Bond risk: How rates, duration, and structure drive fixed-income performance

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There’s always a chance you could take a tumble.

© linavita/stock.adobe.com; Photo illustration Encyclopædia Britannica, Inc

“Stocks are for speculators. Stick to clipping coupons.” For a lot of investors, that quip formed their earliest impressions of bonds as a “safe” investment. It often came from someone who’d lived through recessions, the Great Depression, even world wars—someone like Great-Aunt Geneva, who’d seen enough market cycles to speak with absolute conviction.

Her generation learned that when markets crashed and banks failed, wealthy investors were able to maintain a steady, safe income stream by having their money in bonds and other fixed-income assets—physical pieces of paper with coupons attached. To collect your interest, you’d clip the coupon (yes, with scissors) and take it to the bank or mail it to the paying agent. In the world of investing, that ritual helped cement the belief that bonds were as close as you could get to a sure thing.

Yet, despite appearances, bonds weren’t as safe back then as many believed—and the same can be said today. Here are some of the core risks you should know about if you’re currently a bond investor or looking to become one.

A bond is just a loan. You lend money to a government (Treasury and municipal bonds) or a company (corporate bonds), and they promise regular interest (“coupon”) payments and give your principal back to you at maturity. And right there in that deceptively simple exchange, you’ve got the two biggest risks bondholders face: rates and duration.

Here’s what matters most: Bond prices move inversely to interest rates. For example, if an existing bond pays 3% and a new issue comes out at 5%, investors will only buy the older bond at a discount—enough to bring its yield in line with current rates. So in periods of rate uncertainty, bond volatility increases. How much it increases is directly tied to the concept of duration.

But there’s another piece investors sometimes overlook: If you already own that 3% bond and hold it to maturity, nothing about the market price changes what you ultimately receive. You still collect your 3% coupons and get your principal back at the end. The price drop only matters if you plan to sell before maturity. The real “cost” is opportunity cost—you’re earning 3% while newly issued bonds are paying 5%.

Investors often confuse duration and maturity, but they’re not the same thing.

Generally speaking, duration has a 1-to-1 relationship with price sensitivity. In practical terms, a bond with a 5-year duration will lose about 5% when rates rise 100 basis points, and conversely, gain about 5% for a 100-basis-point drop. For a real-world example, let’s compare a newly issued 2-year Treasury note to its 10-year counterpart. In a rising rate environment where rates increase 1 basis points, the 2-year might drop in price by 2%, whereas the 10-year could fall five times that amount, or 10%.

Counterintuitive or not, longer duration means greater volatility—a sharp contrast to the “bonds are the safe part of the portfolio” narrative many people grew up with.

Just as a house that looks solid from the curb may be hiding foundation problems, bonds can carry structural risks that don’t show up in credit ratings. If you’re looking to bonds for safety and stability in your portfolio, you need to know about these potential red flags.

A callable bond may be redeemed by the issuer before maturity. And it’s no coincidence that such a bond will be “called” when rates fall and the issuer can refinance their debt at a lower rate. Callable bonds can be redeemed at face value (“par”), no matter what the current market price is. When your bond is called, you’ll get your principal back, but your replacement investment will probably come with a lower yield.

Prepayment risk typically affects mortgage-backed securities, which are tied to pools of residential and commercial mortgages. Prepayments are common during periods of falling rates, when homeowners and other mortgagees are more likely to refinance their debt. As an investor, prepayments mean your principal will be returned earlier than expected, and once again you’ll be looking at lower yields on any replacement investment.

Liquidity risk is more common in municipal and small corporate issues that trade infrequently. The lack of liquidity often creates wide bid-ask spreads (the price at which you can buy or sell the bond). Such bonds can become nearly impossible to sell when markets are under stress—exactly when you need liquidity most.

Unsecured bonds rely solely on the issuer’s creditworthiness, whereas secured bonds are backed by specific assets. But the quality of that backing matters. For example, a bond backed by prime real estate carries less risk than one backed by, say, farm equipment or another depreciating asset.

These structural defects come with the territory, hidden in the fine print of the prospectus, but not all bond risk is out of your hands.

There’s no bond that offers high yield with zero risk, but some risks can be managed. You can’t control where interest rates go or how the bond market reacts to central bank policy changes, but you can control the quality of the bonds you buy and how you build your portfolio.

Credit risk boils down to a single question: Can the issuer meet its financial commitments to you (your coupon payments and the return of 100% of your principal)? To help quantify that risk, credit ratings agencies like Moody’s and S&P have created their own respective bond rating scales based on letter grades. AAA (what Moody’s calls Aaa) is highest quality; C indicates near-default. S&P also uses D to signal an actual default.

Both Moody’s and S&P categorize bonds that rate BBB or above as investment grade, while those below are considered “non-investment grade,” also known in industry slang as “junk.” As you can imagine, lower ratings tend to pay higher yields—compensation for the increased risk that things could go wrong.

Diversification is another controllable factor. Although often associated with stocks, it’s just as important in fixed income. Load up on bonds issued by energy companies, and you’re making a bet on oil prices whether you meant to or not. Hold too many municipal bonds from one state, and your risk depends on that region’s fiscal health. And just as stocks in the same sector tend to move together, so do corporate bonds in the same industry. That’s great if the industry is in a strong uptrend, but not so great if it isn’t. For example, during the financial crisis of 2007–08, financial sector corporate bonds experienced massive price volatility—and more than a few defaults.

Great-Aunt Geneva wasn’t wrong—bonds are generally safer than stocks. But “safer” isn’t the same as “safe.” Interest rates move, call provisions and prepayments kick in at the most inopportune times, and putting all your money in the wrong sector at the wrong time can backfire spectacularly.

The good news? Once you know what to look for, you can manage—or at least mitigate—most of these risks. Some risks you sidestep entirely; some you diversify away; and some you accept because they’re part of the risk and reward of earning yield. The key is going in with clear eyes, rather than assuming bonds are automatically the safe, low-risk choice.