Whether tax loss harvesting is worth it comes down to your capital gains rate and how much you have to harvest. For investors in taxable brokerage accounts facing the 15%, 20%, or 23.8% federal rates on investment profits, the tax savings usually justify the effort, especially when a robo-advisor automates it. For investors whose income keeps them in the 0% long-term capital gains bracket, the strategy saves nothing on long-term gains and can lower your future cost basis for no reason. Everything else is a question of degree.
Who Actually Saves Money
The value of a harvested loss equals the tax rate it shields you from. That rate depends entirely on your income.
For 2026, the long-term capital gains rate is 0% if your taxable income stays below $49,450 (single), $98,900 (married filing jointly), or $66,200 (head of household).1Internal Revenue Service. Revenue Procedure 2025-32 Inside that band, harvesting a long-term loss to offset a long-term gain saves you nothing, because the gain already carries a zero rate.
The 15% rate applies between those thresholds and $545,500 (single), $613,700 (married filing jointly), or $579,600 (head of household). Income above those levels hits 20%.1Internal Revenue Service. Revenue Procedure 2025-322Internal Revenue Service. Net Investment Income Tax3Internal Revenue Service. Questions and Answers on the Net Investment Income Tax
The dollar difference matters. A $10,000 harvested loss saves an investor in the combined 23.8% bracket $2,380. The same loss saves a 15% taxpayer $1,500. It saves a 0%-bracket taxpayer nothing on long-term gains. Short-term gains are a separate story: they’re taxed at ordinary income rates as high as 37%, so a loss applied against short-term gains can produce much larger savings than one applied against long-term gains.4Internal Revenue Service. Topic No. 409, Capital Gains and Losses
The strategy rewards higher earners disproportionately. That’s not a fairness observation; it’s the arithmetic of what “worth it” means.
Deferral Is Not Elimination — Usually
Most descriptions of tax loss harvesting oversell it. In the ordinary case, you’re not erasing a tax bill; you’re moving it. When you sell at a loss and buy a similar replacement, your new position starts with a lower cost basis. When that replacement eventually recovers and you sell, the gain is larger than it otherwise would have been. Same asset, same appreciation, different timing.
Deferral still has real value. Money you keep invested compounds, so a tax paid ten years from now costs less in real terms than a tax paid today. If you also expect to sit in a lower bracket later, in retirement for example, the deferred gain gets taxed at a lower rate when it finally comes due.
There is one scenario where harvested losses become permanent savings rather than deferral. Under federal law, when a person dies the cost basis of their assets resets to fair market value on the date of death.5Office of the Law Revision Counsel. 26 USC 1014 – Basis of Property Acquired from a Decedent All the embedded gain that harvesting had built up disappears. Heirs inherit at the current value and owe no capital gains tax on the appreciation that occurred during the decedent’s lifetime. For a long-term investor who plans to hold until death, tax loss harvesting effectively becomes permanent tax elimination.
The opposite fact is also worth knowing: unused capital loss carryovers don’t survive you. They can be used on the final tax return (and, for a surviving spouse filing jointly for the year of death, on that return), but they don’t pass to the estate or to heirs.6Internal Revenue Service. Decedents and Related Issues
When It Isn’t Worth the Effort
Several situations flip the calculation:
- You’re in the 0% long-term capital gains bracket. Long-term gains are already tax-free, so harvesting against them just lowers your future basis for no current benefit.
- The losses are small. Chasing a $30 tax saving on a $200 loss while tracking basis adjustments and wash sale windows for years isn’t productive unless your broker handles it automatically.
- You can’t find a good replacement. The wash sale rule keeps you out of the identical security for 31 days. If nothing comparable exists, you’re trading market exposure for a tax break. Missing a 5% rally to save 1% in taxes is a bad deal.
- You expect a higher bracket later. Deferring a gain taxed at 15% today into a year you’ll pay 23.8% means you paid more total tax to wait.
- Everything you own is in retirement accounts. Sales inside IRAs, 401(k)s, and other tax-advantaged accounts don’t generate deductible losses.
For investors with large taxable portfolios and high marginal rates, the strategy almost always pays off, particularly with automated harvesting from a robo-advisor doing the bookkeeping. For everyone else, run the numbers against your bracket and portfolio size before assuming the savings justify the complexity.
The Wash Sale Rule and What It Costs You
You cannot sell an investment at a loss and immediately buy it back. Federal law disallows the loss if you purchase a “substantially identical” security within 30 days before or 30 days after the sale, a 61-day window that includes the sale date itself.7Office of the Law Revision Counsel. 26 USC 1091 – Loss from Wash Sales of Stock or Securities In a taxable account, a wash sale isn’t fatal: the disallowed loss gets added to the basis of the replacement shares, so you recover it when you eventually sell.
The IRS hasn’t drawn a bright line on what counts as substantially identical. Publication 550 says all the facts and circumstances matter, and notes that shares of one corporation are “ordinarily” not substantially identical to shares of another.8Internal Revenue Service. Publication 550 (2024), Investment Income and Expenses Two S&P 500 index funds from different providers hold nearly identical portfolios, and calling them meaningfully different is a hard argument. Swapping an S&P 500 fund for a total stock market fund or a large-cap value fund creates real differences in holdings and strategy. Most tax advisors treat that kind of swap as safe. The further apart the two funds are in index, methodology, and holdings, the stronger the position.
The IRA Trap That Erases Your Loss
The costliest wash sale mistake involves retirement accounts. If you sell a stock at a loss in your taxable brokerage account and buy the same stock in your IRA or Roth IRA within the 61-day window, the wash sale rule still applies. The IRS confirmed this in Revenue Ruling 2008-5.9Internal Revenue Service. Revenue Ruling 2008-5 – Section 1091, Loss from Wash Sales of Stock or Securities
Here’s what makes this uniquely painful. In a taxable account, a disallowed wash sale loss is added to the basis of the replacement shares, so you eventually recover it. When the replacement purchase happens inside an IRA, there’s no mechanism to adjust the IRA’s basis. The loss doesn’t defer. It disappears. Permanently. This applies to both traditional and Roth IRAs, so watch the timing of any retirement account purchases while you’re harvesting losses in a taxable account.
Don’t Expect a Huge One-Year Tax Break
When your capital losses for the year exceed your capital gains, you can deduct up to $3,000 of the remaining loss against ordinary income such as wages, salary, or interest. Married filing separately, the cap is $1,500.10Office of the Law Revision Counsel. 26 USC 1211 – Limitation on Capital Losses
Losses above that threshold carry forward indefinitely. You keep applying them against future gains and up to $3,000 of ordinary income each year until they’re used up. Carryovers are tracked on Schedule D, and the IRS provides a Capital Loss Carryover Worksheet.11Internal Revenue Service. 2024 Instructions for Schedule D If a bad market year hands you losses far in excess of gains, absorbing them at $3,000 per year against ordinary income can take a long time. That’s not a reason to skip harvesting. It’s a reason to size your expectations: the biggest year-one savings come from offsetting gains, not from the ordinary-income deduction.