2 still missing from Mike Lynch's sunken yacht in Sicily
On Wednesday four bodies were retrieved from the wreck and transported to nearby hospitals, in the city of Palermo.
A source said a fifth body might have been located late on Wednesday, but the fire brigade and the coast guard, overseeing the operations, did not confirm this.
Italian authorities did not officially identify the corpses, but Britain's Daily Telegraph reported that two of the dead were Lynch and his 18-year-old daughter. Italy's Corriere della Sera said the only bodies identified so far were Morgan Stanley banker Jonathan Bloomer and U.S. lawyer Chris Morvillo.
The British-flagged Bayesian, a 56-meter-long superyacht carrying 22 passengers and crew, was anchored off the port of Porticello, near Palermo, when it disappeared beneath the waves in a matter of minutes after a fierce storm struck.
Fifteen people, including Lynch's wife, managed to escape the boat before it capsized, while the body of the onboard chef, Canadian-Antiguan national Recaldo Thomas, was found near the wreck hours after the disaster.
Operations have been challenging due to the depth and the narrowness of the places that the divers are scouring, the fire brigade said in a statement.
It compared the efforts to those carried out, on a larger scale, for the Costa Concordia, the luxury cruise liner that capsized off the Italian island of Giglio in January 2012, killing 32 people.
Unsinkable
The disaster has baffled naval marine experts who said such a vessel, built by Italian high-end yacht manufacturer Perini and presumed to have top-class fittings and safety features, should have been able to withstand such weather.
Prosecutors in the nearby town of Termini Imerese have opened an investigation and authorities have started questioning passengers and witnesses.
The captain and crew have made no official comment on the disaster.
Giovanni Constantino, CEO of the Italian Sea Group TISGR.MI, which includes Perini, said the Bayesian was "one of the safest boats in the world" and basically unsinkable.
He added that he believed the disaster was caused by a chain of human mistakes and that the storm had been expected, in interviews with Italian media.
"The ship sank because it took on water, from where investigators will have to say," Costantino told television news program TG1 late on Wednesday.
Citing data from the yacht's automatic tracking and based on available footage, Costantino said it took 16 minutes from when the wind began buffeting the yacht and it began taking on water for it to sink.
Costantino said the Milan-listed group had suffered "enormous damage" to its reputation, with shares falling 2.5% since the disaster.