In an open letter to city Comptroller William Thompson, Aon executive chairman Patrick Ryan said the company would "indefinitely suspend" its business ties with Iran from April 1.
"As of that date, neither Aon nor any of its subsidiaries will maintain an office or other physical presences in Iran or do work for government or business entities domiciled there," Ryan said.
A group of funds, including the New York City Police Pension Fund and the New York City Board of Education Retirement System, filed a shareholder proposal requesting Aon to review its links to Iran in late 2004, with particular attention to potential financial and reputational risks.
"Aon has made the right decision, and one that I hope other companies will achieve as well," Thompson said.
"I am pleased that Aon has examined its overseas operations and realized that its corporate connections to Iran were not in the best interests of its shareholders, and this country," he added.