Mortgage GSEs, or government-sponsored enterprises, are basically financial services corporations. All were created by Congress with the aim of improving the flow of credit into certain housing markets while reducing the cost of that same credit. The two most widely known examples of mortgage GSEs are Fannie Mae and Freddie Mac. Besides Fannie and Freddie, another popular GSE is Ginnie Mae. A separate group of 12 federal home loan banks also works as a mortgage GSE.