Swiss Re, the major insurer of the World Trade Centre, has claimed in a US court that WTC owner Larry Silverstein had "a post-loss fantasy" that insurers should pay him for two events.
The Court of Appeals in New York heard yesterday that Swiss Re said his hiring of a top PR consultant after the 11 September attacks could prove Silverstein's "fantasy".
Also, Swiss Re claimed Silverstein's risk manager acknowledged that $3.2bn (£1.9bn) was the specified limit of coverage available.
The brief said: "Silverstein concocted a legal strategy to 'get me two events' after recognising that he had insured the World Trade Centre for substantially less than its full replacement value."
In response, a spokesman for Silverstein said: "The only hoax we see here is the one being perpetrated by Swiss Re.
"As we have said over and over, this was the largest insurance programme ever put together for a single group of buildings and the coverage was more than twice what the Port Authority itself carried for the trade centre."
The appeal will decide the difference between a $3.2 (£1.9bn) and a $6.7bn (£4bn) payout.