Wall Street reacts negatively to AstraZeneca-Bristol Myers merger talks, shares tumble

A report in the Financial Times, followed by Reuters, said AstraZeneca and Bristol Myers Squibb have been discussing a possible combination in recent months.

The news triggered a sharp sell-off. AstraZeneca stock fell more than 8%, erasing about $22 billion of market value, while Bristol Myers shares slipped roughly 1.5%.

The proposed merger would create one of the largest pharma groups, with a combined valuation close to $400 billion. AstraZeneca recently completed a direct listing on the NYSE, though its primary listing remains in London.

Analysts said the talks are still preliminary and could stall or be delayed, leaving investors wary of the potential deal.