The Willis Group, the insurance broker, has persuaded Joseph Plumeri, who retired earlier this year after 32 years at Citigroup, to become its new executive chairman and chief executive officer.

Until his retirement, Plumeri oversaw the integration of Citibank's retail networks following the merger with Travelers Group in 1999. Before that, as president of Shearson, he oversaw the integration of Shearson with Smith Barney.