Quoted: “Once you have an exemption for [foreign-exchange] transactions, you immediately have one that also covers interest rate transactions, and the two together represent roughly 90%” of over-the-counter derivatives trades, said Antonio Mello, a finance professor at the University Of Wisconsin (Madison) School of Business. “So that would be a major portion of the [over-the-counter] market that would immediately become somewhat exempted” from the new derivatives rules.