How to use tax-loss harvesting for large-cap stock portfolios

You hold a concentrated portfolio of blue-chip stocks. Some positions are down double digits. You know you should sell to capture the loss, but you worry about missing a rebound or triggering the wash-sale rule.

Tax-loss harvesting lets you turn those paper losses into real tax savings. The strategy is straightforward: sell a losing position, use the loss to offset capital gains, and then redeploy the cash into a similar—but not substantially identical—holding to stay invested.

How the wash-sale rule applies to large-cap stocks

The IRS wash-sale rule disallows a loss if you buy a substantially identical security within 30 days before or after the sale. For large-cap stocks, "substantially identical" typically means the same stock or an ETF that tracks the same index. You can sell Apple at a loss and immediately buy Microsoft without triggering a wash sale, because they are not substantially identical.

Step-by-step harvesting process

1. Identify losing positions. Review your portfolio for stocks trading below your cost basis. Focus on positions with the largest unrealized losses.
2. Check the 61-day window. Do not repurchase the same stock or a substantially identical ETF within 30 days before or after the sale.
3. Execute the sale. Sell the losing position to realize the capital loss.
4. Replace the exposure. Buy a different large-cap stock or a broad-market ETF that is not substantially identical to maintain market exposure.
5. Offset gains. Use the realized loss to offset capital gains from other sales. If losses exceed gains, you can deduct up to $3,000 against ordinary income each year and carry forward the remainder indefinitely.

Timing and frequency

You can harvest losses year-round, not just in December. Continuous harvesting captures more losses and compounds tax savings over time. For large-cap portfolios, volatility creates frequent opportunities.

Common pitfalls to avoid

• Rebuying too soon. Wait at least 31 days before repurchasing the same stock.
• Ignoring dividend reinvestment. If your account automatically reinvests dividends, that purchase can trigger a wash sale if it occurs within the 61-day window.
• Harvesting in retirement accounts. Losses in IRAs or 401(k)s do not generate tax benefits.

Quiz: Test your knowledge

Which of the following statements about the wash-sale rule is correct?

A. The wash-sale rule allows you to deduct up to $3,000 of capital losses per year. B. The wash-sale rule disallows a loss if you buy substantially identical securities within 30 days before or after the sale. C. The wash-sale rule applies to cryptocurrency trading.

How the Resident Expert Can Help

Navigating tax-loss harvesting within a concentrated large-cap portfolio requires precision and discipline. Mehle Capital integrates tax-aware strategies into its institutional equity approach, helping qualified investors manage concentrated positions while optimizing after-tax returns. Led by founder and CIO Chad Mehle, the firm combines a high-conviction equity portfolio with an active options overlay and a Bitcoin commodity treasury—all designed for long-duration capital in an inflationary environment.