Shares of AstraZeneca fell after reports that it could merge with Bristol Myers Squibb in a deal worth nearly $400 billion — a combination that would rank among the largest in pharmaceutical history, if it happens.
The Financial Times first reported the potential tie-up on August 3, 2026, saying any deal would involve both cash and shares, though the structure was unclear. Neither company confirmed the talks: AstraZeneca declined to comment and Bristol Myers did not immediately respond. AstraZeneca is valued at roughly $245 billion and Bristol Myers at about $133 billion.
Investors were skeptical
Rather than cheering, the market recoiled. AstraZeneca’s stock fell — reports put the drop at anywhere from around 2.7% to more than 8% during the session — while Bristol Myers shares slipped too. The wariness reflects doubts about why AstraZeneca, which has been growing strongly on its own, would want a giant, complex acquisition.
Why analysts are dubious
“If there is one company that doesn’t need financial engineering, it’s AstraZeneca,” Jefferies analyst Michael Leuchten wrote. AstraZeneca has projected topping $80 billion in sales by 2030 with more than 25 billion-dollar products, while Bristol Myers faces looming patent cliffs on top sellers like Opdivo and Eliquis. Analysts also flagged heavy antitrust scrutiny, particularly in the U.K., where AstraZeneca is a cornerstone of biopharma research. For now, it remains an unconfirmed rumor — but one big enough to move markets.