Stock prices for Novo Nordisk fell by about 3% at market open after the Biden administration selected its revolutionary drugs for mandatory price negotiations.

A shake-up may be brewing in the market for GLP-1 diet drugs Friday, and it's making itself felt all across the field of companies selling (or hoping to sell) semaglutide and related drugs for treating diabetes and losing weight.

The U.S. government targets Novo Nordisk's drugs, including Ozempic and Wegovy, for Medicare price negotiations in 2027. Despite opposition from the pharmaceutical giant and other companies, these medications are part of the second wave under the Inflation Reduction Act to reduce costs for senior citizens.