In spite of the blows landed on it, the private equity punchbag keeps on swinging back. Buy-out firm Warburg Pincus has raised $15bn for its latest fund, as investors continue to pour money into the industry in spite of the credit crisis and economic slowdown.

If history is any guide, investors are right to keep the faith – funds raised when financial markets are strong probably make for relatively unremarkable returns. A range of private equity funds had difficulty reaching their capital-raising targets during the last US economic downturn in 2001. But funds of that year’s vintage posted a median internal rate of return of 28.9 per cent, the second-highest of any year between 1996 and 2005, according to Private Equity Insider. Meanwhile, money raised in the boom of 1999 and 2000 generated returns of 12.4 per cent and 17.4 per cent, respectively.