The S&P was down nearly 2.7% as of 10:39 am ET, a drop of more than 10% from its 52-week high of 2,940.91, set on Sept. 21. The Dow, which was down almost 500 points in mid-morning trading, was within 231 points of correction territory as well.

Market corrections are worrisome milestones for investors, as they tend to last longer than pullbacks. The last 22 corrections in the S&P have lasted an average of 148 days and resulted in an average loss of 13.8%, according to CFRA. Once the low is hit, it has historically taken four months to rebound.

Corrections don’t always mean bear markets, though. And the markets of late have been fighting hard to avoid one. Big dips one day are followed by big rebounds the next.

Inflation fears are the biggest problem on Wall Street these days, along with rising interest rates. Earnings concerns could be impacting the market today as Amazon reported lighter than expected holiday sales forecasts. (The company’s stock is taking a hit today as a result.)

Stocks have been on a roller coaster all week, but one that has ultimately gone downhill. Since Monday, the Dow is down over 1,000 points; the S&P 500 is off 139 points; and the Nasdaq Composite Index has fallen more than 450 points.