Wall Street plunges, S&P 500 erases 2018's gains

(Reuters) - U.S. stocks plunged in highly volatile trading on Monday, with both the S&P 500 and Dow Industrials indices slumping more than 4.0 percent, as the Dow notched its biggest intraday decline in history with a nearly 1,600-point drop and Wall Street erased its gains for the year.