Dollar Duration

Why dollar duration matters

Duration alone does not reveal the amount of capital at risk. A small highly sensitive bond may create less monetary exposure than a very large short-duration position. Dollar duration supports hedging, asset-liability management, risk limits, and aggregation across portfolios. Traders often use DV01, the estimated value change for a one-basis-point move, to size futures or swaps and balance exposures along the yield curve.

How it is applied

Multiply modified duration by full market value to obtain the approximate currency change for a 100-percentage-point yield move under decimal convention, then scale to the desired shock. DV01 multiplies by 0.0001 for one basis point. Effective duration can replace modified duration for securities with options. Key-rate dollar durations show exposure at separate curve maturities. Sign conventions should be explicit because long bond prices usually fall when yields rise.

Formula

Portfolio example

A $10 million bond position has modified duration of 6. Its DV01 is approximately $6,000. A one-basis-point yield rise therefore implies about a $6,000 price decline, while a 50-basis-point rise implies roughly $300,000 before convexity and spread effects. A hedge with equal opposite DV01 can neutralize a parallel rate move but still leave curve, spread, basis, and option risk.

How to interpret it

Larger absolute dollar duration means greater monetary sensitivity. Positive or negative signs depend on reporting convention and whether the position is long or short. Aggregate DV01 near zero does not guarantee low rate risk if large exposures at different maturities offset. Key-rate profiles reveal steepener or flattener positions. The estimate is local and should be compared with stress revaluation for larger and nonparallel moves.

Limitations and common misconceptions

The measure assumes small yield changes and linear price behavior. Convexity, embedded options, spread changes, currencies, and cash-flow changes create deviations. Market value and duration move through time. A single DV01 collapses the curve and can conceal basis risk. Hedge instruments introduce liquidity, margin, and counterparty exposure. Full revaluation and multiple detailed curve scenarios are always necessary for complex or stressed portfolios.