The race for next-generation AI memory chips just got narrower, and Micron Technology Inc. (MU) is on the outside looking in. Samsung Electronics Co. Ltd. (SSNLF) and SK Hynix are now set to dominate the supply of sixth-generation high-bandwidth memory (HBM4) for Nvidia Corp. (NVDA)'s upcoming Vera Rubin AI accelerators.

Two Suppliers, Zero Micron

According to SemiAnalysis, Nvidia plans to source HBM4 for Vera Rubin almost entirely from SK Hynix and Samsung, with Micron no longer part of the equation. The firm slashed Micron's projected HBM4 share for Vera Rubin to zero and now expects SK Hynix to supply roughly 70% and Samsung about 30%, the Chosun Daily reported Monday.

This matters because Vera Rubin, Nvidia's successor to its Blackwell architecture, will be the first AI chip designed around HBM4 memory. Getting locked out of that supply chain is a pretty big deal.

Why Micron Couldn't Keep Up

So what happened? Analysts point to Micron's struggles meeting Nvidia's stricter technical requirements. TrendForce and industry sources say Nvidia raised HBM4 data-transfer speed targets above 11 gigabits per second last year. That's a tough bar to clear, and apparently Micron couldn't clear it in time.

The technical demands for cutting-edge AI memory are no joke. When you're building chips that power the data centers driving the AI boom, you need components that can handle massive data throughput without bottlenecking performance.

Samsung Charges Ahead With February Shipments

Meanwhile, Samsung is gearing up to begin mass production of HBM4 chips. Bloomberg reported Monday, citing Yonhap News, that Samsung plans to start shipping the chips to Nvidia as early as the third week of February. The memory will support Nvidia's Vera Rubin accelerators, giving Samsung a significant foothold in the next wave of AI infrastructure.

This progress signals that Samsung is narrowing the gap with SK Hynix, which has dominated Nvidia's memory supplier rankings. Samsung stock gained on the news, helped along by rising memory-chip prices driven by heavy AI demand from hyperscalers like Amazon.com Inc. (AMZN) and Alphabet Inc. (GOOGL).

The broader context matters here too. Investor optimism around the data center spending boom has lifted AI-linked tech stocks across the board. Major hyperscalers are expected to spend about $650 billion this year on infrastructure, and Nvidia shares jumped nearly 8% on Friday alone.

MU Price Action: Micron Technology shares were down 2.23% at $385.88 during premarket trading on Monday, according to market data.