Stocks of storage and memory products manufacturers were the S&P 500 index's top performers in 2025 by a country mile.

Four of them posted gains of more than 200% for the year -- quite a bit more than the 17.9% gain for the S&P 500 during 2025.

Those four stocks were:

Sandisk (NASDAQ: SNDK) makes data storage devices based on NAND flash technology, a type of nonvolatile storage technology that can retain data without a power source. ("NAND" combines the words "not" and "and," referring to the logic gates that are central to the devices.) The stock skyrocketed 559% in 2025. It was the best-performing stock in the S&P 500 last year.

Western Digital (WDC 0.27%) also makes data storage products, though it's focused on hard drives rather than flash memory. It soared 282% last year.

Seagate Technology Holdings (STX +1.85%) makes personal storage devices that include gaming hard drives, network storage, and similar products. It was up 219% last year.

Micron Technology (MU +7.68%) provides memory and storage solutions -- specifically, the high-performance memory (dynamic random access memory, or DRAM) and storage devices (NAND) used in data centers and other computing devices. It was up 239% in 2025.

A supply-demand imbalance sent storage prices much higher during the year

The driving factor behind those incredible gains for data storage providers? An unprecedented, persistent memory chip shortage, with demand for storage and related devices materially outpacing supply. Demand for storage has been driven primarily by artificial intelligence (AI) workloads, which need huge amounts of digital storage and require far more memory than consumer devices like smartphones and PCs.

Source: Getty Images.

That sent DRAM prices 170% higher during the year. NAND prices climbed almost 250% from early 2025 through December.

As you might expect, the trends sending prices of memory storage devices higher did not end on Dec. 31, 2025. Instead, they've continued into this year. In fact, DRAM memory prices are expected to climb 50% or more this quarter, compared to the fourth quarter of 2025.

As a result, memory storage stocks have continued to soar in early 2026.

At the time of this writing, Sandisk is up 63% so far this year, Western Digital has climbed 23%, Seagate Technology is up 16%, and Micron Technology is already 19% higher for the year. And that's after fewer than 10 trading days. The S&P 500 index, by contrast, is up less than 2% in 2026.

The demand for storage doesn't look like it will end any time soon, as it's driven by the frenetic AI buildout. Of course, markets are dynamic, and manufacturers always eventually adjust to supply-demand imbalances. So, eventually, ongoing demand for the devices these companies manufacture -- and the high prices they currently command -- will attract more storage capacity, either among the current highfliers or new entrants to the market.

Nothing lasts forever -- certainly not in the stock market. But at the moment, these four memory device providers continue to look promising for investors.