AstraZeneca Falls 9% in London on Merger Speculation; Bristol Myers Squibb Swings
As of last Friday, AstraZeneca had a market value of about US$264 billion and Bristol Myers Squibb (BMS) about US$133 billion. Speculation of a merger sent AstraZeneca shares down 9% in London on Monday, its biggest daily drop since March 2020, with a similar decline in the US. BMS shares rose nearly 8% premarket before reversing. The companies compete in oncology with Imfinzi and Opdivo; 2025 revenues were US$6 billion and US$10 billion respectively. BMS faces patent expiries for Eliquis and Opdivo, which together contribute over half its revenue. AstraZeneca posted first-half 2026 revenue of US$30.672 billion, up 6%, while BMS had US$24.462 billion, up 4%, with oncology products over 40% of BMS revenue. Regulatory and integration challenges loom.
As of last Friday, AstraZeneca had a market value of about US$264 billion, and Bristol Myers Squibb about US$133 billion.
Markets reacted sharply to the merger news. AstraZeneca closed down 9% in London on Monday, its biggest one-day decline since March 2020, and fell nearly 9% in the US market. Bristol Myers Squibb shares rose nearly 8% in premarket trading before turning lower. The previous trading day, AstraZeneca closed at US$169.64 on the New York Stock Exchange, and Bristol Myers Squibb at US$65.31.
The two companies have overlapping businesses. AstraZeneca's Imfinzi and Bristol Myers Squibb's Opdivo are both immune checkpoint inhibitors, competing directly in non-small cell lung cancer. In 2025, Opdivo generated US$10 billion in global revenue, while Imfinzi brought in US$6 billion. Moreover, Bristol Myers Squibb's core products Eliquis and Opdivo face patent expirations, with the two drugs together accounting for more than half of the company's revenue. AstraZeneca reported first-half 2026 revenue of US$30.672 billion, up 6% year on year, including US$14.123 billion from oncology. Bristol Myers Squibb posted first-half revenue of US$24.462 billion, up 4%, with oncology products representing over 40% of revenue.
The deal faces multiple regulatory reviews. In addition, integration would involve differences in R&D systems, commercial teams and corporate culture, making execution challenging. AstraZeneca's 2025 revenue was US$59 billion, and the company has previously set a target of US$80 billion in revenue by 2030. Bristol Myers Squibb's pipeline includes the anticoagulant milvexian and the schizophrenia drug Cobenfy, with key trial results not yet released.