Banks have a lot of money
… but they don't have enough money to provide all the funding for loans that they need in order to be profitable without the help of the larger secondary market.
The secondary market is where the primary lender can sell loans and receive a profit in the exchange. The secondary market includes two primary elements: the first is private and the second is governmental.
The recent liquidity issues have come as a result of the secondary market having less interest in purchasing loans from the originating institutions. In order for lenders to offer new loans to new buyers, they have to continually market a portion of their portfolios. If they are not able to resell loans to the secondary market, they quickly lose their ability to issue loans as they will run out of money. Still, there are some originators that are large enough to hold their full portfolio but very few lenders are that large (an example of one that often keeps their loans in house is Wells Fargo).
The reason for the lack of strength in the secondary market relates directly to the probability of default on loans. Even with the various sorts of insurance available, no one wants to own a loan that is going to default. This is even truer in a market with falling home values where the equity buffer is eroding.
The “governmental” side of the secondary market includes the institutions of Fannie Mae and Freddie Mac. Fannie Mae and Freddie Mac purchase loans from primary lenders and resell them on the secondary market. Their activity accounts for approximately 20% of all US mortgage funds. These two entities are sometimes referred to as “conduits” because of how they function by buying loans and re-marketing them.
The non-governmental or private sector of the secondary market accounts for about 80% of the funds available to back loans. Loans are sold on the secondary private market through many different mechanisms that are owned by a broad range of investors who are looking for reasonably secure investment instruments that have a predefined schedule for repayment.
The main investors in the secondary private market include pension funds, life insurance companies, commercial banks, and thrifts. So what is it that the secondary market purchases? Sometimes they purchase the actual loans, sometimes they purchase pools of mortgage backed securities, and sometimes they purchase bonds that are backed by mortgages.
Contrary to the popular perception, there is no explicit guarantee by the federal government to back Fannie Mae or Freddie Mac. In fact, these are private corporations that are only chartered by the federal government - they are not governmental organizations at all. They are private for profit companies. But, you can bet that Uncle Sam keeps close tabs on them. Have you ever heard of Ginnie Mae? This is a true governmental organization that backs FHA and VA loans. The guarantees of Ginnie Mae are explicit not implicit.
There are upper limits to the loan amounts that Fannie Mae and Freddie Mac are permitted to handle. These limits change from time to time and have been manipulated recently as a mechanism to help stimulate the issuance of loans.
As long as your loan is below the maximum limit currently available, it is considered to be a conforming loan. If it is above those limits, it is considered to be non-conforming or jumbo loan. There are additional costs for obtaining jumbo or nonconforming loans (including higher interest rates) so it is to your advantage to stay below that limit if possible.