By Marcin Frąckiewicz
Publication Date: 2025-12-18 00:00:00
As of 6:00 p.m. ET on Wednesday, December 17, 2025, U.S.-listed semiconductor stocks have wrapped up a bruising regular session—then immediately pivoted into a very different after-hours story led by Micron Technology.
The day’s defining theme was a renewed wave of “AI trade” de-risking that hit chipmakers, chip-equipment names, and data-center exposed semiconductor plays. In the background: fresh headlines around AI infrastructure financing, competitive pressure in AI chips, and policy and security scrutiny that investors are treating as real, near-term risk—not just narrative. [1]
US stock market close: semiconductors dragged the Nasdaq lower
Wall Street extended its pullback for a fourth straight session. The S&P 500 fell 1.2% to 6,721.43, the Nasdaq slid 1.8% to 22,693.32, and the Dow dropped 0.5% to 47,885.97—a risk-off tape that set the stage for chip stocks to underperform. [2]
Within tech, semiconductors were singled out as one of the market’s weakest pockets: the Philadelphia Semiconductor Index (SOX) fell about 3.8% on the day, according to a late-afternoon market wrap carried by Nasdaq. [3]
ETF proxies told the same story. The iShares Semiconductor ETF (SOXX) closed down about 3.8% and the VanEck Semiconductor ETF (SMH) fell roughly 3.7%.
Biggest US semiconductor stock moves today: broad declines across AI, foundry, and chip equipment
In the regular session, the selloff was broad—spanning AI accelerators, analog, smartphone chips,…