Suspicious share trading activity preceded 41% of UK takeover announcements in 2025, a record high that signals growing concerns at the Financial Conduct Authority (FCA) regarding market leaks and insider trading. This figure represents an increase from nearly 38% of deals in 2024 and surpasses the five-year average of 33.7%.

The FCA attributes the rise in "abnormal trading activity" partly to elevated global economic and geopolitical volatility, which can influence price movements. However, the trend represents a setback for the regulator's efforts to combat financial crime, a stated objective in its recent strategy. The watchdog has previously warned market participants about potential leaks of sensitive deal information.

The data also revealed abnormal trading increases before 8.1% of other price-sensitive announcements by UK-listed companies, up from 5.6% in the prior year. The FCA secured four insider trading convictions and levied £1.77 million in fines last year, but overall financial fraud, including investment and push payment scams, more than doubled to £1.2 billion. This suggests broader challenges for the FCA in achieving its financial crime reduction goals.