Converting losses into tax-free gains
Tax-loss harvesting is a technique where investors deliberately realize losses on underwater positions to offset capital gains elsewhere in the portfolio, reducing taxes owed. If you have a 5,000 dollar loss in one stock and a 5,000 dollar gain in another, selling both nets a zero tax impact while completing a rebalancing trade.
The strategy becomes powerful over time. Losses harvested in down markets can shelter years of future gains, particularly in tax-deferred gains from underlying portfolio appreciation. Over a 20-year period, disciplined tax-loss harvesting can reduce tax drag by 0.5-1% annually on a taxable portfolio, compounding into substantial after-tax outperformance.
The wash-sale rule and reinvestment discipline
The IRS restricts tax-loss harvesting via the wash-sale rule: selling a security at a loss and repurchasing the same security (or a 'substantially identical' one) within 30 days negates the loss. To harvest losses, investors must either wait 31 days before rebuying the position or immediately switch to a similar (but not identical) replacement. For equity positions, this is easy: swap one large-cap stock for another similar fund, or one international fund for a different one. The key is staying invested in a similar asset class while avoiding identical repurchases.