What Is Tax-Loss Harvesting and How Much Can You Claim?

‍Tax-loss harvesting is the practice of selling an investment that has fallen below what you paid for it, so the realized capital loss can offset taxable capital gains elsewhere in your portfolio. Capital losses offset capital gains dollar for dollar with no annual ceiling. Once your gains are fully absorbed, up to $3,000 of leftover loss reduces ordinary income each year, and anything past that carries forward indefinitely.

The sections below cover how the mechanics work, exactly how much you can claim in a single year, how long unused losses survive, the wash sale rule that disallows a loss you harvest carelessly, how the rules land on cryptocurrency and retirement accounts, which cost basis method produces the largest deduction, what the peer-reviewed research says the strategy is actually worth, and how the treatment changes for a business entity rather than an individual filer.

Key Takeaways

• Capital losses offset capital gains with no dollar limit. The $3,000 cap applies only to the leftover loss you push against ordinary income.
• The $3,000 annual limit ($1,500 for married taxpayers filing separately) has been frozen since 1978 and has never been indexed for inflation.
• Unused losses carry forward indefinitely for individuals, keeping their short-term or long-term character each year.
• The wash sale rule disallows a harvested loss if you buy the same or a substantially identical security inside a 61-day window, spanning 30 days before and 30 days after the sale.
• A disallowed loss is deferred rather than destroyed. It attaches to the cost basis of the replacement position.
• Peer-reviewed research puts the annual after-tax benefit at roughly 0.5% to 1.3%, and the size of that benefit depends heavily on your own tax rates and behavior.
• Tax-loss harvesting works only inside taxable brokerage accounts. Losses realized inside an IRA or 401(k) produce no deduction.

What Is Tax-Loss Harvesting?

Tax-loss harvesting is the deliberate sale of a depreciated position in a taxable account to convert a paper loss into a realized capital loss the tax code recognizes. The paper loss on a position you still hold carries no tax value at all. The sale is the event that turns a decline in value into a deduction.

A realized capital loss functions as a credit against realized capital gains. Realized capital gains arrive from selling appreciated stock, closing a profitable fund position, receiving a capital gain distribution from a mutual fund, or disposing of a digital asset at a profit. Each of those events adds taxable gain to your return, and a harvested loss subtracts from that total before any capital gains tax is calculated.

The strategy does not require you to leave the market. Most investors who harvest a loss immediately reinvest the proceeds into a comparable position that fills the same role in the portfolio, which preserves market exposure while banking the deduction. Preserving that exposure is the difference between tax-loss harvesting and simply selling in a panic.

How Does Tax-Loss Harvesting Work?

Tax-loss harvesting works by realizing a loss, netting that loss against your realized gains, applying any remainder to ordinary income up to the annual cap, and carrying the rest forward. The sequence runs the same way on every return, regardless of portfolio size.

Consider a straightforward year. You sell one position at a $30,000 loss and another at a $25,000 gain. The loss wipes out the entire gain, so your capital gains tax on that pair of transactions drops to zero, and $5,000 of loss remains. You apply $3,000 of that remainder against your wages or business income this year and carry the final $2,000 into next year. Nothing evaporates in that sequence, because the code preserves every dollar of loss until you use it.

How Much Can You Write Off With Tax-Loss Harvesting?

You can write off an unlimited amount of capital gains with harvested losses, plus up to $3,000 of ordinary income per year, or $1,500 if you are married filing separately. Those two limits behave very differently, and confusing them is the most common error in this area.

The gain offset carries no ceiling whatsoever. A taxpayer with $400,000 in realized gains and $400,000 in realized losses reports a net capital gain of zero and owes no federal capital gains tax on those transactions. The $3,000 figure never enters that calculation, because the cap governs only the portion of loss that survives after every gain has been absorbed.

The ordinary income offset is where the ceiling bites. According to IRS Topic No. 409, once your capital losses exceed your capital gains, the deductible excess equals the lesser of $3,000 or your total net loss. That $3,000 applies to the return rather than to each spouse, so a married couple filing jointly receives one $3,000 deduction between them. Deliberate tax planning throughout the year is what determines whether a given loss lands against a 37% ordinary income bracket or gets stranded behind an already-empty gain column.

What Is the $3,000 Loss Rule?

The $3,000 loss rule is the statutory limit under Internal Revenue Code Section 1211(b) on how much net capital loss an individual can deduct against ordinary income in a single tax year. Ordinary income here covers wages, self-employment earnings, interest, and non-qualified distributions.

The number has a history worth knowing. According to the Congressional Research Service, the $3,000 limit has stood unchanged since 1978, when Congress raised it from $1,000. Nearly five decades of inflation have passed without a single adjustment, and analysts who index the original figure to consumer prices put its equivalent value above $13,000 today. Over sixty provisions in the tax code adjust automatically each year for cost of living. This one does not.

The practical consequence falls hardest on investors holding large carryforward balances. A taxpayer sitting on $90,000 of unused loss and no future gains would need thirty years to absorb it at $3,000 per year. That arithmetic is precisely why the gain offset, which has no cap, deserves far more planning attention than the ordinary income offset.

Can You Write Off 100% of Stock Losses?

You can write off 100% of stock losses against capital gains, but you cannot write off 100% of stock losses against ordinary income in the same year. The full loss is always deductible eventually. The question is only how many tax years the deduction takes to run its course.

A single scenario makes the split obvious. An investor realizing $50,000 in stock losses and $50,000 in stock gains deducts the entire loss immediately, because gains absorb losses without limit. Change the facts so the same investor has $50,000 in losses and no gains at all, and the deduction stretches across seventeen tax years at $3,000 annually. Identical losses, radically different timing, driven entirely by whether realized gains exist to absorb them.

How Long Do You Have to Write Off Stock Losses?

You have an unlimited amount of time to write off stock losses, because capital loss carryforwards never expire for individual taxpayers. According to IRS Publication 550, the unused portion carries forward year after year until it is fully absorbed.

Carried-forward losses retain their original character. A long-term loss stays long-term when it arrives in next year's netting calculation, and a short-term loss stays short-term. Character preservation matters because the netting order treats the two categories separately before combining them, which the next section walks through step by step.

Recordkeeping is the practical constraint rather than the statute. The carryforward figure moves from one year's Schedule D to the next through the Capital Loss Carryover Worksheet, and a single skipped year breaks the chain. Taxpayers who switch software or preparers frequently lose track of six-figure carryforward balances simply because the number never got transcribed.

What Happens to Capital Loss Carryovers When You Die?

Capital loss carryovers expire at death and cannot be transferred to your heirs or to your estate. Any unused balance is deductible on the decedent's final individual return and then disappears permanently.

Permanent expiration reframes what a large carryforward actually represents. An investor in their late seventies carrying $200,000 in unused losses and no realized gains holds an asset that will almost certainly never be used. Recognizing appreciated positions deliberately during life, so gains exist for the carryforward to absorb, converts a wasting balance into real tax savings. Coordinating that sequence across a family's holdings is standard work inside a family office engagement.

How Do Short-Term and Long-Term Losses Get Netted?

Short-term and long-term losses get netted against gains of the same type first, and only the surviving remainder crosses over to offset the other category. The ordering rule is mechanical, and it determines how much tax a given loss actually saves.

The rate spread is what gives the ordering its weight. Short-term capital gains, from assets held one year or less, are taxed as ordinary income at rates from 10% to 37%, according to the IRS. Long-term capital gains, from assets held more than one year, are taxed at 0%, 15%, or 20%. In 2026, the 0% tier reaches taxable income of $49,450 for single filers and $98,900 for joint filers, and the 20% tier begins above $545,500 and $613,700 respectively, under IRS Revenue Procedure 2025-32. A loss that cancels a short-term gain therefore saves substantially more tax than the identical loss applied against a long-term gain.

The netting calculation runs in this order on your return:

1. Separate every transaction by holding period. One year or less is short-term. More than one year is long-term.
2. Net short-term losses against short-term gains. This pairing is the most valuable, because short-term gains carry ordinary rates.
3. Net long-term losses against long-term gains. Same-category netting always happens before any crossover.
4. Cross the surviving remainder over. Excess short-term loss offsets net long-term gain, and excess long-term loss offsets net short-term gain.
5. Apply up to $3,000 of any remaining net loss to ordinary income. The figure drops to $1,500 for married taxpayers filing separately.
6. Carry the balance forward. The remainder moves into next year with its short-term or long-term character intact.

One additional rate layer sits above this grid. The net investment income tax adds 3.8% to investment income once modified adjusted gross income passes $200,000 for single filers or $250,000 for joint filers. Fidelity reports that the surtax pushes the effective top rate to 40.8% on short-term gains and 23.8% on long-term gains, which raises the value of every harvested loss for taxpayers above those thresholds.

What Is the Wash Sale Rule?

The wash sale rule is the provision under Internal Revenue Code Section 1091 that disallows a capital loss when you acquire the same or a substantially identical security within 30 days before or 30 days after the sale that produced the loss. Counting both sides of the sale date creates a 61-day window in total.

The window catches purchases made before the sale as readily as purchases made after it. An investor who buys additional shares on March 1 and then sells the older lot at a loss on March 20 has triggered the rule, even though the purchase preceded the harvest. Sequence provides no protection. Only distance from the sale date does.

The rule also reaches across accounts rather than sitting inside a single brokerage statement. Purchases in a second taxable account, in a retirement account, and in a spouse's account all count toward the same 61-day test, whether or not the spouses file jointly.

What Counts as a Substantially Identical Security?

A substantially identical security is one with essentially the same economic characteristics and rights as the position you sold, which generally means the same issuer and the same class of stock. Common stock in a company and common stock in the same company is the clearest case.

Different issuers in the same industry are generally not substantially identical. Selling one large technology company at a loss and purchasing a different large technology company does not trigger the rule, even though the two positions may move together. The same logic extends to funds. Selling an index fund tracking one benchmark and buying a fund tracking a different benchmark with a similar objective is widely treated as a valid replacement, while selling a fund and repurchasing the same fund in a different share class is not.

Can You Buy Back a Stock After Selling at a Loss?

You can buy back a stock after selling at a loss and keep the deduction, provided you wait at least 31 days from the sale date. Waiting past the window removes the disallowance entirely and requires no election, form, or disclosure.

Waiting carries its own cost, since a position that rebounds during the 31 days rebounds without you. Investors who want continuous exposure typically buy a comparable but distinguishable replacement immediately, then either hold the replacement permanently or rotate back after the window closes. Choose the replacement before you place the sale, if the position occupies a meaningful share of the portfolio.

How Do You Avoid Triggering a Wash Sale?

You avoid triggering a wash sale by controlling every purchase of the security across every account you and your spouse own during the full 61-day window. The trades that create problems are rarely the deliberate ones. They are the automated and forgotten ones listed below.

• Automatic recurring investments. A monthly transfer into the same fund you just harvested disallows a proportional share of the loss. Pause the contribution before the sale.
• Purchases inside an IRA or 401(k). Buying the security in a retirement account during the window disallows the loss in the taxable account permanently, with no basis adjustment available to recover it.
• A spouse's separate account. The rule treats spouses as one purchaser regardless of filing status, so an uncoordinated trade in a partner's account defeats the harvest.
• Dividend reinvestment. A reinvested dividend is a purchase. A position set to reinvest automatically can trigger the rule days after you thought the harvest was complete.
• Equity compensation events. A vesting date or an employee stock purchase plan execution inside the window counts as an acquisition of company stock.

What Happens to a Disallowed Loss?

A disallowed loss is not destroyed, because the amount attaches to the cost basis of the replacement shares and remains available when you eventually sell that position. The wash sale rule defers the deduction rather than eliminating it.

The basis adjustment works arithmetically. Buy a stock at $50, sell it at $30 for a $20 loss, then repurchase at $25 inside the window. The $20 loss is disallowed for the current year, and your basis in the repurchased shares becomes $45 rather than $25. Selling those shares later at $60 produces a $15 gain instead of a $35 gain, which recovers the full benefit of the original loss.

Two conditions break this consolation. A disallowed loss caused by a purchase in a retirement account is lost outright, because there is no taxable basis for the adjustment to attach to. And the holding period of the disallowed position carries over to the replacement shares, which can convert what looks like a short-term position into a long-term one.

Does the Wash Sale Rule Apply to Crypto?

The wash sale rule does not currently apply to directly held cryptocurrency, because Section 1091 governs stock and securities while the IRS classifies digital assets as property. Selling a token at a loss and repurchasing it immediately preserves the deduction under current federal law.

Two carve-outs sit inside that general answer. Spot crypto exchange-traded products and equity in crypto-related companies are securities, so the 61-day rule applies to them in full. And the exemption is a function of current statute rather than a permanent feature, since proposals to extend Section 1091 to digital assets have appeared in draft legislation repeatedly since 2021 without passing.

Reporting has already moved ahead of the rule. Brokers began reporting gross proceeds on Form 1099-DA for transactions effected on or after January 1, 2025, and basis reporting became mandatory for covered digital assets acquired on or after January 1, 2026, according to the IRS. Form 1099-DA also contains a field for wash sale losses disallowed, which means the reporting infrastructure exists before the substantive rule does. Assets held in self-custody or acquired before the covered date remain the taxpayer's responsibility to substantiate, and reconstructing that history across exchanges and wallets is the bulk of the work in a crypto tax engagement.

Can You Tax-Loss Harvest in an IRA or 401(k)?

You cannot tax-loss harvest in an IRA or 401(k), because gains and losses inside tax-advantaged accounts produce no current tax consequence at all. Selling a position at a loss inside a retirement account generates nothing you can report on Schedule D.

Retirement accounts convert investment results into a different tax character entirely. Traditional account withdrawals arrive as ordinary income regardless of whether the underlying growth came from capital appreciation, and qualified Roth withdrawals arrive untaxed. Neither structure has a mechanism for recognizing a capital loss along the way.

The asymmetry creates a trap worth naming clearly. A retirement account cannot generate a usable loss, and yet a purchase inside that same account can destroy a loss harvested in your taxable brokerage account. The account gives you no upside on the harvest and full downside on the wash sale, which is why the pause-the-contributions step matters more for retirement accounts than for any other holding.

Which Cost Basis Method Produces the Largest Loss?

Specific identification produces the largest harvested loss, because the method lets you designate the highest-cost lots for sale rather than accepting a default the broker selects for you. Every share purchase creates a separate tax lot with its own basis and acquisition date, and the method you elect determines which lot leaves the account.

The difference between methods is measured in real dollars. An investor who bought the same fund at $40, $60, and $80 per share and now sells at $50 realizes a $30 loss per share under specific identification targeting the $80 lot, and a $10 gain per share under first in first out. Same sale, same market price, opposite tax outcomes.

Cost Basis MethodHow Shares Are SelectedEffect on Harvested LossRecordkeeping BurdenSpecific identificationYou designate the exact lots at the time of saleLargest available lossHighest, requires lot-level election before settlementHighest in, first outThe most expensive lots sell first automaticallyNear-largest loss without manual selectionLow, applied by the broker as a standing instructionFirst in, first outThe oldest lots sell firstSmallest loss on appreciated holdingsNone, this is the standard broker default for stockAverage costAll lots blend into one weighted basis figureModerate loss, no lot targeting possibleLow, available for mutual funds and dividend reinvestment plans

Sources: IRS Publication 550, Investment Income and Expenses; IRS Publication 551, Basis of Assets; IRS regulations on broker basis reporting under Section 6045.

The election has a deadline. Specific identification requires you to identify the lots at or before the sale settles, and a lot designation made after settlement is not valid. Set the account default before you need it, rather than during a volatile week.

When Is the Best Time to Tax-Loss Harvest?

The best time to tax-loss harvest is whenever a position drops meaningfully below its basis, rather than in the final weeks of December. A loss available in March frequently disappears by November, and the December-only approach forfeits every opportunity the year presented earlier.

December still carries one hard constraint. All harvesting transactions must be executed and settled by the close of the calendar year, which normally means December 31, or the preceding business day when the date falls on a weekend. Settlement timing rather than trade timing controls, so trades placed in the final days of December can fail to count.

Late-year harvesting does offer better information, since you know your realized gains and your approximate income by then. The practical resolution is to monitor for harvestable losses continuously, execute when the opportunity appears, and reserve December for the final reconciliation rather than for discovery. That rhythm is exactly what year-round planning is built to produce.

Is Tax-Loss Harvesting Worth It?

Tax-loss harvesting is worth roughly 0.5% to 1.3% in additional annual after-tax return for investors with meaningful taxable holdings and a high marginal rate, according to peer-reviewed research. The benefit is real and measurable, and it is also far more variable than most published guidance suggests.

The most cited measurement comes from Chaudhuri, Burnham, and Lo, published in the Financial Analysts Journal in 2020. Their simulation across the 500 largest US securities from 1926 to 2018 produced a tax alpha of 1.08% per year before transaction costs, assuming long-term and short-term rates of 15% and 35%. Constraining the same strategy with the wash sale rule reduced that figure to 0.82% per year, which quantifies the cost of the rule with unusual precision.

Variability across market environments is substantial in the same study. The 1926 to 1949 sub-period delivered 2.29% annually, while the 1949 to 1972 sub-period delivered just 0.57%. Volatile markets with wide dispersion between individual securities generate harvestable losses. Steadily rising markets with narrow dispersion do not.

Vanguard's own 2024 research reaches a compatible conclusion from a different angle, placing tax-loss harvesting alpha between 0.47% and 1.27% annually and attributing roughly one-third of the variation each to investor characteristics, investor behavior, and market environment. The single behavior that mattered most was reinvesting the tax savings rather than spending them. A separate 2021 study by Vanguard researchers in the Financial Analysts Journal found that investor profiles alone drove close to 60% of the variation in outcomes, and Vanguard's Advisor's Alpha framework values the strategy at up to 150 basis points for the investors positioned to use it.

What Is the Downside of Tax-Loss Harvesting?

The downside of tax-loss harvesting is that it lowers your cost basis, which converts today's deduction into a larger taxable gain later. Every harvest is a deferral, and the deferral only pays off if your rate at the eventual sale is equal to or lower than your rate today.

Three conditions turn a harvest against you, and each has a direct response. Selling into a permanently higher future bracket erodes the benefit, so investors expecting a large liquidity event ahead should model the exit before harvesting aggressively today. Replacing a position with a poorly matched substitute introduces tracking difference, so the replacement should share the sold position's role in the portfolio. And accumulating carryforwards you have no realistic path to using produces effort without payoff, which is the situation the deliberate gain-recognition approach described earlier is designed to prevent.

Do Capital Losses Reduce State Taxes?

Capital losses reduce state taxes only in states that impose an income tax on capital gains, and the treatment varies significantly from one state to the next. Federal treatment is uniform across the country. State treatment is not.

Nine states levy no state capital gains tax at all, and Florida is among them. For a Miami investor, a harvested loss delivers federal savings and nothing else, because there is no state capital gains liability for the loss to offset. The same harvested loss in a state with a top rate above 10% carries a meaningfully larger combined benefit. Residency at the moment of sale therefore changes the value of the strategy itself, not merely the size of the tax bill.

Carryforward treatment diverges as well. Some states allow indefinite loss carryforwards that mirror the federal rules, while others limit or disallow them entirely, which reduces the value of harvesting beyond the current year's gains. The federal surtax layer compounds the calculation for higher-income households, and the Bipartisan Policy Center reports that 8.1 million returns paid more than $39 billion in net investment income tax in 2023, more than double the number of returns that paid it in the tax's first year.