Plus500 has stopped taking on new customers as it attempts to clear the backlog of frozen accounts. It said last week that the debacle had so far cost it $4m in revenue at its UK business.

“Recent events and associated publicity have meant that Plus500 has become the subject of increased scrutiny and has received additional requests for information from its regulators in the jurisdictions in which it is licensed,” the two companies said on Monday.

“Whilst Plus500’s products, technology and marketing skills remain strong, the recent regulatory scrutiny placed on Plus500 has highlighted the advantages of expanding the operational infrastructure to support a business of its size.”

Numis analyst Jonathan Goslin said: “Given the ongoing uncertainty surrounding how the FCA may react, what proportion of clients can ultimately be verified and the potential reputational impact on the group, we believe this represents a good deal for shareholders.”