Why Do Bond ETFs Fall When Interest Rates Rise? Duration Explained

A fixed-rate bond promises specified interest payments and principal under its terms. If investors can now buy similar new bonds at higher yields, an older bond with a lower coupon is less attractive at its previous price. Its market price generally has to fall to make its remaining payments competitive with the new market yield. When market interest rates rise, bond prices generally fall; FINRA and the SEC’s fixed-income investor bulletin explain this inverse relationship.

A bond ETF owns many bonds, often with different coupons, issuers, and maturities. The fund’s net asset value (NAV) reflects the market value of those holdings and other fund assets and liabilities. If the prices of bonds in the portfolio fall, the NAV per ETF share can fall too. The ETF’s exchange-traded price can move as buyers and sellers update their valuations, and it may trade at a premium or discount to NAV. Rate exposure is one part of the fund’s price behavior, not a complete explanation of every daily move.

“Interest rates” can mean several different numbers. A central bank’s policy target is a short-term benchmark. A bond’s market yield is the return implied by that bond’s current traded price and promised cash flows. Treasury yields vary by maturity, while corporate yields also reflect credit and liquidity risk. These market yields respond to investors’ expectations, inflation outlook, bond supply and demand, and other factors, so they can move before a policy announcement or in a different direction from the policy target.

A rate increase announced by the Federal Reserve therefore does not mechanically subtract the same percentage from every bond ETF. The portfolio’s bonds may respond to changes in the yields relevant to their maturities and credit categories. The FINRA bond overview describes how market rates and bond prices interact and notes that bond prices are affected by multiple market forces. When someone says a fund “fell because rates rose,” ask which market yields changed, over what period, and whether credit spreads or other forces moved at the same time.

Duration is stated in years, which can make it sound like a countdown. For this purpose, treat it as a sensitivity measure: effective duration estimates the percentage change in a bond or bond portfolio’s price for a 1 percentage-point (100-basis-point) change in relevant yields, with the direction reversed. A six-year effective duration suggests that a small 1 percentage-point yield rise could correspond to roughly a 6% price decline before other effects. FINRA’s duration explainer describes duration as a way to gauge bond-price fluctuations and distinguishes effective duration from simpler duration measures.

Effective duration is not the bond’s remaining maturity, the ETF’s holding period, or the time an investor must wait to recover a price decline. For bonds with options—such as callable bonds or mortgage-backed securities—expected cash flows can change when yields change. An effective-duration calculation estimates that response using a model. For a fund, the displayed number is a portfolio estimate based on holdings, assumptions, and a measurement date. It can change when the bond prices, holdings, or embedded-option assumptions change.

A common first-order approximation is: percentage price change ≈ −effective duration × change in yield. Convert the yield move to percentage points: 25 basis points (bp) equals 0.25 percentage point, or 0.0025 as a decimal. With a hypothetical 6.0-year effective duration and a parallel +25 bp move in the market yields relevant to the portfolio, the estimate is −6.0 × 0.0025 = −0.015, or about −1.5%.

For a hypothetical $10,000 position, 1.5% of $10,000 is about $150. The simple estimate would put the position’s market value near $9,850, before other changes. It is a model-based illustration, not a prediction that every bond ETF with a displayed duration of 6.0 will fall by exactly $150 after a 25 bp move. It also does not assume the Federal Reserve’s policy target itself rose by 25 bp; it assumes the relevant market yields shifted in parallel by that amount.

The estimate above is about the approximate change in value of the bond portfolio, which is reflected in NAV. ETF shares also trade on an exchange. Their market price can temporarily sit above or below NAV as trading supply, demand, and the value of underlying bonds change. In less liquid or fast-moving markets, quotes for bonds may update at a different pace from ETF trading, and the premium or discount can widen or narrow.

That difference means an investor’s exact share-price move can be larger or smaller than the portfolio’s duration estimate. [ETF NAV versus market price and premiums or discounts](/en/learn/etf-nav-vs-market-price-premium-discount-explained) explains how those two prices relate. Duration does not estimate the premium or discount, and a duration calculation for NAV should not be treated as an exact prediction for the ETF’s exchange price.

A traditional bond fund generally does not hold every bond until one common maturity date. It may receive principal from maturing bonds, sell holdings, add new bonds, or adjust weights to follow its mandate. That turnover changes the portfolio’s duration and its exposure to different maturity ranges, coupons, issuers, and credit risks. A bond fund’s duration is therefore a snapshot, not a fixed characteristic for the life of your ETF shares.

If market yields rise, newly purchased bonds may offer higher yields than the bonds they replace, and the fund’s income may adjust over time. But a possible increase in future income does not erase an immediate mark-to-market decline by arithmetic, does not arrive on a guaranteed schedule, and may be offset by other factors. The fund’s distributions also depend on income, expenses, realized gains or losses, and distribution policy. The SEC’s bond-funds overview notes that bond funds face interest-rate risk and that a fund’s holdings and risks depend on its objectives and portfolio.

The −duration × yield-change calculation is a first-order estimate under simplifying assumptions. It does not include convexity, which describes how price sensitivity itself changes as yields move; for a larger rate move, that curvature can make the result differ from a straight-line estimate. It also assumes a parallel shift in the relevant yield curve. In practice, short-, intermediate-, and long-term yields can move by different amounts or in different directions.

Duration alone also leaves out changes in credit spreads, income earned during the measurement period, fund expenses and trading costs, portfolio turnover, and changes in the ETF’s premium or discount to NAV. For callable bonds and mortgage-backed securities, prepayment behavior can alter expected cash flows and effective duration. Issuer credit quality, defaults, liquidity, foreign exchange exposure, and other risks can matter too. FINRA and Investor.gov emphasize that bond funds face multiple risks; duration isolates only one sensitivity and cannot describe all possible outcomes.

When reading a bond ETF fact sheet, note the duration value and its date, the type of duration reported, and whether it is effective, modified, or another measure. Then look at average maturity, yield measures, credit quality, government or corporate exposure, callable and mortgage holdings, and the fund’s stated objective. Two funds with the same duration may still have different credit, spread, liquidity, and cash-flow risks. For context on income-related measures, see [SEC yield, distribution yield, and yield to maturity](/en/learn/etf-sec-yield-vs-distribution-yield-explained).

A Treasury STRIP is a zero-coupon security whose value is especially sensitive to yields for its maturity because it pays no interim coupons. The guide to [Treasury STRIPS and zero-coupon bonds](/en/learn/treasury-strips-zero-coupon-bonds-explained) shows why maturity and duration can be close for that specific type of bond, while they are not interchangeable for every bond or bond ETF. Review a fund’s prospectus and current fact sheet for its own definitions and portfolio details; a single duration number is a starting point for understanding interest-rate sensitivity, not a complete risk score or a forecast.

Duration helps answer a focused question: if relevant market yields changed modestly, about how sensitive might the bond portfolio’s price be, all else equal? It can help compare similar portfolios on the same date and make a hypothetical rate scenario concrete. It cannot tell you the exact return you will earn, when prices will recover, or whether a particular fund fits your circumstances.

Keep the distinction clear: an individual bond has a contractual maturity, while an ETF share does not mature at the average maturity or duration of its holdings. Market prices can move in either direction, and the fund’s income, holdings, costs, and trading price can change too. Treat every duration calculation as an approximate, conditional estimate, and consider the fund’s full disclosures rather than relying on one statistic.