C3is Inc. (the "Company") (NASDAQ:CISS) today announced that its board of directors has determined to effect a one-for-seven (1-for-7) reverse stock split of the Company's common stock, par value $0.01 per share.

The reverse stock split will take effect at 11:59 pm Eastern Time on April 26, 2026, and the Company's common stock will begin trading on a split-adjusted basis on The Nasdaq Capital Market ("Nasdaq") as of the opening of trading on April 27, 2026. The CUSIP number of Y18284300 will be assigned to the Company's common stock when the reverse stock split becomes effective.