Market Share Fannie Mae and Freddie Mac make money by borrowing in the bond market and reinvesting the proceeds in higher-yielding mortgages and securities backed by home loans. Congress created Freddie Mac and expanded Fannie Mae in 1970 to promote home buying in the US. The companies' charters give the Treasury the authority to buy as much as $US2.25 billion in each of their securities in the event of possible default, implying the government will stand behind the companies' debt.