What Is a Bond and How Does It Work?

If a stock makes you a part-owner of a company, a bond makes you a lender. You hand over money for a set period, the borrower pays you interest along the way, and you get your money back at the end. That basic structure is behind a huge share of the money invested worldwide, and it's worth understanding even if you never buy an individual bond.

Finch & Fortune shares general educational information, not financial advice. Everyone's situation is different — consider speaking with a qualified financial professional before making major money decisions.

What a bond actually is

A bond is a loan, packaged so it can be bought and sold. When a government, city, or company needs to raise money, one option is to issue bonds. Investors buy them, effectively lending the issuer cash. In return, the issuer promises two things: to pay interest at a stated rate on a schedule, and to repay the original amount in full on a specific future date.

The jargon is simple once you match it to the loan idea:

• Face value (or par): The amount the issuer will repay at the end, usually $1,000 per bond.
• Coupon: The interest rate the bond pays, expressed as a percentage of face value. A 4% coupon on a $1,000 bond pays $40 a year, typically split into two $20 payments.
• Maturity: The date the issuer repays the face value and the bond ends. Bonds can mature in a few months or in 30 years.
• Issuer: Who's borrowing — the U.S. Treasury, a state or city (municipal bonds), or a corporation.

How a bond works, start to finish

1. Issue. A company issues a 10-year bond with a $1,000 face value and a 5% coupon.
2. You buy it. You pay roughly $1,000 and now hold the bond.
3. You collect interest. Every year for 10 years, the company pays you $50, usually as $25 every six months.
4. It matures. At the end of year 10, the company pays you back your $1,000. The bond is done.

If you buy a bond at issue and hold it to maturity, and the issuer doesn't default, your return is essentially the coupon. The complications come from selling early and from what happens to bond prices in between.

Why bond prices move

Here's the part that trips people up: once a bond is issued, its price can rise or fall on the open market, and it moves opposite to interest rates.

Say you own that 5% bond. Then new bonds start being issued at 7% because rates have risen. Nobody wants your 5% bond at full price when they can get 7% elsewhere, so if you want to sell, you'll have to accept less than $1,000. Your bond's price falls. If rates instead drop to 3%, your 5% bond looks generous, and buyers will pay more than $1,000 for it. Its price rises.

This is the core trade-off. When interest rates go up, existing bond prices go down, and vice versa. Longer-maturity bonds swing more from this effect than short-term ones. If you hold to maturity, these price moves don't matter to your final outcome (you still get face value back), but they matter a lot if you might sell early or if you own a bond fund.

The main risks

• Interest rate risk: The price swings described above. Longer bonds carry more of it.
• Credit (default) risk: The chance the issuer can't make payments. U.S. Treasury bonds are considered extremely low risk; corporate bonds range from very safe to highly speculative ("junk" or high-yield bonds pay more precisely because they're riskier).
• Inflation risk: A fixed 4% coupon loses purchasing power if inflation runs at 5%. Your dollars come back, but they buy less.
• Reinvestment risk: When a bond matures or pays interest, you may have to reinvest that money at lower rates than you were getting.

Credit rating agencies grade bonds (AAA down to D) to signal default risk, though ratings are opinions, not guarantees.

Common types of bonds

• Treasuries: Issued by the U.S. federal government. Includes short-term T-bills, medium-term T-notes, long-term T-bonds, and inflation-adjusted TIPS. Backed by the U.S. government, so default risk is treated as near zero.
• Municipal bonds ("munis"): Issued by states, cities, and local agencies. Interest is often exempt from federal income tax, and sometimes state tax, which appeals to higher earners.
• Corporate bonds: Issued by companies. Higher yields than Treasuries to compensate for higher risk. Split into investment-grade and high-yield.
• Savings bonds: Non-tradable bonds sold directly to individuals by the Treasury, such as Series I bonds tied to inflation.

Why hold bonds at all

Bonds generally do two jobs in a portfolio. They produce steadier income than stocks, and they tend to be less volatile, which can cushion a portfolio when stock markets fall. That's why the classic advice pairs stocks and bonds, with the bond share often rising as someone gets closer to needing the money. Bonds are not risk-free and can lose value in a year, as 2022 showed when rising rates pushed bond prices down sharply. But over most periods they move less dramatically than stocks.

Individual bonds vs. bond funds

Most people get bond exposure through mutual funds or ETFs rather than buying individual bonds. A fund holds hundreds or thousands of bonds, spreads out default risk, and handles reinvestment automatically. The trade-off is that a fund never "matures" — its price floats with interest rates indefinitely, so you're always exposed to those swings. Buying individual bonds and holding to maturity gives you a known outcome, but requires more money to diversify properly and more effort to manage.

The takeaway

A bond is a tradable loan: you lend money, collect interest, and get your principal back at maturity. The return is straightforward if you hold to the end and the issuer pays. The nuance is that bond prices move opposite to interest rates, so selling early can mean a gain or a loss, and different issuers carry very different default risk. In a portfolio, bonds are the steadier counterweight to stocks — lower expected return, but a smoother ride and reliable income.

Frequently asked questions

Can you lose money on a bond?
Yes. You can lose money if the issuer defaults and can't repay you, or if you sell before maturity for less than you paid because interest rates have risen. If you hold a bond to maturity and the issuer pays as promised, you get the full face value back regardless of price swings in between.

Why do bond prices fall when interest rates rise?
Because newly issued bonds then offer higher interest, making your older, lower-rate bond less attractive. To sell it, you'd have to lower the price until its effective yield matches what a buyer could get on a new bond.

Are bonds safer than stocks?
Generally they're less volatile and more predictable, especially high-quality government bonds. But "safer" depends on the bond — a high-yield corporate bond can carry substantial risk, and even safe bonds can lose value in a year when rates rise or inflation outpaces the coupon.

How do I actually buy bonds?
Treasury bonds can be bought directly through TreasuryDirect.gov or through a brokerage account. Municipal and corporate bonds are usually bought through a broker. Most individual investors, though, get bond exposure through low-cost bond mutual funds or ETFs inside a regular brokerage or retirement account.

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Further reading & trusted sources

• CFPB: free consumer money tools
• MyMoney.gov: the U.S. government financial education hub