The year 2008 was full of nasty surprises. One of the biggest was the government takeover of twin mortgage giants Federal National Mortgage Association (FNMA, or Fannie Mae) and Federal Housing Lending Mortgage Corporation (FHLMC, or Freddie Mac).

The takeover happened almost overnight. Homes values were sinking fast. Between the two companies, they guaranteed most of the $7 trillion of home mortgages outstanding. At one point, almost 30% of homes with mortgages were underwater.

The situation seemed dire. So, the U.S. Treasury “offered” to lend the mortgage companies tens of billions of dollars, which later became an open-ended line of credit.

The Treasury demanded three things in exchange.

The companies would go into conservatorship – meaning they could continue to operate, but only with the Treasury there to offer support.

They would issue the Treasury $1 billion in preferred stock with a 10% dividend.

Finally, they'd issue warrants for up to 79% of the companies to the Treasury.

The boards had no choice. They agreed and were promptly dismissed.

All told the U.S. Treasury extended $187.5 billion in loans to Fannie Mae and Freddie Mac. Part of that was just so they could make good on their required dividend payment back to the government.

When housing turned up again, these two companies started earning profits. By the end of 2014 they had paid the U.S. Treasury almost $230 billion, or $40 billion more than the loans they'd received.

But here's a little-known part of the deal – the mortgage giants still owe the U.S. Treasury the original $187.5 billion in loans. The government does not consider any of the $230 billion as repayment of debt or retirement of shares outstanding.

All of it is simply profit to the government. How convenient.

Now that it effectively controls the two entities, the government can decide how to treat the money that rolls in. Since it's shown little interest in letting go of the cash cows, it will likely continue holding that $187.5 billion over their heads.