Lees has managed the £78m fund since September 2008, though it has consistently lagged its benchmark and its peer group.
Over three years to 3 December, the fund returned 25.4% versus 51.8% from the FTSE All Share and 60% average from the IMA UK All Companies sector, according to FE Analytics.
The fund currently has a high weighting to financials with Prudential, Lloyds and Barclays among the top 10 holdings.
A spokesman for F&C said: “Michael and Tom have extensive experience in managing UK equity portfolios and a strong performance track record. We are aware that performance of the fund has been disappointing and are confident the team is well-placed to turn this around.”