Fact #1: Economists believe that the US unemployment rate is now over 15%, which is the highest it has been since the Great Depression.

Fact #2: The S&P 500 is down from its February peak, but is still higher than it was on June 1, 2019.
The only way to reconcile these two facts is to assume that the stock market believes that social distancing restrictions will be decreased, and that the consequences of this action will be mild.

This leads me to make the following prediction:

If decreasing social distancing restrictions in the absence of better testing and treatments leads to a second wave of Covid-19 deaths, the stock market will conclude that its prior belief was incorrect, and respond accordingly.