The number of so-called 'dawn raids' conducted by the Financial Conduct Authority has almost doubled in one year.
According to law firm Reynolds Porter Chamberlain (RPC), the regulator conducted 20 raids in 2013 versus 11 in 2012.
RPC attributed the rise to the financial watchdog's crackdown on 'boiler room' scams.
The number is set to escalate further this year after 110 people, including 20 in the UK, were arrested in dawn raids as part of Operation Rico, a multi-jurisdiction investigation into boiler room fraud.
Last week the National Crime Agency and Kent police arrested a 21-year-old as part of the financial watchdog's investigation.
RPC regulatory partner Richard Burger said: 'Looking at all the current FCA criminal investigations it is clear that the FCA is widening the scope of its investigative responsibilities.'
He added: 'It is important that the FCA meets its consumer protection remit by cracking down on boiler room frauds but it is crucial that it doesn’t lose momentum in tackling complex financial crime like insider dealing.'