US chip stocks plunge: memory index down 15%, Philadelphia Semiconductor Index falls over 10%

The scale of this move matters more than any single name: a memory index down about 15% and the Philadelphia Semiconductor Index off more than 10% points to a sector-wide repricing rather than an isolated earnings miss, and the fact that the S&P 500 and Nasdaq 100 fell far less shows the selloff was concentrated in chips. The breadth is notable — losses of 16% or more across Micron, Western Digital, AMD and Seagate, alongside SanDisk's 22.3% drop, hit memory, storage and logic names alike, suggesting investors treated the group as one trade. Whether the selling stays confined to semiconductors or bleeds into the broader tech sector is the open question worth watching.