The Philadelphia semiconductor index slid about 3.4% and Oracle lost 4% after a report questioned OpenAI's revenue run rate, while an Australian data-center IPO struggled to find buyers. Energy stocks rose about 3%.
The selling in U.S. stocks on Thursday was deep in one corner of the market and shallow almost everywhere else.
The Nasdaq Composite fell about 1.4% in early afternoon, and the S&P 500 about 0.6%. The Dow Jones Industrial Average was little changed and the Russell 2000 slipped about 0.1%. An exchange-traded fund that weights every S&P 500 stock equally traded slightly higher.
The gap came from chips and the companies most exposed to artificial-intelligence spending. The PHLX Semiconductor Index fell about 3.4%. Intel lost 6.7%, Marvell Technology 5.7%, Sandisk 5.6%, Micron Technology 4.8%, Advanced Micro Devices 4.4%, Broadcom 3.9% and Nvidia 2.7%. CoreWeave, the AI cloud provider, fell 7.4%. Oracle, which supplies cloud capacity to OpenAI, dropped about 4%.
The OpenAI report
A published report put OpenAI's yearly revenue pace roughly $20 billion short of earlier indications, and chip shares, already down, fell further once it circulated. The Nasdaq touched its session low after the report. OpenAI has not publicly addressed the figure.
The figure may weigh on the chip trade because a large share of hardware buying is financed against expected AI revenue. OpenAI is the anchor customer behind several of the largest commitments in the sector, including the custom chip Broadcom is developing with it and Oracle's data-center build-out.
The Firmus listing
Earlier in the day, investors got a separate read on public appetite for AI infrastructure. Firmus Grid, the Nvidia-backed Australian data-center operator, closed the order book for its planned listing without setting a price. Advisers were weighing a cut in the size of the offering and in the price to A$8.25 a share from the A$11 marketed, according to people familiar with the deal. Shares of Maas Group, which owns 3.2% of Firmus, closed down 22.4% after falling as much as 30%, and the Australian exchange queried the company about the drop.
Samsung and TSMC
Two of the sector's largest manufacturers reported strong numbers this week and still traded lower. Samsung Electronics' shares fell 2.4% after it forecast record quarterly operating profit. Taiwan Semiconductor Manufacturing's September revenue was 55% higher than a year ago and 0.6% lower than in August, and its American depositary shares lost about 3.4%.
Gainers
The S&P 500's energy sector rose about 3% as Brent crude traded above $104 a barrel. Palantir Technologies gained about 2% after Goldman Sachs upgraded it to buy, with analyst Gabriela Borges arguing the company's addressable market "may be setting up for another step function change." Health care, by contrast, was among the weakest sectors.
Two views
One reading is that the selloff reflects a specific question about AI revenue, now sharpened by a report on the sector's anchor customer and by a data-center IPO that could not clear at its marketed price. On that view, chip stocks are repricing the gap between spending and sales.
Another reading is that the move is about rates and positioning. Long-term Treasury yields hit their highest levels since 2002 this week, high-multiple stocks are the most sensitive to them, and the decline was concentrated in AI-linked stocks while most of the market held up.
Upcoming tests
Any response from OpenAI on its revenue, Firmus' final price and whether its Oct 23, 2026 listing proceeds, and TSMC's quarterly report later this month, with its capital-spending outlook, will show whether Thursday's decline was about AI demand or about the price investors will pay for it.