It is a short-term bank loan of the equity in the home you are selling. You may take out a bridge loan, or interim financing, to help with a knotty situation: closing on the home you are buying before you close on the property you are selling. This loan basically enables you to have a place to live after the closing on the old home.
The key to a bridge loan is having a qualified buyer and a signed contract. Usually, the lender issuing the mortgage loan on the new home will write the interim financing as a personal note due at settlement on the property being sold.
If, however, there is no buyer for the property you have up for sale, most lenders will place a lien on the property, thereby making that bridge loan a kind of second mortgage.
Things to consider: interest rates, points are high, and there are costs and fees involved on bridge loans. It may be cheaper to borrow from your 401(K). Actually, any secured loan is acceptable to lenders for the down payment. So if you have stocks or bonds or an insurance policy, you can borrow against them as well.