May funded his gambling by stealing more than £1.3m from the outdoor clothing company Sealskinz, the court heard, spending almost all of it with online gambling firms.
Betting records show that he lost more than £600,000 with Betway between January 2017 and January 2019, and the court heard that £461,000 of it came from stolen funds.
The firm only asked him for evidence of his wealth after he had lost £116,000. It accepted financial statements, which May told the Guardian he had doctored using Microsoft Paint.
In one three-week spree that followed, winning bets took his account balance up to £1.2m, which he then lost over 33 days.
The series of huge bets prompted no further intervention other than offers such as free bets and tickets to an England football match.
May also lost an estimated £437,000 with Betfair, part of the Flutter group that includes Paddy Power. The court heard that £268,000 of this was stolen.
During a lull when he stopped placing huge bets, a Betfair VIP manager sent him a message saying: “Long time no speak. I noticed you are depositing less than previously, is everything OK?”