BOSTON: Five people who were aboard submersible that went missing while on an expedition to explore wreckage of Titanic did not survive, according to company that arranged trip.

Passengers on 21-foot sub were British businessman Hamish Harding; Pakistani businessman Shahzada Dawood and his teenage son, Suleman; French explorer Paul-Henri Nargeolet and Stockton Rush, CEO of OceanGate, company that operates vessel.

"We now believe that our CEO Stockton Rush, Shahzada Dawood and his son Suleman Dawood, Hamish Harding and Paul-Henri Nargeolet have sadly been lost," OceanGate said in statement to CBS News.

Harding was chairman of company called Action Aviation, which sells aircraft to Fortune 100 companies, international corporations, heads of state and people in entertainment and sports industries, according to its website.

British businessman is referred to as billionaire in British press, but Forbes magazine noted that he's not included on its list of world's richest people.

Shahzada Dawood, who was 48 was Vice Chairman of Dawood Hercules, an investment and holding company based in Karachi, Pakistan.

Dawood Hercules is part of Dawood Group, family business for more than century, according to his biography at SETI Institute, where he also served on board. Dawood was heir to one of Pakistan's largest family fortunes, according to New York Times.

Dawood was resident of UK with his wife and two children, Suleman and daughter Alina, SETI Institute noted. He was also an "Ardent animal lover" and had master's degree in global textile marketing from Philadelphia University in US and law degree from Buckingham University in UK.

Suleman Dawood was 19 years old, according to UK's Daily Mail. He was science fiction fan and also enjoyed solving Rubik's Cubes and playing volleyball, according to DH Group and Engro Corporation, part of Dawood Hercules Group.

Nargeolet was known as Titanic expert, according to OceanGate website. He led six expeditions to ship's wreckage site and was known as "Titanic's Greatest Explorer," company said.

Nargeolet was also director of underwater research for RMS Titanic, an American company that owns salvage rights to wreck and operates exhibits featuring artifacts from ship. About 30 million people have visited its exhibits, according to company.

Rush, CEO of company running expedition, was also sub's pilot. When he was 19, Rush was youngest person to become jet transport-rated pilot when he earned DC-8 Type/Captain's rating at United Airlines Jet Training Institute, according to his biography at OceanGate.