C3is Inc. filed a Form 6-K with the U.S. Securities and Exchange Commission on November 9, 2026, disclosing that the company effected a one-for-5 reverse stock split of its common stock, with the split becoming effective at 11:59 p.m. Eastern time on November 8, 2026.

Key Highlights

  • Split ratio: The company effected a one-for-5 reverse stock split of its issued and outstanding shares of common stock, par value $0.01 per share.
  • Share count reduction: Outstanding shares of common stock were reduced from approximately 4.2 million shares to approximately 0.84 million shares.
  • Trading commencement: Common stock began trading on a split-adjusted basis on the Nasdaq Capital Market as of the opening of trading on November 9, 2026.
  • New CUSIP: The post-reverse split common shares carry a new CUSIP number, Y18284508, and continue to trade under the symbol "CISS."
  • No fractional shares: No fractional shares were issued; stockholders who would otherwise hold a fractional share received a cash payment in lieu of such fractional share.
  • Warrant and preferred stock adjustments: Outstanding warrants and Series A Convertible Preferred Stock will be proportionately adjusted to reflect the reverse stock split, including further price adjustments tied to a ten-trading-day volume weighted average price window.

C3is Inc. Reverse Split Details and Impact on Securities

According to the filing, C3is Inc., a Greece-based shipping company whose common stock trades on the Nasdaq Capital Market under the symbol "CISS" (NASDAQ:CISS), filed an amendment to its Restated Articles of Incorporation on November 6, 2026, to authorize the reverse stock split. The split became effective at 11:59 p.m. Eastern time on November 8, 2026, and the company's shares began trading on a split-adjusted basis at the market open on November 9, 2026. The filing states that the par value and other terms of the company's shares of common stock were not affected by the reverse stock split.

The filing further discloses that the exercise price of the Class B-1, B-2, C-1, and C-2 Warrants, and the conversion price of the Series A Convertible Preferred Stock, will be further adjusted to the lowest daily volume weighted average price during the period covering five consecutive trading days immediately preceding and five consecutive trading days following the effective time of the reverse split, provided that adjusted price is lower than the then-current exercise price. The Class B-1 and C-1 warrants are also described as exercisable pursuant to an alternative zero cash exercise exchange option. The filing states that the aggregate exercise price of the warrants as of their original issuance date will remain unchanged following adjustments to the number of shares issuable upon exercise.

The report on Form 6-K is incorporated by reference into the company's Registration Statement on Form S-8 (Reg. No. 333-273306), filed on July 18, 2023, and its Registration Statement on Form F-3 (Reg. No. 333-285135), filed on February 21, 2025, according to the filing. The report was signed by Nina Pyndiah, Chief Financial Officer of C3is Inc., on November 9, 2026.

What Was Disclosed

C3is Inc. disclosed the completion of a one-for-5 reverse stock split effective November 8, 2026, reducing outstanding common shares from approximately 4.2 million to approximately 0.84 million, with related adjustments to warrants and Series A Convertible Preferred Stock, and a new CUSIP number assigned to the post-split shares.