New Delhi, Feb. 3 -- 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...