Impact of Market Conditions on Tax-Loss Harvesting: The Role of Portfolio Breadth in Industry-Based Strategies
Year: 2026
Type: article
Abstract: How much portfolio breadth does tax loss harvesting require? Using cap-weighted Fama-French industry portfolios (10, 17, 30 industries) over 1995-2025 with tiered swap mechanisms (four wash-salecompliant tiers per industry), we show that volatility is the primary driver of harvest opportunity while correlation limits how much breadth can exploit it. High-volatility regimes generate substantially more tax loss capture (TLC) at every breadth level than calm regimes. But high volatility often elevates correlation, compressing the effective number of bets (ENB) by roughly 40%, from 1.8 to 1.1 at crisis peaks, which flattens the breadth-TLC curve. The result is a strongly concave relationship: the 1-to-10 step is generally the dominant increment, and breadth beyond 10 industries adds little. Regime conditioning sharpens this: breadth delivers meaningful incremental value only in differentiated decline (high volatility, low correlation; 21.2% of occurrences), where the 1-to-10 step adds 3.61pp while further expansion to 30 industries adds 0.95pp. In coordinated decline (high volatility, high correlation; 28.7% of occurrences), harvest volume is the highest but the 1-to-10 step shrinks to 1.68pp and further expansion to 30 industries adds only 0.47pp. In calm regimes, breadth generally adds only modestly, with some variation across volatility and correlation levels. We conclude that a moderate breadth of 10 industries captures the majority of available benefits; the marginal value of further expansion is modest and regime-dependent.
Authors: Harsh Parikh, Brian Ahrens
Language: English
Subfield: Finance
Domain: Social Sciences
Open Access status: green
OpenAlex ID: W7221306735
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