A single residential or commercial mortgage that a lender has issued to a borrower and that has not been securitized. Whole loan lenders commonly sell their whole loans in the secondary mortgage market to buyers such as Fannie Mae. One reason lenders sell whole loans is to reduce their risk. Instead of holding a mortgage for 15 or 30 years and hoping that the borrower will repay the money, the lender can get the principal back almost immediately.