Coutts has put aside £110m to compensate clients who may have been sold unsuitable investments over the past 60 years.
The decision comes after the RBS-owned private bank initiated an investigation into advice it has given over several decades. It settled on the figure after RBS published its results earlier this month, meaning it was not included at the time.
According to the FT, the firm has contacted 15,000 customers to inform them about the situation.
Coutts UK chief executive Michael Morley told the paper there have been “some instances” where the previous advice process “could have been better”.
The problems with Coutts’ advice are closely linked to record-keeping, much of which had been paper-based. The review is ongoing, and is expected to be completed early next year.