What Is Tax-Loss Harvesting? Turning Investment Losses Into Tax Savings

What Is Tax-Loss Harvesting?

Tax-loss harvesting is an investment strategy that involves deliberately selling investments that have declined in value to realize a capital loss, then using that loss to offset capital gains elsewhere in your portfolio — reducing your tax liability for the year. The sold investment is typically replaced with a similar (but not identical) investment to maintain your portfolio's market exposure.

Done correctly, tax-loss harvesting doesn't change your investment strategy — it simply makes it more tax-efficient by converting paper losses into real tax savings.

How Capital Gains and Losses Work

When you sell an investment for more than you paid, you realize a capital gain. When you sell for less, you realize a capital loss. The IRS allows capital losses to offset capital gains dollar-for-dollar. If losses exceed gains in a given year, you can deduct up to $3,000 of the excess loss against ordinary income, and carry any remaining losses forward to future years.

Tax rates on capital gains depend on how long you held the investment:

• Short-term capital gains (held less than 1 year): Taxed as ordinary income — up to 37%
• Long-term capital gains (held 1 year or more): Taxed at preferential rates — 0%, 15%, or 20% depending on income

Losses first offset gains of the same type (short-term vs. long-term), then can offset gains of the other type.

A Simple Example

Suppose you have a $10,000 gain on Apple stock you've held for 2 years (taxed at long-term rates — say 15%, so you owe $1,500). In December, you notice your emerging markets ETF is down $8,000 from your purchase price.

You sell the emerging markets ETF, realizing an $8,000 loss. This offsets $8,000 of your $10,000 Apple gain — reducing your taxable gain to $2,000. Tax owed: $300 instead of $1,500. You've saved $1,200 this year.

You immediately reinvest the proceeds into a similar (but different) emerging markets ETF to maintain your portfolio allocation.

The Wash-Sale Rule: The Critical Constraint

The IRS's wash-sale rule prevents you from claiming a tax loss if you buy the "same or substantially identical" security within 30 days before or after the sale. The wash-sale window is 61 days total — 30 days before, the day of sale, and 30 days after.

This means if you sell a fund at a loss and buy back the same fund within 30 days, the loss is disallowed (though it's added to your cost basis in the new shares, delaying rather than eliminating the tax benefit).

The solution: replace the sold investment with a similar but not identical security. For example:

• Sell a Vanguard S&P 500 ETF (VOO), buy an iShares S&P 500 ETF (IVV) — different funds, same index, not wash-sale
• Sell a total US market fund, buy a large-cap ETF plus a mid-cap ETF

Cryptocurrency is NOT currently subject to the wash-sale rule — you can sell Bitcoin at a loss and immediately rebuy, claiming the tax benefit.

Who Benefits Most?

Tax-loss harvesting is most valuable when:

• You are in a high tax bracket (15% or 20% long-term capital gains rate)
• You have significant realized gains to offset in the same year
• You have a taxable brokerage account (not an IRA or 401(k), where gains are already tax-deferred)
• Your portfolio is large enough that transaction costs are small relative to tax savings

For investors in the 0% capital gains bracket (income under ~$47,000 for single filers in 2024), tax-loss harvesting provides little immediate benefit.

Manual vs. Automated Tax-Loss Harvesting

You can harvest losses manually by reviewing your portfolio during market downturns and executing trades yourself. This works but requires discipline and vigilance.

Robo-advisors like Betterment and Wealthfront automate tax-loss harvesting continuously, scanning your portfolio daily for harvesting opportunities. Betterment claims tax-loss harvesting can add 0.48–0.77% in after-tax returns annually for higher earners — potentially worth more than the management fee itself.

Limitations and Cautions

• Tax-loss harvesting defers rather than eliminates taxes — your replacement investment has a lower cost basis, meaning you'll have a larger gain when you eventually sell.
• Trading costs and possible bid-ask spreads reduce net benefit.
• It only works in taxable accounts — IRAs and 401(k)s don't have capital gains taxes to offset.
• State taxes also apply — the benefit may be lower in high state-tax states than federal rates suggest.