Micron's HBM4 Certification: A Milestone That Couldn't Stop the Sell-Off

Micron’s HBM4 certification by Jensen Huang for Nvidia’s Vera Rubin AI platform fails to lift stock as Broadcom guidance miss, strong US jobs data, and stretched valuation trigger 8.6% sell-off.

Jensen Huang gave Micron the ultimate vote of confidence on Friday, personally certifying its HBM4 memory chips for Nvidia's next-generation "Vera Rubin" AI platform. The stock market responded by unloading the shares. By the end of the session, Micron had tumbled as much as 10.42% to €769.90, before recovering slightly to close at €785.90 — still down 8.56% on the day. The rout came just two days after the stock hit an all-time high of €938.70 on June 3, a peak that now looks distant.

The certification itself is a genuine engineering coup. Micron began volume shipments of its HBM4 36GB 12H device in the first calendar quarter of 2026, boasting pin speeds of over 11 Gb/s, bandwidth exceeding 2.8 TB/s, and a 2.3-fold improvement over HBM3E. The nod from Huang places Micron squarely inside the most critical hardware supply chain for artificial intelligence, with first deliveries for Vera Rubin scheduled for the third quarter of 2026. Yet the market's reaction underscores a harsh reality: being certified does not mean being dominant. Analysts estimate that SK Hynix controls 60–70% of Vera Rubin's HBM volume, Samsung takes 25–30%, and Micron gets the remainder. The fight for pricing power and margin among three certified suppliers is only intensifying.

What triggered the sell-off was a perfect storm of sector and macro headwinds. Broadcom, a bellwether for AI infrastructure, reported a record AI revenue of $10.8 billion but guided third-quarter sales to around $16 billion — below the $17.2 billion analysts had baked into their models. After weeks of relentless rallies, the market was primed for an upward revision, not a mere in-line forecast. The disappointment immediately fueled fears that the massive capital spending by tech giants may be approaching a plateau. Adding to the pressure, rumors swirled that Nvidia's Vera Rubin architecture could slash standard server memory capacity per rack from 55 to 28 terabytes, a move aimed at lowering system costs. Even though the adjustment targets conventional DRAM rather than high-margin HBM4 modules, the prospect of lower memory content in the next AI generation was enough to trigger broad profit-taking across the semiconductor space.

Macroeconomic data poured gasoline on the fire. The U.S. Labor Department reported that 172,000 nonfarm jobs were created in May — more than double the 80,000 consensus estimate. The robust print crushed hopes for an imminent Federal Reserve rate cut and sent bond yields climbing, which mechanically discounts the future cash flows of high-valuation growth stocks like Micron. For a name that had surged 746% over the past twelve months, with a year-to-date gain between 186% and 192% depending on the price point, the margin for error had all but evaporated. The stock was trading roughly 47% above its 50-day moving average and 20% above the consensus analyst price target of around €624 — a stretched valuation for a company with annualized volatility of 97%.

Micron now faces a critical test on June 24, when it reports fiscal third-quarter results. Management has set a gross margin target of 81%, a level that must be defended amid the architectural shifts and competitive dynamics playing out among Nvidia's memory suppliers. The structural demand for high-bandwidth memory from AI data centers remains intact — the company has already locked in its entire HBM supply for 2026 through price and volume agreements. But the market has shifted from rewarding strong results to demanding flawless execution and ever-higher forecasts. Friday's drop was not a referendum on Micron's technology; it was a reminder that when a stock is priced for perfection, even near-perfection can be sold.