Fannie Mae and Freddie Mac sell short term ( 3 -- 6 month ) bills at auction on a weekly schedule .
Longer - term ( 1 -- 10 year ) notes at monthly auctions .
Fannie Mae and Freddie Mac sell short term ( 3 -- 6 month ) bills at auction on a weekly schedule , and longer - term ( 1 -- 10 year ) notes at monthly auctions .