Shares of Meta jumped about 8% after strong results boosted confidence in the company’s aggressive artificial intelligence push, while Microsoft tumbled about 10% as surging AI spending rattled investors.

About 20 minutes into trading, the Dow Jones Industrial Average was down less than 0.1% at 49,004.48.

The broad-based S&P 500 declined 0.4% to 6951.01, while the tech-rich Nasdaq Composite Index dropped 1.0% to 23,625.19.

With AI, “initially, a rising tide lifted all boats”, said CFRA Research’s Sam Stovall. “But this time around, investors will look at stocks on a company-by-company basis because not all are benefiting now at the same rate of pace.”