Fraudsters have tried to use the brands of Royal London Asset Management and Seven Investment Management to lure customers into scams.
The Financial Conduct Authority issued two separate warning notices on Thursday, cautioning consumers to be on their guard as fraudsters used the brands to trick people into parting with their cash.
"Fraudsters are using the details of firms we authorise to try and convince people that they work for a genuine, authorised firm," the regulator said.
In the notice warning of a clone firm calling itself Seveninvest Management Limited, the regulator warned the company was not authorised or registered by the regulator, but had been targeting people in the UK claiming to be authorised.
Similarly, the regulator also warned that a clone company operating as Royal London Asset Management had been cold calling customers, using a firm reference number the regulator had given the genuinely authorised firm of the same name.
In a statement, Seven Investment Management said it had become aware a clone firm was attempting to defraud investors using original material from its website and contacted the FCA, Companies House, Action Fraud and the UK Insolvency Service.
It stressed it had no link with the company and did not have any business dealings in cryptocurrency investments, which the other firm had purportedly tried to promote.
"We very much hope that swift and decisive action will be taken to close this operation down and minimise the loss that anyone will be taken in by its reprehensible activities," it added.
A spokesperson at Royal London Asset Management, said: "We are aware of a clone firm purporting to be Royal London Asset Management, who are cold calling customers offering loan products.
"We do not use any cold calling practices nor offer loan products. We are making this clear in a statement on our website’s homepage and encourage any individual that may have concerns to contact us.
"We take any activity of this nature very seriously and are committed to protecting our customers and future customers against any fraudulent activity."
Garry Heath, director general of the financial advisers’ trade association Libertatem, said the FCA faced a difficult task, but have an obligation to guard the reputations of regulated businesses.
"The regulator has to be permanently on the lookout," he said. "There is a big task for the regulator to try and police the walls of the City. That’s the job. If we are in a regulated environment, we are effectively in a walled city. People outside of the wall, shouldn’t be able to get in.
"Sometimes I wonder whether the regulator is so busy dealing with the market that it is not guarding the wall as much as it should. If they receive any information they have to spread that information quickly and it is a damn difficult thing."
Mr Heath said clone firms were increasingly finding ways to appear credible and have even contacted Libertatem in the past, in an attempt to legitimise their operations.
"It is getting worse," he said. "A lot of them are sophisticated and literally look like the firms they are cloning."
