Guardian columnist Nils Pratley argues AstraZeneca does not need a $400bn (£300bn) mega-merger with US firm Bristol Myers Squibb, warning that pursuing one would risk undermining chief executive Sir Pascal Soriot's otherwise successful tenure. Reports of the potential tie-up sent AstraZeneca shares down 8.9%, reflecting investor unease about a deal that would saddle the Anglo-Swedish drugmaker with substantial debt despite AZ already having a strong, self-sufficient growth strategy.

Soriot has built AZ's success on developing its own drugs alongside smart licensing and partnerships, notably in China, rather than large-scale consolidation, and analysts including Jefferies note the company has no need for such "financial engineering". A merger would also mean inheriting BMS's looming patent cliff, with sales of its blockbuster Opdivo cancer drug expected to fall sharply before 2030, while a combined oncology giant would likely face a long and distracting US regulatory approval process. Soriot recently reaffirmed confidence in AZ's 2030 target of $80bn in annual revenue, despite one late-stage drug trial failure, citing 20 major drug results due over the next 18 months as reason to stick with the current strategy.