The Yellow Sam betting coup was a successful sports betting coup, widely remembered within Irish and British thoroughbred horse racing.
It happened at Bellewstown on 26 June 1975, and was orchestrated by Barney Curley, an Irish professional gambler, philanthropist behind a charity for impoverished children in Zambia(which he set up after his son's death in 1995), former trainer, former Jesuit seminarian, failed pub owner, former pop group manager, and entrepreneur. By taking advantage of an under-handicapped horse and the lack of easy communications between the Bellewstown racing course and off-course bookmakers, Curley made a profit of over IR£300,000 (>€1.7m adjusted for inflation) – one of the largest betting coups in Irish history.
Barney Curley again made headlines when four horses linked to him won on 22 January 2014, and were estimated to have cost bookmakers "something in the region of £2million", reportedly just the latest of many successes since the Yellow Sam coup.
Yellow Sam was a "slow but steady" horse bought by Curley and was given his name from his father's nickname at the races. Curley instructed the horse's trainer, Liam Brennan, to train Yellow Sam specifically for the somewhat obscure annual National Hunt race at Bellewstown, featuring mostly amateur jockeys. To ensure that the horse would run at least once with a much lighter handicap than would normally be the case, Curley first ran the horse in a series of races on other tracks in unfavourable conditions.
Curley spent weeks developing the plan and putting people in place. On the day of the race, Yellow Sam's starting price was 20–1, but if large sums of money were being placed on the horse, that figure would drop quickly, drastically reducing the coup's potential take. It was for this reason that Yellow Sam was to race at Bellewstown specifically, as the track was serviced by just two telephone lines, one public telephone box and a private telephone line belonging to the Extel company which supplied racing data to betting shops. The Extel line was put out of use [probably cut] early in the day leaving just one telephone line available to communicate to the course bookies who determined the starting prices for the participants.