Veteran insurance figure Joe Plumeri has joined investment bank Kohlberg Kravis Roberts (KKR) as a senior adviser, a month after retiring as chairman of Willis.

He also joins the board of KKR company First Data, which processes payment transactions.

Mr Plumeri left Willis after 12 years, including serving as CEO until January.

KKR co-founder Henry Kravis says he worked with Mr Plumeri when KKR acquired Willis in 1998, listing it on the New York Stock Exchange in 2001.

“Joe Plumeri is a leader known to be a catalyst for positive change,” he said. “Joe led the transformation of Willis from a company with an enterprise value of less than $US2 billion ($2.2 billion) to one with nearly $US10 billion ($11.07 billion).”

“At Willis, he earned a reputation for being passionate about client service and for his commitment to integrity and transparency.”