In a letter to CEOs yesterday Mr Bailey reminded firms’ senior managers and boards of what constitutes “fair, clear and unambiguous” financial promotions.

The warning came after the watchdog discovered firms were issuing financial promotions which suggested or implied that all of the activities which they undertake were regulated when that was not the case.

The letter, which has been seen by Financial Planning Today, read: “Some of the firms that we regulate undertake both regulated and unregulated business.

“We have recently become aware of firms issuing financial promotions which suggest or imply that all of the activities which they undertake are regulated by us and/or the PRA when, in fact, they are not.

Elsewhere in the letter Mr Bailey wrote: “All financial promotions must be fair, clear and not misleading.

“Part of meeting this standard includes ensuring that (where relevant) those to whom a financial promotion is addressed, or at whom it is directed, understand the extent of the relevant firm’s business that is regulated.”

Commenting on the letter Jonathan Davidson, executive director of supervision – retail and authorisations at the FCA, warned: “It is completely unacceptable for firms, which are regulated for some of their business, to market unregulated investments by implying to customers that all their business is regulated. 

“We are committed to stamping out this misleading practice and recommend that customers should ask firms whether what they are buying is really regulated by the FCA.”