Investors have received less than a quarter of the cash invested in European private equity funds at the height of the buyout market, a factor that is leaving many over-exposed to the asset class and unable to make new commitments.

Around 23% of capital deployed in European mid and large-cap buyouts between 2006 and 2008 has been returned to investors while the remainder continues to draw management fees, according to a research paper by private equity advisory firm Acanthus.