Sandisk (SNDK +1.21%) was the best-performing stock in the S&P 500 (^GSPC +0.04%) index last year, with an incredible return of 559% from when it started trading publicly in February 2025 through the end of the year.
Headquartered in Milpitas, California, in the heart of Silicon Valley, Sandisk makes data storage devices based on NAND flash technology, which is a type of nonvolatile storage technology that can retain data without a power source. "NAND" combines the words "Not" and "And" and refers to the logic gate that is critical to the devices.
Memory and data storage stocks like Sandisk had an incredible 2025 due to the massive artificial intelligence (AI) infrastructure buildout during the year. NAND technology in particular is seeing demand grow at a compound annual growth rate of 13% due to AI, cloud, and device expansion.
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Demand for memory chips is outpacing supply
That driving demand for memory chips and devices is coupled with a shortage of them, pushing prices higher. In fact, contract prices for solid-state memory devices are expected to increase at least 40% quarter over quarter in the first quarter of 2026, according to TrendForce.

NASDAQ: SNDK
Key Data Points
And because investment trends don't tend to halt or reverse on New Year's Eve, it's no surprise that the stock's ascent has continued into 2026. Sandisk shares are up another 59% so far this year, which makes the stock the best performer in the S&P 500, as of this writing.
Not a bad start to 2026 for Sandisk and its shareholders.






