Shares of US drugmaker Pfizer Inc. slumped on Tuesday following a fourth quarter loss due to a large write-down. It also forecast lower revenues for 2026.

The pharma giant highlighted another fall in quarterly revenues tied to Covid-19 products, and $4.4 billion in asset impairments that were needed “due to changes in development plans and updated long-range commercial forecasts,” Pfizer said in a statement.

The results also indicated that the firm again plans no share buyback this year as it works to limit its debt while funding a research and development program intended to offset the hit from lost patent advantages.

“Current financial guidance does not anticipate any share repurchases in 2026,” said Pfizer.

The company anticipates R&D expenses between $10.5 billion and $11.5 billion in 2026. In 2025, it spent $10.4 billion on R&D.

At 1:01 p.m. EST, Pfizer stock was down 3.60%, or $0.96, at $25.70.

The drugmaker reported a loss of $1.6 billion for October-December 2025 period when compared with $410 million profit in the fourth quarter of 2024.

Its quarterly revenue dropped 2% to $62.6 billion.

Pfizer’s Chief Executive Officer Albert Bourla said the company’s 2025 “solid” performance provides a “foundation for future growth.”

2026 “will be an important year rich in key catalysts, including our expectation for approximately 20 key pivotal study starts, and continued strategic investment to maximize our opportunities for industry-leading growth at the end of the decade,” added Bourla.

The company forecast its 2026 revenue of $59.5 billion to $62.5 billion, slightly down from $62.6 billion last year. Its overall outlook for this year stood in line with December projections.

Drop in Covid-19 Vaccine Revenue

In the December quarter of 2025, the drugmaker recorded a 35% drop in revenue from Covid-19 vaccine, Comirnaty, and a 75% decline in sales tied to therapeutic drug, Paxlovid.

Since the pandemic, Pfizer has completed acquisitions of oncology drug specialist Seagen and Metsera, which is known for weight loss products.

Pfizer said half of the 20 trials in 2026 are for “ultra-long-acting obesity assets” acquired from Metsera.

A range of clinical trial results for anti-obesity products were “encouraging,” but the company was targeting the first of government approvals only in 2028, said Pfizer Chief Scientific Officer Chris Boshoff in a statement.

However, investors are looking for combinations of treatments that can produce more weight loss than current medicines, while keeping gastrointestinal side effects to a minimum.

Pfizer needed to come in with a far better product on efficacy or safety to get established in the space, said analysts.