While it might be true that stocks are undervalued during crises such as this (in that their long-term value is relatively unaffected), that doesn’t change the fact that the stock market does generally go down during such times.
So, basing the below theory on actual market moves rather than market value:
The stock market has recovered a bit recently. In my pathetically-uninformed opinion, that’s because traders see the beginnings of a reopening of the economy and think that’s a trend that will continue somewhat uninterrupted. I don’t think they’re taking into account the virtually-inevitable second wave that will occur, if not this summer (due to warmer weather), then this fall.
It could also be that they’re counting on better testing and contract tracing. Obviously we should’ve had that the first time around. But we didn’t, and here we are. To count on this administration to have the testing and contact tracing necessary to withstand another wave without either massive economic interruption or unacceptable deaths is like throwing away money, if you ask me.
Or, they could be counting on the U.S. just giving up on people dying and sacrificing them for the economy. I could see that happening, unfortunately.
Or they think that herd immunity is closer than most scientists do, and that herd immunity will prevent a second wave.
Of course, they could be smart, long-term investors who understand that the effect of such a crisis on market value is relatively small. (had to throw a little humor in here.)
But I see the most likely scenario as another wave of coronavirus followed by more shutdowns followed by further drops in the stock market.
Just my 2 cents, but probably not worth even that.