Bristol Myers Squibb and AstraZeneca have held talks to merge, according to reports on Aug. 3, but analysts say the deal is unlikely due to significant business overlap that could lead to antitrust scrutiny.
AstraZeneca’s shares fell more than 4% in pre-market trading Monday morning to $162.13, while Bristol Myers Squibb rose nearly 6% to $69.20 following news of the discussions. The Financial Times reported rumors of the potential mega-merger over the weekend. If completed, it would be the largest pharmaceutical industry deal in history.
Analysts from BMO Capital Markets said Sunday evening, “Based on significant business overlap, we believe a deal is less likely to materialize.” They added that both companies’ commercial portfolios contain several areas of overlap, which could reduce the odds of a successful merger. In particular, both compete in non-small cell lung cancer with Bristol Myers Squibb’s Opdivo and AstraZeneca’s Imfinzi—Opdivo brought in $10.05 billion worldwide in 2025 and Imfinzi took in $6.06 billion.
“Multiple other therapeutic overlaps exist between the two companies to varying degrees of competition, likely raising FTC questions on potential anti-competitive issues with a deal,” BMO said.
Bristol Myers Squibb previously acquired Celgene for $74 billion in 2019 and was required by regulators to divest psoriasis drug Otezla as part of that transaction. According to BMO analysts, neither company has sufficient resources for an outright acquisition; they estimate Bristol Myers Squibb’s deal capacity at about $32 billion and AstraZeneca’s at around $37 billion.
If a merger were successful despite these challenges, Jefferies analysts wrote Sunday that it “could trigger a new wave of M&A among large global pharma companies.” They also noted such a combination would create an entity with annual sales exceeding $100 billion and what they described as “the deepest oncology portfolio in the industry.” Jefferies added, “Combination therapies increasingly define the standard of care in oncology, and the ability to develop and commercialize more complex multi-drug regimens without cross-company negotiations may ultimately prove one of the most compelling strategic rationales for a merger.”
