The mortgage giant Freddie Mac has filed suit against more than a dozen banks for losses stemming from the manipulation of the global interest rate Libor. The rigging of Libor altered the benchmark for rates on trillions of dollars in transactions across the globe, meaning millions of borrowers paid the wrong amount on their loans. Along with Fannie Mae, Freddie Mac’s losses from the Libor scandal could top more than $3 billion. Freddie Mac’s suit targets banks including Bank of America, JPMorgan Chase and Credit Suisse. The lawsuit accuses the firms of fixing Libor “to hide their financial problems and to boost their profits.”