In the past the European Growth fund held about 50-60 stocks, Global Growth 75-100 and the Capital fund 65-70. After a six-month review the European Growth and Capital funds each invest in about 100 stocks and Global Growth now has a target range of 150-200.

The review followed a year of underperformance by the three funds, which in total contain assets of £2.55 billion.

Nick Wells, product and communications director at Artemis, says the problem with quant systems is that they struggle during periods of extreme volatility.

"We have spent six months looking at the way the process works," he says. "The process itself is fine. Instead what we have looked to improve is how we implement the ideas at a subjective level.

"In the past when a company's SmartGARP score has improved we have tended to wait for a period to confirm our thoughts. By raising the number of holdings we can make smaller initial purchases to buy into those companies at a much earlier stage."

Wells says the increases in holdings have not made the funds less concentrated in their focus. "The stocks we really like can now represent a bigger portion of the portfolio," he says.

The biggest stock in the European Growth fund was typically about 3.5%. Now it can be 5%.

The top 50 stocks in the European Growth fund also represent 80% of the fund. In Global Growth the top 75 stocks are 75% of the portfolio and in the Capital fund the top 50 stocks still represent 85% of the fund.

In another change on the European Growth, the quant process controls 90% of the portfolio. Before, 75% was managed by SmartGARP and 25% controlled according to the manager's judgment.

In the short term the changes seems to be working. European Growth has moved from fourth quartile over one year to third quartile over three months. The Capital fund is 46th out 323 funds in the IMA UK All Companies sector over three months.