When an investment loses value, there's a tax code provision that lets you use that loss to offset gains elsewhere in your portfolio — and in some cases, to offset ordinary income. The strategy is called tax-loss harvesting, and it's one of the few places where a market decline produces a direct financial benefit. Most discussions of tax-loss harvesting focus on working-age investors with large taxable portfolios. But the strategy has important applications in retirement — and some specific interactions with retirement income, RMDs, and Medicare that change how it should be applied.
Tax-loss harvesting involves selling a security that has declined below your purchase price, realizing the loss, and using that loss to offset realized capital gains elsewhere in your portfolio. The mechanics: Realized losses first offset realized capital gains of the same type — short-term losses offset short-term gains, and long-term losses offset long-term gains. After that, losses of one type can offset gains of the other. If total realized losses exceed total realized gains for the year, up to $3,000 of the remaining net loss can be applied against ordinary income — wages, pension income, IRA withdrawals. Any loss beyond $3,000 that isn't used in the current year carries forward indefinitely to offset future gains or the $3,000 ordinary income deduction in future years.
The wash-sale rule is the primary operational constraint on tax-loss harvesting. It prohibits claiming a loss if you purchase a 'substantially identical' security within 30 days before or after the sale — a 61-day window centered on the sale date. 'Substantially identical' is defined broadly by the IRS. Selling a specific S&P 500 index fund and immediately buying another S&P 500 index fund from a different fund company is generally considered a wash sale. Selling an S&P 500 fund and buying a total market index fund with broader holdings is generally not, because the underlying securities are different — though this involves judgment, not bright-line rules. The wash-sale rule applies across all accounts the taxpayer controls. A critical trap in retirement: selling a position at a loss in a taxable brokerage account and purchasing the same security in an IRA within the wash-sale window triggers the rule. The loss is disallowed. Worse, when the IRA is eventually distributed, there's no opportunity to recover it — the disallowed loss is simply gone. Action Wash Sale? Result Sell S&P 500 ETF (Fund Generally no Loss preserved; similar A) at a loss; buy S&P market exposure 500 ETF (Fund B) maintained immediately Sell S&P 500 ETF at a Yes Loss disallowed; added loss; buy back same ETF to cost basis of within 30 days repurchased shares Sell stock in taxable Yes Loss disallowed; cannot account at a loss; buy be recovered on IRA same stock in IRA distribution within 30 days Sell bond fund at a Generally no Loss preserved if funds loss; buy similar but are sufficiently different bond fund distinct immediately
In retirement, tax-loss harvesting serves several specific purposes beyond simple gain offsetting. Portfolio rebalancing without tax cost: If a taxable account needs rebalancing — selling an overweight position — using positions at a loss to fund the rebalance converts what would be a taxable gain event into a tax-neutral or even tax-beneficial one. Selling the loser to rebalance, while buying the target allocation with the proceeds, achieves the same portfolio goal at lower or zero tax cost. Generating 'free cash flow': In years when a retiree needs income from a taxable account, selling positions with a high cost basis or at a loss generates cash without generating net taxable gain. This can be particularly useful in years when other income is already elevated and additional gains would push into a higher bracket or across an IRMAA threshold. Ordinary income offset: The $3,000 annual deduction against ordinary income is modest, but it applies against whatever the highest-taxed income in the retirement picture is — pension income, IRA distributions, or Social Security. In a 22% bracket, $3,000 of loss deduction is worth $660 in annual tax savings.
The interaction between tax-loss harvesting and the 0% long-term capital gains bracket creates an interesting dynamic. In years when taxable income is very low — the bridge years before Social Security and RMDs begin — realized capital gains may already be at 0% federally. In those years, harvesting losses to offset 0%-rate gains provides minimal benefit. The value of harvested losses shifts when income is higher: in years with significant RMDs, large capital gains events, or elevated ordinary income, the same stored carryforward losses become more valuable. Tax-loss harvesting doesn't have to be used in the year of harvest. Generating and storing losses in early retirement for use against the higher-income RMD years is a legitimate multi-year strategy. **Tax-loss harvesting has specific rules and interactions with retirement accounts. A CPA can help you identify harvesting opportunities in your taxable accounts while avoiding wash-sale traps.**
Capital loss carryforwards don't expire. If you harvest a $30,000|Unlike capital gains harvesting — where you can immediately