Both Fannie Mae and Freddie Mac are independent, privately run companies that operate under special congressional charters. Their mandate is to ensure that mortgage funds are made available to a broad spectrum of the American public. They do this by buying mortgages from approved lenders and then packaging those monies into securities backed by Fannie Mae/Freddie Mac. Those securities are then sold to investors in the secondary mortgage market. Fannie Mae and Freddie Mac are independently owned companies that compete with each other for mortgage business. This competition ensures that there is an ample supply of low cost mortgage money available to the American home buyer.