At the end of June 2011 AUM was at £24.8bn after the group recorded inflows of £700m in the preceding six months.
In comparison, the six months to 30 June 2012 witnessed £300m in outflows, with pre-tax profit also down year-on-year.
Jupiter reported pre-tax profit of £31.2m, for the six months to 30 June, down from £37.3m for the same period last year.
Edward Bonham Carter, chief executive of Jupiter, said: "Against a challenging market backdrop, it was encouraging that we saw strong investment performance, positive net mutual fund flows and growth in assets under management over the last six months."
In his market review Bonham Carter said bond and equity markets remain unconvinced that enough action is being taken by Europe’s leaders to stabilise the region.
He said despite challenging market conditions UK fund flows had improved during the period, although most assets were directed towards fixed income strategies.
Bond and money market funds also remain popular in Europe, while equity and balanced funds have experienced outflows.
The company’s private clients made a net contribution to mutual funds of £37m, but its segregated mandates did not fare so well, with net outflows of £302m for the period.
Bonham Carter said volatile market conditions often favour his fund managers’ investment approach, with their defensive positioning boosting relative performance.
Over three years to 30 June 26 out of 41 mutual funds outperformed their benchmarks (76% by AUM), while over one year to 30 June 30 out of 51 mutual funds outperformed their benchmarks (84% by AUM).