Billionaire Stanley Druckenmiller Dumped Sandisk and Nearly Quadrupled His Position in a Virtual Monopoly That's Up Over 12,000% Since Its IPO

By Sean Williams – Mar 13, 2026 at 5:06AM ESTKey PointsForm 13Fs let investors track which stocks Wall Street's preeminent money managers bought and sold in the latest quarter.

Billionaire Stanley Druckenmiller jettisoned his fund's entire stake in NAND flash memory company Sandisk -- and profit-taking may be only part of the story. Meanwhile, a 282,800-share purchase of one of Wall Street's most influential businesses indicates conviction in this company's outlook.Although earnings season tends to garner most of the glory each quarter, few data releases are more important than quarterly filed Form 13Fs. A 13F provides investors with a way to track which stocks Wall Street's brightest money managers bought and sold in the latest quarter.

Billionaire Stanley Druckenmiller of Duquesne Family Office is among the most-followed (and active) money managers. During the fourth quarter, Duquesne's billionaire boss sold out of 31 stocks, reduced 16 holdings, added to 13 existing stakes, and opened 28 new positions. Perhaps most eyebrow-raising, Druckenmiller dumped his fund's entire position in storage solutions titan Sandisk (SNDK 5.59%) and nearly quadrupled his stake in a virtual monopoly that's skyrocketed 12,100% since its initial public offering (IPO) in 2004. Image source: Getty Images.

Billionaire Stanley Druckenmiller sent Sandisk to the chopping block On average, Druckenmiller has held the 62 securities in his fund's portfolio for 7.5 months. In the case of Sandisk, Druckenmiller's hold time was even shorter. After purchasing 166,235 shares in the third quarter, he sent every share to the chopping block during the fourth quarter. The most logical reason for this selling is simple profit-taking. Though we don't know precisely when Duquesne's chief investor purchased or sold Sandisk stock, we do know that it spent much of its time between $40 and $100 per share during the third quarter, and $110 to $240 per share in the fourth quarter. It's quite possible that Druckenmiller generated triple-digit returns in mere months from this stake. ExpandNASDAQ: SNDKSandiskToday's Change(-5.59%) $-36.61Current Price$618.82Key Data PointsMarket Cap$91BDay's Range$612.21 - $651.9952wk Range$27.89 - $725.00Volume48KAvg Vol17MGross Margin34.81% Sandisk's outperformance reflects the insatiable demand for NAND flash memory and solid-state drives in artificial intelligence (AI)-accelerated data centers. With memory in short supply, Sandisk has been enjoying premium pricing power. However, Druckenmiller dumping Sandisk may also signal skepticism toward the AI revolution. In a May 2024 interview with CNBC, he noted that "AI might be a little overhyped now, but underhyped long term." Every game-changing technology since the advent of the internet three decades ago has navigated an early stage bubble-bursting event. These bubbles are caused by investors overestimating the adoption or optimization of a new technology. We're likely still years away from businesses optimizing AI, suggesting Sandisk's parabolic rally may not be sustainable. Image source: Getty Images. Duquesne's billionaire boss is piling into this virtual monopoly On the other end of the spectrum, billionaire Stanley Druckenmiller added 282,800 shares of Google parent Alphabet (GOOGL 1.67%)(GOOG 1.69%). This purchase increased Duquesne's stake in the Class A shares (GOOGL) by 277% from Sept. 30. Alphabet's shares haven't rallied over 12,000% since its IPO by accident. These gains reflect its virtual monopoly in internet search and the growing importance of its cloud infrastructure services platform, Google Cloud. ExpandNASDAQ: GOOGLAlphabetToday's Change(-1.67%) $-5.15Current Price$303.55Key Data PointsMarket Cap$3.7TDay's Range$301.03 - $308.9452wk Range$140.53 - $349.00Volume54KAvg Vol34MGross Margin59.68%Dividend Yield0.28% According to GlobalStats, Google has accounted for an 89% to 93% share of global internet search traffic over the trailing decade. This sustainable moat ensures exceptional ad-pricing power and makes Google the go-to for businesses wanting to target large audiences with their message(s). Advertising is the foundational cash cow of Alphabet's business. However, Google Cloud is no slouch, either. The incorporation of generative AI and large language model solutions into the world's No. 3 cloud infrastructure services platform is reaccelerating its growth. Google Cloud's sales vaulted 48% in the fourth quarter from the prior-year period. With cloud margins handily outpacing advertising margins, Google Cloud is on pace to eventually become Alphabet's premier source of cash flow.Read NextMar 12, 2026 •By Lyle DalyIf I Had $5,000 to Invest in Artificial Intelligence (AI), I'd Put It in This StockMar 12, 2026 •By Geoffrey SeilerGot $5,000? 3 Tech Stocks to Buy and Hold for the Long TermMar 9, 2026 •By Lyle DalyNvidia vs. Alphabet: Which Stock Will Make You Richer?Mar 9, 2026 •By Prosper Junior BakinyBillionaire David Tepper Sold Nvidia Stock and Piled Into This AI Stock That's Up Nearly 200% in the Past 5 YearsMar 9, 2026 •By John BallardYou Don't Need Polymarket to Make a Winning Bet.

Just Buy This AI Stock.Mar 9, 2026 •By Sean WilliamsFor the First Time in 13 Quarters, Billionaire Chase Coleman's No. 1 Holding Isn't Meta Platforms or Microsoft -- but It Is a "Magnificent" StockAbout the AuthorSean Williams is a data-driven Motley Fool contributing analyst who's been investing for 27 years and has penned north of 15,000 articles. You'll find him at the intersection of politics and investing tackling macroeconomic topics of interest (Social Security and Donald Trump's economic/tax policies), analyzing which stocks billionaire investors (e.g., Warren Buffett) are buying and selling, and digging into how the world's most-influential businesses and trends -- everything from the evolution of artificial intelligence (AI) to the next stock split -- are changing Wall Street. He holds a B.A. in Economics from the University of California, San Diego.TMFUltraLongX@AMCScamStocks MentionedAlphabetNASDAQ: GOOGL$303.57(-1.66%)-$5.13AlphabetNASDAQ: GOOG$303.23(-1.68%)-$5.19SandiskNASDAQ: SNDK$618.82(-5.59%)-$36.61*Average returns of all recommendations since inception. Cost basis and return based on previous market day close.