Blackstone and Aon plc recently signed a deal in which Blackstone will buy Aon’s benefits administration and HR BPO platform for $4.3 billion, with an additional $500 million or more on the table tied to future performance.

"This transaction reinforces Aon's position as the leading, global professional services firm focused on risk, retirement and health," Aon President and CEO Greg Case said. "The sale of our outsourcing platform creates incremental capital to strengthen growth in core operations, and accelerates the pursuit of inorganic growth opportunities that address emerging client needs, similar to recent acquisitions in cyber risk advisory and health brokerage solutions."

The agreement, which is subject to closing conditions like antitrust clearances, is slated for completion by the second quarter of this year. Aon expects that it will improve its return on invested capital and announced that it plans to use some of the proceeds in its ongoing share repurchase program.

"We believe that this world-class platform will thrive under Blackstone's ownership, providing clients the level of service and performance they have come to expect and allowing us to further reshape our portfolio to focus on stronger growth and higher return on invested capital opportunities consistent with our strategy," Case said.