Boutique fund manager Bellwether Partners won its first institutional investment mandate after the $430 million Combined Fund invested in its high performing flagship fund.

Combined Fund, acting under the advice of its asset consultant, Counterpoint Group, invested the mandate in the Bellwether Australian Share Fund, which offers a concentrated portfolio of large cap Australian stocks. The mandate amount was not disclosed.

Since its inception in 2004, Bellwether's Australian Share Fund has delivered strong performance - returning 16.14 per cent per annum to investors over a three year period to June 30. The fund outperformed the S&P/ASX 300 Accumulation Index by 4.72 per cent.

More recently, the fund reported losses of 8.15 per cent for the year to June 30, against the index's loss of 13.67 per cent.

Bruce Bell, founder and chief investment officer of Bellwether, called the mandate "a significant vote of confidence" in Bellwether's investment approach.

He attributed the success in high conviction portfolios to discipline and an ability to filter market noise - a strategy Bellwether implements via quantitative and qualitative screens.

"Our structure, which tightly integrates portfolio management skill, dealing and analysis allows rapid assimilation of information and has visibly added value," said Bell.