Novo took the active ingredient of Ozempic, semaglutide, and rebranded it as Wegovy to be used specifically for weight loss. Together, these blockbuster drugs made Novo the most valuable publicly listed company in Europe. At one point, its market capitalization was even bigger than the size of Denmark’s economy.

Novo Nordisk A/S understated the impact of lookalike weight-loss injections on its market share before lowering its 2025 sales and profit outlook, which resulted in a record stock drop, a proposed class action said.

Shares in Novo Nordisk fell as much as 6% on Friday before recovering some ground later in the session, extending recent losses that threaten to wipe out all the gains since the drugmaker launched its blockbuster weight-loss treatment Wegovy four years ago.