A mortgage is an interest or ownership (or transfer of interest) in property as collateral or security for debt. This is usually in exchange for money or a loan. Loans are commonly made to people buying residential or commercial property and the mortgage acts as the lender's security or assurance of repayment. People can leverage their buying power for property by borrowing and lenders earn interest usually measured by an annual percentage rate (APR). The mortgage is retired or the interest in the property surrendered to the lender when the loan is satisfied or paid in full. A mortgage note or instrument is often referred to as a deed or deed of trust.