What does a bond duration measure?
Duration is the weighted average term to maturity of a bonds cash flows and therefore, is a valuable tool in assessing bond price sensitivity to interest rate shocks. It is the most common technique for quantifying this sensitivity and is generally used to approximate changes in the price of the bond for every 100 basis point change in yields( modified duration). As a general rule, the greater the value of duration, the more price volatility results from interest rate movements.

Let's take a look at the formula that Frederick Macaulay devised to calculate duration.
Remember, the present value of the cash flows can be derived by using the yield to maturity as the discount factor. Therefore, you can see that the lower the yield on the bond, the greater the duration on the bond.

Let's take an example on a 5 year bond yielding 5% and calculate the Macaulay duration.

Based on this example, the duration would be calculated as such: 8970.87 / 2 X 1000 = 4.49.
Now that we have calculated the duration, we can go on to define the price volatility that would result from a shift in market yields. The following formula will define this relationship between duration and bond price volatility and also account for compounding yield.

Assuming a 100 basis point shift in interest rates, the % change in bond price would be calculated as follows:
-(4.39 * .01 * 100) / (1 + .025) = 4.28% change in bond price.
Notice the negative sign in front of this equation and remember that bond prices move in the opposite direction as interest rate. Therefore, if interest rates are lowered by 100 basis points, we would insert a -.01 into the formula which would yield a positive price shift.

As you can see, duration is a useful measure in approximating interest rate risk; however, it does not work as well when there are large shifts in yields. The difference between the estimated change in bond price that we just calculated and the actual change in bond price is known as convexity and this must be included in the price change calculations when the yield change is large.

How you can use the concept of Duration
A general rule is that a bond with a longer duration is far more volatile than a bond with a shorter duration. Additionally, zero coupon bonds have the same duration and maturity and therefore have the highest risk to interest rate changes. Zero coupon bonds aside, the duration of a bond will always be shorter than its term to maturity. One final generalization we can make is that lower coupon bonds will have higher durations than larger coupon bonds and therefore, larger coupon bonds will be less volatile when interest rates are changed. For example, if were looking at purchasing a bond and had three options (a discount bond, premium bond, or zero coupon bond) with the same yield to maturity, the premium bond would be the least volatile followed by the discount bond and zero coupon bond being the most volatile.
In conclusion, duration is a very effective means for determining interest rate risk for the individual investor. However, institutions may be more interested in looking at the bond convexity to be more precise with the estimates.

If you are new to investing perhaps you are not familiar with bonds. Before you get started, you need to understand some of the risks associated with bond investing. Most people assume that all interest-bearing securities are completely risk free, but this is not the case. Even if you know a lot about investing, you may not be aware of some of the risk characteristics associated with bonds.

The most important thing to take into account is the interest rate. The Federal Reserve (also known as the Fed) meets every 6-8 weeks to evaluate the health of the economy. At each meeting, the Fed renders a decision regarding interest rates.

If inflation is rising, the Fed will need to raise interest rates to tighten the money supply. If inflation is moderate or contained, the Fed will likely leave rates unchanged. However, if the economy is slowing down and there is very little inflation or maybe even deflation, then the Fed might decide to reduce interest rates to create a stimulus for economic growth.

The reason why you need to consider present and future interest rate levels is because as interest rates increase, bond prices go down, and vice versa. If you are able to hold your bond until maturity, then interest rate movements do not really matter, because you will redeem the principal upon redemption. But often, investors have to cash out their bonds well before the maturity date. If interest rates have moved up since you purchased the bond, and you sell it prior to maturity, then the bond will be worth less than your initial investment.

You should also be aware of the claim status of the bond you are buying. Claim status refers to your ability to liquidate your investment in the event the bond issuer goes bankrupt. If you are buying a government bond, such as a Treasury Bill, claim status is irrelevant, because the odds of the Federal Government going bankrupt are slim and none. If you are buying a corporate bond, however, there is always a chance that the issuer could go out of business. In the event of liquidation, bondholders are given priority over stockholders. However, there are often different classes of bondholders. Senior note holders can often claim against certain kinds of physical collateral in the event of bankruptcy, such as equipment (computers, machines, etc.). Regular bondholders can not always claim against physically collateral, and are next in line after the senior note holders.

Next, you should always check the three main features of the bond you are buying; the coupon rate, the maturity date, and the call provisions. The coupon rate is the interest rate. Most bonds pay an interest rate semiannually or annually.

The maturity date is the date that the bond will be redeemed by the issuer; simply put, the maturity date is when the company must pay back to you the principal you loaned to them. The call provisions are the rights of the issuer to buy back your bond prior to maturity. Some bonds are non-callable, while others are callable, meaning that the company can buy your bond back before maturity, usually at a higher price than what you paid. Finally, you should also understand that if economic conditions become more favorable after you a buy a bond, and interest rates start to go down again, the issuer will likely issue a lot more bonds to take advantage of the low interest rates, and will use the proceeds to try to buy back any callable bonds it issued previously. So, when interest rates go down, there is an increasing likelihood that your bond will be redeemed prior to maturity, if in fact the bond is callable.

You should invest in bonds. However, you should also take into account the risk factors we have covered. Your portfolio should contain a mix of corporate, federal, municipal, and even junk bonds (there is always a default risk associated with junk bonds, but they pay a huge interest rate). Talk to your broker about diversifying the kinds of bonds in your portfolio and you will reduce your overall risk and maximize your return.

How Did I Lose Money On My Bond Investments?

If you are new to investing perhaps you are not familiar with bonds. Before you get started, you need to understand some of the risks associated with bond investing. Most people assume that all interest-bearing securities are completely risk free, but this is not the case. Even if you know a lot about investing, you may not be aware of some of the risk characteristics associated with bonds.

The most important thing to take into account is the interest rate. The Federal Reserve (also known as the Fed) meets every 6-8 weeks to evaluate the health of the economy. At each meeting, the Fed renders a decision regarding interest rates.

If inflation is rising, the Fed will need to raise interest rates to tighten the money supply. If inflation is moderate or contained, the Fed will likely leave rates unchanged. However, if the economy is slowing down and there is very little inflation or maybe even deflation, then the Fed might decide to reduce interest rates to create a stimulus for economic growth. The reason why you need to consider present and future interest rate levels is because as interest rates increase, bond prices go down, and vice versa. If you are able to hold your bond until maturity, then interest rate movements do not really matter, because you will redeem the principal upon redemption. But often, investors have to cash out their bonds well before the maturity date. If interest rates have moved up since you purchased the bond, and you sell it prior to maturity, then the bond will be worth less than your initial investment.

You should also be aware of the claim status of the bond you are buying. Claim status refers to your ability to liquidate your investment in the event the bond issuer goes bankrupt. If you are buying a government bond, such as a Treasury Bill, claim status is irrelevant, because the odds of the Federal Government going bankrupt are slim and none.

If you are buying a corporate bond, however, there is always a chance that the issuer could go out of business. In the event of liquidation, bondholders are given priority over stockholders. However, there are often different classes of bondholders. Senior note holders can often claim against certain kinds of physical collateral in the event of bankruptcy, such as equipment (computers, machines, etc.). Regular bondholders can not always claim against physically collateral, and are next in line after the senior note holders.

Next, you should always check the three main features of the bond you are buying; the coupon rate, the maturity date, and the call provisions. The coupon rate is the interest rate. Most bonds pay an interest rate semiannually or annually. The maturity date is the date that the bond will be redeemed by the issuer; simply put, the maturity date is when the company must pay back to you the principal you loaned to them. The call provisions are the rights of the issuer to buy back your bond prior to maturity. Some bonds are non-callable, while others are callable, meaning that the company can buy your bond back before maturity, usually at a higher price than what you paid.

Finally, you should also understand that if economic conditions become more favorable after you a buy a bond, and interest rates start to go down again, the issuer will likely issue a lot more bonds to take advantage of the low interest rates, and will use the proceeds to try to buy back any callable bonds it issued previously. So, when interest rates go down, there is an increasing likelihood that your bond will be redeemed prior to maturity, if in fact the bond is callable.

You should invest in bonds. However, you should also take into account the risk factors we have covered. Your portfolio should contain a mix of corporate, federal, municipal, and even junk bonds (there is always a default risk associated with junk bonds, but they pay a huge interest rate). Talk to your broker about diversifying the kinds of bonds in your portfolio and you will reduce your overall risk and maximize your return.