Many believe a short sale can only occur if a person is behind on their payments, in fact, that's quite untrue. A person can be behind on their payments and sell their home to make a profit for that matter. A short sale is when the proceeds from the sale do not cover the liabilities, period.

So must one be behind to sell their home for less than they owe?  Nope.

If you have a need to sell (hardship), and you sell your home for market value and do not net enough to cover the proceeds from your home, you can still short sale.  You may be in a position of seasonal employment or foresee a time in the future when you will not be able to continue making payments on your home, or you may need to move to take care of family or take another job, in this instance you would need to sell your home, and possibly short sale.

Some schools of thought may believe that if you aren't behind on payments, why would the bank negotiate?  This may be true for some banks, but for most their short sale departments are accepting current-on-payment short sales.    You can, as a strategy stop making payments during the short sale, but this is a decision between you, your tax accountant and attorney.