Arguably, no data release carries more weight than the quarterly filing of Form 13Fs with the Securities and Exchange Commission. A 13F provides a concise snapshot of the stocks Wall Street's smartest money managers bought and sold in the latest quarter -- and Feb. 17 was the filing deadline for fourth-quarter trading activity.
With Warren Buffett now retired, attention turns to Wall Street's other prominent and highly successful billionaire investors, such as Stanley Druckenmiller at Duquesne Family Office. Duquesne's 13F shows its billionaire boss dumped shares of four scorching-hot artificial intelligence (AI) stocks -- Meta Platforms (META 2.43%), Sandisk (SNDK 5.39%), Seagate Technology (STX 2.27%), and Arm Holdings (ARM 4.41%) -- and nearly quadrupled his stake in another "magnificent" company.
Image source: Getty Images.
Billionaire Stanley Druckenmiller rings the register on several AI winners
Druckenmiller was a busy bee during the fourth quarter, with 16 holdings reduced in size and 31 previous positions exited entirely. This includes:
- Meta Platforms: 76,100 shares sold
- Sandisk: 166,235 shares sold
- Seagate Technology: 85,900 shares sold
- Arm Holdings: 167,900 shares sold
Profit-taking is the likeliest catalyst for this selling. The 62 positions in Duquesne's $4.5 billion investment portfolio at the end of 2025 have been held for an average of roughly 7.5 months. Druckenmiller has shown he's willing to ring the register when given the opportunity. Sandisk and Seagate enjoyed near-parabolic gains of 1,540% and 318%, respectively, over the trailing year.
NASDAQ: SNDK
Key Data Points
But there's also the possibility that Duquesne's billionaire chief sent these stocks packing due to concerns about an AI bubble.
Every game-changing technology since the advent and proliferation of the internet has endured an early stage bubble-bursting event. Although AI hardware adoption is robust, businesses aren't particularly close to optimizing AI solutions to maximize sales and profits.
In a May 2024 interview with CNBC, Druckenmiller stated, "AI might be a little overhyped now, but underhyped long term." Sandisk and Seagate would, presumably, be hit hard if the AI bubble bursts. Meta, which generates nearly 98% of its sales from ads on its world-leading social media platforms, and Arm Holdings, whose intellectual property royalties and licensing revenue extend well beyond AI chips, would likely sidestep the brunt of a potential bubble-bursting event.
Image source: Getty Images.
Duquesne's billionaire investor can't get enough of this trillion-dollar stock
On the other hand, Stanley Druckenmiller bought 28 new securities and added to 13 existing holdings in the December-ended quarter. No add looms larger than the 282,800 shares of Google parent Alphabet (GOOGL 1.35%)(GOOG 1.45%). Druckenmiller's purchase of the Class A shares (GOOGL) increased his fund's stake by 277%.
Like Meta, Alphabet has a rock-solid foundation in advertising to fall back on if the AI bubble bursts. Google is a virtual monopoly in global internet search, accounting for a 90% share of search traffic in January.
NASDAQ: GOOGL
Key Data Points
But the buzz about Alphabet centers on its incorporation of generative AI and large language model solutions into Google Cloud, the world's No. 3 cloud infrastructure platform by total spend. This high-margin operating segment delivered 48% sales growth in the fourth quarter and should become Alphabet's core cash flow driver in the coming years.
Alphabet's reasonably low forward price-to-earnings ratio of 23 has made it the "Magnificent Seven" stock to own in 2026.
