Tax-loss harvesting is a tax-management technique that sells investments at a loss to offset capital gains and, up to an annual limit, ordinary income. The Internal Revenue Service explains that realized capital losses first offset capital gains and then up to three thousand dollars per year of ordinary income, with excess losses carried forward to future years. This tax benefit depends on individual tax circumstances, holding periods, and transaction costs.
How to execute tax-loss harvesting
Identify underperforming securities in your taxable account and compare the tax benefit of realizing a loss to the trading cost and portfolio impact. Sell the loss position to realize the loss, then avoid repurchasing the same or a “substantially identical” security within 30 days before or after the sale to comply with the wash-sale rule. The Internal Revenue Service Publication 550 describes that wash sales disallow a loss if the substantially identical asset is acquired within that window, and the disallowed loss adjusts the basis of the replacement holding.
Vanguard Group recommends using broadly diversified and tax-efficient replacements—such as different index funds or ETFs with similar exposures—to maintain market exposure while avoiding the wash-sale rule. Replacing with a similar but not identical fund keeps risk exposure consistent but can slightly change sector or factor tilts.
Practical considerations and consequences
Evaluate time horizon and tax bracket because the value of harvesting depends on whether losses offset long-term or short-term gains and future expected tax rates. Fidelity Investments notes that short-term losses often offset short-term gains taxed at higher ordinary-income rates, increasing immediate tax value. Keep records of trade dates and bases; wash-sale adjustments and carryforwards complicate cost-basis reporting and may require brokerage statements during tax filing.
There are behavioral and territorial nuances: investors in high-tax jurisdictions derive greater benefit from harvesting, while frequent trading in small accounts may be eroded by fees and bid-ask spreads. Institutional guidance emphasizes that automated harvesting services can simplify execution but may generate different tracking error and administrative complexity. For many investors, a disciplined, selective approach—targeting sizable unrealized losses or concentrated positions—produces the best trade-off between tax benefit and portfolio integrity.