https://www.statnews.com/2020/05/19/vaccine-experts-say-moderna-didnt-produce-data-critical-to-assessing-covid-19-vaccine/

This article explains why Moderna (MRNA) gave back half of the amazing gain yesterday. The data they presented was evidently more words than data. Hopefully, the staff working on the vaccine itself are as good as the PR folks in the Comms department. It seems MRNA has a bit of reputation for this type of thing.

The best strategy may be to sell into these good news days and buy back after the dust settles and the company is huddled back in their offices planning their next PR offensive.

In spite of this down day, the centrality of the Covid Vaccine quest has been underlined. Criticism of Moderna essentially tanked the whole market. The whole 390 Dow loss occurred from 2:30 on - the same time as the negative article came out.