Losing money on an investment stings, but it can also come with a silver lining at tax time. Here is how tax-loss harvesting works, in plain English.
Nobody likes seeing a red number next to an investment. But there is a quiet tax trick that lets investors turn some of those losses into real savings. It is called tax-loss harvesting, and with the end of the year coming up, now is a smart time to understand it.
Don't worry if the phrase sounds intimidating. At its core, it just means selling an investment that has dropped in value so the loss can offset taxes you owe on gains elsewhere. Let's walk through how it works, step by step.
When you sell an investment for more than you paid, you have a capital gain, and you may owe tax on it. When you sell for less than you paid, you have a capital loss. The tax code lets you use losses to cancel out gains.
Here is the order it generally works in. Losses first offset gains of the same type (short-term against short-term, long-term against long-term). Then leftover losses offset the other type. If you still have losses left, you can deduct up to $3,000 against your regular income each year ($1,500 if married filing separately). Anything beyond that carries forward to future years.
Only taxable brokerage accounts matter here. Losses inside a 401(k) or IRA do not count, because those accounts already have their own tax treatment.
There is a catch, and it is the most important rule in this whole topic. The IRS has a wash sale rule: if you sell an investment at a loss and buy the same or a "substantially identical" one within 30 days before or after the sale, you cannot claim the loss right now.
That is a 61-day window in total. It also applies across accounts, so buying the same fund in your IRA can trigger it. The disallowed loss is not gone forever; it is added to the cost basis of the new purchase. But you lose the timing benefit you were after.
The usual workaround is to replace what you sold with something similar but not identical. For example, selling one total market index fund and buying a different one that tracks a different index can keep you invested while avoiding the rule. If you are newer to index funds, our guide to building a passive income portfolio with index funds is a helpful starting point.
Tax-loss harvesting is not for everyone. It tends to help people who:
Have a taxable brokerage account with meaningful holdings.
Are in a higher tax bracket, where each dollar of offset is worth more.
Have realized gains from selling other investments or receiving fund distributions.
If you are mostly investing inside retirement accounts, or your balances are small, the effort may not pay off. Harvesting also does not erase a loss; it generally defers taxes, because your lower cost basis means a bigger gain later. The value comes from keeping money invested and compounding in the meantime, and from possibly paying a lower rate later.
You can harvest manually: look through your holdings for positions below your purchase price, sell, and buy a similar replacement. Many people do this once a year in the fall or December.
Some automated platforms do it continuously. If you want a hands-off approach, our comparison of robo-advisors vs. DIY investing explains the tradeoffs, and you can browse more on our investing hub. Also keep your withholding in mind; our tax withholding guide can help you avoid overpaying all year.
Meet Elena and David, two investors in the 24% federal bracket.
Elena sold shares of a tech fund earlier this year and realized a $6,000 long-term gain. She also owns an energy fund that is down $4,000 from what she paid. In December, she sells the energy fund, locking in the $4,000 loss, and immediately buys a different energy fund so she stays invested. The loss offsets her gain, so only $2,000 is taxed. At a 15% long-term capital gains rate, she saves about $600 compared with doing nothing.
David has no gains this year, but he harvests a $5,000 loss. He deducts $3,000 against his salary this year, which at a 24% rate saves about $720. The remaining $2,000 carries forward to next year, where it can offset future gains or income.
Neither of them lost their market exposure, and both lowered their bill. Notice, though, that these savings are not free money: their cost basis is lower, so a future sale of the replacement funds may create a larger gain.
Triggering a wash sale. Buying the same fund in any account within 30 days either side cancels the loss for now.
Forgetting automatic reinvestment. Dividend reinvestment can accidentally buy shares during the window.
Selling just for the tax benefit. Never sell an investment you believe in only to harvest a small loss.
Ignoring trading costs. Fees and bid-ask spreads can eat a small tax saving.
Harvesting inside retirement accounts. It does nothing there.
Not tracking cost basis. Know what you actually paid for each lot.
Log in to your taxable brokerage account and sort holdings by unrealized loss.
Check your realized gains for the year so you know how much you need to offset.
Pick a replacement that is similar but not substantially identical.
Turn off dividend reinvestment on the sold position for 30 days.
Sell, then buy the replacement the same day.
Save the trade confirmations for tax filing, and ask a professional if you are unsure.
Tax-loss harvesting lets you turn a market dip into a smaller tax bill by selling losers to offset gains, deducting up to $3,000 against income, and carrying the rest forward. Respect the wash sale rule, remember the benefit is usually a deferral, and make sure the investment decisions still make sense on their own.
This article is for general education only and is not tax, legal, investment, or financial advice. Investing involves risk, including loss of principal. Tax rules vary by situation, so consult a qualified tax or financial professional.
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