Moderna had the best day in its history on Wednesday. The bill came due on Thursday.
The stock gave back as much as 25.69% in morning trading, putting it on track for its worst session ever. Just a day earlier, shares had closed up a staggering 176.97% after Moderna and Merck announced positive late-stage results for intismeran autogene, a cancer vaccine tailored to the mutations in each patient's tumor.
This is the first mRNA cancer therapy to clear a Phase 3 trial, the final hurdle before regulators decide whether to approve it. That's a big deal, and the market reacted accordingly.
But here's the twist: Moderna was one of the most heavily shorted stocks on the market, with short interest hovering around 12.5% of float. That set the stage for a classic squeeze on Wednesday, as shorts scrambled to cover. Now, with the initial euphoria fading, the stock is feeling the weight of profit-taking and renewed bearish pressure.
For retail investors, this is a reminder that biotech rallies can be as brutal as they are spectacular. The science is promising, but the stock's swings are driven as much by positioning as by fundamentals.
