In the six months to the end of June, AUMA rose to £577.5bn from £608.1mln last year.
Net outflows fell to £15.9bn from £16.9bn as a lower level of redemptions offset a drop in gross inflows.
In July, Lloyds agreed to pay SLA a £140mln settlement after severing the fund manager’s contract to run its Scottish Widows portfolio.
SLA will manage the £35bn in assets until at least April 2020.
The company also secured £3.5bn of assets from Virgin Money and a contract to provide multi-manager funds to clients of Skipton Building Society’s £4.6 billion investment service.
Investment performance improves but political uncertainty weighs on sentiment
The group’s investment performance improved in the first half with 65% of its AUM ahead of the benchmark, compared to 50% a year ago.
“However, despite this improvement in investment performance, demand for equities remains low across the wider market and we continued to see elevated equity net outflows,” the company said.
“Our industry leading platforms continued to attract net inflows however these were lower given weaker investor sentiment caused by ongoing political uncertainty in the UK and a reduction in defined benefit to defined contribution pension transfer activity.”
Adjusted pre-tax profit fell to £280mln from £311mln last year as fee based revenue declined to £815mln from £966mln.
SLA maintained its interim dividend at 7.3p.
Looking ahead, the firm said the “current environment for asset management remains tough” as macroeconomic and political uncertainties continue to hurt investor sentiment.
But a strong balance sheet and cost control measures will allow the group to invest for growth and generate sustainable dividends and returns for shareholders, SLA added.
Shares fell 5.8% to 265p in morning trading.
“While less negative than last year, outflows remain Standard Life Aberdeen’s Achilles heel with billions of pounds of investors’ money walking out the door every quarter," said George Salmon, equity analyst at Hargreaves Lansdown.
"That’s particularly problematic because a strategic repositioning that culminated in the sale of the Phoenix business means the group is increasingly focused on asset management rather than insurance."
He added: "Another reason outflows are hurting is that they’re coming in the group’s higher margin segments, equity and total return.
"Key to turning this around will be an uptick in performance, and while the group says 65% of all its funds have beaten their benchmark across the last three years, only 27% of equity funds have done so over that same period, and 79% of multi-asset money is behind the curve over the last year.”