Amlin said it has had a good start to 2015 with limited loss activity and what the company called "an excellent investment return" ahead of expectations at 1.7%, with average funds under management of £4.4bn.
But profits were down to £258.7m from £325.7m and investment income down from £160.4m to £118.5m against the first quarter of 2014, when the return was 3.6%.
Charles Philipps, chief executive, pointed out that equity markets were particularly strong in the first quarter of 2014 and that the group's investment performance in the first quarter of 2015 was "a highly creditable result against a challenging economic background."
In its quarterly management statement, the group said bonds returned 0.9% in this period, zero-duration bonds 1.0%, cash and cash equivalents 0.1%, equities 5.7% and property 2.5%.
The asset allocation (based on allocations to sub-advisors) at 31 March 2015 was 21% bonds, 50% zero-duration bonds, 5% cash and cash equivalents, 17% equities and 7% property.
The average duration of the portfolios at the end of March was 0.4 years. Towards the end of April, the equity weighting was reduced to 16%, with the proceeds invested predominantly in zero-duration bonds.
The outlook for global economic growth is supportive for equities and property, noted Amlin, but investment return accumulation is expected to be more muted for the rest of the year with volatility picking up as the US Federal Reserve starts to raise rates from current historically low levels.