Year-End Tax-Loss Harvesting

When markets get choppy, it is easy to feel like you are losing twice: once on your account balance, and again in taxes if you sold winners earlier in the year. Year-end tax-loss harvesting is one of the few tools that can turn a frustrating market moment into something genuinely useful. The idea is simple: realize capital losses by selling investments below your cost basis, use those losses to offset realized capital gains, and keep your portfolio aligned with your long-term plan.

This is not about gaming the system or panic-selling. Done correctly, tax-loss harvesting is disciplined tax planning that can reduce your capital gains tax bill while you stay invested in the market.

What tax-loss harvesting does

Tax-loss harvesting means you sell an investment for less than you paid for it to realize a capital loss on your tax return. That realized loss can then be used in three main ways:

• Offset capital gains you already realized this year (from selling appreciated stocks, ETFs, mutual funds, or other taxable investments).
• Offset up to $3,000 of ordinary income per year if your losses exceed your gains (for most individual filers; if married filing separately, the limit is typically $1,500).
• Carry forward unused losses to future tax years if you still have more losses than you can use this year. Under current federal rules, capital loss carryforwards are not subject to an expiration date, but confirm your situation with your tax professional and consider state rules.

The key phrase is realized. Losses only count when you sell. An investment being down on paper does not help your taxes until you realize the loss.

Also note: harvesting is generally irrelevant inside retirement accounts (IRAs, Roth IRAs, and most workplace plans) because gains and losses are not currently recognized for tax purposes inside those accounts.

Start with the math: netting rules

Capital gains and losses are grouped by holding period:

• Short-term: held one year or less, taxed at ordinary income tax rates.
• Long-term: held more than one year, taxed at long-term capital gains rates.

In general, the IRS netting rules work like this:

1. Net short-term gains and short-term losses against each other.
2. Net long-term gains and long-term losses against each other.
3. Then net the two results against each other.

Why you should care: short-term gains are usually the most expensive because they are taxed at your regular income rate. Also, the character of what remains after netting matters. A net short-term gain is taxed at ordinary rates, while a net long-term gain is taxed at long-term capital gains rates. Harvesting losses that reduce short-term gains can be especially valuable in high-income years.

A quick example

Say you realized $18,000 of long-term gains earlier this year. You also have an ETF position currently down $12,000 and a stock position down $7,000.

• If you harvest both losses, you have $19,000 in realized losses.
• $18,000 offsets your gains, bringing your net capital gain to $0.
• The extra $1,000 can reduce ordinary income (up to the $3,000 annual limit).
• If you had $10,000 extra losses instead, you would use $3,000 this year and carry forward $7,000.

Who benefits most

Tax-loss harvesting tends to be most powerful for people who have:

• Taxable brokerage accounts (not retirement accounts, where gains and losses are not currently taxable).
• Realized gains this year, whether from investing, selling a business stake, RSU sales, or concentrated stock trimming.
• Higher income or meaningful short-term gains, where every dollar of offset can save more in tax.
• A long time horizon, so they can stay invested and let compounding do its job.

It can still be useful even without gains this year because of the $3,000 income offset and the carryforward feature. Think of carryforwards as a “bank” of future tax relief you can use when you rebalance, take profits, or sell a business interest later.

The tradeoff: lower basis today, higher gains later

One real-world nuance: when you harvest a loss and buy a replacement investment, you are typically resetting your cost basis lower than it would have been if you simply held through the downturn. That can mean higher taxable gains in the future when the market recovers.

In many cases, this is still a win because it is a form of tax deferral, and deferral has value. And sometimes it can become closer to permanent, depending on what you do later (for example, donating appreciated shares to charity, or a step-up in basis rules at death under current law). The right lens is “after-tax, over time,” not just “this year’s tax bill.”

How to harvest without derailing your portfolio

1) Find real taxable opportunities

Look at positions in your taxable accounts that are below their cost basis. Many brokerages show unrealized gains and losses directly. If you have multiple tax lots, you may have some lots at a loss even if the overall position is flat.

2) Define what you are offsetting

Before you sell anything, clarify your goal:

• Offset a specific realized gain amount.
• Reduce exposure to a position you no longer want.
• Rebalance in a tax-smart way.
• Build loss carryforwards for future years.

This keeps the strategy grounded in your plan, not the mood of the market.

3) Sell, then replace thoughtfully

In most cases, you do not want to sit in cash for 31 days just to avoid the wash sale rule. The practical approach is to swap into a similar, but not “substantially identical,” investment to keep your market exposure.

Examples that are commonly used (always confirm fit and compliance for your situation):

• Sell a total US stock market ETF and buy a different broad US market ETF from another provider.
• Sell an S&P 500 index fund and buy a US large-cap fund that tracks a different index.
• Sell a sector ETF and buy a different sector ETF with a different index methodology, or temporarily use a broader market fund.

The point is to keep your risk exposure close to what your plan requires, while still creating a tax loss.

4) Track dates and tax lots

Turn on specific identification for cost basis if your brokerage allows it, especially if you have been buying over time. It gives you more control over which lots you sell and can create more harvesting opportunities.

Wash sales: how people mess this up

The wash sale rule disallows your loss if you buy the same or a “substantially identical” security within 30 days before or after the sale that generated the loss. That is a 61-day window total.

Two important gotchas I see every year:

• Automatic reinvestment: Dividend reinvestment can trigger a wash sale if it buys back shares inside the window. If you are harvesting, consider turning off automatic reinvestment temporarily.
• Cross-account purchases: Buying the same security in an IRA or spouse’s account during the window can still create a wash sale. In some IRA wash sale scenarios, the disallowed loss is not recoverable in the way it often is in taxable accounts. If there is any chance of an IRA involvement, get advice and be conservative.

A practical “substantially identical” warning: selling an ETF in your taxable account and buying the exact same ETF in another account (including an IRA) during the window is the clearest wash sale. Also be cautious with funds that are different share classes of the same fund, or products designed to track the same index in nearly identical ways. The IRS has not defined “substantially identical” perfectly in all cases, so careful documentation and conservative substitutions matter.

If you trigger a wash sale

You do not lose the loss forever in many taxable cases. It is typically added to the cost basis of the replacement shares, and the holding period may be adjusted. But you do lose the immediate tax benefit, which is usually the whole point of harvesting at year-end.

What losses can offset

Capital gains

Harvested capital losses can offset realized capital gains from stocks, bonds, mutual funds, ETFs, and many other capital assets held in taxable accounts.

Ordinary income, limited

If total losses exceed total gains, you can generally deduct up to $3,000 against ordinary income each year, with the remainder carried forward.

Not payroll taxes

The $3,000 deduction can reduce taxable income, but it does not directly reduce self-employment tax the way certain business deductions can. This is one reason founders often benefit from coordinating harvesting with broader year-end planning.

State taxes vary

Most of the mechanics above are federal. State tax treatment can differ, including how capital losses and carryforwards are handled. If you are in a high-tax state, this can change the math meaningfully.

Timing: when year-end matters

Harvesting is available year-round, but year-end is when people finally have enough clarity to plan because:

• You have a better picture of realized gains, income, and tax bracket.
• You can pair harvesting with rebalancing and risk management.
• You can coordinate around distributions from funds, which can create taxable gains even if the fund’s price fell.

One year-end nuance: if you hold mutual funds in taxable accounts, pay attention to capital gains distributions. A fund can distribute taxable gains late in the year, and buying right before a distribution can create a tax bill you did not expect. Check the fund company’s distribution calendar when possible.

ETFs often have fewer capital gains distributions than mutual funds due to how creations and redemptions work, but they are not guaranteed to be distribution-free. It is still worth checking distribution history and announcements, especially with certain fixed income and niche ETFs.

Entrepreneurs and concentrated positions

If you are an entrepreneur, you often have taxes hitting from multiple directions: a good year in the business, a liquidity event, RSUs, option exercises, or simply trimming a concentrated position to reduce risk. Harvesting can be a smart pressure valve in those years.

Practical ways founders use this:

• Offset gains from diversification: If you sell part of a concentrated holding, harvested losses elsewhere can soften the tax impact.
• Create carryforwards ahead of a future sale: If you expect to sell a business interest in the next few years, building carryforwards can help later.
• Rebalance after a downturn: Harvest losses while moving toward a target allocation, instead of waiting for a perfect market moment that never comes.

If any of your holdings include qualified small business stock (QSBS), private equity interests, or partnership K-1 complexity, get professional guidance. The planning opportunities can be meaningful, but the rules are not DIY-simple.

Common mistakes

• Harvesting purely for taxes and ending up with a portfolio you do not actually want.
• Forgetting the wash sale window, especially via dividend reinvestment or purchases in other accounts.
• Ignoring transaction costs and spreads, which can eat into the benefit for smaller positions.
• Selling without a replacement plan, then sitting in cash longer than intended.
• Over-concentrating in a “temporary” substitute that is riskier than what you sold.

The best harvesting is boring: you execute, you stay diversified, and you move on.

Year-end checklist

• Confirm which accounts are taxable and which are retirement accounts.
• Estimate realized gains and losses year-to-date.
• Review positions with unrealized losses and check tax lots.
• Turn off dividend reinvestment temporarily if needed.
• Pick replacement investments that maintain your target exposure.
• Log trade dates to avoid wash sales in the 61-day window.
• Save confirmations and document your rationale for substitutions.
• Coordinate with your CPA if you have K-1s, a liquidity event, or significant short-term gains.
• Sanity-check state tax impact if you live in a state with different capital loss rules.

FAQ

Can I tax-loss harvest in my IRA or 401(k)?

No. Tax-loss harvesting applies to taxable accounts because capital gains and losses are not currently recognized inside most retirement accounts.

Do I have to wait 31 days to buy back in?

You only need to wait if you want to buy back the same or substantially identical security. Many investors stay invested by buying a similar alternative immediately, then optionally swapping back after the wash sale window.

If I have no gains this year, is it still worth doing?

Often, yes. You may be able to deduct up to $3,000 of excess losses against ordinary income and carry forward the rest. Whether it is worth the effort depends on your tax bracket, position sizes, state tax treatment, and how cleanly you can maintain your portfolio strategy.

Will harvesting hurt my long-term returns?

Not necessarily. If you remain invested in a similar exposure, the goal is to keep your risk and expected return profile intact while improving your after-tax result. The real risk is executing poorly, like sitting in cash too long, triggering wash sales, or buying a replacement that does not match your plan.

Bottom line

Year-end tax-loss harvesting is one of the most straightforward ways to turn market volatility into tax savings. The secret is not clever trading. It is staying disciplined: harvest losses intentionally, avoid wash sales, keep your portfolio aligned, and coordinate the move with your broader year-end tax picture.

If you want to do this confidently, pull your realized gain and loss report, map out the positions you would be willing to replace, and treat the rest like what it is: long-term investing, with taxes managed on purpose.