There are two primary reasons a bond might be worth less than its listed face value. A savings bond, for example, is sold at a discount to its face value and steadily appreciates in price as the bond approaches its maturity date. Upon maturity, the bond is redeemed for the full face value. Other types of tradeable bonds are sold on the secondary market, and their valuations depend on the relationship between yields and interest rates, among other factors.
All bonds are redeemed at face value when they reach maturity unless there is a default by the issuer. Many bonds pay interest to the bondholder at specific intervals between the date of purchase and the date of maturity. However, certain bonds do not provide the owner with periodic interest payments. Instead, these bonds are sold at a discount to their face values, and they become more and more valuable until they reach maturity.
Not all bondholders hold onto their bonds until maturity. In the secondary market, bond prices can fluctuate dramatically. Bonds compete with all other interest-bearing investments. The market price of a bond is influenced by investor demand, the timing of interest payments, the quality of the bond issuer, and any differences between the bond's current yield and other returns in the market.
An Example of Fluctuating Bond Price
For instance, consider a $1,000 bond that has a 5% coupon. Its current yield is 5%, or $50 / $1000. If the market interest rate paid on other comparable investments is 6%, no one is going to purchase the bond at $1,000 and earn a lower return for their money. The price of the bond then drops on the open market. Given a 6% market interest rate, the bond ends up being priced at $833.33. The coupon is still $50, but the yield for the bond is 6% ($50 / $833.33).