The stock market lost more than $2 trillion in October

October 2018 is set to be the worst October for stocks since 2008, when the S&P 500 plunged 16.9 percent, according to Silverblatt.

The S&P 500 slipped past two closely watched levels on Oct. 26, falling below its 200-day moving average and more than 10 percent from its intraday high hit on Sept. 21, a correction as defined on Wall Street. The 200-day moving average is one of the most popular technical indicators used by investors. October is set to be the fourth month this year that the S&P 500 bottomed at that key level.

The Dow Jones Industrial Average closed down 13 days in October as the index headed toward its worst month since January 2016. Both the Dow and S&P 500 are slightly positive year-to-date.

The third-quarter earnings season was also on track to have been the worst for stocks since 2011, according to Bespoke Investment Group on Oct. 23. Roughly third-quarters of stocks had suffered a one-day decline on their earnings results this season, Bespoke found. The poor stock reactions were despite this third quarter being much better than last year’s earnings season, with nearly 8 in 10 companies reporting better-than-expected earnings.

Dow components such as Caterpillar, 3M and DowDuPont were especially battered following earnings reports, as company leaders commented on increased costs from global risks such as rising interest rates, a strengthening dollar and the trade war with China.

“While this is a significant pullback, some of it does appear to be reallocation and money is sitting on the sidelines,” Silverblatt said. “That should gives us a stronger base. Earnings were good but perception is everything: We expected a lot more.”

The dollar index, which measures the strength of the U.S. dollar against a basket of currencies, has risen 2.1 percent this month.

Semiconductors were one of the hardest hit sectors in the stock market, with the VanEck Vectors Semiconductor ETF set to end the month down 12 percent. Shares of Nvidia, Advanced Micro Devices, Micron and Applied Materials are all on pace to post double-digit losses for October as investors fled following the companies’ earnings reports this month. Those chip giants are also all in what some traders consider ‘bear market’ territory, down more than 20 percent from their recent highs.

AMD has had a particularly rough month — that stock was far and away the best performing stock in the S&P 500 at the end of September. But shares have plunged more than 20 percent since the start of October, its worst monthly performance since 1992.

– CNBC’s
J.R. Reed
,
Kate Rooney
and
Fred Imbert
contributed to this report.