Two US companies have formed a $3.6bn (€2.5bn) fund to finance private equity deals as the global credit crunch has robbed sponsors of firepower and buyouts have plummeted to the lowest proportion of global M&A since the start of 2003.

Private equity acquisitions made up just 7% of global M&A volumes in the last quarter, the lowest proportion since the first three months of 2003 and less than a third of their level in the same period last year, according to Dealogic, the investment banking research provider.