UK lower mid-market buyout funds last year posted their widest level of outperformance over larger funds, marking only the second time that smaller funds have outperformed their larger rivals.

Small buyout funds - defined as those which typically make investments of up to £10m in size - posted since-inception internal rates of return of 16% to December 2012, according to the BVCA Private Equity and Venture Capital Performance Measurement Survey 2012.