“I would expect the market for next season to be bulging,” Mr Henderson said yesterday after the leading British bookmaker maintained a reduced profit forecast for the year.
William Hill lost about £2 million (€2.5m) on the Premier League after having to pay out on 25 wagers placed on Leicester at long odds.
The success of such a big outsider has generated headlines around the world, and the publicity is likely to benefit bookmakers as fans bet on their team to pull off the feat next season.
“It was similar to Dettori Day,” Mr Henderson said, referring to the day in 1996 when jockey Frankie Dettori won all seven races at an Ascot race meeting at combined odds of more than 25,000/1, costing the betting industry more than £30m.
William Hill’s net revenue fell 3% in the 17 weeks to the end of April, hurt by the industry’s worst ever Cheltenham Festival in March and unfavourable soccer results in Europe.
The company continues to expect 2016 operating profit of £260m-£280m, a forecast it reduced in March after new rules made it easier for online gamblers to take a breather from their betting accounts.
Leicester City fans will not have the chance to back their heroes at such fanciful prices next season.
William Hill has them at only 25/1 to repeat its success, while the odds of the club being relegated from the top tier have lengthened to 33/1.