Mike Lynch , a British tech entrepreneur, is one of several people missing after a luxury superyacht sank off the coast of Sicily, according to Italian officials.

Six people are still missing, including Lynch and three other British nationals, according to the Italian Coast Guard. A total of 22 people were aboard the vessel when it was hit by a severe thunderstorm early Monday morning, the coast guard said.

Lynch’s wife, Angela Bacares, was among the people who were rescued, according to a person familiar with the situation.

Karsten Borner , the captain of the boat that rescued survivors, told RAI TV that the “yacht tipped to its side and sank within a few minutes. It all happened in really little time.”

“After the storm was over we noticed that the yacht behind us was gone,” he said.

The British-registered Bayesian yacht was sailing off the northern coast of the Italian island near the capital Palermo, according to ship-tracking website MarineTraffic.

A person with knowledge of the matter said the yacht was likely owned by Lynch. It was managed by London-based brokers Camper & Nicholsons.

Lynch founded software company Autonomy in the 1990s, which was bought by American tech company Hewlett-Packard   for $11 billion in 2011 .

In 2018, the U.S. government charged Lynch with fraud, after Hewlett-Packard took an $8.8 billion write-down related to the deal and said it was duped into overpaying because of what it said appeared to be willfully inflated financial statements.

Lynch was acquitted of criminal charges in June, ending a nearly 13-year saga that began with a deal that has since been described as one of the worst in Silicon Valley history.

Write to Joseph Pisani at joseph.pisani@wsj.com , Costas Paris at costas.paris@wsj.com and Gareth Vipers at gareth.vipers@wsj.com