Fannie Mae and Freddie Mac are set to sell portions of credit risk on U.S. residential mortgages “to the tune of a very sizeable increase” year-over-year, according to a report by Fitch Ratings. The two GSEs have completed 11 transactions since the risk-sharing initiative was initiated in July 2013, with Fannie and Freddie expected to issue credit-linked notes on a quarterly basis, said Fitch. …