Bookies toasted Neptune Collonges' win after punters laid millions on Seabass in the run up to the race to make it joint favourite with Synchronised.
Fred Done, chairman of bookmaker Betfred, said:
Paying out on Neptune Collonges' National victory is a drop in the ocean compared to the fortune I would have had to shell out if Seabass would have won.
Katie Walsh winning the world's biggest race could have cost me well over a million quid.
One of the most dramatic Grand Nationals in memory, with a runaway horse and two false starts, ends with the deaths of two horses.
A gallery of the good, bad and the just plain odd hats from Ladies Day at the 2012 Grand National in Aintree.