Key Highlights

● Micron slid Friday as concerns about China's CXMT hit memory stocks.

● Sandisk, Seagate and Western Digital also tumbled during the session.

● All 30 PHLX Semiconductor Index members fell, and the index closed at 11,137.29.

● Western Digital reports Oct 22 and Lam Research Oct 21; the Fed decides Oct 28.

Memory under pressure

Micron Technology (NASDAQ:MU) slid on Friday, according to market reports, as worries about Chinese competition in memory chips hit one of the Nasdaq-100's best-known semiconductor names. The concern centered on CXMT, a Chinese maker of DRAM memory chips, and reports of its progress with 4F2 DRAM technology. One report linked the decline to worries that CXMT is advancing in DDR5, the current generation of mainstream computer memory.

Micron makes DRAM and NAND flash memory used in data centers, personal computers, smartphones and cars. High-bandwidth memory for AI processors has become one of its most closely watched products, making it sensitive to any sign that rivals are catching up.

Peers fell too

The memory selloff was not limited to Micron. Sandisk (NASDAQ:SNDK), Seagate Technology (NASDAQ:STX) and Western Digital (NASDAQ:WDC) tumbled on Friday. Over the week, SK Hynix, Sandisk and Micron all posted steep pullbacks, market data showed.

Micron also ranked third among the most discussed stocks with retail traders, based on mention counts on a social platform.

A rout across chips

Friday's selling reached every corner of the semiconductor industry. All 30 members of the PHLX Semiconductor Index fell, and the index closed at 11,137.29. Advanced Micro Devices (NASDAQ:AMD) sank, Arm Holdings (NASDAQ:ARM) tumbled and Broadcom (NASDAQ:AVGO) fell. Reports differed on the length of the sector's losing streak, with some counting eight straight declines and another describing a ninth.

The Nasdaq-100, home to many of the market's largest technology companies, fell sharply, though reports differed on the size of the move. The Nasdaq Composite tumbled 572.99 points to 26,140.03, while the S&P 500 lost 84.62 points to 7,659.44 and the Dow Jones Industrial Average slipped 175.28 points to 52,002.41.

The financing backdrop

Beyond memory-specific worries, chip stocks were pressured by a broader shift in sentiment about artificial intelligence. Market commentary said investors had moved from asking what AI can do to how it will be financed, with debt-funded infrastructure companies hit hardest. Micron's decline was also tied to fears about financing at AI-focused "neocloud" providers. A published report said more than $1 trillion was erased from semiconductor and AI-related stocks during the week.

One market commentator said, "That is a change in character, and it's another reason the leaders no longer look like a safe haven."

On the supply side, TSMC (NYSE:TSM) reported third-quarter revenue of $46.72 billion, above its guidance, and kept its 2026 capital spending plan at $60 billion to $64 billion, a sign that the chip-manufacturing build-out continues.

Rates and the Fed

Treasury yields eased during the week, with the 10-year finishing near 5.1. Fed Chair Kevin Warsh, at an IMF gathering in Bangkok, said, "I don't prejudge meetings." The Fed's next decision is due October 28.

Micron Watches CXMT and Western Digital

Western Digital reports on October 22 after the close and Lam Research (NASDAQ:LRCX), a supplier of chipmaking equipment, on October 21, offering read-throughs on memory demand and spending. Meta Platforms (NASDAQ:META)'s October 21 report will also be scrutinized for data-center budgets that drive demand for AI memory. Investors will watch for further details on CXMT's technology and any response from established memory makers.