U.S. equity markets closed lower on Thursday, July 16, 2026, as a steep decline in semiconductor stocks underscored growing concerns about market concentration. The S&P 500 fell 0.51% to 7,533.86, while the tech-heavy Nasdaq Composite dropped 1.47% to 25,881.95. The Dow Jones Industrial Average showed relative resilience, slipping just 0.20% to 52,553.50.
The PHLX Semiconductor Sector Index tumbled 4.29% to 11,867.50, more than eight times the S&P 500's percentage loss. This divergence highlights the outsized influence of chip stocks on broader market performance. According to Paul Nolte, senior wealth adviser at Murphy & Sylvest, semiconductors now represent over 20% of the S&P 500, up from roughly 8% three to four years ago.
“If you look at the rest of the market, it’s doing fine,” Nolte noted, pointing to the Dow's modest decline. However, Gene Goldman, chief investment officer at Cetera, warned that the artificial intelligence trade is “priced on perfection,” leaving little room for error.
Taiwan Semiconductor Manufacturing Co. (NYSE: TSM) reported second-quarter revenue of $40.20 billion and projected third-quarter sales between $44.6 billion and $45.8 billion. Net profit surged 77%, yet its U.S. shares fell 2.32% to $409.74. The earnings beat failed to satisfy market expectations, turning a strong quarter into a valuation question.
Other chipmakers faced steeper losses. Micron Technology (NASDAQ: MU) declined 5.65% to $853.20, while SanDisk (NASDAQ: SNDK) slid 12.63% to $1,411.08. Western Digital (NASDAQ: WDC) dropped 9.15% to $466.81. The sell-off was broad but concentrated among names with heavy AI exposure.
Providing a counterbalance, UnitedHealth Group (NYSE: UNH) rose 1.16% to $423.38 after reporting quarterly revenue of $112.0 billion. The insurer raised its adjusted earnings outlook for 2026 to a range of $19.50 to $20.00 per share, offering a bright spot amid the tech rout.
Macroeconomic data remained mixed but stable. Retail sales increased 0.2% in June, matching consensus estimates. Unemployment claims declined, but housing data came in weaker than anticipated. The earnings outlook remains elevated, with LSEG projecting S&P 500 profits to rise 24.8% year-over-year, driven by a 65.5% surge in technology sector earnings.
Last week, the S&P 500 gained 1.2% and the Nasdaq advanced 1.7%, while the Dow retreated 0.5%, ending a four-week winning streak. Thursday’s reversal underscored the rapid shifts in chip sector leadership. Investors are now looking ahead to the preliminary University of Michigan sentiment survey due Friday and Texas Instruments (NASDAQ: TXN) earnings on July 22, which will provide further clues on whether weakness extends beyond AI-focused names.
Geopolitical risks remain, as an escalation of U.S.-Iran tensions could push oil prices and Treasury yields higher. Disappointing chip outlooks could trigger broader sell-offs, while strong guidance might quickly reverse the decline.
