What Happened?
A number of stocks fell in the afternoon session after a report that South Korea's SK Hynix is slowing its high-bandwidth memory (HBM) expansion rattled the AI-chip complex.
The selling started in Asia as SK Hynix and Samsung each dropped more than 12%, dragging the KOSPI down about 10% and triggering a 20-minute market-wide circuit breaker, then carried into Europe (ASML −5%, Infineon, ASM International and STMicroelectronics down 5–8%) and the U.S., where the Philadelphia Semiconductor Index opened down roughly 7% a day after closing at a record high.
The headline sounds bearish for AI, but the underlying report is a margin story, not a demand story. SK Hynix is deliberately slowing its HBM4 ramp to redirect capacity into conventional DRAM, where shortages have pushed operating margins above HBM's. Korean analysts pegged the margin gap at more than 15 points.
HBM is the memory bolted onto Nvidia's AI accelerators, so any "slowing HBM" signal instinctively sparks fears the AI build-out is cooling which is why the reflex was to sell. The more accurate read is that all three memory makers are running the market tight (Samsung flagged a 146% DRAM ASP jump in Q1, SK Hynix mid-60%), keeping pricing power with sellers.
The bigger driver appeared like profit-taking after a parabolic run. Micron rose ~300% since the start of the year, colliding with a hawkish rate shift: traders pricing 50bps of Fed hikes by December under new Chair Kevin Warsh, making debt-funded AI capex harder to justify at record valuations. The divergence confirmed it: memory names took the brunt (Micron −11%) while logic-heavy Nvidia fell only ~3.6%. Wedbush framed the drop as a buying opportunity with enterprise demand intact.
The stock market overreacts to news, and big price drops can present good opportunities to buy high-quality stocks.
Among others, the following stocks were impacted:
- Analog Semiconductors company Vishay Intertechnology (NYSE:VSH) fell 8.2%. Is now the time to buy Vishay Intertechnology? Access our full analysis report here, it’s free.
- Semiconductor Manufacturing company Amtech (NASDAQ:ASYS) fell 8.4%. Is now the time to buy Amtech? Access our full analysis report here, it’s free.
- Semiconductor Manufacturing company FormFactor (NASDAQ:FORM) fell 8.4%. Is now the time to buy FormFactor? Access our full analysis report here, it’s free.
Zooming In On Amtech (ASYS)
Amtech’s shares are extremely volatile and have had 73 moves greater than 5% over the last year. In that context, today’s move indicates the market considers this news meaningful but not something that would fundamentally change its perception of the business.
The previous big move we wrote about was 12 days ago when the stock gained 13.1% on the news that the company announced it will be added to the Russell 2000 and Russell 3000 stock indexes.
The inclusion, which would become effective after the U.S. market opens on June 29, is part of the Russell US Indexes' annual reconstitution. Joining these widely followed indexes is a significant development for Amtech, as it often leads to increased demand for a company's stock. Funds that track the Russell indexes will be required to purchase Amtech shares to match the index holdings. CEO Bob Daigle called the inclusion a "pivotal milestone" and a "testament to our continued commitment to driving value for our shareholders.".
Amtech is up 53.7% since the beginning of the year, but at $19.91 per share, it is still trading 12.8% below its 52-week high of $22.82 from May 2026. Investors who bought $1,000 worth of Amtech’s shares 5 years ago would now be looking at an investment worth $2,252.
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