Bond prices and interest rates move in opposite directions, and that single fact explains most of what confuses investors about the fixed income side of a portfolio. Many people buy bonds expecting stability, then open a statement and find that the “safe” portion of their account lost value. Nothing broke. The relationship worked exactly as designed. Understanding why it happens, and how to measure it in your own holdings, is one of the more useful pieces of investment literacy a household can pick up.
Why Bond Prices and Interest Rates Move in Opposite Directions
A bond is a loan with a fixed payment schedule. When you buy a newly issued bond, the coupon is set to match what the market demands at that moment, and that coupon does not change for the life of the bond.
Now suppose market rates rise after you buy. A newly issued bond of the same quality and maturity pays more than yours does. No buyer would pay full price for the older, lower-paying bond when a better one is available. The only way your bond becomes competitive is for its price to fall until the remaining coupons plus the discount produce a yield comparable to the new issue.
The reverse holds as well. When market rates fall, your older bond pays more than newly issued bonds, and buyers bid its price up. The Securities and Exchange Commission covers this directly in its investor bulletin on interest rate risk, and it notes that this risk applies to all fixed-rate bonds, including United States Treasury bonds. Credit quality does not protect against it.
Duration: The Number That Measures the Risk
Knowing that prices fall when rates rise is only half the picture. The more useful question is how far. That is what duration measures.
Duration is expressed in years, which causes confusion because it is not the same thing as maturity. Maturity is the date the principal comes back. Duration weighs the timing of every payment the bond makes, including the coupons along the way. As a rule of thumb, duration tells you the approximate percentage change in price for each one percentage point change in interest rates.
The rule of thumb in practice
If a bond or bond fund has a duration of six years, a one percentage point rise in rates would be expected to reduce its price by roughly six percent. A one percentage point decline would be expected to increase it by roughly six percent. The table below shows how sensitivity scales.
| Average duration | Approximate price change if rates rise 1% | Approximate price change if rates fall 1% |
|---|---|---|
| 2 years (short term) | Down about 2% | Up about 2% |
| 6 years (intermediate term) | Down about 6% | Up about 6% |
| 12 years (long term) | Down about 12% | Up about 12% |
Two bonds maturing on the same day can carry different durations. A bond with a lower coupon returns less cash early, so more of its value sits further out in time, which makes it more sensitive to rate changes.
Test Yourself
Work through the question below before reading further. Open any option to see why it is or is not correct.
A. Nothing. Bonds pay a fixed rate, so the price does not move.
B. The price falls by roughly 1 percent, matching the rate change.
C. The price falls by roughly 6 percent.
D. The price rises by roughly 6 percent, because the fund now earns more.
Where Rates Stand in 2026
At its meeting on June 17, 2026, the Federal Open Market Committee voted twelve to zero to maintain the target range for the federal funds rate at 3-1/2 to 3-3/4 percent, a level in place since December 2025. The Committee noted that inflation remains elevated relative to its two percent goal.
On the savings side, the Treasury announced on May 1, 2026 that Series I savings bonds issued from May through October 2026 earn a composite rate of 4.26 percent, combining a 0.90 percent fixed rate with the semiannual inflation adjustment.
The point of citing these figures is not to predict where rates go next. The point is that yields are meaningfully higher than they were in the 2010s, which changes the arithmetic. Bond prices and interest rates still move against each other, but investors are now paid considerably more to accept that risk than they were a decade ago.
What This Means for Your Portfolio
Match duration to when you need the money
The most practical use of duration is as a matching tool. Money you expect to spend within two or three years generally does not belong in a long-duration bond fund, because a rate move could push the value below what you need at the moment you need it. Money earmarked for spending fifteen years out can tolerate far more interest rate movement, because there is time for higher reinvestment rates to offset the initial price decline.
A falling bond fund is not a broken bond fund
An individual bond held to maturity returns its face value regardless of what happened to its price along the way, assuming the issuer does not default. A bond fund never matures, which leads some investors to conclude that a price decline is permanent. A fund continuously replaces maturing holdings with new bonds at current rates, so a period of rising rates lowers the price today and raises the income stream going forward. Over a holding period roughly equal to the fund’s duration, those two effects tend to substantially offset one another.
Know what you actually own
Most investors we speak with can name their bond funds but cannot name their duration. It is published on the fund’s fact sheet, usually listed as average effective duration. Looking it up takes about a minute and tells you more about your likely experience in a rate move than the fund’s name ever will. Investor.gov maintains useful background on how bonds and fixed income products work.
Common Mistakes We See
- Treating all bonds as interchangeable. A short-term Treasury fund and a long-term corporate fund behave very differently in the same rate environment.
- Selling after a rate-driven decline. Doing so locks in the price loss and forfeits the higher income that follows.
- Reaching for yield without checking duration. A higher payout often reflects longer duration, additional credit risk, or both.
- Holding long-duration bonds for short-term goals. This is the mismatch most likely to cause damage.
Reviewing Your Own Fixed Income
If the exercise above left you unsure what duration your own holdings carry, that is a reasonable place to start a conversation. We help clients in the Sacramento region look at how their bond holdings are positioned relative to when they plan to spend the money, and whether the risk they are carrying is the risk they intended to carry. You are welcome to schedule a free 30-minute call to talk it through, at no cost and no obligation.
Rooney Wealth Management LLC is an investment adviser registered with the state of California. This article is for educational purposes only and is not tax, legal, or investment advice. Please consult your tax or financial professional regarding your specific situation.
