Bond Investing Explained: What Bonds Are and How They Work

Bonds are often called 'boring' — but they've preserved and grown wealth for centuries. In a diversified portfolio, bonds reduce volatility, provide income, and protect against stock market crashes. Here's what you need to know.

What Is a Bond?

A bond is a loan you make to a government or corporation. They promise to pay you a fixed interest rate (coupon) for a set period, then return your principal at maturity. Example: You buy a 10-year US Treasury bond at $1,000 with a 4.5% coupon. You receive $45/year for 10 years, then get your $1,000 back.

Types of Bonds

• US Treasury bonds: Backed by the US government — essentially zero default risk. Yields currently 4–5%.
• Municipal bonds: Issued by states/cities. Interest is federal tax-exempt — great for high-income investors.
• Corporate bonds: Higher yield than Treasuries, but more default risk. Investment-grade pays 5–7%, junk bonds 8–12%.
• I-Bonds: Inflation-linked US savings bonds. Rate adjusts with CPI — great for inflation protection.

The Bond-Stock Relationship

Bonds and stocks often move in opposite directions. When the stock market crashes, investors flee to bonds (pushing bond prices up). This is why a 60/40 portfolio (60% stocks, 40% bonds) has historically provided 80% of the return of all-stocks with significantly less volatility.

How Bond Prices Work

Bond prices move inversely to interest rates. When rates rise, existing bonds become less attractive (they pay less than new bonds), so prices fall. When rates fall, existing bonds paying higher rates become more valuable. If you hold bonds to maturity, price fluctuations don't matter — you get your principal back.

Bond Funds vs Individual Bonds

For most investors, bond index funds (like BND, AGG, or VBTLX) are better than individual bonds. They provide instant diversification across hundreds of bonds, automatic reinvestment, and professional management at low cost (0.03–0.10% expense ratio).