River and Mercantile registered a net inflow of £3.8 billion in the 12 months to the end of June.
This was split between net sales of £2.2 billion and 'positive rebalancing flows in Derivative Solutions of £1.6 billion'.
Meanwhile positive investment performance across all its divisions added £1.7 billion worth of assets.
Overall, fee earning assets under management increased by 22% to £31 billion.
Performance fees for the 12 months are estimated to be £12.5 million.
Commenting to the performance, River and Mercantile chief executive Mike Faulkner told the market:
'Our client orientated solutions and low attrition rates have resulted in positive net flows in each of the last thirteen quarters since the IPO in 2014.'
He added: 'We remain well positioned to continue this growth and will continue to invest in our operating platform, international capabilities and new product launches.
'I believe it is rare for any investment firm to have this consistency across product offerings, and that is testament to both the quality of our people and the focus of the business on those areas we are confident we can do well.'