If the behaviour of a company starts to look unethical, or falls out of favour, Ms Duncan will sell it completely.
Due to the ethical screening, the fund may avoid entire sectors. This means its performance can differ quite significantly from the benchmark and exhibit a different volatility profile in comparison to the sector average.
However, the cumulative long-term returns speak for themselves: over one and three years, the fund is top decile in the UK All Companies sector, outperforming the average fund by 10 per cent and 16 per cent respectively.
It is top quartile over five and 10 years, outperforming by 25 per cent and 31 per cent (data according to FE Analytics, total return, as at 26 September).
It goes to show that good investing behaviour can be rewarded.
Darius McDermott is managing director of FundCalibre