Building a Bond Portfolio

I'm Andy Temte and welcome to Money Lessons! Join me every Saturday morning for bite-sized lessons that are designed to improve financial literacy around the world. Today is March 7th, 2026.

Last week, we explored duration—the measure that tells you how sensitive a bond's price is to changes in interest rates. We learned that Frederick Macaulay gave us this essential tool back in 1938, and we saw how devastating interest rate moves can be when we looked at the 2022 bond market. Today, we're wrapping up our debt securities series by putting everything together: how to actually build a bond portfolio that serves your financial goals.

Over the past fourteen weeks, we've traveled from Mesopotamian clay tablets to modern credit ratings, from ancient promises scratched in cuneiform to sophisticated measures like yield curves and duration. Now comes the practical question—what do you actually do with all this knowledge?

Why Bonds Belong in Your Portfolio

Let's start with the fundamental question: why own bonds at all when stocks have historically delivered higher returns? Here's what it comes down to—bonds play three distinct roles in a portfolio.

First, bonds provide income. Unlike stocks, which may or may not pay dividends, bonds contractually obligate the issuer to make regular interest payments. Predictable cash flow matters, especially as you approach or enter retirement.

Second, bonds provide stability. Remember our discussion of the inverse relationship between interest rates and bond prices? While that relationship creates risk, bonds are generally less volatile than stocks. When stock markets plunge, high-quality bonds often hold their value or even appreciate as investors flee to safety.

Third, bonds provide diversification. Stocks and bonds don't always move together. During the 2008 financial crisis, while the S&P 500 fell nearly 40%, Treasury bonds gained value. That negative correlation—when one goes up while the other goes down—can smooth out your portfolio's overall ride considerably.

Bond Funds vs. Individual Bonds

For most individual investors, bond mutual funds or exchange-traded funds offer a more practical path than buying individual bonds.

A single total bond market fund might hold thousands of different bonds—Treasuries, corporate bonds, and mortgage-backed securities—spreading your risk across many issuers. The typical expense ratio for a broad bond index fund runs around 0.03% to 0.05%—or three to five basis points—annually, meaning you pay just three to five dollars per year for every ten thousand dollars invested. You can invest with as little as one dollar through fractional shares and buy or sell any business day. Compare that to individual bonds, where the minimum is typically one thousand dollars per bond and building a diversified portfolio requires tens of thousands of dollars.

However, individual bonds have one significant advantage: if you hold them to maturity, you eliminate interest rate risk entirely. You know exactly what you'll receive and when. Bond funds have no maturity date—they constantly buy and sell bonds—so you can't simply wait out a period of rising rates the way you can with an individual bond.

For investors who want to buy individual Treasury securities directly, TreasuryDirect.gov allows purchases with a minimum of just one hundred dollars, without paying any broker fees.

The Bond Ladder Strategy

Here's an approach that combines the benefits of both individual bonds and bond funds. Instead of putting fifty thousand dollars into a single bond maturing in ten years, you might buy five bonds of ten thousand dollars each, maturing in two, four, six, eight, and ten years. This is called a bond ladder.

As each bond matures, you reinvest at the long end. When your two-year bond matures, you use the proceeds to buy a new ten-year bond. This provides regular access to your money, averages out your interest rate exposure over time, and gives you the certainty of known maturity dates—a combination that's hard to replicate with funds alone.

Thinking About Allocation

How much of your portfolio should be in bonds? There's no universal answer, but several popular guidelines exist. One suggests subtracting your age from 110 or 120 to determine your stock allocation, with the remainder in bonds. Under this approach, a thirty-year-old might hold 80–90% stocks and 10–20% bonds, while a sixty-year-old might hold 50–60% stocks and 40–50% bonds.

The logic is straightforward: younger investors have decades to recover from market downturns, while older investors need more stability and income. But here's what I want to emphasize—age isn't everything. Your personal risk tolerance matters enormously. We spent four weeks on risk tolerance earlier in this series for good reason. The right allocation is the one you can stick with through bull and bear markets without losing sleep.

Matching Duration to Your Horizon

This is where last week's discussion becomes practical. If you're investing money you'll need in three years, a bond fund with an average duration of ten years exposes you to unnecessary interest rate risk. A shorter-duration fund—one to three years—better matches your timeline. Conversely, if you're thirty years from retirement, you can accept longer-duration bonds that typically offer higher yields. Match your bond holdings to when you'll actually need the money.

Common Bond Fund Categories

When you look at bond funds, you'll encounter several major categories. Treasury funds invest exclusively in U.S. government debt—the safest bonds available but typically the lowest yields. Corporate bond funds hold debt issued by companies, offering higher yields with more credit risk. Municipal bond funds invest in state and local government debt, with interest that's often exempt from federal taxes—particularly valuable for investors in high tax brackets. Total bond market funds blend these categories, offering broad diversification in a single holding.

Wrapping Up the Series

We've covered a lot of ground these past fourteen weeks. We started with the simple concept that all debt is a promise—whether scratched on a Mesopotamian clay tablet or encoded in a modern bond indenture. We traced sovereign borrowing from the Fugger bankers to today's Treasury market, learned to read yield curves and credit ratings, and discovered how duration measures interest rate risk. The fundamentals haven't changed in four thousand years. Lenders still evaluate borrowers. Interest still compensates for time and risk. Trust still underpins every transaction. What has changed is your access to these markets and your ability to use them wisely. You now have the tools to evaluate those ancient promises for yourself.

Next week, we shift our focus back to equity securities. While we covered the history of stock ownership earlier in this series, we never explored the mechanics the way we have with bonds. Over the coming weeks, we'll dig into how stock prices actually work, what shareholders truly own, how dividends function, and how to measure and understand equity risk. It's time to give stocks the same thorough treatment we've given bonds.

Until next week...

Grace. Dignity. Compassion.