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By David Koch, CFP®, AIF®, CFA, Senior Wealth Advisor

Part 4, Common Risks with Bonds – Duration Risk

Like a seesaw, bond prices move inversely with interest rates. Interest rates move down = bond prices move up. Interest rates move up, bond prices move down. This is called duration risk, or interest rate risk. Let me explain why this is so.

Like we mentioned in Part 2, bond yields are a function of the interest rate earned on U.S. government bonds plus an additional charge to take on the credit risk, called the spread. But besides the amount of the spread, those underlying interest rates on the Treasuries are ever-changing as well.

A quick example

If you lend a company $1,000 for 10 years at 5%, and then rates drop and the going rate to lend to the same or a similar company drops to 4% – your 5% bond just got more valuable. The inverse is also true. If you lock up a 10-year bond for 3%, and then rates go up to 4%, your bond got less valuable.

If current rates rise, for example, no one is going to pay you face value for that same bond when they can go buy a new one with a better interest rate. It’s as simple as that, and the estimated change in price for a 1% move in rates is called “duration.”

If someone says that the duration of their bond portfolio is 5, then you should expect that if interest rates were to go up 1%, then the value of that portfolio would drop by 5%. This kind of estimate is a little bit of a round-peg/square-hole problem: But it is an estimate, and a measure of risk in your portfolio.

If you own a portfolio of bonds that all mature next year, then your duration will be small, also known as short duration. In this case, it doesn’t matter a whole lot what interest rates do. Your portfolio’s value won’t fluctuate much because the bonds are going to mature soon and you’re going to get your par value back soon.

Duration and maturity

But if you own a portfolio of bonds that are going to mature far out in the future, duration can be a much bigger issue. This is balanced with the fact that in order to entice lenders to lend for longer time periods, longer-duration bonds tend to pay more.

For example, you can almost always find a better rate on a 2-year CD than a 6-month CD. Same goes for mortgages. You can almost always find a better rate on a 15-year than a 30-year. If borrowers want to borrow for longer periods of time, lenders want to be compensated more for taking on duration – that interest rate risk.

The yield curve

For any given credit risk, there isn’t just one interest rate, there are many: from short-term rates to long-term rates. This spectrum of rates is called the “yield curve” because in normal times rates curve up from lower short-term rates, to higher long-term rates. Think about going from low-yield, short-term CD rates on one end (like 0.5%), to higher-yield mortgage rates on the long end (like 4.5%).

One way to mitigate duration is to keep all your maturities short. If all your bonds mature in, say, less than two years, you’re going to limit how much your bonds’ values will change if there is a change in interest rates. This will also, however, likely result in a lower yield since short-term bonds tend to earn less than longer-term bonds.

There are ways to approach investing in bonds that provide a trade-off between the two, which I’ll cover next in Part 5. This final post will discuss the considerations involved with building a portfolio of bonds.

If you missed my first three segments, you can read them here, Part 1, Bond Basics and Bond Jargon, here, Part 2, Types of Bonds, and here Part 3, Credit Risk.

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Disclaimer: 

Halbert Hargrove Global Advisors, LLC (“HH”) is an SEC registered investment adviser located in Long Beach, California. Registration does not imply a certain level of skill or training. Additional information about HH, including our registration status, fees, and services can be found at www.halberthargrove.com. This article is provided for informational purposes only and should not be construed as a solicitation to offer personal securities transactions or provide personalized investment advice. The views contained herein are not to be taken as an advice or recommendation to buy or sell any investment. Any forecasts, figures, opinions or investment techniques and strategies set out are for information purposes only, based on certain assumptions and current market conditions and are subject to change without previous notice. This material should not be relied upon by you in evaluating the merits of investing in any securities or products mentioned herein. In addition, the Investor should make an independent assessment of the legal, regulatory, tax, credit, and accounting and determine, together with their own professional advisers if any of the investments mentioned herein are suitable to their personal goals. Investors should ensure that they obtain all available relevant information before making any investment.