NEW YORK (AP) — A slump in several big companies weighed down the stock market Tuesday, leaving most major indexes lower.

The S&P 500 index fell 0.8% and the Nasdaq composite, which is heavily weighted with technology companies, lost 2.3%.

Big gains for McDonald's and UnitedHealth helped push the Dow Jones Industrial Average up 0.2%.

A stark profit warning from Snapchat's parent company spooked investors into dumping the stocks of major social media companies. Snap sank 43.1%, while Facebook's parent company lost 7.6%.

Retailers and banks also fell. The yield on the 10-year Treasury fell sharply, to 2.76%.