Here's Why Merck Lost Nearly $40 Billion in Value During November

Shares of pharma giant Merck (NYSE: MRK) fell by 14.9% during the month of November, according to data from S&P Global Market Intelligence. Although the drugmaker did take a hit from a clinical setback for its once-weekly oral treatment, MK-8507, for HIV-1 infection last month, the main reason Merck's stock slumped in November is the evolving situation surrounding its oral coronavirus pill molnupiravir. In brief, this COVID-19 pill, which is being jointly developed with privately held Ridgeback Biotherapeutics, exhibited a significant drop in efficacy following the final analysis of the full data set, compared to a prior interim data readout.