The S&P 500 (SPX) fell 13 points, or 1.2%, at the open. A bear market is typically defined as a 20% drop from a recent high, which all three major indexes hit on April 29. After closing at 1363.61 on April 29, the S&P 500 is now at that 20% threshold.

The Dow Jones industrial average (INDU) slid 133 points, or 1.3%. The Nasdaq (COMP) fell 18 points, or 0.8%. Both indexes are just a few percentage points shy of falling into bear territory.

On Monday, stocks kicked off the fourth quarter with a huge sell-off, as worries about Greece’s solvency remained in the spotlight.