President-elect Donald Trump shakes hands with Jonathan Gray, member of the Board of Directors at Blackstone, following their meeting at Trump International Golf Club, November 20, 2016 in Bedminster Township, New Jersey. (Credit: Drew Angerer—Getty Images) Private equity firms are taking longer to return cash to investors and finding it more difficult to raise new funds. The industry could use a long-awaited surge in M&A, and there are signs of optimism when it comes to big money transactions.