There have been plenty of press reports touting the Colombia international with a switch to Old Trafford after a report in Spanish newspaper Marca claimed that United were close to agreeing a deal.
Sky Bet cut the Red Devils from 11/1 to 6/5 to sign Falcao in the next transfer window but Ferguson has now played down the rumours.
"Do you honestly believe that?" he is quoted as saying on the club's official website.
"Really? It does amaze me that you come up with that one."