The 33-1 success of Silver Birch in the John Smith's Grand National had the major bookmakers declaring the biggest betting day of the year a "bookies' benefit".
A major last-minute gamble on Monkerhostin forced his odds into 8-1 from the 25-1 available in the morning, but that went astray when he refused at the seventh.
Along with Joes Edge, Point Barrow and Hedgehunter, none of the well-backed horses reached the frame.
Coral's Simon Clare said: "The 2007 National can only be described as a major 'bookies' benefit'."
William Hill's Ben Clarke added: "The Irish stranglehold on the Grand National continues and this horse will have dented the coffers of our shops in Ireland.
"However, in what was the most open National in a decade and with none of the fancied horses making the frame, it's like Christmas come early."
Paddy Power said: "Silver Birch seemed to slip under the radar for most Irish Punters, who were more keen on Point Barrow and Hedgehunter.
"It's been a very lucky get off for us as either of those boys winning or the furiously gambled Monkerhostin would have cost us dearly."
Damian Walker of totesport said: "There may have been record temperatures on Grand National Day, but it was the punters who were left out in the cold by this result.
"Over £250m (€366) was gambled on the National and a fair portion of that will stay with the bookmakers."
Ladbrokes' David Williams said: "Silver Birch was a decent result. With turnover up significantly up on last year and the placed horses going in our favour we are not complaining."
Silver Birch was handed a quote of 25-1 for next year's race by Ladbrokes.
The crowd figure of 68,100 was down on last year's figure of 69,680.