FWIW, I very much wanted to adjust my investments based on the covid news, but was stopped from doing so mainly via friction:
1. I made recent profits from my stocks, so selling them (even for a short window) would have had bad capital gains repercussions for me… in the US it’s a PITA to deleverage stocks that are in the green.
2. I’m not enough of a trading wonk to feel comfortable buying puts, and the little in the past that I’ve played around with those tools seemed to indicate that it’s hard for a non-professional to avoid excessive fees.
3. I just randomly happened to not be aware of the “zoom” phenomenon, so I didn’t invest in that. I DID invest in 3M (because of their mask business) but they actually have lost a ton of money during the crisis for some reason (I assume the “price gouging” laws that prevent them from making any profits are a big part of that)
So, to me this is a story mainly of market inefficiencies preventing EMH from coming into play.
HOWEVER, there was also one other reason why I didn’t profit off the crisis, which is actually compatible with EMH: I was expecting a large cash infusion from the fed, so I was expecting stock prices to remain stable, at the cost of subsector price inflation. Turns out, I partially got this wrong (because I didn’t consider that inflation takes time to develop, so stock prices plummeted despite fed efforts) but was partially right (stocks have mostly recovered, precisely because of the Fed intervention)
TLDR: I was mostly a rational actor that understood the covid threat, but misunderstood the effect of Fed intervention… but you needed to have BOTH in this case, because of the extra overhead of non-EMH market inefficiencies.