Billionaire Stephen Mandel Dumped His Fund's Entire Stake in Meta Platforms -- Meaning This AI Stock Is Lone Pine's New No. 1 Holding

You may not realize it, but one of the most important data releases of the entire quarter occurred last week. Feb. 17 marked the deadline for institutional investors with at least $100 million in assets under management to file Form 13F with regulators.

A 13F offers a concise snapshot of the stocks that were bought and sold in the latest quarter by Wall Street's savviest money managers, including billionaire Stephen Mandel of Lone Pine Capital. Mandel, whose hedge fund is known for its blend of value and growth stocks, completely jettisoned former top holding Meta Platforms (NASDAQ: META) during the fourth quarter and has since seen another industry-leading artificial intelligence (AI) stock become his No. 1 position.

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Lone Pine Capital's billionaire boss sent Meta Platforms packing

At the end of September, Mandel's fund held 1,322,260 shares of Meta, worth approximately $971 million (7.1% of Lone Pine's invested assets). By the end of 2025, every share of this social media titan had been sent to the chopping block.

Some of this selling likely stems from simple profit-taking. Meta had been a continuous holding for Mandel's fund since the third quarter of 2023. Over the last two years and change, shares have more than doubled. The average hold time for Lone Pine is only 16.5 months, as of Dec. 31, 2025, signaling that Mandel isn't afraid to cash in his chips when given the opportunity.

But there may be more to Meta's departure than just profit-taking.

In particular, Meta shares were clobbered in late October after the company's AI capital expenditure guidance came in ahead of Wall Street's expectations. While investors have been generally tolerant of aggressive spending on AI infrastructure, Mark Zuckerberg has been increasing his company's AI capex on a near-quarterly basis.

Nevertheless, Meta owns rock-solid social media assets that command top-dollar ad rates. Even if the bulk of Meta's AI investments are years away from meaningfully moving the needle, this looks to be a sale Mandel is likely to regret.

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Say hello to billionaire Stephen Mandel's new top holding: Taiwan Semiconductor

With Lone Pine completely exiting its stake in Meta Platforms, Mandel's fund has a new No. 1 holding: Taiwan Semiconductor Manufacturing (NYSE: TSM).

Even though Mandel has been reducing his fund's stake in world-leading chip fabricator TSMC, as Taiwan Semiconductor is more commonly known, over the last three years, the near-parabolic rise in its stock has made it Lone Pine's new top holding by market value.

TSMC's biggest growth driver is undoubtedly the AI revolution. Demand for graphics processing units (GPUs) is off the charts, prompting TSMC to expand its monthly chip-on-wafer-on-substrate capacity at a breathtaking pace. With demand for AI hardware outpacing supply, Taiwan Semiconductor has enjoyed a healthy backlog and substantial pricing power.

Just keep in mind that TSMC had a solid foundation long before "artificial intelligence" became Wall Street's favorite phrase. It remains a key supplier of advanced chips for smartphones, computers, and Internet of Things devices.

Mandel has likely also been attracted to TSMC's reasonably inexpensive valuation. A forward price-to-earnings ratio of 21 isn't egregious for a nearly $2 trillion company that's projected to grow its sales by 24% in 2027.

Sean Williams has positions in Meta Platforms. The Motley Fool has positions in and recommends Meta Platforms and Taiwan Semiconductor Manufacturing. The Motley Fool has a disclosure policy.