The bond market is the venue in which debt securities are traded prior to maturity. An investor in the bond market buys a debt instrument, which stems from what is essentially a loan to a corporation or government. In exchange for this money, the bond investor receives an interest rate. Debt instruments make interest payments at fixed intervals and for a fixed period of time; therefore, they are called fixed-income securities. The interest rate that the issuer pays is called a coupon. At maturity, the full amount of capital is returned to the investor. For investors in the bond market, two main criteria for buying a debt instrument is duration and credit quality. Duration for the bond market represents the length of the investment; credit quality refers to how strong the borrower is and how able they are to repay the full amount of debt.