Fees paid by private equity firms, a lucrative source of income during the buyout boom, accounted for a significantly smaller proportion of investment banks’ revenues in the first quarter this year as deal volumes plummeted by 65%.

There were 507 buyouts globally totalling $63.1bn (€40.6bn), according to data provider Dealogic, a 65% fall from the $179.8bn from 569 deals done in the first quarter of last year.