Pricing disparity between the GSEs has almost disappeared since single-security efforts began, according to a new paper by the Urban Institute. The authors called the progress on the initiative an “unheralded success” in a paper released this week. In 2012 and 2013, Freddie’s 3, 3.5, and 4 percent coupons traded at more than a $0.30 discount to Fannie Mae’s. That number narrowed to about $0.15 in 2014 and 2015 and by early 2017 it had largely converged, said the UI. “Interestingly, the pricing disparity has all but disappeared since the single-security effort began,” said Laurie Goodman, Jim Parrott and Bing Bai, authors of the study.