Not Micron. Not Sandisk. This Memory Stock Is Quietly Gaining Share.

In the past, the memory chip market was a cyclical industry that went through boom-and-bust cycles every few years. But over the past few years, the rapid growth of the generative AI market has caused the demand for new memory chips to consistently outstrip its supply.

A major bottleneck for the AI market has been the availability of high-bandwidth memory (HBM) chips. Data center GPUs can't process AI workloads efficiently at data centers without HBM chips, which are produced by only a handful of memory chipmakers. Those data centers also need to store their data on high-speed solid-state drives (SSDs), which use NAND (flash) memory chips, rather than older platter-based hard disk drives (HDDs).

Image source: Getty Images.

That's why shares of Micron (NASDAQ: MU), a major producer of HBM chips, and Sandisk (NASDAQ: SNDK), a leader in SSDs, skyrocketed as the AI market expanded.

Over the past three years, Micron's stock has surged 1,400%. Sandisk's stock has soared 4,420% since its spin-off from Western Digital (NASDAQ: WDC) on Feb. 24, 2025. Both stocks still look surprisingly cheap relative to their forward earnings (assuming the AI boom continues), but there's another memory chipmaker you shouldn't ignore: SK Hynix (NASDAQ: SKHY).

Why does SK Hynix deserve more attention?

SK Hynix, which is based in South Korea, is the world's second-largest producer of DRAM and NAND memory chips after Samsung. It was founded in 1983 (as Hynudai Electronics), went public in South Korea in 1996, but wasn't listed in the U.S. until its IPO on July 10, 2026.

In the U.S., SK Hynix went public at $149 per ADS. Today, its stock trades at about $170.

SK Hynix's South Korean shares had already more than tripled year-to-date before its U.S. debut. The retail and institutional accumulation of its U.S. stock also caused it to initially trade at a premium to its South Korean shares, which were much harder to purchase.

But today, SK Hynix's stock trades at just five times next year's earnings. Micron and Sandisk trade at six and seven times forward earnings, respectively. While SK Hynix isn't growing as quickly as its smaller rival Micron, it's growing a lot faster than Sandisk.

Data source: Marketscreener.

SK Hynix also controls more than half of the HBM market, thanks to its early shift toward HBM3 chips in late 2021, and it produces over half of the current-gen HBM4 chips that support Nvidia's (NASDAQ: NVDA) top-tier data center GPUs. That scale puts SK Hynix in a stronger position than Samsung and Micron -- which typically control 25%-40% and 5%-20% of the HBM market, respectively -- to roll out its newest HBM4E and HBM5 chips to data center operators.

In the NAND market, SK Hynix is ramping up production of high-capacity quad-level cell (QLC) enterprise SSDs to store massive amounts of data that AI agents can quickly access. By bundling those SSDs with its HBM chips, it can lock in more customers as a "one-stop shop" for AI infrastructure upgrades and widen its moat against its competitors in both markets.

Why is SK Hynix worth buying right now?

SK Hynix's scale and diversification make it a safer long-term investment than Micron, which is well-diversified but still an underdog in the DRAM, HBM, and NAND memory markets, and Sandisk, which is a pure play on NAND chips. From 2025 to 2028, analysts expect its EPS to grow at a 107% CAGR -- so it has significant upside potential if it's revalued as a high-growth stock.

Leo Sun has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends Micron Technology, Nvidia, and Western Digital. The Motley Fool has a disclosure policy.