While 14.6 million might seem like a lot, it's not the real number when you consider negative equity in housing's recovery. That's because it doesn't factor in "effective" negative equity, which is borrowers who have so little equity in their homes that they cannot afford to move.

Consider the following from mortgage analyst Mark Hanson:

On US totals, if you figure average house prices use conforming loan balances, then a repeat buyer has to have roughly 10 percent down to buy in addition to the 6 percent Realtor fee to sell. Thus, the effective negative equity target would be 85%. You also have to factor in secondary financing, which most measures leave out. Based on that, over 50 percent of all mortgaged households in the US are effectively underwater — unable to sell for enough to pay a Realtor and put a down payment on a new purchase without coming out of pocket. Because repeat buyers have always carried the market as the foundation, this is why demand has not come back. It's as if half the potential buyers in America died over a two-year period of time.

The foreclosure crisis grabs most of the media attention these days, but in order for housing to recover, the market needs to see activity.