Investment products that use derivatives to improve returns are threatening the reputation of the $3.6 trillion market for exchange-traded funds, according to one of five commissioners at the U.S. Securities and Exchange Commission. “The risk with levered ETFs is that the entire asset class will be painted with this brush,” said Robert Jackson Jr., adding that he fears Americans will buy and hold these products in their retirement accounts, and then get a nasty surprise when they lose their money. Jackson spoke at an event organized by Bloomberg LP and the CFA Society of New York on Friday.