Hargreaves Lansdown's assets under administration rose to £77.0bn in the four months to the end of April - up 10%.
Net new business was £3.3bn during the period, taking year to date net inflows to £5.6bn.
The group said this performance was driven by a recovery in investor confidence ahead of tax year end, the launches of the CF Woodford Income Focus Fund and its HL Select UK Income Shares fund, the new higher ISA allowance from 6 April 2017 and the launch of Lifetime ISA.
Net revenue for the period was £130.9m, benefiting from net new business, higher market levels and strong share dealing volumes.
It said this had resulted in year to date net revenue of £315.7m, 17% higher than last year.
At 9:09am: (LON:HL.) Hargreaves Lansdown PLC share price was -56p at 1291p