The coupon rate is the bond’s stated interest rate when it is issued. This is the rate the issuer promises to pay the bondholder each year to use the money until maturity. On the other hand, a bond’s yield is its effective rate of return based on the purchase price of the bond. If purchased at par, then the yield will effectively match the coupon. However, when purchased after the bond has been issued and commences trading, the yield may differ from the coupon as price moves up or down. It is important to note that the yield and the price have an inverse relationship. If price goes up then yield goes down and vice versa.