(Reuters) - - The S&P 500's 4.10 percent slump on Monday was the deepest one-day percentage drop since Aug. 18, 2011, when the index fell 4.46 percent over fears about a weakening economy;
- Since last Thursday's close, the S&P 500 has declined 6.13 percent, its deepest two-session loss since August 2015;
- The S&P 500 is down 7.79 percent from a record closing high on Jan. 26, and has declined 0.92 percent year-to-date. Monday was the first time in 2018 that the S&P 500 closed in negative territory for the year-to-date;
- The Dow Jones Industrial Average's 4.6 percent loss on Monday was its largest in percentage terms since August 10, 2011, and the day's 1,175 point loss was its largest ever in absolute terms. The index was briefly down more than 6 percent before recovering;
- Wall Street has been in a nine-year bull market that has tripled the S&P 500's value since the 2008/2009 financial crisis. Investors in recent months have become more wary of a pullback;
- The Dow's worst-performing stock on Monday was Boeing, down 5.74 percent;
- Microsoft and Wells Fargo & Co fell 4.12 and 9.22 percent, respectively, and hurt the S&P 500 more than any other stocks;
- Around 6,986 U.S. stocks fell during the session, the greatest number in a single session since September 2016;
- Trading volume on Wall Street reached 11.5 billion shares, the highest since November 2016.
(Reporting by Noel Randewich; Editing by Leslie Adler)