A Chinese memory maker's claim and a round of profit-taking sent chip and optical stocks sliding
CXMT said it plans a denser server-memory product by the end of 2026, and Micron, Sandisk and Seagate fell. Optical-networking stocks that rallied on Friday gave back more: Ciena and Lumentum lost close to 10%, and Cerebras fell almost 11%.
Photo: Nicolas Foster / Pexels
Monday was a reminder that the AI hardware trade can move on news from companies most US investors cannot buy. A Chinese memory maker described a technology milestone over the weekend, and by the close the Philadelphia semiconductor index had fallen about 2.7% to 12,236.79, which Reuters said was a three-week low.
The CXMT claim
ChangXin Memory Technologies, or CXMT, is not listed in the US. Its president, Cao Kanyu, said at an industry event in Shanghai over the weekend that the company had made key progress on a new memory-cell architecture designed to store more data in the same space, according to a company statement cited by Invezz and 24/7 Wall St. Samsung Electronics and SK Hynix are pursuing the same kind of design.
CXMT said it plans to introduce a server-memory product based on the technology by the end of 2026, and expects to release a new generation of DDR5 memory modules for enterprise servers by the end of the year. It has not disclosed detailed specifications or an exact launch date. The Information reported last month that CXMT had begun producing high-bandwidth memory, the kind used alongside AI processors, in small quantities.
How the memory stocks closed
Memory shares took the brunt of it. Micron Technology fell about 3.9% to $989.04, and Sandisk dropped about 6% to $1,487.33. CNBC reported midday declines of about 3% for Seagate Technology and more than 2% for Western Digital, and said the Roundhill Memory ETF was down about 4% at that point. SK Hynix also fell in Seoul.
The reaction says more about positioning than about anything CXMT has shipped. Memory has been one of the strongest corners of the AI trade this year, because demand from data-centre builders has absorbed nearly everything the industry can produce. That kind of run leaves shares sensitive to any hint of new supply. As 24/7 Wall St. noted, sceptics see a familiar memory-cycle pattern in a new entrant arriving with a denser design, while others point out that CXMT's server product is still a stated target with nothing shipping yet.
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Optical names gave back Friday's bounce
The steepest losses came from a different part of the AI build-out: the companies that move data between chips and across data centres. Several had rebounded on Friday, and CNBC described Monday's selling as investors taking some chips off the table.
By the close, according to Yahoo Finance data and a Business Upturn tally that matched it, Cerebras Systems had fallen 10.69% to $146.62, Semtech 10.15% to $168.28, Ciena 9.95% to $405.01 and Lumentum 9.78% to $995.41. Fastly lost 9.80%. Those were among the worst performances in the US market on the day.
The larger chip names fell less. Nvidia slipped about 1.3% to $226.32. Earlier in the session, Livemint reported intraday declines of about 3.3% for Advanced Micro Devices, 3.6% for Intel and 4.2% for Marvell Technology.
Not every AI chip story was negative
The same session produced a different kind of chip headline. Microsoft unveiled Maia 300, the third generation of its in-house AI accelerator, and said the Maia family will become its primary system for running AI models in its products. Production of Maia 300 starts in 2027. Microsoft shares rose about 1.1%.
For chipmakers, that is a reminder of a longer-running theme: the largest buyers of AI hardware are designing more of their own silicon. Microsoft still works closely with Nvidia, and its executives said it partners with Nvidia and AMD for training models.
What to watch
The next test for the group arrives quickly. ASML, the Dutch maker of chipmaking equipment, reports this week, and options markets were pricing a move of about 6% around its results, according to MarketDash. Taiwan Semiconductor Manufacturing reports on Thursday. Both will offer a read on whether AI-related orders are still running at the pace that lifted memory and optical stocks this year.
For CXMT, the questions are concrete: whether the server product arrives on schedule, at what volume, and whether it finds customers outside China. Until there are answers, Monday's selling shows how little it takes to shake a crowded corner of the market.
