American business tycoon John Stewart has declared he will go up to $6 million to buy super mare Imperatriz at the Magic Millions mares sale this month, revealing he could pull her out of retirement and continue racing if he buys her.

Stewart, who famously went to $9m on Winx’s Pierro filly last month and still lost out, says he is determined to buy “horses I like” and believes many talented horses are retired from racing too early with connections looking to cash in at the breeding barn instead.

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Starting with one horse in September last year, the Kentucky-based Stewart now has more than 100 on his books along with a 1000-acre farm to house his new “breed to race” operation called Resolute Racing.

American racehorse owner John Stewart (right).

Imperatriz is due to go under the hammer at Magic Millions on May 28 and Stewart believes the 10-time Group 1 winner could have more to offer on the racetrack should he be successful in bidding for the five-year-old.

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“She fits right in to what I am looking for,” Stewart told Racenet.

“She is on our list and there are a few more at that Magic Millions sale we are looking for.

“I think she goes for between $5m and $6m … $6m probably buys her and I would be willing to pay that for her.

“I know my friends at Coolmore want her to, they may be my friends, but if I want the horse I am buying it. She is a being sold as a broodmare prospect, even though I think she could still race. Their intention is to retire her, but we would talk to the trainers and see what they wanted to do.

John Stewart believes horses are retired too early these days. Picture: Vince Caligiuri — Getty Images.

“I think too many of these people are taking these horses out too early because of the breeding.

“If you go back 15 or 20 years ago, these horses run until they are eight years old or so. There is some good racing for them, a lot of these horses get more competitive. If they can run, I want to run them.”

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After buying a share in Magic Millions winner Storm Boy, Stewart, who owns a private equity firm, says he became hooked on Australian racing and purchased six yearlings at the Inglis Easter Sale earlier this year.

He also struck last week at the Inglis Chairman’s Sale, buying the Chris Waller-trained Tutta La Vita for $3.2m, who is on a Queensland Oaks campaign.

“When you buy mares, you have to wait until all the breeding is done before you have something to race,” Stewart said.

“I am a competitive person, so I don’t want to just sit around and wait, so I have been filling in the gaps with horses of racing age, especially if there are fillies with stakes-level potential.

“Instead of buying the horses for $700,000, $800,000 or $1m which are fine, I prefer to pay a bit more and get the one I really want.

“The only one I haven’t got is the Winx filly, I think I gave it a good go but.”