The French coastguard on Tuesday searched for Pierre Agnes, the chief executive of US surfwear retailer Boardriders Inc, after his 36-foot (10.97 m) sailboat was found washed up on the country's Atlantic coast.
Rescuers were scouring the Bay of Biscay waters off Hossegor, a well-known surfing resort from where the 54-year-old Agnes set sail early in the morning, the local Landes prefecture said.
Agnes sent a message to port authorities indicating that he was delaying his return because of thick fog. His beached boat was later found empty not far from Hossegor.
"An air and sea search operation is underway," the Landes prefecture said in a statement, adding that two helicopters and two boats were involved in the rescue operation.
Winds were light, the prefecture added, but waves as high as eight feet were hampering visibility.
Boardriders, which is 85% controlled by US private equity firm Oaktree Capital, owns the Quicksilver, Roxy and DC Shoes brands.
Boardriders Inc announced on January 5 that it had agreed to buy Australia's Billabong International Ltd in a deal that valued the company at A$ 197.7mn ($159.92mn).