NEW YORK — Drops for stocks in the artificial-intelligence industry are dragging markets down worldwide on Thursday, while oil prices hit their highest levels since May on worries about the war with Iran.

The S&P 500 tumbled 1.4% following even sharper losses in Asia, whose markets are full of AI and other technology stocks. The Nasdaq composite was down 2.2%, as of 10:45 a.m. Eastern time, but stocks outside of tech did better, and the Dow Jones Industrial Average was down a more modest 0.6%, or 295 points.

AI-related stocks have been shaky on worries that their boom may be under threat because of…