Legendary investor Bill Miller lost 90% of his fortune in the late 2000s. Bitcoin and Amazon stock have made him a billionaire.

• Bill Miller has become a billionaire thanks to Amazon and bitcoin.
• The value investor's Amazon stake made up 83% of his personal portfolio last year.
• Miller says his bitcoin holdings are now worth more than his Amazon position.
• See more stories on Insider's business page.

Bill Miller, a star fund manager who was brought to his knees during the financial crisis, has staged a remarkable comeback and become a billionaire thanks to Amazon and bitcoin.

The journalist William Green interviewed the value investor for his new book, "Richer, Wiser, Happier: How the World's Greatest Investors Win in Markets and Life," and for a recent Barron's article.

Miller beat the benchmark S&P 500 index for 15 straight years as the manager of the Legg Mason Value Trust. However, his fortunes soured when he made leveraged bets on Bear Stearns, Freddie Mac, and other hard-hit financial stocks in 2008 but the Federal Reserve failed to swoop in and help as much as he'd expected.

Miller's flagship fund tumbled 55% that year, and an investor exodus slashed his assets under management from about $77 billion to $800 million, Miller told Green. The heavy losses coupled with a recent divorce settlement meant Miller's personal fortune shrunk by about 90% in a matter of months.

Luckily for Miller, he had started investing in Amazon soon after it went public in 1997, and he'd boosted his stake in the e-commerce group after the dot-com bubble burst. Though he was forced to sell some of his shares when investors pulled money out of his funds in 2008, he also snapped up bullish call options on Amazon stock when it tanked that year.

Amazon shares, on a split-adjusted basis, have skyrocketed to about $3,300 from less than $40 in November 2008. Miller told Green last year that the position made up 83% of his personal portfolio and that he was likely the largest individual shareholder of Amazon "whose last name isn't Bezos" - excluding MacKenzie Scott, who divorced Amazon CEO Jeff Bezos and dropped his last name in 2019.

Miller's bitcoin bet has surpassed his Amazon stake in value, he told Green in the recent Barron's interview. He started buying when it cost $200 to $300 a coin, and his average cost is about $500, he said. Bitcoin has surged by more than 600% since the start of last year, to about $50,000, suggesting Miller has scored a roughly 10,000% gain on his investment.

Miller told Green that thanks to his Amazon and bitcoin wagers, he's now a billionaire.

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The Miller Value Partners chief remains bullish on both assets. He expects Amazon stock to double in the next three years as the company expands its cloud-hosting, advertising, business-to-business, and private-label operations. He's also confident that bitcoin will rise tenfold as demand outstrips supply and investors recognize it's "far superior to gold," he told Green.

While Miller managed to hold Amazon and bitcoin through their highs and lows in recent years, his fund virtually eliminated its GameStop stake in 2018. If his team hadn't given up on the video-game retailer, its stake would have been worth $800 million at the height of the short squeeze in January and more than $250 million today.