Tax Loss Harvesting: How It Works
Use investment losses to offset gains and reduce taxes.
Tax loss harvesting means selling investments at a loss to reduce taxable gains. It is one of the most effective strategies for reducing your investment tax bill year after year. Whether you have a large portfolio or just a few index funds, understanding tax loss harvesting rules can save you hundreds or thousands annually.
Key Takeaways
- Losses first offset capital gains, then up to $3,000 of ordinary income.
- Avoid wash sales by waiting 30 days or using a different security.
- Harvesting can be repeated annually to smooth taxes and build carryforwards.
Tax Loss Harvesting Step-by-Step
- Identify positions with unrealized losses.
- Sell to realize the loss.
- Replace with a similar but not identical investment to stay invested while claiming the tax benefit.
Watch Out For Wash Sales When Tax Loss Harvesting
The wash sale rule is the biggest pitfall of tax loss harvesting. Buying the same or “substantially identical” security within 30 days before or after the sale disallows the loss. That creates a 61-day window centered on your sale date. The wash sale window applies across all your accounts, including IRAs and a spouse’s accounts.
Safe replacement examples:
- Sell Vanguard S&P 500 ETF (VOO), buy Schwab U.S. Broad Market ETF (SCHB)
- Sell a total bond fund, buy a similar duration Treasury fund from a different provider
How Much Can Tax Loss Harvesting Save You?
The value of tax loss harvesting depends on your gains and marginal tax bracket:
| Scenario | Loss Harvested | Tax Rate | Tax Savings |
|---|---|---|---|
| Offset short-term gains | $10,000 | 32% | $3,200 |
| Offset long-term gains | $10,000 | 15% | $1,500 |
| Offset ordinary income (max) | $3,000 | 24% | $720 |
Unused losses carry forward indefinitely, so even losses without current gains to offset will eventually provide tax savings.
When Tax Loss Harvesting Might Not Help
- You are in the 0% long-term capital gains bracket. The immediate tax savings could be $0.
- You will repurchase soon. If you plan to buy the same security within 30 days, you risk a wash sale.
- Short-term losses offset long-term gains. This can be good, but it may reduce the benefit if you were already in a low bracket.
- High bid-ask spreads or trading costs. Frictional costs can wipe out the benefit.
Lot Selection Matters
When you sell, choose the specific tax lot with the largest unrealized loss or the highest cost basis. Most brokers let you choose lots at trade time. If you do not, they default to FIFO, which may reduce your harvested loss.
Tax-Gain Harvesting (The Opposite Strategy)
If you are in a low-income year, you might intentionally realize gains at 0% long-term capital gains rates. This “tax-gain harvesting” can reset your cost basis higher and reduce future taxes. Pair it with tax loss harvesting in a later year to keep your overall plan flexible. This approach is especially useful during Roth conversion ladder years or early retirement.
Forms and Carryforwards
- Losses are reported on Form 8949 and Schedule D.
- Unused losses carry forward to future years---there is no expiration.
- Your carryforward amount appears on the prior year’s Schedule D worksheet.
Related Guides
- How to Execute a Tax Loss Harvesting Strategy — worked example, DIY checklist, and net benefit calculation
- Capital Gains Tax Strategies — broader approaches to managing gains
- Capital Gains vs Ordinary Income — understanding the rate differences
- Asset Location Guide — placing assets in the most tax-efficient accounts
- Wash Sale Rule Explained — detailed rules for avoiding disallowed losses
- Direct Indexing Tax Strategy — automated loss harvesting at the individual stock level
- Tax Basis Tracking Guide — keeping accurate records of cost basis
- DIY Tax Planning for Investors — a broader framework for investment tax decisions
- Tax Strategy Stacking — combine loss harvesting with other moves for compounding savings
- Tax on Stock Gains — rates and reporting for stock sales
How sharper.tax Helps
When you upload your tax return to sharper.tax, we analyze your capital gains and losses to identify whether tax loss harvesting could reduce your tax bill. We detect unrealized opportunities based on your investment income patterns and calculate the potential savings at your actual marginal rate. Sophisticated tax planning used to require a high-end CPA---we make it available for free.
Sources
The information above is educational and not tax advice.