What to do if you're upside down on your mortgage

Also see my related post: What if You're Upside Down on Your Mortgage and Need to Move?

A lot of blame for the housing crisis is placed on "sub-prime" borrowers and the banks that loaned to them. It is true that at one point earlier in the decade it was probably too easy for someone with bad credit to obtain a loan. But declining house values and the subsequent emergence of negative equity also affected many intelligent, well-educated homeowners with decent credit. Many of them Gen Xers and Gen Yers that were buying their home because they were entering the home-owning phases of their lives -- not because low-payment mortgages were falling from the sky like raindrops.
Many of these homeowners that are in trouble had simply overestimated their luck in hopes of making a good investment. I'm sure that many of them, before buying a home, analyzed the cost of renting vs the cost and appreciation associated with owning. Given the numbers at the time, buying made sense. Additionally, many of the homeowners in trouble believed their lenders were looking out for their best interests; a belief that was unfortunately discredited for thousands. And TV shows like HGTV's "My House is Worth WHAT?" gave intelligent homeowners false hope about the financial returns they could receive by spending thousands on home upgrades (and financing them with home equity lines of credit).
So if you find yourself in an upside-down situation, what do you do? Should you pay down your balance until your equity is positive? Not necesarily. You should treat your loan -- upside-down or right-side-up -- just like any other loan that you're considering to pay off early. The higher the interest rate on your loan and the lower the interest rate at which you can save, the more sense it makes to pay extra. But if you have a reasonable rate, let's say below 6.5%, I'd rather see you hold on to your money. Throwing more money at your morgage isn't going to increase the value of your home. Only time and inflation will.

If you're upside down on your mortgage, don't expect to be able to move anytime soon. Save as much money as you can in an interest-bearing savings account that is easy to access until the time comes to sell your house. If you're able to wait long enough, your upside-down issue will eventually correct itself. If you need to sell before then, your savings will enable you to send a heap of cash to your lender a week before the sale, bringing your equity back into the green in one fell swoop.
In the future, never forget the old addage "if it seems too good to be true, it probably is." I'm not saying that good investment opportunities don't exist. They certainly do. But truly exceptional opportunities rarely exist in the stubborn, slow, and steady real estate market. If you ever see your equity in your home growing faster and faster faster to a level that you can't believe, be cautious. It's like watching a racecar driving 300 miles per hour (they usually don't go much faster than 200). Sooner or later, it's going to crash.