Tax-Loss Harvesting: Turning Losses Into Tax Savings
Every portfolio has losing positions at some point. Tax-loss harvesting turns those paper losses into real tax savings by strategically selling at a loss to offset capital gains and up to $3,000 per year in ordinary income. Done right, it is one of the simplest ways to improve your after-tax returns.
How Tax-Loss Harvesting Works
The concept is straightforward: sell an investment that has declined in value to realize a capital loss. That loss can then be used to offset capital gains elsewhere in your portfolio. If your losses exceed your gains for the year, you can deduct up to $3,000 per year ($1,500 if married filing separately) against ordinary income. Any remaining losses carry forward indefinitely to future tax years.
The key is that you maintain your desired market exposure. After selling the losing investment, you immediately purchase a similar (but not substantially identical) investment. Your portfolio allocation stays essentially the same, but you have generated a tax benefit.
Example: Basic Tax-Loss Harvest
You invested $50,000 in a U.S. large-cap index fund that is now worth $42,000, an $8,000 loss. You also sold another investment earlier this year for a $5,000 gain. You sell the index fund, realizing the $8,000 loss. You immediately buy a different large-cap index fund (tracking a different index) with the $42,000 proceeds. The $8,000 loss offsets your $5,000 gain, eliminating the capital gains tax. The remaining $3,000 loss offsets ordinary income, saving you roughly $660-$1,110 depending on your tax bracket.
The Wash Sale Rule
The IRS's wash sale rule is the primary constraint on tax-loss harvesting. It disallows the loss deduction if you buy a substantially identical security within 30 days before or after the sale. The 30-day window runs in both directions, creating a 61-day total wash sale window.
The definition of "substantially identical" is not precisely defined in the tax code, but the general consensus is that different index funds tracking different indices are not substantially identical, even if they have very similar performance. For example, selling a fund tracking the S&P 500 and buying one tracking the Russell 1000 or total stock market is generally acceptable.
Watch out: The wash sale rule applies across all your accounts, including your IRA and your spouse's accounts. If you sell a fund at a loss in your taxable account and buy the same fund in your IRA within 30 days, the loss is disallowed and the cost basis adjustment is permanently lost (since IRA accounts have no cost basis tracking).
Where Tax-Loss Harvesting Works (and Doesn't)
Tax-loss harvesting only applies to taxable brokerage accounts. It does not work in tax-advantaged accounts like 401(k)s, IRAs, or Roth IRAs because gains and losses inside those accounts are not taxed annually. This means the strategy is most relevant for investors with significant holdings in taxable accounts.
The strategy is most valuable in years with large capital gains from selling investments, rebalancing a portfolio, selling real estate or a business, or receiving capital gain distributions from mutual funds. It is also valuable for investors in higher tax brackets where the tax savings per dollar of harvested loss are greater.
The Carry-Forward Advantage
Unused capital losses carry forward indefinitely. There is no expiration date. If you harvest $50,000 in losses during a market downturn but only have $5,000 in gains that year, you use $5,000 to offset gains and $3,000 against ordinary income. The remaining $42,000 carries forward to future years, available to offset future gains or $3,000 per year of ordinary income.
Carry-Forward Strategy During Market Downturns
Major market declines are the best opportunities for tax-loss harvesting. A 30% market drop on a $500,000 taxable portfolio creates approximately $150,000 in potential harvesting opportunities. Even if you have no gains to offset immediately, banking those losses gives you years or decades of future tax flexibility. At $3,000 per year against ordinary income alone, $150,000 in carried-forward losses would take 50 years to fully use. But any future capital gains, including those from selling a home or business, can be offset in larger amounts.
Best Practices
To maximize the value of tax-loss harvesting, harvest throughout the year rather than only in December. Market volatility creates opportunities at any time, and spreading harvesting across the year captures more losses. Keep replacement funds ready so you can immediately reinvest after selling a losing position, maintaining your target asset allocation.
Be mindful of the trade-off with cost basis. When you harvest a loss and reinvest, the replacement investment has a lower cost basis. This means you have effectively deferred the capital gains tax rather than eliminated it entirely. However, the time value of the deferral is significant, and if you hold the replacement investment until death, the step-up in basis at death can eliminate the deferred gain permanently.
Finally, consider transaction costs and tax lot selection. Use specific identification of tax lots rather than average cost, so you can selectively sell only the lots that are at a loss while retaining lots that are at a gain. Most brokerages support this with their online platforms.
At death, losses disappear: Unlike gains, which receive a step-up in basis at death, capital loss carry-forwards do not transfer to heirs. If you have large accumulated losses, consider using them before the end of life by realizing gains to consume the losses. Otherwise, the tax benefit dies with you.
How Talk Through Wealth Helps
Tax-loss harvesting interacts with your overall capital gains picture, tax brackets, and long-term investment strategy. Our projection engine models harvesting opportunities alongside your retirement withdrawals, Roth conversions, and income sources to show you the optimal timing and amount of losses to harvest each year for maximum after-tax wealth.
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