In a Q3 trading update, published on Thursday, the firm said the 3% increase was buoyed by £1.3bn of net new business during the period stemming from continued investment in digital marketing, higher client numbers and ongoing wealth consolidation onto its platform.
Its AUA was further enhanced during the quarter by £1.2bn of positive market movements.
However, Hargreaves Lansdown chief executive Chris Hill (pictured) said: “The past quarter has seen an uncertain market environment and weak investor sentiment resulting in an industry-wide slowdown in net retail flows.”
The broker and platform provider’s shares fell 6% in mid-morning trading on Thursday.
Hill added: “Despite this backdrop, we believe the strength of our business model positions us well for when sentiment improves.”
Elsewhere, the firm reported a 16% increase in net revenue for the period, from £104m in Q3 2017 to £121m in Q3 2018.
It also added 29,000 clients during the period, taking the total to 1.12 million.
In August, Hargreaves Lansdown reported that Hill received a £2.5m remuneration package in the financial year ending 30 June 2018.