Quote from Vinny1:
What if you don't have any assets or a job? Is the loss just forgiven with the bank taking the hit?
1. Bank would try to collect against your other assets and wages.
2. When bank determines that you have nothing left, it will "forgive the debt" and write it off.
3. When bank "forgives debt", the amount of forgiven debt becomes ordinary income to the defaulter and is taxable. So, the bank might leave the defaulter alone at this point, but now the defaulter has to contend with the IRS asking for the tax money.