One of the most confusing facts for new investors is that bond prices fall when interest rates rise, and rise when rates fall. This inverse relationship is not a quirk, because it follows directly from how fixed payments are valued. This guide explains the mechanism and why some bonds react far more than others.
The core relationship
A bond pays a fixed coupon set when it was issued. When market interest rates rise, newly issued bonds pay more, making your older, lower-paying bond less attractive. To sell it, you must drop the price until its effective yield matches the new, higher rates. When rates fall, the opposite happens and your higher-coupon bond becomes more valuable. Price moves inversely to rates to keep yields competitive.
A simple illustration
Suppose you own a $1,000 bond paying a 4% coupon, or $40 a year. If market rates jump to 5%, buyers can get $50 a year elsewhere for the same $1,000, so no one will pay full price for your bond. Its price falls until the $40 payment represents a competitive yield for a new buyer. If rates instead drop to 3%, your 4% bond looks generous and its price rises above par.
Duration and sensitivity
How much a bond's price moves for a given rate change is measured by duration, expressed in years. Longer-maturity bonds have higher duration, so their prices swing more when rates move. A 30-year bond can lose far more value than a 2-year bond for the same rate increase. This is why investors worried about rising rates often favor shorter-duration bonds.
What it means for investors
If you hold a bond to maturity, these price swings do not change the coupons or the par value you receive, so day-to-day prices matter less. They matter most if you need to sell early or if you own a bond fund, whose share price reflects current market values. Rising rates hurt existing bond prices but also mean new bonds and reinvested coupons earn more. Understanding duration helps you match your bonds to your time horizon.
You hold a $1,000 bond paying 4%. Market rates rise to 5%, so a new buyer wants a 5% yield, and your bond's price must fall below $1,000 for its fixed $40 payment to deliver that yield. A comparable 30-year bond would drop much more than a 2-year bond because of its longer duration.
Key takeaways
- Bond prices and interest rates move in opposite directions.
- Prices adjust so an older bond's fixed coupon stays competitive with new rates.
- Duration measures how sharply a bond's price reacts to rate changes.
- Longer maturities have higher duration and bigger price swings.
- Held to maturity, a bond still pays its coupons and returns par regardless of price moves.
Common mistakes
- Panic-selling bond funds after a rate hike and locking in the price drop.
- Ignoring duration and holding long bonds when you may need cash soon.
- Believing a bond that fell in price has permanently lost value even if held to maturity.
FAQ
If rates rise, did my bond lose money for good?
Only if you sell before maturity. Hold it to the end and you still collect every coupon plus the full par value.
Why do long-term bonds fall more than short-term ones?
They have higher duration, meaning more future payments are exposed to the new rate, so their present value drops further.