The chief executive of Boardriders, which this month agreed to add Billabong to its portfolio of surf and sportswear brands, has gone missing at sea, but his boat has been recovered from a beach on the French coast.
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.
Three helicopters and two boats were searching for Agnes while agents scoured the coast.
"His boat was recovered on the beach near his hometown and Pierre has not been heard from since", the company said in a statement.
Authorities from the Landes prefecture said winds were mild in the region, but waves nearing 2.5 metres in height were limiting visibility.
Jordan Clarkson Offered to Pistons for Avery Bradley
With a 14-6 start this season, the Detroit Pistons were one of the more surprising teams in the National Basketball Association . Bradley still remains one of the league's best perimeter defenders and is a career 37 percent shooter from the three-point line.
Rescue services were unable to say if the Frenchman had been alone.
Quiksilver, which was founded in Australia, makes clothing for surfers and surfing aficionados.
Quiksilver filed for bankruptcy in 2015.
Agnes recently oversaw a deal that brought Quiksilver together with rival surf brand Billabong under the Boardriders umbrella. It was bailed out by Oaktree Capital Management, a Los Angeles-based investment firm that specializes in buying companies in financial difficulties and turning them around.