Surf legend Kelly Slater has already given a tribute to Mr Agnes and while he was still "praying for a miracle", he indicated that he thought the Quiksilver CEO was dead by speaking about him in past tense.
Pierre Agnes, chief executive of Boardriders, which owns brands including Quiksilver, Roxy and DC Shoes, set sail from the French surfing resort of Hossegor at around 7.30am on Tuesday. "We are concentrating on working with the local authorities on the search and rescue effort and supporting Pierre's family".
"An air and sea search operation is underway", the Landes prefecture said in a statement.
The French coastguard have been unable to determine whether Mr Agnès was alone on the boat. He lives in Capbreton, his hometown, with his wife and three children.
Quiksilver, which was founded in Australia, makes clothing for surfers and surfing aficionados.
Quiksilver's parent company, Boardriders Inc., now controls an extensive portfolio of action sports brands including Quiksilver, Roxy, DC Shoes, Billabong, RVCA, Element, VonZipper, and Xcel.
Their popularity peaked in the 1990s, when their board shorts were a common sight on beaches from Bondi to Hawaii.
It posted losses in north America and filed for bankruptcy protection, although its European and Asian businesses remained profitable.
L.A. -based Oaktree Capital Management owns most of Boardriders.