What is Tax-Loss Harvesting
Tax-loss harvesting is an investment strategy of selling assets that have declined in value to realize a capital loss, which offsets taxable gains elsewhere in your portfolio — reducing your tax bill while maintaining overall market exposure.
Tax-loss harvesting is an investment strategy involving the deliberate sale of securities (stocks, ETFs, funds) that have declined in value to realize a capital loss for tax purposes — then using that loss to offset capital gains elsewhere in your portfolio or reduce ordinary income, lowering your overall tax bill.
After selling the losing position, you typically reinvest the proceeds in a similar (but not identical) investment to maintain your desired market exposure, so your portfolio stays on track while you capture a tax benefit.
How Tax-Loss Harvesting Works
Step 1: Identify investments in your taxable brokerage account trading below your purchase price.
Step 2: Sell the losing position, realizing a capital loss.
Step 3: Use the tax loss to:
- Offset capital gains (e.g., offset a $5,000 gain with a $5,000 loss = $0 net taxable gain)
- If losses exceed gains, deduct up to $3,000 of losses against ordinary income per year
- Carry forward remaining losses to future tax years indefinitely
Step 4: Reinvest proceeds in a similar investment to maintain portfolio exposure (e.g., sell Vanguard Total Market ETF, buy iShares equivalent).
Example: The Tax Benefit
Suppose you have:
- $10,000 in long-term capital gains from selling appreciated stock
- A position in another fund that has dropped $6,000 below your purchase price
By selling the losing position:
- Your net taxable capital gain drops from $10,000 to $4,000
- At a 15% long-term capital gains rate, you save $900 in taxes
- You still have market exposure through a similar replacement investment
The Wash-Sale Rule
The critical constraint on tax-loss harvesting: the wash-sale rule (IRS Rule). If you sell a security at a loss and buy a "substantially identical" security within 30 days before or after the sale, the IRS disallows the loss for tax purposes.
What's "substantially identical":
- Same stock (selling Apple, buying Apple back in 29 days)
- Same fund from same fund family (selling Vanguard S&P 500 ETF, buying Vanguard S&P 500 Admiral Fund)
What avoids wash-sale:
- Different fund tracking a different index (sell Vanguard Total Market / VTI, buy Schwab Total Market / SCHB — same broad exposure, different fund = not substantially identical)
- Waiting 31+ days before buying back the original
- Buying in a different account (though the IRS will cross retirement accounts in some situations)
When Tax-Loss Harvesting Adds the Most Value
High tax bracket: The higher your marginal rate, the more valuable sheltering gains becomes.
Large realized gains: If you've sold appreciated assets, available losses directly offset taxable income.
High-volatility markets: Bear markets and volatile years create more harvesting opportunities.
Regular portfolio rebalancing: Loss harvesting can be done opportunistically when individual positions are down during rebalancing.
Active investors and frequent traders: More turnover = more gain realization events to offset.
Limitations and Misconceptions
It defers, not eliminates tax: When the replacement investment eventually sells at a gain, you'll owe tax on that gain (unless you die holding it, in which case heirs get a stepped-up cost basis). You're pushing the tax bill into the future — valuable, but not free.
Only applies to taxable accounts: Tax-loss harvesting doesn't apply to IRAs, 401(k)s, and other tax-advantaged accounts because gains and losses in those accounts have no annual tax impact.
Transaction costs: Selling and buying generates transaction costs (minimal with commission-free brokers, but real with some funds).
Complexity increases with scale: Multi-year loss carryforwards, multiple positions, and wash-sale tracking benefit from tax software or a financial advisor.
Many robo-advisors (Betterment, Wealthfront) offer automated tax-loss harvesting as a feature, continuously scanning portfolios for harvesting opportunities — making this strategy accessible without manual monitoring.