U.S. stocks tumbled, sending the Standard & Poor’s 500 Index to the lowest level since May 1, on concern technology spending will slow and second-quarter earnings will fail justify a four-month rally in equities.

Microsoft Corp. and Google Inc. lost more than 2.8 percent after researcher Gartner Inc. predicted spending on information technology will drop 6 percent this year. Discover Financial Services slumped 11 percent on plans to sell $500 million in shares. Valero Energy Corp., the largest U.S. refiner, slid 4.7 percent as gasoline sank to a seven-week low.

The S&P 500 slid 2 percent to 881.03 at 4:15 p.m. in New York, accelerating losses after falling below its average level over the past 200 days. The Dow Jones Industrial Average sank 161.27 points, or 1.9 percent, to 8,163.6. The Nasdaq Composite slipped 2.3 percent to 1,746.17 as Google, owner of the world’s most popular Internet search engine, traded under $400 for the first time in six weeks.