Fears grow for Quiksilver chief executive after boat found overturned on remote French beach

Pierre Agnes was last seen setting out in rough seas on Tuesday morning

The speedboat belonging to Quiksilver's CEO Pierre Agnes on the beach of Hossegor, southwestern France (AP)

Fears are growing for the multi-millionaire boss of American sports giant Quiksilver after his empty powerboat was found upside down on an isolated French beach.

Pierre Agnes, the 54-year-old father of three who is the company's CEO, was reportedly last seen setting out in rough seas early on Tuesday morning.

The Frenchman was alone on board the 11 metre 'Mascaret III' as it headed off into the Atlantic close to the seaside resort of Biarritz.

The port authority of the Atlantic beach town of Capbreton said the search was launched after Mr Agnes' empty boat was found washed up Tuesday in nearby Hossegor.

Maritime authorities said two boats and three helicopters are involved in the search.

The area is known for intense, sometimes dangerous waves that are prized by surfers.

Mr Agnes had said he was going on a solo fishing expedition at Capbreton. His last recorded call was to the local French maritime authorities, saying he was 'postponing my trip home' because of thick fog.

After friends and family were unable to contact him, a Mayday alert was launched.

Two speedboats and three helicopters were used to try and fined Mr Agnes, who was officially declared “Missing At Sea”.

A ship in the area was also involved in the search.

Mr Agnes is a former international surfer for France who joined Quiksilver 30 years ago.

In March 2015 he became became CEO of the brand, which was founded in Torquay, Australia, in 1969 before moving to the West Coast of America.

Soon after Mr Agnes took over, Quiksilver changed its name to Boardriders, as it took the Roxy and DC Shoes brands under its corporate umbrella. It is currently involved in an ambitious bid for Australian rival Billabong, in a deal that would significantly increase its multi-billion turnover.

Despite being heavily involved in his worldwide business, Mr Agnes is known for spending as much time as possible in south west France, and for shunning publicity.

AP contributed to this report