During the past two weeks Fannie Mae and Freddie Mac have reported losses of more than $3.5 billion, enough to worry Wall Street investors and drive down stock values for both companies. But the question is: What about you? Should you be concerned?

The answer is "yes" and here's why: Fannie Mae and Freddie Mac buy more than half of all U.S. home loans. If they falter, the result will be less mortgage financing, higher interest rates and fewer home sales.

Fannie Mae and Freddie Mac play an important role in the real estate marketplace. They buy loans from local lenders with money obtained from investors on Wall Street. The money paid to local lenders is then used to create new loans. The result is plenty of mortgage money for every borrower, no matter where you're located.

The catch is that many investors believe Fannie Mae and Freddie Mac can't fail. The reason? Both companies are so-called GSEs -- government sponsored enterprises. Once federal agencies, they were spun off to the private sector years ago. Now shareholder owned, both companies still have a unique ability to borrow directly from the U.S. Treasury if they get into trouble.

In recent months there's been a lot of talk about increasing the size of both companies by allowing them to make bigger loans and take on some subprime lending.

The idea is to bail out borrowers stuck with high-cost toxic mortgages and make homes in expensive markets easier to sell. Now thoughts about expanding Fannie Mae and Freddie Mac are likely to be placed on hold because the government will not want to increase the risk to either company.

The bottom line: If you're now considering a home purchase or refinance, speak with lenders today. Rates are now around 6.25 percent for 30-year fixed-rate financing -- a rate which won't last long if problems in the mortgage marketplace grow.