This Billionaire's Biggest Holding Is Up 80% Since April...and He Just Bought More. Could It Double From Here?

Key Points

• Stephen Mandel's Lone Pine Capital has bought more shares of electricity company Vistra Corporation.

• Vistra's stock is up more than 875% over the last five years, making it Lone Pine's No. 1 holding.

• Skyrocketing electricity demand and limited supply may push the stock even higher.

• 10 stocks we like better than Vistra ›

You know a billionaire investor must be good when other billionaire investors compliment him, and Stephen Mandel has been called "probably the greatest analyst of all time" by fellow billionaire hedge fund founder Julian Robertson.

Mandel's Lone Pine Capital has more than $14 billion under management, and it just reported its latest buys. In a surprise move, it increased its stake in an under-the-radar energy company by 40.5%, even though that company's stock is already up 80% since April.

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Here's what Vistra Corporation (NYSE: VST) does, and why Mandel's new No. 1 holding might soar even higher.

Image source: Getty Images.

We've got the power

Vistra is the largest competitive power generator in the U.S., with approximately 41,000 megawatts of generation capacity. That capacity primarily consists of natural gas generation plants (59% of capacity), but includes a significant amount of coal (21%) and nuclear (16%) production capacity as well. Just 4% of its generation capacity comes from renewables other than nuclear. Vistra's plants are primarily located in Texas, Illinois, and Ohio, with smaller presences in California, the Mid-Atlantic, and New England.

As a "competitive" power generator, Vistra differs from a regulated utility. It's able to sell the electricity it generates on the wholesale market to utilities or other entities to meet the needs of their customers. Vistra also owns several retail electricity brands that can sell its power directly to residential or commercial customers in certain regions. If you've ever looked into switching to an electricity provider other than your local utility, you might have considered one of Vistra's subsidiaries like U.S. Gas & Electric or Dynegy. Vistra currently serves about 5 million retail customers in 16 states.

A surging share price

Before 2024, Vistra was a pretty unexciting company from an investment standpoint. It ran its plants, sold its power to its regular customers, and made a few investments in renewable energy and battery storage projects. In 2024, however, the stock suddenly got very exciting, with its price soaring 257.9% for the calendar year. It eased off its highs in early 2025, but starting in April it went on another tear, and is up 80% since then. Over the past five years, shares have risen more than 875%.

Lone Pine has timed its Vistra investments impeccably well. It first bought shares of the company in Q1 2024 -- right at the beginning of the stock's meteoric rise. Its most recent investment of 1.9 million shares was in Q2 2025, at or near the stock's 2025 low point. Those shares are now collectively worth $1.25 billion, making it Lone Pine's No. 1 holding at 8.92% of the portfolio and dethroning Meta Platforms (NASDAQ: META) from the top spot.

Juicing future returns

The sudden rise in Vistra's share price is due to simple supply and demand.

After staying flat for more than a decade, demand for electricity in the U.S. is suddenly skyrocketing thanks in part to power-hungry data centers and artificial intelligence (AI) applications. Meanwhile, because new electricity generation facilities require years to plan, construct, and bring online, supply is limited. As a result, wholesale and retail electricity prices are rising, which benefits Vistra as both a wholesaler and a retailer.

Just 4% of Vistra's generation portfolio comes from non-nuclear renewables. Because the Trump Administration has promoted nuclear power over solar and wind energy, Vistra's operations are unlikely to be seriously hurt by policy changes like those that have derailed a number of planned solar and wind generation projects. Indeed, in its most recent quarter, Vistra was granted a 20-year license extension for its Perry Nuclear Plant, which had been set to shut down next year. Now all six of Vistra's nuclear plants are licensed through at least 2036, allowing the company to continue to benefit from the nuclear production tax credit even as other renewable energy tax credits expire.

Because solar and wind projects account for the vast majority of new electricity generation in the U.S., any delays in bringing them online will almost certainly result in additional near-term capacity constraints. That would drive additional demand for Vistra's existing generation capacity. This might not be good for ratepayers, but it's likely to improve Vistra's fortunes over the short term and keep its stock moving upward as well.

John Bromels has positions in Meta Platforms. The Motley Fool has positions in and recommends Meta Platforms. The Motley Fool has a disclosure policy.