When interest rates rise, the prices of existing bonds fall, and when interest rates drop, existing bond prices rise. This inverse relationship exists because bonds pay a fixed amount of interest, so the only way an older bond can compete with newer, higher-paying bonds is by dropping in price. The logic works in reverse too: when new bonds offer lower rates, older bonds with higher payouts become more valuable. Understanding this mechanism helps you make sense of nearly everything that happens in the bond market.
The Fixed Coupon Problem
A bond is essentially a loan you make to a government or corporation. When you buy a bond, the issuer promises to pay you a set interest rate (called the coupon) for the life of the bond, then return your principal at maturity. That coupon rate is locked in on the day the bond is issued and never changes.
This creates a problem whenever market interest rates move. Say you buy a 10-year Treasury bond paying 3% when that’s the going rate. A year later, new Treasury bonds start offering 4%. Your bond is still paying 3%, which is less attractive to any buyer. If you try to sell it on the open market, nobody will pay full price for a 3% bond when they can buy a brand-new 4% bond instead. So your bond’s price has to drop until the total return a buyer would earn matches the 4% available elsewhere.
The SEC illustrates this with a concrete example. A $1,000 bond with a 3% coupon and 10 years to maturity would sell at face value when market rates are also 3%. One year later, if market rates have risen to 4%, that same bond (now with 9 years remaining) would sell for roughly $925. The buyer who pays $925 still collects the 3% coupon payments plus the full $1,000 at maturity, and that combination of discount and interest works out to an effective yield of about 4%, matching the new market rate.
How Price Adjustments Create New Yields
The number that ties price and interest rate together is called yield to maturity (YTM). It represents the total annual return you would earn if you bought a bond at its current market price and held it until it matures, collecting every coupon payment along the way and receiving the face value at the end. When a bond trades at exactly its face value, the yield to maturity equals the coupon rate. When the price drops below face value, the yield rises above the coupon rate because you’re getting the same stream of payments for less money upfront.
This is why you’ll sometimes hear that “price and yield move in opposite directions.” They have to. A lower purchase price means each dollar of coupon income represents a bigger percentage return, pushing the yield up. A higher purchase price dilutes that return, pushing the yield down. The market constantly adjusts bond prices so that every bond’s yield stays in line with prevailing interest rates for bonds of similar risk and maturity.
Why Longer Bonds Move More
Not all bonds react to interest rate changes by the same amount. The key factor is how long you’re locked into the bond’s fixed payments. A bond maturing in two years won’t lose much value when rates rise because you’ll get your principal back soon and can reinvest at the new, higher rate. A bond maturing in 20 years, on the other hand, locks you into below-market payments for a long time, so its price must fall much further to compensate a buyer.
Bond investors measure this sensitivity with a concept called duration, expressed in years. Duration estimates how much a bond’s price will change for each 1 percentage point move in interest rates. A bond fund with a duration of five years would lose roughly 5% of its value if rates rose by one percentage point. A fund with a duration of 11 years would lose about 11% from the same rate increase. The relationship works in the other direction too: if rates fell by one percentage point, that 11-year-duration fund would gain roughly 11%.
This is why long-term government bonds can be surprisingly volatile even though they’re considered safe from default. During periods of rising rates, 20- or 30-year bonds can lose a significant share of their market value, even though the issuer will still pay every dollar owed at maturity.
A Real-World Example
The bond market in recent years provides a clear illustration. The Federal Reserve cut its benchmark interest rate by nearly 2 percentage points over about a year and a half leading into 2025. Lower short-term rates generally support bond prices, and the Bloomberg US Aggregate Bond Index returned about 7% through late November 2025. But the picture was more complicated for longer maturities. Rates on intermediate and longer-term bonds stayed relatively high even as the Fed was cutting, partly because investors began demanding a larger “term premium,” the extra yield they require for tying up money for longer periods. That divergence between short-term and long-term rates fueled significant price volatility in 2025, showing that the inverse relationship plays out differently across the maturity spectrum.
How Inflation-Protected Bonds Fit In
Treasury Inflation-Protected Securities (TIPS) follow the same inverse rule, but with a twist. TIPS adjust their principal value based on inflation, so their prices respond to changes in real yields (the interest rate after subtracting inflation) rather than nominal yields. When real yields fall, TIPS prices rise. When real yields climb, TIPS prices drop. This means TIPS prices can sometimes move in a different direction than regular Treasury bonds if inflation expectations shift independently of overall interest rates. For instance, real yields can rise even when nominal yields stay flat, which would push TIPS prices down while conventional bond prices hold steady.
TIPS issued by the U.S. government also come with a deflation floor at maturity: even if deflation erodes the inflation-adjusted principal below the original face value, you still receive at least the full par amount when the bond matures.
What This Means for Your Portfolio
The inverse relationship between interest rates and bond prices has a few practical implications worth keeping in mind. First, if you hold a bond to maturity, price fluctuations along the way don’t affect the total amount you receive. You’ll collect every coupon payment and get your face value back. The inverse relationship only creates a real gain or loss when you sell before maturity.
Second, your exposure to interest rate risk depends heavily on the duration of your bonds. Short-term bonds and bond funds (with durations of one to three years) won’t move much when rates shift. Long-term bonds (durations of 10 years or more) can swing dramatically. Choosing the right duration depends on whether you think rates are headed up or down, and on how long you can afford to wait for your money.
Third, rising rates aren’t entirely bad news for bond investors with a long time horizon. While existing bond prices fall in the short term, you can reinvest your coupon payments and maturing principal into new bonds at higher rates. Over time, the higher income can more than offset the initial price decline. The pain is concentrated in the transition period, especially for investors who need to sell before maturity.