Tax-Loss Harvesting: The Complete Guide for Investors in 2026

Affiliate disclosure: This article contains links to tax software including TurboTax. We may earn a commission if you purchase through our links. Our analysis is independent — we recommend what actually works.

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Most investing strategies help you make money. Tax-loss harvesting is the rare strategy that helps you keep more of what you've already made.

The mechanics aren't complicated. But the rules — specifically the wash-sale rule — trip up even experienced investors. Get it wrong, and the IRS disallows your loss without warning you until tax season.

This guide walks through everything: what TLH actually is, how to do it correctly, where the wash-sale landmines are, which accounts work, when harvesting is actually a bad idea, and the exact tax forms you'll need to file.

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What Is Tax-Loss Harvesting?

When you own investments in a taxable brokerage account, you pay capital gains tax when you sell at a profit.

Tax-loss harvesting is selling investments at a loss to generate a tax loss you can use to offset gains. The goal: reduce the total tax you owe this year without meaningfully changing your investment exposure.

Simple example:

• You own $10,000 of Stock A. It's now worth $7,000. You're sitting on a $3,000 unrealized loss.
• You sold Stock B earlier this year for a $3,000 capital gain. You owe tax on that gain.
• You sell Stock A, realizing the $3,000 loss. The loss offsets the $3,000 gain. Net taxable capital gains: $0.
• You immediately buy Stock C — a similar but not identical investment to A — to stay invested.

You've eliminated a tax bill without meaningfully changing your portfolio strategy.

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

Step 1: Identify Positions With Unrealized Losses

Log into your taxable brokerage account and look at cost basis vs. current value for each position. Any position showing a loss is a potential harvest candidate.

What to look for:

• Short-term losses (positions held under 1 year) are most valuable — they offset short-term gains, which are taxed at ordinary income rates (up to 37%)
• Long-term losses (held over 1 year) offset long-term gains, taxed at 0%, 15%, or 20%

Step 2: Calculate Whether It's Worth It

Harvesting has transaction costs (usually zero with commission-free brokerages today, but was meaningful a decade ago). The bigger cost is timing risk — if the market moves while you're temporarily out of position.

Quick math: If you're in the 22% federal bracket and you have $5,000 in short-term losses to harvest, you're saving roughly $1,100 in federal taxes. In most cases, that's worth the 1-2 minutes of executing the trade.

Step 3: Sell the Losing Position

Place a market or limit order to sell the position. The sale is what "realizes" the loss for tax purposes. An unrealized loss sitting in your account provides zero tax benefit.

Step 4: Buy a Similar Replacement

This is where the wash-sale rule matters. You need to buy something similar but not identical to maintain your investment exposure while staying clear of the rule.

Examples of valid replacements:

• Sell VOO (Vanguard S&P 500 ETF) → Buy IVV (iShares S&P 500 ETF) — same index, different fund
• Sell VTI (Vanguard Total Market) → Buy SCHB (Schwab Total Market) — similar index, different fund
• Sell individual stock in a sector → Buy a sector ETF covering that area

Examples that trigger wash-sale:

• Sell VOO → Buy SPY (also S&P 500 — same underlying index — considered substantially identical by most tax professionals)
• Sell a stock → Buy it back 25 days later (within the 30-day window)

Step 5: Wait Out the Window (or Don't Come Back)

You must wait 31+ days before repurchasing the original investment, or simply stay in the replacement investment permanently. Many investors who switch from VOO to IVV for a harvest never switch back — the funds are nearly identical in performance.

Step 6: Report on Form 8949 and Schedule D

Every stock or fund sale goes on Form 8949. Your broker provides a 1099-B with all the transaction details. Form 8949 feeds into Schedule D, which calculates your net capital gain/loss and feeds into your main 1040 return.

💡 TurboTax handles Form 8949 automatically — it imports your 1099-B directly from your broker, categorizes each transaction as short-term or long-term, and applies any wash-sale adjustments your broker has already flagged. You review and confirm. Get TurboTax here.

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The Wash-Sale Rule: Where Investors Get Burned

The wash-sale rule is the most important concept in TLH. It's also the most commonly misunderstood.

The rule: You cannot deduct a loss on a sale if you buy a "substantially identical" security within 30 days before OR after the sale date.

The 61-day window: The rule covers 30 days before the sale + the day of sale + 30 days after = 61 days total.

Real Wash-Sale Examples

Example 1 — The Classic Mistake:

• Nov 30: Sell 100 shares of AAPL at a $2,000 loss
• Dec 15: Buy 100 shares of AAPL back (the price dipped further)
• Result: The $2,000 loss is disallowed — the 15-day repurchase is inside the 30-day window. The disallowed loss is added to the cost basis of the newly purchased AAPL shares.

Example 2 — Cross-Account Wash Sale:

• Dec 1: Sell VTI at a $1,500 loss in your taxable account
• Dec 10: Your spouse buys VTI in their IRA
• Result: Still a wash sale. The rule applies across all accounts you control, including your spouse's accounts. (Yes, the IRS considers spousal accounts for this purpose.)

Example 3 — The Safe Swap:

• Nov 30: Sell 100 shares of VTI at a $3,000 loss
• Nov 30 (same day): Buy 100 shares of SCHB (Schwab Total Market ETF — similar but not identical)
• Result: No wash sale. Different fund, different issuer. Loss is valid.

What "substantially identical" means:

• The same stock: always substantially identical
• Different share classes of the same fund: substantially identical
• Different ETFs tracking different indexes (even similar ones): generally not substantially identical
• Options and futures: can be substantially identical in some circumstances

Note: The IRS has not published a bright-line definition. Consult a tax professional if you're uncertain about a specific swap.

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Which Accounts Work for Tax-Loss Harvesting

Taxable brokerage accounts ONLY.

| Account Type | TLH Works? | Why | |-------------|-----------|-----| | Taxable brokerage | ✅ Yes | Capital gains are taxable; losses can offset them | | Roth IRA | ❌ No | Growth is tax-free; no capital gains tax to offset | | Traditional IRA | ❌ No | Withdrawals taxed as ordinary income regardless of what happens inside | | 401k / 403b | ❌ No | Tax-deferred; gains inside aren't taxed until withdrawal | | HSA | ❌ No | Tax-advantaged; same logic as retirement accounts |

The math only works when capital gains are taxable — which only happens in a standard brokerage account.

⚠️ Critical misconception: Selling an investment at a loss inside an IRA (Traditional or Roth) does NOT generate a deductible loss on your tax return. The loss simply disappears — you cannot claim it on Form 8949, you cannot use it to offset gains in your taxable account, and you cannot carry it forward. IRAs are a one-way street for tax purposes: you get the tax advantage on contributions or growth, but you give up the ability to recognize investment losses. Never sell at a loss in an IRA expecting a tax benefit.

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When NOT to Tax-Loss Harvest

Harvesting is often smart. But not always.

1. When you're in the 0% capital gains bracket In 2026, single filers with taxable income under ~$47,025 and married filers under ~$94,050 pay 0% on long-term capital gains. If that's you, harvesting long-term losses provides zero benefit — you weren't going to owe tax on those gains anyway.

2. When the replacement investment is meaningfully worse If the best available swap is an inferior fund with higher expense ratios or lower diversification, the long-term cost of holding an inferior investment can exceed the tax savings. Quality of the replacement matters.

3. When you trigger short-term recognition on a long-term position If you sell a position you've held for 11 months, you lose the long-term capital gains rate (15%) and the replacement shares start a new holding period. If that position subsequently gains, you're back to short-term rates on the replacement. Do the math.

4. When state taxes dominate Some states (like California) tax capital gains as ordinary income regardless of holding period. In high-state-tax situations, the wash-sale risk and transaction friction may outweigh the federal savings — especially for smaller harvest amounts.

5. When the market is moving fast Executing a harvest during high volatility means you might sell the dip and miss the bounce during the 1-2 business days it takes to complete the buy-sell-rebuy sequence. Timing risk is real.

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The Tax Forms: What You'll File

Form 1099-B

Your broker sends this by mid-February. It lists every security you sold during the year, the proceeds, your cost basis, and whether each sale was short-term (held ≤1 year) or long-term (held >1 year). If you triggered any wash sales, your broker should flag them on the 1099-B.

Form 8949

You report every individual sale on Form 8949. The form has two parts:

• Part I: Short-term sales (assets held 1 year or less)
• Part II: Long-term sales (assets held more than 1 year)

For each sale, you report: description, date acquired, date sold, proceeds, cost basis, wash-sale adjustments (if any), and net gain or loss.

TurboTax imports your 1099-B directly from your broker and auto-populates Form 8949. You review the entries, confirm, and it flows to Schedule D automatically. Start with TurboTax.

Schedule D

This is where all your Form 8949 numbers roll up. Schedule D calculates your total net short-term and long-term capital gains or losses. The net figure flows to your Form 1040.

Capital loss carryforward: If your harvested losses exceed all capital gains in a year, you can deduct up to $3,000 against ordinary income. The remaining losses carry forward to future years — indefinitely. If you harvest $15,000 in losses this year and have no gains to offset, you'll deduct $3,000 this year and carry $12,000 forward to future years.

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Evaluate Your Portfolio Before You Harvest

Before selling anything, you need to know which positions are actually worth holding through a replacement and which might have underlying problems.

Use our free stock calculator at valueofstock.com/calculator to run a Graham Number analysis on any individual stock you're considering harvesting — you want to know if you're selling a genuinely undervalued position or deadweight that should be exited permanently.

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The Complete Tax Investor Toolkit

Our Gumroad store includes a tax-lot tracking spreadsheet, a wash-sale window calculator, a cost basis optimizer, and a capital gains projection tool. Everything you need to plan harvests before year-end, not scramble in December.

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Quick Reference: Tax-Loss Harvesting Checklist

• [ ] Identify positions with unrealized losses in taxable accounts only
• [ ] Confirm you're not in the 0% capital gains bracket (offsetting $0 gains saves nothing)
• [ ] Choose a replacement investment — similar but not identical
• [ ] Execute sell and immediate buy in the same session
• [ ] Set a calendar reminder 31 days out if you want to return to the original position
• [ ] Watch for cross-account wash sales (including spousal accounts)
• [ ] Collect 1099-B in February
• [ ] File Form 8949 + Schedule D with your 1040
• [ ] Track any loss carryforward for future years

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Financial Disclaimer: This guide is for educational purposes only and does not constitute tax advice. Tax laws change frequently. Consult a qualified CPA or tax professional before making tax-related investment decisions. The IRS rules around "substantially identical" securities are not fully defined in regulation — when in doubt, consult a tax advisor for guidance on specific swaps. Nothing in this article creates a tax-professional relationship.