C3is shares surge 28.95% after-hours after SEC filing reveals Imperial Petroleum owns 81.9%.

C3is Inc. (CISS) surged 28.95% in after-hours trading following a Securities and Exchange Commission filing disclosing that Imperial Petroleum Inc. owns 81.9% of the company. The filing revealed Imperial Petroleum’s beneficial ownership of 9.9 million shares, reflecting adjustments to C3is’s preferred stock conversion price after a 1-for-20 reverse stock split. Additionally, management ties between the two companies—such as Harry N. Vafias, Imperial Petroleum’s CEO, serving as C3is’s non-executive chairman—highlighted strategic alignment, potentially boosting investor confidence. Despite C3is’s historically weak performance and proximity to its 52-week low, the ownership disclosure signaled potential for capital restructuring or operational synergy, driving the sharp after-hours rally. Other news, including future fleet expansion plans, did not align with the timing of the price movement.