Warren Buffett's big Amazon investment is finally paying off, 8 months after he lamented not buying sooner

• Warren Buffett spent years watching Amazon soar from the sidelines, before his holding company Berkshire Hathaway started purchasing shares earlier this year.
• Shares skyrocketed Friday, with Amazon hitting a $1 trillion market capitalization for the second time in its history.
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Before his holding company, Berkshire Hathaway, bought shares in Amazon this year, Warren Buffett had spent years ruing not buying them earlier on.

But Buffett is surely glad Berkshire bought before Amazon's most recent earnings report. The company beat Wall Street expectations on both revenue and profit Thursday, sending the company past a $1 trillion market capitalization as trading opened Friday.

Buffett announced Berkshire had bought Amazon stock last May. He discussed the investment in a CNBC interview, explaining that though Buffett himself didn't execute the buy: "I'm a fan, and I've been an idiot for not buying."

By August, Berkshire had raised its stake in Amazon by 11%, according to a regulatory filing reflecting the company's holdings as of the second quarter.

Shares spiked as much as 9.89% Friday. It was the second time in Amazon's history that it surpassed the trillion-dollar valuation. The first time was in 2018, before Buffett had bought.