As an investor in the bond market, why should you be concerned about changes in interest rates?

Like other investments, when you invest in bonds and bond funds, you face the risk that you might lose money. Here are some common risk factors to be aware of with respect to bond and bond fund investments.

Interest Rate Risk

Remember the cardinal rule of bonds: When interest rates fall, bond prices rise, and when interest rates rise, bond prices fall. Interest rate risk is the risk that changes in interest rates (in the U.S. or other world markets) may reduce (or increase) the market value of a bond you hold. Interest rate risk—also referred to as market risk—increases the longer you hold a bond.

Let's look at the risks inherent in rising interest rates.

Say you bought a 10-year, $1,000 bond today at a coupon rate of 4 percent, and interest rates rise to 6 percent.

If you need to sell your 4 percent bond prior to maturity you must compete with newer bonds carrying higher coupon rates. These higher coupon rate bonds decrease the appetite for older bonds that pay lower interest. This decreased demand depresses the price of older bonds in the secondary market, which would translate into you receiving a lower price for your bond if you need to sell it. In fact, you may have to sell your bond for less than you paid for it. This is why interest rate risk is also referred to as market risk.

Rising interest rates also make new bonds more attractive (because they earn a higher coupon rate). This results in what's known as opportunity risk—the risk that a better opportunity will come around that you may be unable to act upon. The longer the term of your bond, the greater the chance that a more attractive investment opportunity will become available, or that any number of other factors may occur that negatively impact your investment. This also is referred to as holding-period risk—the risk that not only a better opportunity might be missed, but that something may happen during the time you hold a bond to negatively affect your investment.

Bond fund managers face the same risks as individual bondholders. When interest rates rise—especially when they go up sharply in a short period of time—the value of the fund's existing bonds drops, which can put a drag on overall fund performance.

Call Risk

Similar to when a homeowner seeks to refinance a mortgage at a lower rate to save money when loan rates decline, a bond issuer often calls a bond when interest rates drop, allowing the issuer to sell new bonds paying lower interest rates—thus saving the issuer money. For this reason, a bond is often called following interest rate declines. The bond's principal is repaid early, but the investor is left unable to find a similar bond with as attractive a yield. This is known as call risk.

With a callable bond, you might not receive the bond's original coupon rate for the entire term of the bond, and it might be difficult or impossible to find an equivalent investment paying rates as high as the original rate. This is known as reinvestment risk. Additionally, once the call date has been reached, the stream of a callable bond's interest payments is uncertain, and any appreciation in the market value of the bond may not rise above the call price.

Duration Risk

If you own bonds or have money in a bond fund, there is a number you should know. It is called duration. Although stated in years, duration is not simply a measure of time. Instead, duration signals how much the price of your bond investment is likely to fluctuate when there is an up or down movement in interest rates. The higher the duration number, the more sensitive your bond investment will be to changes in interest rates.

Duration risk is the name economists give to the risk associated with the sensitivity of a bond’s price to a one percent change in interest rates.

Refunding Risk and Sinking Funds Provisions

A sinking fund provision, which often is a feature included in bonds issued by industrial and utility companies, requires a bond issuer to retire a certain number of bonds periodically. This can be accomplished in a variety of ways, including through purchases in the secondary market or forced purchases directly from bondholders at a predetermined price, referred to as refunding risk.

Holders of bonds subject to sinking funds should understand that they risk having their bonds retired prior to maturity, which raises reinvestment risk.

Default and Credit Risk

If you have ever loaned money to someone, chances are you gave some thought to the likelihood of being repaid. Some loans are riskier than others. The same is true when you invest in bonds. You are taking a risk that the issuer's promise to repay principal and pay interest on the agreed upon dates and terms will be upheld.

While U.S. Treasury securities are generally deemed to be free of default risk, most bonds face a possibility of default. This means that the bond obligor will either be late paying creditors (including you, as a bondholder), pay a negotiated reduced amount or, in worst-case scenarios, be unable to pay at all.

Using Ratings Agencies to Assess Default & Credit Risk

The Securities and Exchange Commission (SEC) has designated 10 rating agencies as Nationally Recognized Statistical Rating Organizations (NRSROs).

These organizations review information about selected issuers, especially financial information, such as the issuer's financial statements, and assign a rating to an issuer's bonds—from AAA (or Aaa) to D (or no rating).

Each NRSRO uses its own ratings definitions and employs its own criteria for rating a given security. It is entirely possible for the same bond to receive a rating that differs, sometimes substantially, from one NRSRO to the next. While it is a good idea to compare a bond's rating across the various NRSROs, not all bonds are rated by every agency, and some bonds are not rated at all. In such cases, you may find it difficult to assess the overall creditworthiness of the issuer of the bond.

Slow Down When You See "High Yield"

Generally, bonds are lumped into two broad categories—investment grade and non-investment grade. Bonds that are rated BBB, bbb, Baa or higher are generally considered investment grade. Bonds that are rated BB, bb, Ba or lower are non-investment grade. Non-investment grade bonds are also referred to as high-yield or junk bonds. Junk bonds typically offer a higher yield than investment-grade bonds, but the higher yield comes with increased risk—specifically, the risk that the bond’s issuer may default.

Don't Reach
Investors who decide which bonds to buy based solely on a bond's yield are "reaching for yield," one of the most common mistakes bond investors make. See FINRA’s Investor Alert The Grass Isn’t Always Greener—Chasing Return in a Challenging Investment Environment.

Inflation and Liquidity Risk

Inflation risk is the risk that the yield on a bond will not keep pace with purchasing power (in fact, another name for inflation risk is purchasing power risk). For instance, if you buy a five-year bond in which you can realize a coupon rate of 5 percent, but the rate of inflation is 8 percent, the purchasing power of your bond interest has declined. All bonds but those that adjust for inflation, such as TIPS, expose you to some degree of inflation risk.

Liquidity risk is the risk that you will not be easily able to find a buyer for a bond you need to sell. A sign of liquidity, or lack of it, is the general level of trading activity: A bond that is traded frequently in a given trading day is considerably more liquid than one which only shows trading activity a few times a week.

Some bonds, like U.S. Treasury securities, are quite easy to sell because there are many people interested in buying and selling such securities at any given time. These securities are liquid. Others trade much less frequently. Some even turn out to be "no bid" bonds, with no buying interest at all. These securities are illiquid.

Investors can check corporate bond trading activity—and thus liquidity—by using FINRA's Market Data Center. For insight into municipal bond liquidity, investors can use trade data found on the Municipal Securities Rulemaking Board's website.

Event Risk

Mergers, acquisitions, leveraged buyouts and major corporate restructurings are all events that put corporate bonds at risk, thus the name event risk.

Other events can also trigger changes in a company's financial health and prospects, which may trigger a change in a bond's rating. These include a federal investigation of possible wrongdoing, the sudden death of a company's chief executive officer or other key manager, or a product recall. Energy prices, foreign investor demand and world events also are triggers for event risk. Event risk is extremely hard to anticipate and may have a dramatic and negative impact on bondholders.

The Fed is hiking short-term interest rates to slow the economy. Now the bond market is starting to expect less inflation longer term, and so yields on Treasury bonds have declined from their peak. What should bond investors do?

In this episode, Mark Riepe speaks with Kathy Jones, Schwab's chief fixed income strategist. Kathy has analyzed global bond, foreign currency, and commodity markets extensively throughout her career as an investment analyst and strategist, working with both institutional and individual clients. Kathy makes regular broadcast appearances on CNBC, Yahoo Finance, Bloomberg TV, and many other networks and is often quoted by The Wall Street Journal, The New York Times, Financial Times, and Reuters.

Kathy and Mark discuss the reasons why investors typically hold bonds in a portfolio, how the yield curve tends to function, quantitative tightening, and many other topics related to bonds and the current interest-rate environment.

Follow Financial Decoder for free on Apple Podcasts or wherever you listen.

Financial Decoder is an original podcast from Charles Schwab. For more on the series, visit Schwab.com/FinancialDecoder.

If you enjoy the show, please leave us a rating or review on Apple Podcasts.