Pfizer Inc. shares experienced a significant pre-market plunge of 5.06% on Tuesday, following the release of its fourth-quarter earnings report and updated financial guidance.

The pharmaceutical giant reported quarterly results that exceeded analyst expectations for both revenue and adjusted earnings per share. However, investor sentiment turned negative as the company reaffirmed its full-year 2026 financial outlook, which fell short of Wall Street's consensus estimates. The guidance incorporates the anticipated unfavorable impact of government drug pricing policies, including most-favored-nation pricing and TrumpRx, as well as currently imposed tariffs.

Adding to the concerns, Pfizer stated that its current financial guidance does not anticipate any share repurchases in 2026. This comes alongside continued challenges in the company's COVID-19 product portfolio, with revenues for Comirnaty and Paxlovid declining significantly in the fourth quarter due to lower infection rates and narrower vaccine recommendations.