NEW YORK (Bloomberg) ? Aon Corp., the world's second-largest insurance broker, yesterday agreed to sell a specialty property and casualty unit to Old Republic Insurance Co. for $85 million in cash.

Aon will also transfer $300 million in unearned premium and claim reserves to the unit, Construction Property Group, the Chicago-based company said in a statement. Aon plans to abandon its entire specialty property and casualty business, it said.