What is Tax Loss Harvesting?

Tax loss harvesting is selling an investment at a loss on purpose to cancel out capital gains taxes you’d otherwise owe, then buying a similar (but not identical) replacement so your portfolio stays roughly where it was. Done right, it shaves real money off your tax bill without changing your long-term strategy. Done sloppy, it triggers the wash-sale rule and the IRS disallows the loss.

Here’s everything that matters: how it works, who actually benefits, which robo advisors automate it well, and the traps that turn a clever tax move into a paperwork mess.

What is tax loss harvesting?

Tax loss harvesting (TLH) is the practice of selling a security that’s dropped below your purchase price to realize a capital loss, then using that loss to offset capital gains or up to $3,000 of ordinary income per year. Any unused loss carries forward indefinitely.

The catch: you can’t just sell at a loss and buy the same thing back. The IRS wash-sale rule disallows the loss if you buy a “substantially identical” security within 30 days before or after the sale. The workaround is buying a different fund tracking a similar (but not identical) index, which keeps your market exposure intact while booking the tax loss.

How tax loss harvesting works: a worked example

Say you bought $10,000 of VTI (Vanguard Total Stock Market ETF) and it’s now worth $9,000. You have an unrealized $1,000 loss. Three steps:

1. Sell VTI at $9,000. The $1,000 loss is now realized.
2. Immediately buy $9,000 of ITOT (iShares Core S&P Total US Stock Market ETF). Different fund, different issuer, different underlying index methodology – similar exposure, not substantially identical. You stay invested in US total market.
3. Wait 31 days before buying VTI again if you want to swap back. Or just keep ITOT.

At tax time, that $1,000 loss offsets $1,000 of realized capital gains. No gains this year? Apply up to $3,000 against ordinary income (a meaningful deduction if you’re in the 32% federal bracket – roughly $320 saved). Loss bigger than $3,000? Carry the rest forward to next year. And the year after. Forever, until used up.

The wash-sale rule: what triggers it

The wash-sale rule (IRC Section 1091) disallows the loss if you buy a substantially identical security within a 61-day window: 30 days before the sale, the day of, or 30 days after.

What counts as “substantially identical” isn’t perfectly defined, but the IRS and courts have made some calls clear:

• Same ticker = identical. Selling VTI and buying VTI back in 20 days kills the loss.
• Two ETFs tracking the same index (e.g. SPY and IVV, both S&P 500) = risky. Most tax pros treat these as identical.
• Different funds tracking different indexes with similar exposure (VTI vs ITOT, or VOO vs SPLG vs SCHX) = generally safe.
• Buying the security in your IRA while selling at a loss in your taxable account = wash sale. The IRS confirmed this in Rev. Rul. 2008-5. Your spouse’s account counts too.

Get this wrong and the loss is added to the cost basis of the replacement security instead of being deductible. You don’t lose it permanently – it just delays the benefit until you sell the replacement.

The limits: $3,000 ordinary income offset, unlimited carryforward

Two numbers to remember for 2026:

• Unlimited offset against capital gains. Realized losses cancel realized gains dollar-for-dollar. Short-term losses offset short-term gains first, long-term against long-term, and any leftover crosses over.
• $3,000 cap against ordinary income. If your losses exceed your gains, you can deduct up to $3,000 of net losses against ordinary income per year ($1,500 if married filing separately). That number has not moved since 1978 and was not adjusted in 2026.
• Indefinite carryforward. Anything past $3,000 rolls into next year’s return, and the year after, until you’ve used it all. Carry forward losses keep their short-term or long-term character.

Who benefits most from tax loss harvesting

TLH is useful for one specific person: someone with significant taxable investment accounts and a high marginal tax rate. Everyone else gets less out of it, or nothing at all.

• High earners in taxable brokerage accounts: the bigger your marginal bracket (32%, 35%, 37% federal, plus state), the more each $1 of harvested loss saves you. If you have $50K+ in taxable equities and you’re in the top bracket, TLH can save $1,000-$3,000+ per year in average markets.
• People with concentrated stock positions or RSUs: tech employees vesting RSUs often have huge gains to offset. Pairing those gains with harvested losses elsewhere cuts the tax bill on diversification.
• Anyone in IRAs, 401(k)s, 403(b)s, HSAs, or Roth accounts: useless. These accounts are already tax-sheltered. No gains to offset, no losses to deduct. TLH has zero value here.
• Investors in the 0% long-term capital gains bracket: if your taxable income is under ~$48,350 single / $96,700 married (2026), your long-term gains are already taxed at 0%. Harvesting losses to offset 0% gains is pointless. The $3K ordinary income offset still helps, but the math is thin.

For a deeper look at how this fits into a broader high-income strategy, see our breakdown of the best robo advisors for high net worth investors.

Manual vs. automated tax loss harvesting

You can do TLH yourself. People do. It looks like this: monitor your taxable positions, identify ones trading below cost basis, sell at a loss, buy a non-identical replacement, log the trade, track the 30-day clock, avoid wash sales across all your accounts and your spouse’s, and reconcile at tax time.

Doable for a handful of positions. Painful for a diversified portfolio. Impossible to do well on a daily basis without software watching every tick.

That’s why automated TLH exists. A robo advisor scans your portfolio daily (or in some cases, multiple times a day), identifies harvesting opportunities, executes the sell and replacement buy, respects the wash-sale window across linked accounts, and reports it all on a 1099-B at tax time. The strategic decisions are still yours – the bookkeeping isn’t.

If you’re weighing the broader question of where automation ends and a human should step in, our piece on robo advisors vs. financial advisors covers the tradeoffs.

When “we monitor wash sales” isn’t automatic

Robo advisors say they watch for wash sales across your accounts. The SEC has fined two of the biggest names in the category for not doing it.

In 2018, the SEC found that Wealthfront’s TLH marketing falsely claimed the platform “monitors all the accounts it manages for each client to avoid any transactions that might trigger a wash sale,” when its software in fact didn’t check for wash sales against accounts a client held elsewhere. At least 31% of accounts enrolled in Wealthfront’s TLH strategy experienced some wash sales between October 2012 and mid-2016. Wealthfront paid a $250,000 penalty and consented to a censure and cease-and-desist order without admitting or denying the findings (SEC Release No. IA-5086, Dec. 21, 2018).

Betterment got hit for a related problem in 2023. The SEC found that from January 2016 through April 2019, Betterment quietly cut its TLH account-scanning frequency from daily to alternating days without updating its marketing materials, on top of separate coding errors that disabled harvesting for some accounts entirely. Collectively these issues adversely affected more than 25,000 client accounts and cost clients an estimated $4 million in potential tax benefits. Betterment paid a $9 million penalty into a fund for affected clients (SEC Release No. IA-6288, File No. 3-21373, April 18, 2023).

Neither case means automated TLH doesn’t work – the numbers below say it clearly does. It means “the algorithm handles it” is a claim worth checking, not a guarantee. Read the current Form ADV and TLH disclosures before assuming the marketing copy is up to date.

Which robo advisors do tax loss harvesting best

Wealthfront

The class leader. Wealthfront does daily-bar TLH on all taxable accounts with no minimum balance for the basic service. At $100,000+ you get US Direct Indexing, which holds the individual stocks of the US large-cap index instead of a single ETF – more harvesting opportunities at the individual-stock level. At $500,000+ they add Smart Beta. They also offer Nasdaq-100 Direct for concentrated tech exposure with the same direct-indexing tax benefits. Wealthfront’s own 2026 TLH methodology whitepaper reports a 4.00% annualized harvesting yield since inception (October 2012 through December 2025, its most commonly selected risk score) and a median 4.2x ratio of tax benefit to fee – both above the independent academic range below (0.82% to 1.08%), which is what you’d expect from a vendor measuring real client accounts rather than a backtest, but worth reading as marketing as much as data. Read the full Wealthfront review for the rest of the platform.

Betterment

Betterment offers what it calls Tax Loss Harvesting+ on all taxable accounts, no minimum. The algorithm checks daily, coordinates across linked household accounts to avoid wash sales, and handles the replacement-security swap. No direct indexing option, which means Wealthfront edges it for accounts over $100K. Below that, they’re functionally close. Betterment’s own TLH methodology page (updated June 2026) reports that 69% of customers who used the strategy in 2022-2023 saw savings exceeding Betterment’s fees – set next to the 0.82% to 1.08% academic range below, that’s a reminder that “beat the fee” and “hit the top of the published range” aren’t the same claim, and by Betterment’s own arithmetic roughly 31% of its TLH users in that window didn’t clear their fees. Full breakdown in the Betterment review.

Schwab Intelligent Portfolios

Schwab includes TLH on taxable accounts of $50,000 or more. The service is competent but checks less frequently than Wealthfront or Betterment. The bigger gripe: Schwab’s portfolios hold a meaningful cash allocation (which Schwab earns interest on), so you’re paying for “free” management indirectly. See the Schwab Intelligent Portfolios review for the full picture.

Fidelity Go

Fidelity Go activates TLH only on accounts of $25,000 or more, and even then it’s reviewed less aggressively than the Wealthfront/Betterment cadence. Below $25K you get a clean robo with no advisory fee but no tax optimization at all. Details in the Fidelity Go review.

Empower

Empower (formerly Personal Capital) layers TLH onto its advisory service for clients with $100,000+ in managed assets. The fee is higher than the pure-robo crowd (0.89% on the first $1M) because you get human advisors alongside the algorithm. Worth it if you want the hybrid model. Full details in the Empower review.

M1 Finance

M1 offers limited TLH features – mostly tax-minimization at sale (selling the highest-cost-basis lots first) rather than active opportunistic harvesting. Useful, but not the same product.

How much does tax loss harvesting actually save you?

The honest answer: it depends on portfolio size, tax bracket, market conditions, and how disciplined the harvesting is. The most rigorous independent estimate comes from Chaudhuri, Burnham, and Lo’s 2020 Financial Analysts Journal study, which backtested a systematic harvesting strategy on the 500 largest US stocks from 1926 to 2018 (assuming a 15% long-term / 35% short-term capital gains rate): a 1.08% annual “tax alpha” before transaction costs, dropping to 0.82% once the wash-sale rule is enforced. Vanguard’s own historical-simulation research (market data January 1982 to March 2023) puts personalized TLH alpha at 0.47% to 1.27% a year depending on net worth – the top 2% by net worth see the high end, the 75th-90th percentile band the low end – assuming optimal harvesting behavior (daily scanning, full reinvestment of tax savings, direct indexing). Get sloppy about it – quarterly scanning, no direct indexing, half the tax savings reinvested – and that same range collapses to 0.04% to 0.13%, roughly a 10x haircut.

There’s also a shelf life. Vanguard’s simulation shows TLH alpha decaying over time: median annualized alpha starts around 3% in year one and settles near 1% by year twenty, because harvesting keeps pushing the portfolio’s cost basis down, leaving fewer future tax lots sitting below cost basis to harvest. Reinvesting dividends, tax savings, and new contributions creates fresh higher-cost-basis lots and slows the decay, but doesn’t stop it.

That means a $200,000 taxable account in a high bracket might see $1,000 to $3,000 per year in tax savings. A $1M account: $5,000 to $15,000. In years with high market volatility (more dispersion = more harvestable losses) the upper end is realistic. In a long bull market with everything up, opportunities thin out fast.

Important caveat: this isn’t free money. TLH is tax deferral, not tax elimination. Every harvested loss lowers the cost basis of your replacement security, which means a larger taxable gain when you eventually sell. The value comes from (a) deferring the tax bill, letting that capital compound, and (b) potentially paying at a lower rate later (long-term vs short-term, lower bracket in retirement, or step-up at death).

Worth keeping in perspective: fee drag compounds the same way. The SEC’s own investor-education illustration shows a hypothetical $100,000 portfolio growing at a flat 4% annual return before fees ending up worth about $208,000 after 20 years at a 0.25% fee, versus about $179,000 at a 1.00% fee – a $29,000 gap from 75 basis points of annual drag. A percent or two of harvested tax alpha, banked consistently, is playing in the same order of magnitude.

Pitfalls and what to watch for

• Don’t let the tax tail wag the investment dog. Selling a position purely for the tax benefit when it doesn’t fit your strategy is a bad trade. The replacement security has to be one you’d actually want to hold.
• Watch wash sales across all accounts. If your robo advisor is harvesting in your taxable account and your 401(k) automatically buys the same index fund every two weeks, that’s a wash sale the robo can’t see.
• Factor in your capital gains schedule. Harvesting short-term losses to offset long-term gains converts a 15-20% tax saving into a 32-37% one – good. The opposite (long-term loss against short-term gain) is fine too. But shuffling losses around without realized gains to offset just gets you the $3K ordinary-income deduction, which is small money relative to the trading.
• Mind the cost basis trail. Frequent harvesting drives the cost basis of your portfolio toward zero. If you plan to sell in five years, that’s a giant deferred gain. If you plan to die holding it or donate to a donor-advised fund, the step-up or zero-gain donation eliminates that future tax entirely – which is when TLH compounds best.
• Tracking error. Replacement securities aren’t perfect substitutes. VTI and ITOT will diverge slightly over a 30-day window. Usually negligible, occasionally not.

Tax loss harvesting FAQs