Bond Duration: Not Just Passing Time. What You Need to Know.

Investors adding bonds to a stock-heavy lineup may opt for securities with a shelf life designed for today’s investing climate. That’s where bond duration comes in. watch: Bonds, duration, maturity, interest rates
4 min read
Photo by Getty Images

Key Takeaways

  • Know what bond duration is and how it measures interest rate risk
  • Understand the difference between maturity and duration
  • Bond duration can estimate how much price is likely to be affected by interest rate changes

It’s common to talk about the duration of a bond portfolio in simple terms—like time or interest rate sensitivity. But a deeper understanding of duration can be vital these days as interest rates have declined significantly.

First off, it’s important to make the distinction between duration and maturity.

There’s a date a bond is made available in the market (the issue date) and a date it’s expected to be retired (the maturity date). Maturity refers to the length of time a bond is expected to be outstanding. There are several factors that can affect a bond’s maturity, but at maturity, the principal amount of a bond or note is repaid to the investor and interest payments cease.

So what is bond duration, and how is it different from maturity? Duration measures the sensitivity of a fixed-income investment to a change in interest rates and is expressed in years. Duration is the amount a bond’s value is calculated to increase or decrease with a 1% change in interest rates.

Unlike maturity, duration takes into account interest payments that occur throughout the life of the bond. Keep in mind that duration tracks all the income streams from a bond or portfolio of bonds. It can be vital to know your overall exposure if you hold a portfolio that includes several bonds or bond mutual funds or exchange-traded funds. Most actively managed U.S. bond funds can carry about the same interest rate risk as the index they track, according to Morningstar.

Duration is used to measure a bond’s potential price volatility to changes in interest rates. Historically, the higher the duration (the longer an investor needs to wait for the bulk of their interest payments), the more a bond’s price typically dropped as interest rates went up.

If an investor expects interest rates to fall during a bond’s lifetime, a longer duration could be appealing, because the bond’s price may increase more than comparable bonds with shorter durations. On the other hand, if an investor expects interest rates to rise during a bond’s lifetime, a shorter duration may be more appealing because it’s less exposed to fluctuations in interest rates.

A Bond Duration Word Problem

A little math is often the best way to describe duration. And don’t worry; there’s no bond duration formula you need to memorize. Duration is the change in the value of your fixed-income security that might result from a 1% change in interest rates. For example, for a bond with a duration of five years, a 1% increase in interest rates would cause the bond to decrease in value by 5%. Conversely, a 1% decrease in interest rates would cause the bond’s value to increase by 5%.

The duration on any bond that pays coupons will be less than the maturity, because some of the payments are yet to come before the maturity date. A zero-coupon bond (a bond paying no interest) will have a duration equal to its term. And bonds with higher current yields tend to have lower durations than bonds with lower current yields.

How Does It Impact Price?

In simple terms, a bond’s duration is one method used to determine how its price may be affected by interest rate changes. In fact, the bond’s duration, coupon, and yield-to-maturity rate, as well as the extent of the change in interest rates, are all significant variables that ultimately determine how much a bond’s price moves.

Suppose you bought a $1,000 par value bond with a 10-year maturity and a 6% coupon rate. You can earn 6% of $1,000, or $60, each year that you own the bond. Let’s further assume that after one year, you decide to sell it, and at that time, new bonds are being issued with 7% coupons. Investors can choose between your 6% bond and a new 7% bond. To entice someone to buy your bond, you’ll have to discount its price so the new owner will earn the same $60 but will have paid less than $1,000 to buy it, thus raising his or her yield closer to 7%.

Using the same example, suppose that when you sell your bond, new bonds are being issued with 5% coupons. Investors can choose between your 6% bond and a new 5% bond. Comparatively, your bond is now much more attractive. An investor is likely to be willing to pay more than $1,000 to earn 6% rather than 5%.

Discover What the Bond Wizard Offers

Log in to your account and go to Research & Ideas > Bonds & CDs > Overview > Bonds.

Then select the Bond Wizard and you’re on your way.

Why Now?

The Federal Reserve has lowered the federal funds rate five times since August 2019. Interest rates are effectively at zero, mainly due to the COVID-19 pandemic. The yield on the 10-year Treasury now stands at less than 1%, whereas the yield on the 2-year Treasury is less than 0.5%. 

Monetary policy changes impact the front end of the yield curve, and growth drives the long end of the curve. So investors should not look at the increase in rates on the long end over the last two and a half years as a gauge of what to expect in the coming months and years.

Investors should periodically evaluate their fixed-income holdings to determine if they’re being amply compensated for the duration risk of their holdings and that they’re well positioned for the prevailing interest rate environment. This can be especially important for investors who are seeking income.

Whether you’re new to fixed-income investing or a seasoned professional, the TD Ameritrade Bond Wizard’s bond ladder tool can help you discover bonds and CDs that can potentially meet your unique financial needs.


Key Takeaways

  • Know what bond duration is and how it measures interest rate risk
  • Understand the difference between maturity and duration
  • Bond duration can estimate how much price is likely to be affected by interest rate changes

Related Videos

Call Us

Content intended for educational/informational purposes only. Not investment advice, or a recommendation of any security, strategy, or account type.

Be sure to understand all risks involved with each strategy, including commission costs, before attempting to place any trade. Clients must consider all relevant risk factors, including their own personal financial situations, before trading.

Investments in fixed income products are subject to liquidity (or market) risk, interest rate risk (bonds ordinarily decline in price when interest rates rise and rise in price when interest rates fall), financial (or credit) risk, inflation (or purchasing power) risk and special tax liabilities. May be worth less than the original cost upon redemption.


Market volatility, volume, and system availability may delay account access and trade executions.

Past performance of a security or strategy does not guarantee future results or success.

Options are not suitable for all investors as the special risks inherent to options trading may expose investors to potentially rapid and substantial losses. Options trading subject to TD Ameritrade review and approval. Please read Characteristics and Risks of Standardized Options before investing in options.

Supporting documentation for any claims, comparisons, statistics, or other technical data will be supplied upon request.

This is not an offer or solicitation in any jurisdiction where we are not authorized to do business or where such offer or solicitation would be contrary to the local laws and regulations of that jurisdiction, including, but not limited to persons residing in Australia, Canada, Hong Kong, Japan, Saudi Arabia, Singapore, UK, and the countries of the European Union.

TD Ameritrade, Inc., member FINRA/SIPC, a subsidiary of The Charles Schwab Corporation. TD Ameritrade is a trademark jointly owned by TD Ameritrade IP Company, Inc. and The Toronto-Dominion Bank. © 2021 Charles Schwab & Co. Inc. All rights reserved.

Scroll to Top