Warren Buffett bought his first stake in Amazon this week. But company stock isn’t the only thing Buffett wants from CEO Jeff Bezos.

The investing guru would get a transfusion of Bezos’ blood if he could, he jokingly told reporters during the Berkshire Hathaway annual shareholder meeting in Omaha, Nebraska.

Buffett described the digital shopping giant as an “absolute miracle” unlike anything else in the corporate world.

Bezos “kept looking at what was coming in and saw what was possible, and he’s unbelievable,” Buffett said.

Buffett invests in Amazon – ‘I’ve been an idiot for not buying’

He also reminisced about a time that he ran into Bezos a decade ago — before he was a household name and Amazon became an e-commerce powerhouse. Buffett may have remembered the encounter, but he didn’t immediately run out and buy stock. It’s not Berkshire style to bet on young startups.

“If you gave me the 100 top graduates of Stanford, Harvard business school, I wouldn’t know how to pick out the ones” that would become corporate masterminds, Buffett said. But “if you show me somebody that’s run a business for 30 years and has been knocking it out of the park, I can figure that one out.”

Until this week, Buffett’s Berkshire has never added Amazon shares to its esteemed portfolio. He told CNBC that he’d been an “idiot” for not doing it sooner — but it wasn’t his idea to change course.

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“One of the fellows in the office that manage money” made the decision, Buffett had said. He was referring to Berkshire Hathaway’s top investment managers Ted Weschler or Todd Combs, according to CNBC.

It’s not clear how much Berkshire has bet on Amazon. The exact amount will be disclosed in public filings later this month, Buffett said.