David Tepper trimmed his position in Micron and sold off his entire stake in Sandisk during the second quarter of 2026, according to Appaloosa Management's most recent 13F filing with the Securities and Exchange Commission.
Tepper founded Appaloosa in 1993 and built one of the strongest long-term records in the hedge fund industry, generating annualized returns of roughly 25% through mid-2019. The fund posted a 32% gross return in the first half of 2026 alone, according to Yahoo Finance.
Tepper had been a Micron investor since late 2016, carrying the memory chipmaker as his portfolio's largest single holding at various points over the years. In the fourth quarter of last year, he added 1 million shares and took call options controlling an additional 250,000 shares. He added more shares again in the first quarter of 2026. But in the second quarter, he cut his Micron stake by 41%.
Even after that reduction, Micron remained Appaloosa's second-largest position at roughly 15% of the fund's publicly traded equity portfolio. At its peak, the stock had represented as much as 29% of the portfolio.
Tepper also completely exited Sandisk, which had been 3% of the portfolio at the end of the first quarter.
Both Micron and Sandisk have benefited from surging demand for memory chips driven by the rapid pace of artificial intelligence data center construction. Because foundry capacity takes considerable time to expand, limited supply has pushed chip prices and profit margins higher for both companies.
Alongside selling those two stocks, Tepper purchased put options on one of their largest customers. Put options give the holder the right to sell shares at a set price within a defined time period, and buying them can be a way to bet against a stock or hedge against a decline.
Fund managers who oversee more than $100 million in assets are required to disclose their holdings four times a year through 13F filings, submitted roughly 45 days after each quarter ends. Those filings offer a delayed but detailed look at the positions large institutional investors are holding.
The memory chip market has historically moved in cycles, with periods of high demand and rising prices followed by oversupply and sharp downturns. Tepper's moves during the quarter may indicate he sees that cycle turning, though the filing does not include any statement of his reasoning.
