Fixed-Rate Bonds: Locking In the Coupon

Key Takeaways

• A fixed-rate bond locks its coupon rate for the life of the bond, so each interest payment is known in advance and never adjusts to market conditions.
• Because the coupon is fixed, the bond's price must move to keep its yield competitive; when market rates rise, the price falls, and when rates fall, the price rises.
• Duration measures how sensitive the price is to a change in yields; a longer maturity or a lower coupon means a longer duration and larger price swings.
• Holding to maturity returns the face value regardless of price swings along the way, so interest rate risk mainly matters if you may sell early.

What It Is

A fixed-rate bond is a debt security whose coupon rate is set at issuance and stays constant until the bond matures. The issuer, whether a government or a company, promises to pay that fixed percentage of the face value each period, then to return the face value on the maturity date.

Contrast this with a floating-rate note, whose coupon resets periodically against a reference rate. The fixed-rate bond makes no such adjustment. A 4% coupon on a $1,000 bond pays $40 a year for the entire term, whether prevailing rates climb to 8% or drop to 1%.

The Intuition

Because the cash payments are frozen, the only variable that can move is the price. Imagine you own a bond paying 4% and new bonds start offering 5%. No one will pay full price for your lower stream of payments, so the market marks your bond down until its yield to a new buyer matches the 5% available elsewhere. The reverse happens when rates fall: your above-market coupon becomes attractive, and the price rises. This is the price-yield inverse relationship, and it is the source of interest rate risk.

How It Works

Three numbers define a fixed-rate bond: the face value (usually $1,000), the coupon rate, and the maturity. The coupon rate times the face value gives the annual payment, often split into two semiannual installments.

The bond's price is the present value of all future cash flows, the coupons plus the final face value, discounted at the market yield. When that yield changes, every discounted cash flow is repriced. Duration summarizes the result in a single figure: it estimates the percentage price change for a one-percentage-point change in yield. Longer maturities and lower coupons push duration higher because more of the bond's value sits far in the future, where discounting bites hardest.

Worked Example

Take a $1,000 face fixed-rate bond with a 4% annual coupon and 5 years to maturity, issued when market yields are also 4%. It pays $40 each year and $1,000 at the end. At a 4% yield the price equals par, $1,000.

Now suppose market yields jump to 5% the day after issue. Reprice the same cash flows at 5%:

• Present value of the five $40 coupons: $40 times the annuity factor (1 - 1.05^-5) / 0.05 = $40 times 4.3295 = $173.18.
• Present value of the $1,000 face at year 5: $1,000 times 1.05^-5 = $1,000 times 0.78353 = $783.53.
• New price: $173.18 + $783.53 = $956.71.

The price fell about 4.3%, from $1,000 to $956.71, for a 1-point rise in yields. The bond's Macaulay duration here is roughly 4.63 years and its modified duration about 4.45 years, so the duration estimate predicts a drop near 4.45%, close to the exact 4.3%. If you hold to maturity, you still collect every $40 coupon and the full $1,000, so the interim price dip never becomes a realized loss.

Common Mistakes

1. Confusing coupon rate with yield. The coupon is fixed at issue; the yield to maturity floats with the price you actually pay. A 4% coupon bond bought at $956.71 yields about 5%.
2. Assuming a fixed coupon means a fixed value. The payment is fixed, the market price is not. Marking a bond at par when rates have moved overstates or understates what you could sell it for.
3. Ignoring duration when rates are volatile. Two bonds with the same coupon but different maturities carry very different price risk; the longer one falls much harder when yields rise.
4. Forgetting reinvestment risk. If rates fall, the fixed coupons you receive must be reinvested at the new lower rates, which lowers your realized return even as the bond's price rises.

Frequently Asked Questions

Q: What is a fixed-rate bond in simple terms? A fixed-rate bond is a loan to a government or company that pays the same interest amount every period until maturity, then repays the original face value. The coupon rate never changes for the life of the bond.

Q: Why does a fixed-rate bond lose value when interest rates rise? Because the coupon is locked, the bond cannot raise its payments to match newer, higher-yielding bonds. The market instead lowers the price until the bond's yield to a new buyer matches prevailing rates.

Q: How is a fixed-rate bond different from a floating-rate note? A fixed-rate bond keeps one coupon rate for its whole term, while a floating-rate note resets its coupon periodically against a reference rate. The fixed bond carries more interest rate risk; the floater carries less price sensitivity but uncertain payments.

Q: Does interest rate risk matter if I hold to maturity? Less so. If the issuer does not default, you receive every coupon and the face value at maturity regardless of price swings. Interest rate risk mainly affects you if you might sell before maturity.

Q: What does duration tell me about a bond? Duration estimates how much the price moves for a one-percentage-point change in yield. A modified duration of 4.45 means roughly a 4.45% price change per 1% yield move, so higher duration signals larger price swings.

Sources

1. Investopedia. "Fixed-Rate Bond." https://www.investopedia.com/terms/f/fixed-rate-bond.asp
2. U.S. SEC Investor.gov. "Bonds." https://www.investor.gov/introduction-investing/investing-basics/investment-products/bonds-or-fixed-income-products/bonds
3. FINRA. "Bond Basics." https://www.finra.org/investors/investing/investment-products/bonds
4. Investopedia. "Duration." https://www.investopedia.com/terms/d/duration.asp

Disclaimer

This article is educational content only and is not financial advice. Nothing here is a recommendation to buy, sell, or hold any security. Consult a licensed advisor before making investment decisions.