In a senior executive reshuffle, Aon Plc has named Eric Andersen head of the Aon Benfield reinsurance operation and Mike O’Connor to lead the Aon Risk Solutions unit.Both executives will report to Steve McGill, group president of Aon and chief executive officer of the company’s Risk Solutions segment, the London-based company said in a statement. Andersen was most recently CEO of Aon Risk Solutions Americas, while O’Connor was chief operating officer of the risk business.Aon is the world’s second-biggest insurance broker by market value,CEO Greg Case is shuffling managers as he vies with Marsh & McLennan Cos. and Willis Group Holdings Plc to broker coverage and consult with businesses on risk management.Aon also said Bryon Ehrhart will be CEO of Aon Benfield in the Americas.The leadership changes are “a natural evolution,” McGill said in the statement. “We must continue to stay ahead of the curve for our clients.”Aon has rallied 36 percent this year, compared with the 20 percent advance in the Standard & Poor’s 500 Index. New York- based Marsh & McLennan is the largest insurance broker by market value, Bloomberg says.