Mike Lynch, the tech billionaire and founding investor of U.K.-based legal artificial intelligence company Luminance, was declared missing at sea early Monday when the 184-foot superyacht Bayesian he was on sank in a storm off the coast of Sicily.

Lynch, 59, is one of six people still missing. His wife, Angela Bacares, was one of 15 rescued, Legaltech News confirmed with a source close to the company.