Kohlberg Kravis Roberts paid out more to investment banks then any other buyout firm in 2011, a year in which banks earned more from their private equity clients than at any time since 2007.

Private equity-related investment banking fees totalled $12.4bn last year, according to Dealogic. This was largely driven by activity in the first quarter, when $4bn of fees were generated, the highest quarterly total since the second quarter of 2007.