Tax Loss Harvesting

Walks you through the full tax loss harvesting workflow from scanning positions for material unrealized losses through tracking the 61-day wash sale window across all household accounts. Covers the operational details advisors and sophisticated investors actually need: lot selection with specific ID, calculating whether to prioritize short-term over long-term losses, picking replacement securities that maintain factor exposure without triggering substantially identical flags, and coordinating trades with rebalancing. The cross-account wash sale tracking is especially useful since it reminds you to check spouse IRAs and suspend dividend reinvestment, both of which quietly disallow losses if you miss them. More tactical than the general tax efficiency skill.

skills.sh installs: 715
GitHub stars: 224
last updated: Aug 21, 2026

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Install

$ npx -y skills add joellewis/finance_skills --skill tax-loss-harvesting --agent claude-code

Installs into .claude/skills of the current project.

Files

Tax-Loss Harvesting

Core Concepts

Candidate Identification

Scan the portfolio for positions with unrealized losses that meet all three filters:

Materiality threshold: Minimum absolute loss (e.g., $2,000) or minimum loss-to-value ratio (e.g., loss exceeds 5% of position market value). Harvesting a $200 loss on a $50,000 portfolio is not worth the operational cost.
Holding period filter: Positions held less than 31 days may not have meaningful losses and create short-term wash-sale complexity. Positions approaching the one-year mark (days 335-365) may benefit from waiting to convert a short-term loss into a long-term loss only if the position is expected to continue declining.
Loss magnitude ranking: Rank candidates by Tax Benefit = Unrealized Loss * Applicable Tax Rate. Prioritize short-term losses (taxed at ordinary rates up to 37%) over long-term losses (taxed at capital gains rates of 15-20%) when gain/loss budget allows.