What are today's top business/market headlines?

Here's a roundup of the top business and market headlines heading into today, Sunday, October 18, 2026 (U.S. markets are closed for the weekend, so the focus is on Friday's close and developments shaping Monday's open):

Markets Close Out a Rough Week

Major U.S. benchmarks closed significantly lower on Friday, driven by an accelerating retreat from technology and artificial intelligence equities. The Nasdaq Composite dropped 2.1% for the session to bring its five-day loss to 4.5%, successfully halting its previous four-week winning streak. The S&P 500 similarly retreated 1.1% on Friday, while the Dow Jones Industrial Average suffered a milder 0.3% loss but managed to secure a positive overall return for the week. The 10-year Treasury yield hovered near 5.10%.

The sell-off was driven by renewed scrutiny of AI-related spending — with the Nasdaq sinking more than 2% as investors raised questions about AI debt. Separately, memory-chip stocks extended their slide as losses in that sector approached $2.5 trillion amid a broader bear market in chip names.

Oil Spikes on Escalating Middle East Conflict

Crude prices jumped sharply as the Iran-Israel/U.S. war intensified around a critical shipping chokepoint. Crude oil prices rose sharply Friday as Iran escalated attacks in the Strait of Hormuz, Houthi militants fired missiles at Saudi Arabia and Ukraine vowed to keep striking Russian refineries. In the Strait of Hormuz, at least nine tankers and cargo ships have come under attack since Sunday as Iran tries to choke off oil exports through the waterway. Iran sank the container ship GFS Pride on Wednesday, U.S. Central Command said. The crew of the Singapore-registered ship was safely evacuated.

Over the weekend, the situation escalated further: Iran's Revolutionary Guards Navy said two oil tankers caught fire after hitting naval mines while crossing the Strait of Hormuz, carrying about 2 million barrels of crude oil each. The incidents come amid heightened tensions around the strait, a key oil shipping route — disruptions to shipping due to the US-Israeli war on Iran have boosted global energy prices and inflation. The U.S. says its naval blockade has prevented at least $25 billion in Iranian crude oil exports, while Brent crude touched $110 a barrel and US crude held over $100, adding another inflation headache after this week's hot price reports.

China GDP Due Monday

A major data point investors are watching: China's Q3 GDP report is scheduled for Monday, October 19 at 10:00 am China time (10:00 pm ET Sunday), landing while Wall Street is closed and Asian markets are already trading. A Reuters survey of economists indicates GDP rose 4.4% year-on-year for July-September, exceeding the 4.3% recorded in Q2 but falling short of the 4.6% growth predicted earlier — still below the lower bound of Beijing's official 4.5%-5% target. China's trade surplus also expanded beyond forecasts in September amid a surge in exports, putting the country on track to exceed last year's record surplus.

Inflation and Fed-Watch Backdrop

September inflation data came in hotter than expected, with consumer prices rising 3.7% on an annualized basis, higher than the 3.6% economists had forecast, adding to market jitters ahead of the Fed's next moves.

Other Business Storylines

Bottom line heading into the new week: oil-driven inflation fears, an AI/tech valuation reset, and a closely watched China growth report are the three biggest threads likely to drive Monday's trading.