Stocks close lower: Nasdaq 100 falls 2.5% as AI infrastructure sinks, Brent settles at $109.86

U.S. stocks ended the week with a sharp, narrow selloff. The Nasdaq 100 fell 2.50% to 29,187.55 and the Nasdaq Composite dropped 2.15% to 26,140.03, while the S&P 500 lost 1.09% to 7,659.44 and the Russell 2000 slid 1.66% to 2,721.37. The Dow Jones Industrial Average held up best, down 0.34% at 52,002.41, according to Yahoo Finance prices read after the close.

Source: Yahoo Finance. Percent changes are against Thursday's close. By the same data the S&P 500 is down 1.95% and the Nasdaq 100 down 5.49% on the week, and the VIX rose to 19.99 from 16.46.

The AI-infrastructure trade did the damage

The heaviest losses were in companies that borrow to build AI data centers. CoreWeave fell 11.9%, Nebius 12.2% and IREN 11.2%. Micron lost 5.6%, Broadcom 4.5% and Nvidia 1.4%. CoreWeave is down about 25% on the week and Nebius 25%, by the same Yahoo data.

CNBC tied the week's selloff to Anthropic reporting slower revenue growth alongside rising spending, and noted that Jefferies and JPMorgan analysts called the drop overdone while others questioned how ironclad long-term capacity contracts are. We covered the credit side in our report on CoreWeave's default swaps and the session as it unfolded in our midday report.

Banks, which had been under pressure all week, were mixed: JPMorgan rose 1.3% and Wells Fargo 1.4%, while Bank of America fell 0.9%.

Oil climbs on Hormuz and Ukraine

CNBC reported that Brent settled at $109.86, up 3.7% after touching $110 for the first time since May, and WTI settled at $101.41, up 3.5%. WTI gained more than 10% on the week. CNBC cited Iran's attacks on ships in the Strait of Hormuz, Houthi missile fire at Saudi Arabia and Ukraine's vow to keep striking Russian refineries. AAA put the average U.S. diesel price at $6.33 a gallon, more than 70% above a year ago. For a trucking or delivery fleet that is a direct cost, and the energy sector was the day's relative winner: the XLE energy fund rose 2.5%.

Yields ease, and the Fed is next

The Treasury's par curve showed the 10-year at 5.09%, down from 5.10% Thursday, the 2-year at 4.74% from 4.77%, and the 30-year unchanged at 5.43%. CNBC put futures odds of a quarter-point Fed hike on October 28 at 17%. Before then, our calendar shows jobless claims on October 22 and flash PMIs on October 23.

Sources: Yahoo Finance (closes, read after 4:35 p.m. ET); U.S. Treasury; CNBC on oil; CNBC on CoreWeave. This is market information, not investment advice.