Bookmaker Ladbrokes said it was the biggest ever wager on Murray to win at the All England Club.
The gambler, who lives in London and wants to remain anonymous, will pick up £450,000 if Murray clinches a second Wimbledon title.
Meanwhile, a spokesman for William Hill said if Murray wins it will result in an industry pay-out of anything up to £10 million.
The Scot is currently 7/2 to win the tournament, second favourite behind Novak Djokovic who is the 7/4 favourite.
Rafael Nadal is 5/1 and Roger Federer is 11/2, William Hill said.
The spokesman added: "With our national football and cricket side in the doldrums we can really see the public piling in on Murray - we all know he can do it, he is perhaps the only British banker of the summer!"