Tax-loss harvesting is one of the most effective tax strategies for investors. By strategically selling losing investments to offset gains, you can reduce your tax bill without significantly changing your portfolio allocation.
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How Tax-Loss Harvesting Works
- Identify investments trading below your purchase price in taxable accounts
- Sell the losing investment to realize the capital loss
- Use the loss to offset capital gains from other investments you sold at a profit
- Deduct up to $3,000/year in net losses against ordinary income if losses exceed gains
- Carry forward any remaining losses to future years indefinitely
- Reinvest in a similar (but not identical) investment to maintain your portfolio strategy
Example
| Transaction | Amount |
|---|---|
| Sold Stock A for a $15,000 gain | +$15,000 |
| Sold Stock B for a $10,000 loss | -$10,000 |
| Net capital gain | $5,000 |
| Tax at 15% long-term rate | $750 |
| Tax without harvesting (on $15,000 gain) | $2,250 |
| Tax savings from harvesting | $1,500 |
Tax-Loss Harvesting Rules
What Can Be Offset
| Loss Type | Can Offset |
|---|---|
| Short-term losses | Short-term gains first, then long-term gains |
| Long-term losses | Long-term gains first, then short-term gains |
| Net losses (after offsetting all gains) | Up to $3,000 of ordinary income per year |
| Excess net losses | Carried forward to future years indefinitely |
Short-term losses are most valuable because they first offset short-term gains (taxed at up to 37%) before offsetting long-term gains (taxed at up to 20%).
The Wash Sale Rule
The IRS wash sale rule is the key restriction on tax-loss harvesting. You cannot claim a loss if you buy a “substantially identical” security within:
- 30 days before the sale, or
- 30 days after the sale
This creates a 61-day window where you must avoid buying the same security.
What counts as “substantially identical”:
- Same stock or bond
- Options or contracts on the same security
- Substantially identical mutual funds (e.g., two S&P 500 index funds from different providers — debatable but risky)
What does NOT count as substantially identical:
- Different index (selling S&P 500 fund, buying total market fund)
- Different sector ETFs
- Individual stocks vs. ETFs containing that stock
- Bonds with different issuers, maturities, or coupon rates
The Wash Sale Rule Applies Across Accounts
If you sell a stock at a loss in your taxable account and buy it within 30 days in your IRA, the loss is disallowed. The rule applies across all your accounts including retirement accounts.
Tax-Loss Harvesting Strategies
1. Swap to a Similar Investment
Sell the losing investment and immediately buy a similar but not identical one:
- Sell Vanguard S&P 500 ETF (VOO) → Buy Schwab U.S. Broad Market ETF (SCHB)
- Sell Total International Fund → Buy Developed Markets Fund
- Sell individual tech stock → Buy technology sector ETF
This maintains your market exposure while capturing the tax loss.
2. Wait 31 Days and Rebuy
Sell the losing investment, wait 31 days, then buy it back. Risk: the investment may rise during the waiting period, costing you more than the tax benefit.
3. Harvest Losses Year-Round
Don’t wait until December. Market dips throughout the year create harvesting opportunities. Some robo-advisors harvest losses daily.
4. Pair Long-Term and Short-Term Strategically
If you have both types of gains, harvest losses that will offset the gains taxed at the highest rate first.
When Tax-Loss Harvesting Makes Sense
| Situation | Benefit Level |
|---|---|
| High income (32%+ bracket) with short-term gains | Very High |
| 15% or 20% long-term capital gains rate | High |
| Large portfolio with many individual positions | High |
| Volatile markets / market downturns | Excellent opportunities |
| Taxable accounts | Yes |
| 401(k), IRA, Roth IRA | No benefit (tax-advantaged already) |
| 0% capital gains bracket | No benefit |
| Small portfolios (< $10,000) | Minimal benefit |
Tax-Loss Harvesting and the $3,000 Deduction
If your capital losses exceed your capital gains, you can deduct the excess against ordinary income, up to $3,000 per year ($1,500 if married filing separately).
Example: You have $0 in capital gains and $12,000 in realized capital losses.
| Year | Loss Applied to Income | Remaining Carryforward |
|---|---|---|
| Year 1 | $3,000 | $9,000 |
| Year 2 | $3,000 | $6,000 |
| Year 3 | $3,000 | $3,000 |
| Year 4 | $3,000 | $0 |
At a 24% marginal rate, the $3,000 annual deduction saves $720/year in income taxes.
Potential Pitfalls
- Transaction costs: Frequent trading can incur commissions and fees (though most brokers now offer free trades)
- Tracking basis: You must keep careful records of adjusted basis for all repurchased securities
- State taxes: Some states have different rules for carryforwards
- It’s a deferral, not elimination: Eventually, your lower-basis replacement investment will create a larger taxable gain when sold (though deferral still has time value)
- Overcomplicating your portfolio: Too many swaps can create a complex, hard-to-manage portfolio
Tax-Loss Harvesting and Robo-Advisors
Many robo-advisors (Wealthfront, Betterment, etc.) offer automated daily tax-loss harvesting. Studies suggest automated harvesting can add 1-2% in after-tax returns annually, though individual results vary.
The automation is most valuable for large taxable portfolios where manually monitoring every position would be impractical.
Related: Capital Gains Tax Rates | Federal Income Tax Brackets | Compound Interest Calculator
