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gateway/knowledge/trading/strategies/fixed-income/ladders.md

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+---
+description: "A ladder portfolio holds bonds spread evenly across n equidistant maturities to diversify interest rate and reinvestment risk while maintaining an approximately constant duration through systematic roll-down."
+tags: [fixed-income, duration, ladder, diversification, yield-curve]
+---
+
+# Ladders
+
+**Section**: 5.4 | **Asset Class**: Fixed Income | **Type**: Duration-Targeting / Diversification
+
+## Overview
+A ladder holds bonds with (roughly) equal capital allocations across n different maturities T_i (i = 1,...,n), where maturities are equidistant: T_{i+1} = T_i + δ. The strategy maintains an approximately constant duration by selling shorter-maturity bonds as they near maturity and replacing them with new longer-maturity bonds. It diversifies both interest rate risk and reinvestment risk.
+
+## Construction / Mechanics
+- Allocate roughly equal capital to each rung T_i, i = 1,...,n (n is sizable, e.g., n = 10).
+- Equidistant maturities: T_{i+1} = T_i + δ.
+- Average (effective) maturity of the portfolio:
+
+```
+T = (1/n) Σ_{i=1}^n T_i                                             (395)
+```
+
+- As the shortest rung approaches maturity, sell it and purchase a new bond at the longest maturity, maintaining the ladder structure.
+- Also generates regular income from coupon payments across all rungs.
+
+## Payoff / Return Profile
+- Higher average maturity T → higher income (upward-sloping yield curve), but also higher interest rate risk.
+- Rolling shorter bonds into longer bonds continuously captures roll-down return.
+- Diversification across maturities smooths the impact of rate moves: if rates rise, maturing short bonds are reinvested at higher rates; if rates fall, longer bonds appreciate.
+
+## Key Parameters / Signals
+- n: number of rungs (more rungs = more diversification)
+- δ: spacing between maturities
+- T (average maturity): determines the income/risk trade-off
+- Equal capital allocation per rung: ensures no concentration at any maturity
+
+## Variations
+- Unequal allocations tilting toward shorter or longer maturities (incorporating a partial bullet or barbell bias).
+
+## Notes
+- The ladder avoids the concentration risk of bullets and barbells, making it suitable for investors uncertain about the rate environment.
+- The constant-duration property is approximate; exact duration changes as bonds age and are replaced.
+- Reinvestment risk is diversified: proceeds from maturing bonds are spread across the yield curve over time rather than all reinvested at once.
+- Transaction costs from regular rolling must be weighed against the diversification and roll-down benefits.