If AstraZeneca and Bristol Myers Squibb were to successfully become one company, analysts say it could reset the current deal environment, which has picked up greatly in the first half of the year.
News broke over the weekend that Bristol Myers Squibb and AstraZeneca—both massive pharma companies worth more than $130 billion each—have held talks to merge. Analysts largely brushed off the idea as “unlikely,” given the companies have major competing products that would likely snarl the deal in antitrust review.
On Monday morning, AstraZeneca’s shares fell more than 4% in pre-market trading to $162.13. On the flip side, BMS rose nearly 6% to $69.20.
Rumors of such a deal were reported by The Financial Times on Sunday. If the mega-merger did come to pass, it would be the largest in the pharma industry’s history. But analysts are skeptical.
“Based on significant business overlap, we believe a deal is less likely to materialize,” BMO Capital Markets wrote on Sunday evening. The analysts pointed to the heavy scrutiny the deal would likely receive from antitrust officials on both sides of the pond.
“Looking across both Bristol and AstraZeneca’s commercial portfolio, we note several areas of overlap that could reduce the odds of a successful merger,” BMO said.
Most notably, the companies compete in non-small cell lung cancer with BMS’s Opdivo and AstraZeneca’s Imfinzi. Opdivo brought in $10.05 billion worldwide in 2025, while 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.
BMS is no stranger to mega deals. The company bought Celgene in 2019 for $74 billion. To complete that deal, BMS was ordered to divest psoriasis and psoriatic arthritic drug Otezla to Amgen.
Neither BMS nor AstraZeneca has the firepower to buy the other outright, BMO added, making a direct acquisition unlikely. The analysts put BMS’s deal capacity at about $32 billion and AstraZeneca’s around $37 billion. BMS has a current market cap of $133.41 billion, while AstraZeneca is larger at $195.93 billion, according to data from S&P Capital IQ.
If the deal does manage to overcome all the hurdles in front of it, analysts suspect the achievement could reset the current deal environment, which has already been busy in the first half of the year.
“A successful AZN-BMS merger could trigger a new wave of M&A among large global pharma companies,” Jefferies wrote on Sunday.
A new paradigm in cancer treatment
The joining of AstraZeneca and BMS would also reset the cancer landscape, Jefferies noted. The combined company would rake in $100 billion in annual sales with the “deepest oncology portfolio in the industry,” the firm wrote.
“The strategic rationale may be extending beyond cost synergies to a competition for larger portfolios of complementary assets that can support complex combination regimens,” Jefferies said.
Up until now, AstraZeneca has successfully combined its Imfinzi with the Daiichi Sankyo–partnered drug Enhertu and Datroway. Should BMS join AstraZeneca, it would open the door for Opdivo combos.
“A combination with BMS would remove the commercial barriers to exploring more combinations with Opdivo, which has a broader scientific and commercial footprint than Imfinzi,” Jefferies wrote.
The companies could also look at triplet regimens by pairing targeted therapies with immuno-oncology drugs and antibody-drug conjugates (ADCs). AstraZeneca has many of these targeted options in its portfolio, including Tagrisso, Lynparza, Truqap and the investigational camizestrant, which is under FDA review. BMS, meanwhile, has immuno-oncology asset Yervoy and next-generation programs in the clinic, Jefferies said.
Working together, BMS and AstraZeneca could create complex treatment regimens in lung, breast, ovarian and gastrointestinal cancers, Jefferies said.
“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.”
