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Bond Duration Risk: Why Rising Rates Hurt Bond Prices

Bond prices move inversely to interest rates β€” and the magnitude of that move depends on duration. Here is the math of duration, why it matters for your bond allocation, and how to think about interest rate risk in your portfolio.

~14%Price drop on 20-year bond for +1% rate riseDuration approximation

# Bond Duration Risk: Why Rising Rates Hurt Bond Prices

"Bonds are safe" is one of the most persistent misconceptions in personal finance. Bonds are safe from default risk (for investment-grade and government bonds) β€” but they carry significant interest rate risk, and that risk scales directly with duration.

The 2022 bond market provided a painful reminder: the Bloomberg U.S. Aggregate Bond Index fell approximately 13% β€” its worst year in decades β€” as the Federal Reserve raised rates aggressively. Long-duration bond funds fell 25–30%.

What duration means

Duration is a measure of a bond's sensitivity to interest rate changes. Technically, it's the weighted average time to receive a bond's cash flows, expressed in years. Practically, it tells you: if interest rates rise by 1%, how much will this bond or fund lose in value?

The approximation: **Ξ”Price β‰ˆ βˆ’Duration Γ— Ξ”rate**

A bond fund with a duration of 7 years will lose approximately 7% in value if interest rates rise 1%. If rates rise 2%, it loses approximately 14%.

Short-term bonds (1–3 year duration) have minimal rate sensitivity. Long-term bonds (15–20 year duration) are highly sensitive β€” they behave more like equities in terms of volatility.

Interactive Calculator

Interactive Model

Bond Duration Risk Calculator

See how much a bond or fund loses when interest rates change β€” across durations.

6.5 years
+1%
$10,000
4%

Price change (%)

-6.50%

Dollar impact

-$650

New portfolio value

$9,350

Price sensitivity at duration 6.5 across rate scenarios

Rate change% impactDollar impact ($10,000)
-2%+13.00%+$1,300
-1%+6.50%+$650
-0.5%+3.25%+$325
0%+0.00%+-$0
+0.5%-3.25%-$325
+1%-6.50%-$650
+2%-13.00%-$1,300

Duration approximation: Ξ”P/P β‰ˆ βˆ’Duration Γ— Ξ”y. Accurate for small rate changes; convexity errors increase for larger moves. Actual fund performance will vary.

Duration in practice

**The U.S. Aggregate Bond Index** (tracked by BND, AGG) has a duration of approximately 6–7 years. A 1% rate rise means approximately 6–7% price decline.

**Short-term bond funds** (BSV, VGSH) have durations of 2–3 years β€” much lower rate sensitivity, but also lower yield.

**Long-term Treasury funds** (TLT, VGLT) have durations of 15–20 years β€” high yield but enormous rate sensitivity.

The 2022 experience: the Fed raised rates by approximately 4.25% over the year. A fund with duration 7 would have lost approximately 7% Γ— 4.25 = ~30% from rate moves alone (partially offset by coupon income).

How to manage duration risk

**Match duration to your time horizon:** If you need the money in 3 years, a 3-year duration bond fund eliminates rate risk β€” you'll receive your yield regardless of rate moves if you hold to maturity.

**Laddering:** Hold bonds maturing at regular intervals (1, 2, 3, 4, 5 years). As rates rise, maturing bonds are reinvested at higher yields, reducing the impact of rate changes on total return.

**TIPS for inflation protection:** Treasury Inflation-Protected Securities have shorter effective duration because their principal adjusts with inflation β€” they provide rate protection via the inflation adjustment mechanism.

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*Related: [Asset allocation by age](./asset-allocation-age) β€” how much of your portfolio should be in bonds. [Rebalancing](./rebalancing) β€” managing your bond allocation over time.*

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