Aon Corp. on Thursday announced the sale of its Swett & Crawford wholesale insurance brokerage–the nation's largest–to venture capitalists as the fallout from New York Attorney General Elliot Spitzer's probe continues to reshape the industry.

Aon thus became the third major insurance brokerage to sell its wholesale unit since Marsh, Inc. pledged in its $850 million agreement with the state of New York earlier this year, not to funnel business through wholesale brokers unless they get clients' approval beforehand.

Aon announced in February its plan to sell the unit. Announcement of the deal follows the Sept. 7 disclosure by Marsh of a deal to sell its Crump Group, Inc., wholesale brokerage operation, to an affiliate of J.C. Flowers & Co. LLC, a New York-based private equity firm. Willis Group also has announced plans to divest its wholesale brokerage unit.