Wall Street sold off as renewed US-Iran conflict pushed oil toward $100 a barrel, though chipmakers escaped the damage.

• The Dow fell more than 600 points, its worst day in three weeks, with the S&P 500 and Nasdaq also down.
• Oil prices climbing on the Middle East conflict spooked investors as trading resumed after the Labor Day holiday.
• Semiconductors went the other way, with the Philadelphia chip index up on gains from Intel, AMD, and Broadcom.
• TSMC's US-listed shares rose to $439 and UMC's jumped 5%, while Nvidia slipped.
• Qualcomm gained after landing a deal with Amazon to build custom AI chips; Apple eased ahead of its annual product launch.

Outlook: Oil near $100 will keep pressure on the broader market, but money is still flowing into AI chip names.