Tax-Loss Harvesting
An investment strategy that involves deliberately selling securities at a loss to offset capital gains elsewhere in a portfolio, thereby reducing the investor's current tax liability.
Tax-loss harvesting is one of the most powerful tools available to taxable investors for reducing their annual tax bill without sacrificing long-term investment returns. The strategy involves identifying positions in a portfolio that have declined in value, selling them to realize the loss, and using that loss to offset capital gains realized elsewhere — or, if losses exceed gains, deducting up to $3,000 of the net loss against ordinary income per year.
The mechanics are straightforward: capital losses first offset capital gains of the same type (short-term losses offset short-term gains, long-term losses offset long-term gains). If one category of losses exceeds gains in that category, the excess flows over to offset gains of the other type. After all gains are eliminated, up to $3,000 of remaining net capital loss can be deducted against ordinary income. Unused losses carry forward indefinitely to future tax years, where they retain their character as either short-term or long-term.
The key risk in tax-loss harvesting is the wash sale rule (IRS Section 1091), which disallows the loss if you repurchase a substantially identical security within the 30-day window on either side of the sale. To maintain market exposure while avoiding the wash sale rule, investors typically replace the sold position with a similar but not substantially identical security — for example, selling one S&P 500 index fund and buying a different fund tracking a similar but distinct index.
The after-tax benefit of harvesting depends on your tax rates. Harvesting a short-term loss that offsets a short-term gain at 37% is far more valuable than harvesting a long-term loss that offsets a long-term gain at 15%. Sophisticated investors track their blended rate differential carefully. Robo-advisors often automate daily tax-loss harvesting at a scale individual investors cannot match manually.
Long-term, harvesting delays taxes rather than eliminating them: the replacement securities carry a lower basis, so a larger gain will be recognized when they are eventually sold. The benefit comes from the time value of the deferred tax dollars. In some cases — such as holding appreciated replacement shares until death, when heirs receive a step-up in basis — the deferred tax may never be collected at all.