BioNTech shares plummeted 14% in premarket trading Tuesday after the mRNA vaccine maker announced its cofounders plan to leave and form a new biotechnology startup. The company also provided revenue guidance for the coming year that fell short of Wall Street expectations, adding to investor concerns about its post-pandemic transition.

The German pharmaceutical company, which gained prominence during the Covid-19 pandemic through its partnership with Pfizer to develop one of the first mRNA vaccines, is now facing declining sales as global demand for coronavirus shots wanes. The departure of its founding executives comes at a critical juncture as BioNTech attempts to pivot toward developing new therapeutic products beyond its flagship vaccine.

The stock decline reflects broader market skepticism about BioNTech's ability to replicate its pandemic-era success in a more competitive biotech landscape. Investors are closely watching whether the company can accelerate its pipeline development to offset the revenue gap left by diminishing Covid-19 vaccine sales, particularly given the leadership transition.