Roll-Down Return
Roll-down return is the capital gain earned on a fixed income security as it ages along an upward-sloping yield curve, progressively moving to shorter maturities where yields are lower and prices are higher, independent of any parallel shift in the overall level of interest rates.
In a normal upward-sloping yield curve environment, longer-maturity bonds trade at higher yields than shorter-maturity bonds. As time passes and a bond's remaining maturity shortens, it moves along the yield curve to a point where the applicable yield is lower, causing its price to appreciate even if the entire yield curve remains perfectly static. This price appreciation attributable solely to the passage of time and the shape of the yield curve — not to any change in the curve level — is the roll-down return.
To quantify roll-down, consider a 10-year Treasury note currently yielding 4.5%. The 9-year Treasury yield on the same upward-sloping curve is 4.3%. If one year passes and the curve remains unchanged, this 10-year note has become a 9-year note and its yield has dropped from 4.5% to 4.3% — a 20-basis-point decline. Given a modified duration of approximately 7.5 years, this yield decline translates to a price appreciation of roughly 1.5% (= 0.20% x 7.5). This 1.5% is the roll-down return for the year.
Roll-down is a component of total return alongside coupon income and price changes due to yield curve shifts. In a steep yield curve environment, roll-down can be substantial and represents an important source of carry for fixed income investors who hold intermediate and long-duration securities. Portfolio managers who target the steepest part of the yield curve — typically the 5- to 10-year segment — specifically to maximize roll-down income are said to be riding the yield curve.
Roll-down is additive to the carry return of a bond. Total expected return from holding a bond over a period with a static yield curve equals: Coupon Income + Roll-Down Return. For a bond trader or portfolio manager, the combined carry-and-roll measure (sometimes called carry + roll or C+R) is one of the most important metrics for comparing the relative attractiveness of different points on the yield curve.
The roll-down return is larger when the yield curve is steeper and when the bond has a longer duration. In flat or inverted yield curve environments, roll-down return diminishes or disappears entirely, reducing the total return advantage of holding longer-duration instruments beyond their coupon income alone.