Interest rates and bond prices move in opposite directions: when rates rise, the market price of existing bonds falls, and when rates fall, existing bond prices climb. The size of that swing depends mostly on how long the bond has left until it matures and how large its coupon is. Yields move the other way from prices, so a bond that has lost value is now offering a higher return to whoever buys it next.1Federal Reserve Board. The Fed Explained – Monetary Policy
Why the Relationship Is Inverse
A bond’s coupon is fixed at issuance and never changes. If the Federal Reserve raises its target rate, newly issued bonds start paying larger coupons to match the new environment.2Federal Reserve Board. Federal Open Market Committee An older bond stuck at a lower coupon looks worse by comparison, and the only way to sell it is to drop the price until the buyer’s total return matches what new bonds offer.
The reverse plays out when rates fall. An older bond paying a higher coupon becomes valuable, and buyers will pay more than face value to lock in those larger interest payments. This constant repricing is what keeps every bond in the secondary market competitive with current rates, regardless of when it was originally issued.
What the Price Change Actually Looks Like
Say you own a bond with a $1,000 face value paying a 3% coupon. The Treasury then issues a new bond paying 5%. No one wants your 3% bond at $1,000 when they can get 5% brand new. To sell, you might drop your asking price to around $920. The discount compensates the buyer for the smaller coupon payments, and when the bond eventually matures at its full $1,000 face value, that $80 difference becomes part of the buyer’s return.
Treasury auction results show the same math directly: when a bond’s yield to maturity is higher than its coupon rate, the bond sells for less than face value.3TreasuryDirect. Understanding Pricing and Interest Rates When the yield is lower than the coupon, the bond sells at a premium.
Why Longer Bonds Swing Harder
The time left until maturity has a major effect on how much a bond’s price moves after a rate change. A 30-year Treasury bond will move much more than a 2-year note after the same shift in rates. The logic is straightforward: locking in a below-market coupon for 30 years hurts far more than locking it in for two, so the price has to drop more to make the deal fair.
Short bonds barely react. If the principal is coming back in a few months, the holder can reinvest at the new rate almost immediately, so a rate change costs them very little.
Duration: A Rough Rule for How Much Prices Move
Bond investors use a measure called duration to estimate how much a bond’s price will move for a given change in rates. Duration is expressed in years, and the shortcut is to multiply the duration by the rate change to get the approximate percentage price change. A bond with a duration of five years would fall roughly 5% if rates rose by one percentage point, or gain about 5% if rates fell by the same amount.
Two bonds with the same maturity date can still have different durations. A bond with a high coupon returns more cash sooner, which shortens duration and dampens price swings. A low-coupon bond, or a zero-coupon bond that pays nothing until maturity, has a longer duration and moves more sharply. Checking duration before buying is the most direct way to see how much price risk you are taking on.
What Happens to Yield When Price Moves
Yield to maturity is the total annual return you would earn if you held the bond until it matured. It includes the coupon payments plus any gain or loss between the price you paid and the face value you will get back at maturity. When rates rise and existing bond prices fall, the yield to maturity on those bonds automatically rises, because the lower purchase price bakes a bigger gain into the total return.3TreasuryDirect. Understanding Pricing and Interest Rates
Yield to maturity is also the cleanest way to compare bonds that have different coupons, prices, and maturity dates. A bond selling at a discount always shows a yield to maturity above its coupon rate. A bond selling at a premium shows one below its coupon rate.
Real Yield Versus Nominal Yield
The yield to maturity quoted on a bond is a nominal figure. It does not account for inflation. If a bond yields 4% and inflation is running at 3%, purchasing power grows by only about 1%. That 1% is the real yield. Over a decade or more, the gap between nominal and real returns can be large, which is why long-term bond investors watch inflation closely.
Bonds That Don’t Follow the Pattern the Same Way
Not every bond reacts to rate changes with the same intensity. A few are built specifically to blunt it.
Floating-Rate Notes
Floating-rate notes pay interest that resets periodically against a benchmark, most commonly the Secured Overnight Financing Rate (SOFR), published by the Federal Reserve Bank of New York.4Federal Reserve Bank of New York. Secured Overnight Financing Rate Data Because the coupon adjusts as rates move, the bond’s price stays close to face value. The tradeoff is that when rates fall, your income drops with them.
Treasury Inflation-Protected Securities
TIPS carry a fixed interest rate, but the principal itself adjusts up or down with the Consumer Price Index.5TreasuryDirect. TIPS – Treasury Inflation-Protected Securities When inflation rises, the principal grows, and so does each interest payment, because the fixed rate applies to a larger balance. At maturity, you receive either the inflation-adjusted principal or the original face value, whichever is greater.6U.S. Treasury Fiscal Data. TIPS and CPI Data The yield quoted at a TIPS auction is a real yield — the return above inflation.
Callable Bonds
Some corporate and municipal bonds include a call feature that lets the issuer pay them off early. When rates rise, callable bonds fall in price the same as any other bond. When rates fall, though, the upside is capped, because the issuer will call the bond and refinance at the lower rate. Getting principal back early creates reinvestment risk: the money now has to go into a new bond paying less, so future income shrinks.
Credit Quality Sits on Top of All of This
Rates are the main force moving bond prices, but credit quality is a separate one. If an issuer’s financial health deteriorates or a rating agency downgrades its debt, the bond’s price falls no matter what rates are doing. Investors demand a higher yield, called a credit spread, to accept the added risk of default. Rising rates and worsening credit can also hit the same corporate bond at once, deepening the loss beyond what either would cause alone.
Higher-rated bonds like U.S. Treasuries and investment-grade corporates tend to track rates most closely, because credit risk is minimal and rates are effectively the only variable. Lower-rated bonds are driven more by the issuer’s condition, so their prices sometimes move independently of the broader rate environment.