxim Group LLC (the “Representative Warrants”), following the Company’s recent public offering of Common Shares, Class A Warrants and Representative Warrants.

If all of the remaining Class A Warrants are exercised on a zero cash basis after the second warrant reset date on November 18, 2025 (the “Second Reset Date”), there will be 15,674,560 additional Common Shares issued and outstanding. If all of the remaining Representative Warrants are exercised on a zero cash basis after the Second Reset Date, there will be an additional 1,863,052 Common Shares issued and outstanding. See our Current Report on Form 6-K, filed with the U.S. Securities and Exchange Commission on November 7, 2025, for the description of the Class A Warrants.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	Rubico Inc.
Date: November 14, 2025	By: /s/ Nikolaos Papastratis
	Nikolaos Papastratis
	Chief Financial Officer

FAQ

What is Rubico Inc. (RUBI) reporting in this Form 6-K?

It furnished a press release and updated its share count and warrant-related potential issuances.

How many shares of RUBI were outstanding?

40,827,280 Common Shares were issued and outstanding as of November 13, 2025.

How many shares could Class A Warrants add for RUBI?

If all remaining Class A Warrants are exercised on a zero cash basis after November 18, 2025, 15,674,560 additional shares would be issued.

How many shares could Representative Warrants add for RUBI?

If all remaining Representative Warrants are exercised on a zero cash basis after the second reset date, 1,863,052 additional shares would be issued.

What is the 'second warrant reset date' for RUBI warrants?

The second reset date is November 18, 2025, after which the stated zero cash exercises are contemplated.

What recent activity influenced RUBI’s share count?

A recent public offering of Common Shares, Class A Warrants, and Representative Warrants, with some warrants already exercised.