Major companies in the UK are tightening controls over confidential merger and acquisition (M&A) activity, putting pressure on investment banks to restrict access to sensitive information amid growing concerns about leaks and insider trading.
Several investment banks have been approached by their clients in recent weeks with demands to reduce the number of employees informed about ongoing UK takeover transactions, according to sources speaking to the Financial Times. The move comes as regulators and corporate clients express alarm over the frequency of leaks and suspicious trading activity preceding public deal announcements.
A heightened sense of urgency followed a recent Financial Times freedom of information request that revealed nearly 40% of takeovers involving UK-listed companies were reported in the media before being officially announced. The data, provided by the Financial Conduct Authority (FCA), covered transactions from April 2024 through May 2025.
One senior investment banker noted that the UK’s Takeover Panel — the body responsible for enforcing public M&A regulations — has intensified efforts to clamp down on such information leaks, saying: “They’re turning up the heat.”
Rising Regulatory Scrutiny
The FCA and the Takeover Panel have long pressed for tighter information control within banks, especially concerning the number of “permanent insiders” — individuals with ongoing access to market-sensitive, non-public information. Best practices recommend limiting access to a small circle of senior executives directly involved in deal execution.
The FCA has also warned that violations of market abuse regulations can result in unlimited fines, court injunctions, and even bans on regulated firms or individuals. In a 2019 case study, the FCA found that one financial firm had just 12 team members working on a deal, but over 600 employees, including compliance and risk teams, had access to inside information. A follow-up review in 2022 showed that while the number of insiders at large banks had declined, it still ranged between 250 and 450 per deal.
Clients Pushing for Change
Clients are increasingly uncomfortable with the idea that hundreds of bankers and support staff may have access to confidential information. This unease has created an opening for boutique advisory firms, which market their smaller teams as a more secure and leak-proof alternative to larger institutions.
Despite regulatory guidelines, enforcement remains a challenge due to the difficulty in identifying the source of leaks. “It’s relatively common to have internal conversations about leaks,” said one deal monitor. “But people always point fingers at the other side.”
Bankers, due to their sheer numbers on any given deal, are often blamed. However, leaks have also been attributed to corporate strategies aimed at attracting rival bids or deterring unwelcome offers.
Foreign Bidders and Cultural Misunderstandings
Another complication arises from international buyers unfamiliar with the UK’s stringent takeover rules. In the UK, companies are often required to publicly name potential suitors if rumors of a deal surface. “For foreign clients, it can be a bit weird,” one banker explained. “They ask, ‘What’s this Takeover Panel, why can’t I talk?’ It’s very different from doing deals in the US.”
As UK regulators continue to crack down on leaks and insider trading, companies are expected to keep pushing banks toward more disciplined and discreet practices. The trend signals a shift in how sensitive information is handled, with trust and discretion becoming increasingly valuable commodities in the high-stakes world of corporate dealmaking.
