Whether a bond pays the investor a fixed interest rate (also known as the coupon rate), which cannot be changed during the life of a bond, or a variable interest rate, the market price of a municipal bond will vary as market conditions change. If you sell your municipal bonds prior to maturity, you will receive the current market price, which may be more or less than the original price depending on prevailing interest rates at the time of sale. So, for example, a municipal bond issued with a 5.0% coupon will sell at a premium if interest rates at the time of sale are below 5.0%. Consequently, it is important to understand that municipal bond prices fluctuate in response to changing interest rates: prices increase when interest rates decline, and prices decline when interest rates rise.
It’s easy to understand the reasons: