What Is Tax-Loss Harvesting? Saving Money on Taxes

Tax-loss harvesting is the practice of selling investments at a loss to offset capital gains taxes on your winners — reducing your total tax bill without changing your portfolio's market exposure. Done properly, it's one of the most reliable ways to improve after-tax returns. Studies estimate that systematic tax-loss harvesting can add 0.5-1.5% to annual after-tax returns — a meaningful advantage that compounds over decades.

How Tax-Loss Harvesting Works

Suppose you sold Stock A for a $10,000 gain this year and you hold Stock B at a $7,000 loss. By selling Stock B ("harvesting" the loss), you can offset $7,000 of the $10,000 gain — paying taxes on only $3,000 instead of $10,000. At a 20% long-term capital gains rate, that's $1,400 in tax savings. If you still like Stock B's prospects, you can buy a similar (but not identical) stock to maintain your market exposure.

If your harvested losses exceed your gains, you can deduct up to $3,000 of net losses against ordinary income each year ($1,500 if married filing separately). Any remaining losses carry forward indefinitely — you can use them to offset future gains in subsequent years. This carryforward feature makes harvested losses a long-lived tax asset.

The Wash Sale Rule

The IRS disallows the tax benefit if you buy a "substantially identical" security within 30 days before or after the sale — the wash sale rule. If you sell Stock B to harvest the loss and buy it back within 30 days, the loss is disallowed and added to the cost basis of the repurchased shares instead.

The workaround: buy a similar but not identical replacement. If you sell a specific technology stock at a loss, you can immediately buy a different technology stock or a technology sector ETF — maintaining your sector exposure while complying with the wash sale rule. The replacement doesn't need to be identical; it needs to provide similar market exposure.

When to Harvest Losses

Year-end is the most common harvesting period — investors review their portfolios in November and December to identify harvesting opportunities before the tax year closes. But losses can be harvested anytime during the year, and harvesting during sharp market declines (when many positions are temporarily underwater) can be especially productive.

Market-wide sell-offs create the best harvesting opportunities. During the March 2020 COVID crash, investors who harvested losses on temporarily depressed quality stocks — then replaced them with similar holdings — captured significant tax benefits while maintaining their portfolio positioning for the subsequent recovery.

Tax-Loss Harvesting and Quality Investing

Quality investors should harvest losses strategically rather than mechanically. Selling a quality business at a loss just for the tax benefit may cost you more in forgone returns than you save in taxes — especially if the replacement investment is less attractive. The decision should consider both the tax savings and the relative quality of what you're selling versus what you're buying as a replacement.

The ideal harvesting scenario: a quality stock you own has declined due to market-wide selling (not company-specific problems), you harvest the loss, and you replace it with an equally high-quality stock in the same sector that's also been indiscriminately sold. You get the tax benefit while maintaining exposure to quality businesses at depressed prices.