C3is shares surge 28.95% intraday after SEC filing reveals Imperial Petroleum's 81.9% ownership.

C3is Inc. surged 28.95% intraday following an SEC filing revealing Imperial Petroleum Inc. owns 81.9% of the company. The disclosure, which updated beneficial ownership to 9.9 million shares post-reverse stock split, highlighted management ties between the two Greece-based shipping firms, including shared directors and Harry N. Vafias’s dual roles as chairman of both companies. This ownership structure signaled potential strategic alignment and investor confidence, despite C3is trading near its 52-week low. The move contradicted recent weak performance, including an 8.43% intraday decline earlier in the session, suggesting the filing triggered a reversal in sentiment. While fleet expansion and revenue growth were cited in older reports, the immediate catalyst was the ownership transparency and management overlap disclosed in the SEC filing.