Why do interest rates tend to have an inverse relationship with bond prices?
At first glance, the inverse relationship between interest rates and bond prices seems somewhat illogical, but upon closer examination, it makes sense. An easy way to grasp why bond prices move opposite to interest rates is to consider zero-coupon bonds, which don’t paycoupons but derive their value from the difference between the purchase price and the par value paid at maturity.
For instance, if a zero-coupon bond is trading at $950 and has a par value of $1,000 (paid at maturity in one year), the bond’s rate of return at the present time is approximately 5.26% ((1000-950) / 950 = 5.26%).
For a person to pay $950 for this bond, he or she must be happy with receiving a 5.26% return. But his or her satisfaction with this return depends on what else is happening in the bond market. Bond investors, like all investors, typically try to get the best return possible. If current interest rates were to rise, giving newly issued bonds a yield of 10%, then the zero-coupon bond yielding 5.26% would not only be less attractive, it wouldn’t be in demand at all. Who wants a 5.26% yield when they can get 10%? To attract demand, the price of the pre-existing zero-coupon bond would have to decrease enough to match the same return yielded by prevailing interest rates. In this instance, the bond’s price would drop from $950 (which gives a 5.26% yield) to $909 (which gives a 10% yield).
Now that we have an idea of how a bond’s price moves in relation to interest-rate changes, it’s easy to see why a bond’s price would increase if prevailing interest rates were to drop. If rates dropped to 3%, our zero-coupon bond - with its yield of 5.26% - would suddenly look very attractive. More people would buy the bond, which would push the price up until the bond’s yield matched the prevailing 3% rate. In this instance, the price of the bond would increase to approximately $970. Given this increase in price, you can see why bond-holders (the investors selling their bonds) benefit from a decrease in prevailing interest rates.
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BOND (definition):
A debt investment in which an investor loans money to an entity (corporate or governmental) that borrows the funds for a defined period of time at a fixed interest rate. Bonds are used by companies, municipalities, states and U.S. and foreign governments to finance a variety of projects and activities.
Bonds are commonly referred to as fixed-income securities and are one of the three main asset classes, along with stocks and cash equivalents.
The indebted entity (issuer) issues a bond that states the interest rate (coupon) that will be paid and when the loaned funds (bond principal) are to be returned (maturity date). Interest on bonds is usually paid every six months (semi-annually). The main categories of bonds are corporate bonds, municipal bonds, and U.S. Treasury bonds, notes and bills, which are collectively referred to as simply “Treasuries”.
Two features of a bond - credit quality and duration - are the principal determinants of a bond’s interest rate. Bond maturities range from a 90-day Treasury bill to a 30-year government bond. Corporate and municipals are typically in the three to 10-year range.
