I noticed that in the first hours of NYSE trading on October 6, 2020, stock prices for most biotech companies went down.
Examples include: ABBV, BIIB, BMRN, BMY, BSGM, GILD, GSK, LLY, NBIX, PFE, et al.
This is in contrast with the behavior of the rest of the NYSE market.
Looking at news reports, I was not able to find a reason why biotech, as a class, would suddenly lose some valuation.
Does anyone know why it went down (and can explain how you figured it out)?