A markets and valuation concept defining how assets are priced and assessed using cash flows, risk measures, or relative benchmarks. It governs estimation of value, required return, and sensitivity to rate or spread changes across asset classes. It does not guarantee accuracy and depends on input quality, market liquidity, and the suitability of benchmarks and assumptions. It supports investment decisions and reporting by providing structured methods to quantify value and risk exposure. The concept is generally stable, though market structure and valuation conventions evolve over time.

Principle

Duration condenses the timing of cash flows into a single metric: earlier cash flows reduce duration and later cash flows increase it; under small parallel yield shifts, duration relates proportionally to price sensitivity.

Demonstration

A 5-year coupon bond with annual coupons: compute present value of each coupon and principal using the bond yield, divide each PV by total bond price to get weights, and sum payment times times weights to obtain Macaulay duration in years.

Misapplication

Using Macaulay duration as a direct predictor of dollar price change for large or non-parallel yield moves, or applying it unchanged to bonds with embedded options, disregards convexity and option-adjusted behaviour.

Consequence

Duration guides immunization strategies, approximate hedging ratios and comparisons of time-sensitivity across instruments; matching duration can reduce portfolio sensitivity to small parallel rate moves.

Reversal

A cash instrument with zero duration (e.g., money market deposit maturing immediately) contrasts with a pure long-duration instrument (zero-coupon long-maturity bond) that maximizes time sensitivity.

Boundary

Duration applies to fixed cash-flow instruments or to instruments for which cash-flow timing is modelled; it excludes instruments with significant path-dependent cash-flow uncertainty unless converted into an effective duration.

Semantic Tension

Duration vs convexity: duration is the first-order price sensitivity to yield changes; convexity is the second-order term that corrects duration's linear approximation for larger yield moves.

Synthesis

Duration reduces the temporal structure of bond cash flows to a single time-based sensitivity measure: it is foundational for comparing interest-rate exposure and for implementing first-order hedging, subject to convexity and option limitations.