The investment management arm of London and Australia-listed Henderson Group has felt the wrath of the UK's decision to exit the European Union.

London-based Henderson Global Investors has blamed Brexit turbulence for £1 billion ($1.22 billion) of retail net outflow in its third quarter results.

Assets under management grew 6 per cent to £100.9 billion from the end of June to 30 September, 2016, propelled mainly by positive markets and foreign exchange gains caused by sterling weakness.

Institutional net flows contributed a further £400 million. 

Over 70 per cent of the outflow occurred in July during the immediate aftermath of the UK referendum and despite a stronger economic backdrop than initially expected, retail client sentiment remains cautious, Henderson Global Investors said. 

Still, long-term investment performance remained strong, with 77 per cent of funds outperforming over three years.

“This quarter’s retail outflows were concentrated in the period immediately after the UK Referendum, with the rotation out of European assets balanced to some extent by continued demand for absolute return and income generating strategies,” said Andrew Formica, chief executive of Henderson Global Investors.

In light of the company’s acquisition of US-based Janus Capital Group, he added: “Over the next few months, we will continue to serve our clients with our customary dedication, and use the time well to prepare for the launch of Janus Henderson Global Investors.”