Philadelphia Semiconductor Index Tumbles 6.72% as Chip Stocks Shed Over $3 Trillion, Breaking Below 11,000

The Philadelphia Semiconductor Index fell 6.72% on Thursday to close at 10,731.98, breaking below the 11,000 mark in its steepest one-day decline since June and its lowest close since July 29. The drop disrupted an earlier rebound, shifting focus to the 200-day moving average and the 10,450–10,550 support range. All 60 chip stocks tracked by Yahoo Finance have declined since October 6, erasing more than $3 trillion in combined market value, including over $900 billion on Thursday alone. The Nasdaq 100 fell about 7% over the same period, less than half the chip sector's loss. Lam Research (LRCX) and Applied Materials (AMAT) have each fallen roughly 30% since October 6, while AMD lost over 20%. Nvidia (NVDA) declined less in percentage terms but shed over $600 billion in market value. Lam Research dropped 11.76% Thursday despite reporting record revenue, citing supply constraints and an expected sharp decline in China sales for the December quarter. Applied Materials, AMD and Nvidia fell 8.16%, 8.10% and 4.40%, respectively. Bulls need a close back above 11,000 to rebuild momentum, with resistance at 12,600–12,700. Semiconductor ETFs still drew record weekly inflows, per Bloomberg's Eric Balchunas, though buying has yet to halt the slide.