US buy-out firms The Carlyle Group and The Blackstone Group last year made record payments to investors. David Rubenstein, co-founder of Carlyle. said it was a "golden age" for private equity that would not last forever.

Carlyle, which manages the largest buy-out fund in the US, paid out $7bn (€5.7bn) to its investors, Rubenstein, told Bloomberg at the World Economic Forum in Davos.