The stock market is rebounding with the S&P index now 20 points higher than the low at 3177.22. Helping the rebound is the balance near the 38.2% retracement at 3175.25 (from the August low). The index also got closer (but not quite to) its rising 100 day moving average at 3164.88.
When stocks moved lower, the Pavlovian reaction is to buy dips. Traders like to pick out levels/areas where risk can be defined and risk be limited. The 38.2% retracement and 100 day moving average combine to form a potential buying area. Early buyers seem to have stepped in on the first look.
It is impossible to predict the ebbs and flows that are coming out of the coronavirus fears. However, being patient and leaning against technical levels are way that traders can defined and limited risk. If support holds, great. If support doesn't hold, get out and look for the next target (or failure of the break.