U.S. stocks hit by broad selloff; Nasdaq falls nearly 4%, multiple AI supply chain stocks drop over 10%.

U.S. stocks suffered broad selling, with the tech-heavy Nasdaq Composite and Nasdaq 100 leading declines. The S&P 500 fell 2.7%, the Nasdaq dropped about 4%, and the Nasdaq 100 fell 4.52%. The S&P 500 lost its 100-day moving average and September low, while both the Nasdaq Composite and Nasdaq 100 broke below their 200-day moving averages; a short-term rebound would require reclaiming these key technical levels. The AI supply chain came under full-scale selling, with the slump spreading from chips and memory to data center networking equipment, optical communications, AI cloud computing and power suppliers. Memory stocks such as SanDisk, Western Digital, Micron Technology and SK Hynix fell more than 10%; chip stocks including AMD, Qualcomm and Arm fell more than 10%; data center connectivity and optical communications stocks such as AsteraLabs, Lumentum, Coherent, Credo and Marvell Technology fell more than 10%; semiconductor equipment stocks including Lam Research and Applied Materials fell more than 10%; AI cloud computing and data center power suppliers such as Nebius, CoreWeave and BloomEnergy also fell more than 10%, with BloomEnergy and SanDisk down nearly 18%. Market breadth deteriorated in tandem, with decliners on the Nasdaq outnumbering advancers by nearly 4 to 1, decliners on the NYSE outnumbering advancers by about 2.5 to 1, and decliners in the S&P 500 outnumbering advancers by about 1.6 to 1, indicating that the selloff has spread from large-cap tech stocks to the broader market.