Improved investment performance helped to propel the AuM figure higher, it said.
The private banking arm of Royal Bank of Scotland – covering its Coutts and Adam & Co businesses – logged a rise in total assets under management and administration, standing at £29.6 billion ($38.3 billion) at the end of September from £26.4 billion at the end of 2018.
Private banking operating profit rose to £81 million from £75 million in the previous quarter, but fell from £84 million a year earlier. The cost income ratio widened over the 12-month period to 60.1 per cent from 56.4 per cent.
The UK-listed private bank said lending rose by £500 million from the previous quarter of this year to £15.2 billion, while deposits rose by £200 million to £1.0 billion, equating to year-on-year growth of 4 per cent.
Excluding strategic, litigation and conduct costs, operating costs fell by £1 million from the third quarter of 2018.
Across the whole RBS group, it logged an attributable loss of £315 million in the quarter, or a pre-tax loss of £8 million, including a £900 million provision for payment protection insurance, compared with an operating profit of £961 million a year before.