Carry and Roll-Down: Static Bond Return Components

Key Takeaways

• Carry is the coupon income accrued over the holding period; roll-down is the price gain as the bond matures toward a lower yield.
• Roll-down is positive on an upward-sloping curve, near zero on a flat curve, and negative on an inverted curve.
• Funded carry subtracts the repo financing rate; leveraged traders must use funded carry to assess true daily cost.
• Static return (carry plus roll-down) sets a baseline expectation; yield curve moves can easily overwhelm it in weeks.

What It Is

Carry is the coupon income accrued over the holding period. For a simple coupon bond held for a year, carry is approximately the annual coupon divided by the current dirty price.

Roll-down is the price appreciation a bond earns as its remaining maturity shortens and it "rolls down" to a lower point on an upward-sloping yield curve. As the bond ages from, say, 10 years to 9 years, the reference yield becomes the 9-year yield, which is usually lower. Lower yield means higher price, and that price gain is roll-down.

The sum of carry and roll-down is often called static return or CaRD in manager jargon. It is the return you earn if the yield curve stays exactly where it is today.

The Intuition

Bond total return has three drivers: coupon income, price change from the bond aging, and price change from the curve itself shifting. Carry captures the first. Roll-down captures the second. The third is what trader models try to forecast.

Splitting static return into carry and roll-down matters because the two behave differently. Carry is locked in by the coupon and accrues daily. Roll-down depends on the shape of the curve and can be negative if the curve is inverted. A bond trader who is paid to be long rates overnight needs positive total carry-plus-roll-down just to break even against financing costs.

How It Works

The basic decomposition assumes you hold the bond for a horizon h and the curve is unchanged.

Total return ~= Carry + Roll-down + Yield-change return
Carry ~= (Coupon x h) / Price_today
Roll-down ~= Modified Duration x (Y_start - Y_end)

Here Y_start is the current yield for the bond at its current maturity, and Y_end is today's yield on the curve at the shorter maturity the bond will have at the end of the horizon. For an upward-sloping curve, Y_end < Y_start, so roll-down is positive.

A steeper curve means a bigger yield drop as the bond ages, and therefore larger roll-down. Flat curves give near-zero roll-down; inverted curves give negative roll-down because the bond rolls up to a higher yield.

Practical variations include funded carry, which subtracts the repo or financing rate a trader pays to hold the bond. For a hedge-fund book, the relevant figure is coupon plus roll-down minus financing.

Worked Example

Assume a 5-year Treasury note yielding 4.30 percent with a 4.00 percent annual coupon, priced at 98.68. The 4-year yield on the current curve is 4.10 percent. Modified duration of the bond is roughly 4.45.

Over a one-year holding period the static return has two parts.

Carry: 4.00 / 98.68 = 4.05 percent.

Roll-down: the bond rolls from the 5-year point (4.30 percent) down to the 4-year point (4.10 percent), a 20 bp drop. Using modified duration, roll-down is approximately 4.45 x 0.20 percent = 0.89 percent.

Total expected static return: 4.05 + 0.89 = 4.94 percent, materially above the current 4.30 percent yield. The extra 64 bps comes from the shape of the curve.

Now reverse the curve. If the 5-year yielded 4.30 percent and the 4-year yielded 4.50 percent (inverted), roll-down would be -0.89 percent and static return only 3.16 percent. The same bond has very different expected returns depending on curve shape.

Common Mistakes

• Quoting yield-to-maturity as the expected return. YTM only equals return if the bond is held to maturity and coupons reinvest at YTM. Over a shorter horizon, carry and roll-down are the better estimate.
• Ignoring financing costs. A leveraged trader who ignores the repo rate can see a trade that looks like positive carry become negative once funding is subtracted.
• Assuming roll-down is always positive. In inverted curves, rolling down the maturity axis rolls up the yield axis. The trade loses money even if the curve never moves.
• Using flat-curve approximations in steep curves. Modified duration gives a first-order roll-down estimate. For very steep curves, the convexity correction becomes important and a full repricing is safer.
• Forgetting that the curve does move. Static return sets a baseline. A 50 bp yield rise can wipe out a year of carry and roll-down in a week. The concept is a planning tool, not a guarantee.

Frequently Asked Questions

Why is carry and roll-down called "static return"? Static return is the return earned under a static scenario where the yield curve does not move at all from today. It is the baseline before adding any rate forecast. Separating static return from the yield-change component helps managers understand how much they need rates to move to beat or lose to the static scenario, making it a useful framework for sizing rate views.

Can roll-down be the dominant component of total return? Yes, particularly on steep yield curves or for bonds positioned in a steep segment of the curve such as the 5–10 year area. When the curve is steep enough, roll-down can contribute as much as or more than carry to the static total return. This is why professional bond managers analyze both components rather than focusing only on coupon income.

How does repo rate affect the carry calculation for leveraged investors? A leveraged investor borrows money to purchase the bond, paying a short-term repo rate. Net funded carry equals the coupon income less the repo rate times the leverage. In a normal environment where short-term rates are below the coupon rate, funded carry is positive. When the repo rate exceeds the coupon (which can happen in inverted-curve environments), funded carry turns negative, meaning the position loses money each day even before any price move.

Is roll-down a reliable source of return over time? Roll-down is reliable only if the yield curve maintains roughly the same shape over the holding period. In steepening or flattening environments, the yield the bond rolls to changes, and the realized roll-down differs from the forward estimate. Over long periods, curves do shift, so roll-down should be treated as a probabilistic expectation rather than a locked-in return.

How do portfolio managers use carry and roll-down to select bonds? Managers compare the carry-plus-roll-down across the curve to identify sectors offering the highest static return per unit of duration risk. A sector with high static return but low expected volatility is often favored. When two bonds have similar duration but different static returns, the higher static-return bond is preferred unless there is a strong view on curve movement that favors the other one.

Sources

1. Vontobel Asset Management. Fixed Income 101: Roll-down. https://am.vontobel.com/en/income-investing/fixed-income-101-roll-down
2. TwentyFour Asset Management. Fixed Income 101: Roll-down. https://www.twentyfouram.com/education/fixed-income-101-roll-down
3. CFA Institute. Yield Curve Strategies (2026 refresher reading). https://www.cfainstitute.org/insights/professional-learning/refresher-readings/2026/yield-curve-strategies
4. FTSE Russell / LSEG. The Carry Concept: Fixed Income Factor Research Series. https://www.lseg.com/content/dam/ftse-russell/en_us/documents/research/ftse-fixed-income-factor-research-series-carry-concept.pdf

Disclaimer

This article is educational content only and is not financial advice. Nothing here is a recommendation to buy, sell, or hold any security. Consult a licensed advisor before making investment decisions.