Explaining FinReg: Fannie and Freddie

"The right way to think about Fannie Mae and Freddie Mac is to think about the widespread availability -- at least before the crisis -- of 30-year, fixed-rate mortgages with no prepayment penalty. That is not a financial product that flourishes in the state of nature, and for obvious reasons. If you're a bank, why do you want those mortgages? If interest rates go down, people refinance and pay the loan back early. If they go up, you might be losing money on the loan. It's heads they win, tails you lose."