What Is a Bond and How Does It Actually Work

A Bond Is Simply a Loan With Paperwork

Strip away the terminology and a bond is a straightforward arrangement: an investor lends money to a borrower, usually a government or a corporation, and the borrower agrees to pay it back on a fixed schedule. The borrower issues the bond to raise money for something specific — funding a budget deficit, building a factory, refinancing older debt — and in exchange promises two things: regular interest payments, called coupon payments, and the return of the original amount lent, called the face value or par value, when the bond matures.

A typical bond might have a face value of $1,000, a coupon rate of 4%, and a maturity of ten years. That means the holder receives $40 a year for ten years, then gets the original $1,000 back at the end. Governments issue bonds to fund public spending, and corporations issue them as an alternative to bank loans or selling equity, often at a lower cost of capital than either option.

Why Bond Prices Move Opposite to Interest Rates

Here is where bonds confuse people who assume they behave like savings accounts. Once a bond is issued, it can typically be bought and sold on a secondary market before it matures, and its price on that market fluctuates — often significantly.

The mechanism is straightforward once you see it. Suppose you hold a bond paying a 4% coupon, and then prevailing interest rates rise, so newly issued bonds now pay 6%. Nobody would pay you full face value for your 4% bond when they could buy a brand-new bond paying 6% instead. So the market price of your older bond falls until its effective return, given the fixed $40 annual payment, becomes competitive with the new 6% bonds. The reverse happens when interest rates fall: existing bonds with higher coupon rates become more attractive, and their prices rise above face value.

This inverse relationship between bond prices and interest rates is one of the most consistent patterns in finance, and it is why a central bank raising interest rates typically causes bond prices to drop across the market, even though nothing about the bonds themselves has changed.

Coupon Rate, Yield, and Price: Three Different Numbers

Confusion often comes from mixing up three related terms. The coupon rate is fixed at issuance and never changes — it is the percentage of face value paid out each year. The price is whatever the bond currently trades for on the market, which can be above, below, or equal to face value. The yield is the effective annual return an investor gets if they buy at the current price, and it moves inversely with price: buy a bond below face value and your yield is higher than the coupon rate, because you are getting the same fixed payments for less money upfront.

What Determines a Bond's Risk and Reward

Not all bonds carry the same risk. Government bonds from stable, currency-issuing countries are generally considered very low risk of default, since the issuer can raise taxes or, in some cases, create currency to meet obligations. Corporate bonds carry higher default risk, since a struggling company could fail to make payments, and this added risk is compensated with a higher coupon rate. Credit rating agencies assess this default risk and assign ratings, and bonds rated below a certain threshold are commonly referred to as high-yield or junk bonds, reflecting their higher risk and correspondingly higher promised returns.

Maturity length also affects risk. Longer-maturity bonds are generally more sensitive to interest rate changes than short-maturity bonds, because a change in rates affects many more years of future fixed payments relative to the bond's current price.

Common Questions About Bonds

What happens if I hold a bond to maturity?

If you hold the bond until it matures and the issuer does not default, you receive the full face value back regardless of how the price fluctuated in the meantime. Price swings only matter if you plan to sell before maturity.

Are bonds risk-free?

No. Even highly rated bonds carry interest rate risk, since their market value can fall if rates rise, and inflation risk, since fixed payments buy less over time if prices rise faster than expected.

Why do governments and companies both use bonds instead of just borrowing from a bank?

Issuing bonds lets a borrower raise money from many lenders at once, often at more competitive rates than a single bank loan, and spreads the debt across investors who can trade it if their needs change.