This chart shows why October has such a scary reputation on Wall Street

October has lived up to its infamous - and volatile - standing among investors thus far. Through 11 trading sessions this month (including Monday), the S&P 500 has recorded three moves of at least 1 percent. They all came last week as Wall Street posted its worst weekly performance since March.

"Not surprisingly, October's reputation for being a volatile month is justified," said Sam Stovall, chief investment strategist at CFRA Research, in a note. He said equities could take another leg lower from here. "There were 26 years since WWII in which the S&P 500 endured at least two round-trip selloffs exceeding 5%, with the second being deeper than the first in more than two out of every three years."

Stovall added, however, that stocks will eventually regain their footing as the fundamentals remain "firm."

To be sure, the month overall is not bad for the market. The broad index averages a gain of 0.7 percent during Octobers dating back to 1950, according to The Stock Trader's Almanac.

CORRECTION: A previous version of this story mischaracterized CFRA's data.