U.S. stocks nosedive as tech saps rally; Dow slides more than 800 points

Investors slammed the brakes on a record-shattering run that repeatedly lifted the Standard & Poor’s 500 and Nasdaq composite to new heights and pulled the Dow Jones industrial average within reach of its own record high. All three indexes shed at least 2.8 percent, dragged down by Apple, Microsoft, Amazon and other technology stocks.