Semiconductor stocks plunge on AI demand concerns, Meta overcapacity fears

What happened

The Philadelphia Semiconductor Index fell over 7% as chipmakers including FormFactor (down 17.5%) and Allegro MicroSystems (down 15.6%) were hit by sector-wide selling. A Citi analyst questioned whether large cloud platforms would continue high spending on AI infrastructure if they could not demonstrate returns, and reports of Meta's plan to sell access to its AI computing power sparked fears of future overcapacity in the industry.

Why it matters

For two years the semiconductor sector traded on an assumption of an insatiable GPU and memory shortage. If Meta, which guided to as much as $145 billion（約23兆円） of capex this year, has enough spare capacity to lease it out, the market reads that as a signal hyperscalers (large cloud providers) may have over-built—meaning future orders for GPUs, high-bandwidth memory, and NAND storage could shrink. Additional pressure came from reports that Apple was in talks to source chips from Chinese suppliers, raising competitive and pricing concerns.

What to watch

FormFactor has experienced 49 moves greater than 5% over the last year, making this 17.5% drop significant even by the stock's volatile standards. The selling began in Asia as SK Hynix and Samsung each dropped more than 12%, triggering a 20-minute market-wide circuit breaker, then spread to Europe and the U.S.