In an update to the market, the Aim-listed asset manager said assets increased 10% during the third quarter of its financial year ending 30 June.
At the end of March, Impax’s AUM stood at £13.3bn, according to its interim results published on 5 June.
Peel Hunt analyst Stuart Duncan noted a £1bn boon from rising equity markets and a chunky pension fund mandate boosted the firm’s assets during the quarter.
Flows in Q3 included an estimated $200m (£160m) mandate from the California State Teachers’ Retirement System (Calstrs).
Peel Hunt’s note said: “Flows have remained positive and client engagement remains strong. The valuation remains high but we still see value and maintain our add recommendation.”
Peel Hunt also noted a strong pipeline of mandates. It highlighted the West Midlands Pension Fund which has named Impax as one of five managers set to receive part of £1bn it is allocating to sustainable investment strategies.
Impax chief executive Ian Simm (pictured) said: “Impax has again delivered strong growth, with significant net inflows and a rising market contributing to an AUM increase of 10% over the three months to 30 June 2019. The transition to a more sustainable global economy is gaining pace and the specialist expertise that Impax has in this area is resonating with asset owners around the world.”