Tax-Loss Harvesting: How to Cut Your Tax Bill While Investing

What Is Tax-Loss Harvesting?

Tax-loss harvesting is a strategy where you sell investments that have dropped in value to realize a capital loss — and then use that loss to offset capital gains elsewhere in your portfolio. The end result: a lower tax bill, sometimes significantly lower.

Think of it as turning a losing investment into a financial tool. Instead of simply holding a position that’s down and hoping it recovers, you sell it, capture the loss on paper, and reinvest in something similar — keeping your market exposure while reducing what you owe the IRS.

This strategy applies to taxable brokerage accounts, not tax-advantaged accounts like a Roth IRA or traditional 401(k). If you’re investing in a regular brokerage account, tax-loss harvesting is one of the most powerful — and underused — tools available to you.

According to Vanguard, systematic tax-loss harvesting can add up to 0.5% to 1.5% per year in after-tax returns, depending on your tax bracket and market volatility. Over a 20-year investment horizon, that compounds into a meaningful difference.

How Tax-Loss Harvesting Works: A Step-by-Step Example

Let’s say you invested $20,000 in a tech ETF earlier in the year. Due to market volatility, the position is now worth $15,000 — a $5,000 unrealized loss.

At the same time, you sold a rental property and realized a $5,000 capital gain. Without any action, you’d owe taxes on that $5,000 gain. The long-term capital gains tax rate for a married couple earning $150,000 is 15%, meaning a $750 tax bill.

By selling the underperforming tech ETF before December 31, you realize the $5,000 loss. That loss cancels out the $5,000 gain — bringing your taxable capital gain to $0. Tax saved: $750.

Here’s the key: you don’t have to stay out of the market. You can immediately reinvest those proceeds in a similar but not identical fund — such as a broad market ETF — to maintain your investment exposure while locking in the tax benefit.

The Wash-Sale Rule: The One Rule You Cannot Ignore

The IRS has a safeguard called the wash-sale rule. If you sell a security at a loss and buy the same — or a "substantially identical" — security within 30 days before or after the sale, the IRS disallows the loss for tax purposes.

That means you have a 61-day window (30 days before, the day of sale, 30 days after) during which you must avoid repurchasing the same investment. Violating this rule doesn’t just cost you the deduction — it adds complexity to your cost basis going forward.

Selling a Vanguard S&P 500 ETF and buying the Fidelity S&P 500 ETF likely triggers the wash-sale rule since they track the same index. However, selling a technology sector ETF and replacing it with a broad large-cap growth ETF is generally considered acceptable — though always confirm with a tax professional for your specific situation.

Key Benefits of Tax-Loss Harvesting

The IRS allows you to use capital losses to offset capital gains dollar-for-dollar. If your losses exceed your gains, you can deduct up to $3,000 per year against ordinary income (wages, salary, freelance income). Any losses beyond that can be carried forward to future tax years — indefinitely.

Here’s what that means in practice:

• Immediate tax savings: If you’re in the 22% ordinary income bracket, a $3,000 deduction saves you $660 in federal taxes this year.
• Gain offsetting: Large capital gains from a home sale, stock vesting, or business sale can be substantially reduced.
• Loss carryforwards: Unused losses don’t disappear — they roll forward to reduce future tax bills.
• Portfolio rebalancing opportunity: Harvesting losses naturally prompts you to review and realign your asset allocation.

For high-income earners subject to the Net Investment Income Tax (NIIT) — an additional 3.8% tax on investment income above $200,000 single / $250,000 married — tax-loss harvesting can provide compounded savings beyond the standard capital gains rate.

How to Get Started: Actionable Steps

1. Review your taxable brokerage accounts. Log in and identify all positions currently showing an unrealized loss. Most brokerage platforms display unrealized gains and losses clearly in your portfolio view.
2. Calculate your current capital gains situation. Add up any realized gains you’ve already locked in this year — from sales, distributions, or stock vesting. This determines how much loss you actually need to harvest.
3. Identify replacement securities. Before selling, research a suitable replacement investment that gives you similar market exposure without triggering the wash-sale rule. For example: if you’re selling a mid-cap index ETF, consider a total market fund as a replacement.
4. Execute the sale and reinvestment simultaneously. Sell the losing position and immediately invest the proceeds in your replacement. This minimizes the time you’re out of the market.
5. Track your cost basis carefully. When you purchase the replacement fund, record your new cost basis. Your brokerage should do this automatically, but verify.
6. Set a calendar reminder for 31 days. After 31 days, you’re free to return to your original investment if you prefer it over the replacement.
7. Report losses on Schedule D. Your brokerage will send a Form 1099-B at year end, which you or your CPA will use to report the harvested losses on your federal return.

Many brokerages — including Fidelity, Schwab, and Vanguard — now offer automated tax-loss harvesting tools, particularly through their robo-advisor services. Platforms like Betterment and Wealthfront have built this strategy into their daily portfolio management for taxable accounts.

For a complementary strategy that works well alongside tax-loss harvesting, see our guide on Dollar-Cost Averaging: How to Invest Smarter in Any Market.

Costs, Risks, and Limitations

Tax-loss harvesting sounds straightforward, but there are real risks to understand before diving in.

Transaction costs: While most major brokerages now offer commission-free trades, some funds carry redemption fees. Always check before executing a sale.

Short-term vs. long-term treatment: Short-term losses (investments held under one year) offset short-term gains first. Short-term gains are taxed at ordinary income rates — up to 37% federally. Long-term losses offset long-term gains, taxed at 0%, 15%, or 20%. Matching the right loss type to the right gain type matters enormously for your net benefit.

State taxes vary: California, for instance, taxes capital gains as ordinary income with no preferential long-term rate — which changes the calculus for residents there. Confirm your state’s treatment with a local tax professional.

Behavioral risk: Some investors sell losing positions impulsively, miss the reinvestment window, and end up sitting in cash during a market recovery. Discipline matters. Have your replacement investment ready before you sell.

Not beneficial in all situations: If you’re in the 0% long-term capital gains bracket (taxable income under $47,025 single / $94,050 married for 2025), you may already owe no tax on long-term gains. In that case, harvesting losses provides minimal benefit — and you might actually trigger gains recognition unnecessarily.

Common Mistakes to Avoid

Mistake 1: Violating the wash-sale rule. This is the most common — and most costly — error. Buying back the same ETF within 30 days disallows your deduction and complicates your cost basis. Always confirm your replacement is truly distinct. When in doubt, wait 31 days.

Mistake 2: Harvesting losses in tax-advantaged accounts. Selling at a loss inside a traditional IRA or Roth IRA provides zero tax benefit — those accounts already grow tax-deferred or tax-free. Tax-loss harvesting only works in taxable brokerage accounts.

Mistake 3: Focusing on the loss, not the economics. Some investors sell a fundamentally strong investment simply because it’s temporarily down. Always ask: "Would I still want to hold this if there were no tax benefit?" If yes, the tax harvest makes sense. If you’re just eager to sell, the strategy can backfire if the investment rebounds sharply while you’re in your 31-day waiting period.

Mistake 4: Ignoring the $3,000 annual cap on income offsets. If you harvest $25,000 in losses but have only $10,000 in gains, you’ll offset the gains and deduct $3,000 against income this year — but the remaining $12,000 carries forward. That’s fine, but some investors expect to use all losses in one year, which isn’t possible.

Mistake 5: Skipping the strategy during volatile markets. Market downturns are actually the best time to harvest losses — yet many investors emotionally freeze and do nothing. A falling market is a tax-loss harvesting opportunity if you’re prepared.

Alternatives to Consider

Tax-loss harvesting isn’t the only way to manage your investment tax burden. Depending on your situation, these strategies may complement or outperform it:

1. Tax-Gain Harvesting: The mirror image of tax-loss harvesting. If you’re in the 0% capital gains bracket, you can strategically sell appreciated positions, lock in gains tax-free, and reset your cost basis higher — reducing future taxes. This is especially useful for early retirees with temporarily low income.

2. Asset Location Strategy: Place tax-inefficient investments (bonds, REITs, actively managed funds) inside tax-advantaged accounts like IRAs, and keep tax-efficient investments (index ETFs, buy-and-hold equities) in taxable accounts. This reduces the amount of taxable income generated each year without requiring any selling. For more on tax-efficient retirement investing, see our Retirement Income Planning guide.

3. Charitable Giving of Appreciated Securities: Instead of selling appreciated stock and paying capital gains tax, donate shares directly to a charity or donor-advised fund. You get a deduction for the full fair market value and avoid the capital gains entirely. The IRS allows this for donations to qualifying 501(c)(3) organizations.

Each of these strategies has trade-offs. If your portfolio is primarily in retirement accounts like a 401(k), tax-loss harvesting may be irrelevant to you right now — but it becomes critical as you build up a taxable investment account. To understand how bond investments fit into a tax-aware portfolio, see our Bond Investing guide.

Frequently Asked Questions

Can I use tax-loss harvesting every year?
Yes — and you should review your portfolio for opportunities at least annually, ideally in October or November before year-end. The strategy is most effective when markets have experienced volatility, giving you losses to harvest across multiple positions.

What if my losses are larger than my gains?
You can deduct up to $3,000 of excess losses against ordinary income per year. Any amount above that carries forward indefinitely to future tax years. There’s no expiration on carryforward losses under current IRS rules.

Does tax-loss harvesting apply to mutual funds?
Yes, but with an important nuance: mutual funds often generate capital gains distributions that are taxable even if you didn’t sell anything. This makes ETFs generally more tax-efficient than actively managed mutual funds for taxable accounts.

Will my brokerage automatically handle this for me?
Only if you use a robo-advisor service that offers automated tax-loss harvesting (Betterment, Wealthfront, and some Vanguard Digital Advisor accounts). Standard brokerage accounts at Fidelity, Schwab, or E*TRADE require you to execute the strategy manually — though they provide unrealized gain/loss data to help you identify opportunities.

Is tax-loss harvesting legal?
Completely legal. The IRS explicitly permits capital loss deductions under IRC Section 1211 and 1212. The wash-sale rule (Section 1091) exists precisely because Congress anticipated this strategy — and set rules around it rather than prohibiting it.

Final Takeaways: Is Tax-Loss Harvesting Worth It for You?

Tax-loss harvesting is one of the most legitimate and accessible tax-reduction tools available to US investors with taxable brokerage accounts. It doesn’t require predicting the market, taking on extra risk, or making dramatic changes to your portfolio. It simply requires awareness, timing, and discipline.

Generally speaking, the strategy delivers the most value for investors in the 22% or higher tax bracket, those with significant realized capital gains in a given year, and anyone who actively invests in a taxable brokerage account with a diversified, multi-fund approach.

Your most important next step: log into your taxable brokerage account today and review your unrealized gains and losses. If you see positions down 10% or more, consult with a CPA or financial advisor about whether harvesting those losses makes sense for your 2026 tax year before December 31.

This article is for educational purposes only and does not constitute financial, tax, or investment advice. Always consult a licensed financial advisor, CPA, or attorney before making financial decisions.