A potential merger between AstraZeneca and Bristol Myers Squibb is being discussed, with a combined value near $400 billion, potentially creating one of the world’s largest pharmaceutical groups.

Both AstraZeneca and Bristol Myers Squibb have not commented publicly on the reports, and Reuters could not verify the information at publication.

Requests for comment to CNBC about the reports likewise went unanswered as of the article’s publication.

The potential deal comes after AstraZeneca’s recent move to upgrade its listing in New York, a development viewed as a setback for London’s financial center.

Investors will be watching upcoming quarterly results in late October from BMY and AstraZeneca, which could influence expectations around any deal.

AstraZeneca’s growth has been driven by cancer and rare disease drugs, with cancer treatments contributing around $25 billion in 2025 sales, and cardiovascular/renal/metabolism products about $12 billion.

Both companies have pursued strategic initiatives: AstraZeneca has deepened US investment and eyed a US listing, while BMY has pursued acquisitions to diversify its pipeline amid patent cliffs.

The potential merger would come roughly a decade after AstraZeneca narrowly avoided a takeover by Pfizer, highlighting continued U.S. interest in expanding scale and portfolio depth.

The Financial Times reported discussions have occurred in recent months and could materialize, be delayed, or fall apart; Reuters could not independently verify the report.

If completed, the deal would forge a biopharmaceutical powerhouse spanning Europe and the United States and rank among the biggest mergers in history.

The combined company would be valued at roughly $196 billion for AstraZeneca and about $133 billion for Bristol Myers Squibb, underscoring the scale of the potential transaction.

The story is developing, with ongoing discussions and updates expected as talks continue.