What is the largest prize fund offered for a single race?

What is the largest prize fund offered for a single race?  Until fairly recently, the Dubai World Cup, a Group One race run over 2,000 metres, or approximately a mile and a quarter, on dirt at Meydan Racecourse in Dubai, United Arab Emirates in late March each year, was the most valuable horse race in the world. Establised in 1996, Sheikh Mohammed bin Rashid Al Maktoum, Ruler of Dubai, the Dubai World Cup still offers a total prize fund of £9.25 million, of which £5.69 million goes to the winner.

However, since 2020, the most valuable horse race in the world has been the Saudi Cup, a conditions race run over 1,800 netres, or approximately nine furlongs, again on dirt, at King Abdulaziz Racetrack in Riyadh, Saudi Arabia in late February. The total prize fund for the Saudi Cup is £15.4 million, with £7.5 million, or just under half, reserved for the winner. The positioning of the Saudi Cup on the calendar is deliberate, insofar as it allows participants to contest the Dubai World Cup, four weeks later. The most recent winner, Mishriff, trained by John Gosden, ran at the Dubai World Cup Meeting, but opted for, and won, the Dubai Sheema Classic. run over a mile and a half and worth a mere £2.2 million to the winner, rather than the Dubai world Cup itself.