Win or lose the Belmont Stakes, American Pharoah is expected to keep racing for the rest of the year.

At least that's the plan owner Ahmed Zayat has laid out after confirming the sale of breeding rights of his Kentucky Derby and Preakness winner to Coolmore's Ashford Stud near Versailles, Kentucky.

The value of the deal was not disclosed, but even before the announcement, Zayat's son, Justin, said the family had been inundated with offers, some for more than $US20 million ($A25.40 million).

"I will continue to own 100 per cent of the colt until he retires," Zayat told the Associated Press.

"I will make all of the racing decisions. If he runs in the Belmont, and God willing wins, and we're still fortunate, he will continue to race. This is not an issue whatsoever."

American Pharoah will be the favourite to win the Belmont on June 6 and become the first Triple Crown winner since Affirmed in 1978.

Zayat may be optimistic about running his horse after the Belmont, but there are no assurances in racing.

With so much money at stake at the breeding shed, Zayat could easily reconsider the risk of continuing to race - especially if American Pharoah wins the Belmont.

At the start of 2016, Coolmore calls all the shots and Zayat's take is the colt will be retired.

"It's unlikely he would race again (after this year)," Zayat said. "The values are too insane. It's just not economically feasible to continue."

Zayat said he will retain an interest in American Pharoah after he is retired, as he does with many of his stallions.

The breeding rights to Affirmed sold for $14.4 million in 1979. Based on that figure and adjusting for inflation, American Pharoah's value could be around $40 million.