Is Tax-Loss Harvesting Worth It

Tax-loss harvesting is worth it when you have capital gains to offset and a high marginal rate: at the 37% federal bracket, a $50,000 harvested loss shielding long-term gains taxed at 20% plus the 3.8% net investment income tax saves roughly $11,900 in federal tax that year. It is usually not worth it when you have no gains to absorb the loss, expect your tax rate to drop soon, or hold a taxable account too small to justify the monitoring.

The value of a harvest is a function of your rate and what you can offset, not the size of the loss.

What Tax-Loss Harvesting Actually Does

When a taxable investment falls below your cost basis, harvesting means selling to realize the loss, then immediately redeploying the proceeds into a similar (not identical) investment so your market exposure stays roughly intact.

The realized loss offsets capital gains dollar for dollar. If losses exceed gains, up to $3,000 of the excess offsets ordinary income in the current year, and the remainder carries forward indefinitely. A deduction's value scales with your marginal rate: the same harvest produces a fraction of that $11,900 at a 22% bracket.

The Rules and Tradeoffs That Matter

Sell at a loss and buy the same or a "substantially identical" security within 30 days before or after the sale, and the wash-sale rule disallows the loss. The disallowed amount is added to your basis in the replacement shares, deferring rather than destroying the benefit, but the current-year harvest you counted on is gone. Swapping into a fund tracking a meaningfully different index is generally considered compliant; buying the same fund back in 28 days is not.

The second tradeoff is less discussed. Harvesting resets your cost basis lower, so the eventual sale produces a larger taxable gain. You are deferring tax, not eliminating it. Deferral is real money for a HENRY (high earner, not rich yet); for someone two years from a planned step-down in rates, the calculus shifts.

Third, the best harvesting windows open and close within days during volatile stretches. Capturing them takes systematic monitoring, not casual attention.

An Illustrative Example: When It Works and When It Doesn't

Consider two clients, both in the 37% federal bracket, both with $200,000 in unrealized losses in a down-market year.

Client A has $180,000 in realized short-term capital gains from a business asset sale. The harvested losses offset those gains almost entirely, saving roughly $66,600 in federal tax at ordinary income rates. Unambiguously worth doing.

Client B has no realized gains and similar income expected next year. She harvests the same $200,000, captures $3,000 against ordinary income, and carries forward $197,000. Those carryforwards pay off only when future gains appear to absorb them, and may sit unused for decades if none do. Still worth doing, but with far less urgency.

The difference is not the size of the loss. It is what you have to offset it against.

How This Connects to Tax-Loss Harvesting

The parent pillar, Tax-Loss Harvesting: How to Turn a Down Market Into Real Tax Savings, covers the complete mechanic, the wash-sale rule in depth, and how harvesting pairs with Roth conversions for a combined benefit larger than either move alone. In the Sporos framework this is Soil-layer work: the tax architecture that determines what you keep.

Frequently Asked Questions

Does tax-loss harvesting work in an IRA or 401(k)?

No. Losses inside tax-deferred or Roth accounts have no tax consequence, so harvesting only applies to taxable brokerage accounts.

What counts as "substantially identical" under the wash-sale rule?

The IRS has not published a complete definition. Buying back the same security is clearly prohibited; replacing a fund with one tracking a meaningfully different index or composition is generally considered acceptable.

Can I harvest losses and convert to Roth in the same year?

Yes, and coordinating the two can reduce the overall tax cost of the conversion year. The sequencing requires planning across the full tax year, not just at year-end.

Is there a minimum portfolio size where this makes sense?

There is no hard floor, but systematic harvesting is typically most cost-effective above $250,000 to $500,000 in taxable assets. Below that, the benefit often does not clear the cost of careful execution.

What happens to carryforward losses if I die?

Unused capital loss carryforwards do not transfer to heirs; they disappear at death. Accumulating large carryforwards without a plan to absorb them is a planning gap, not an asset.

What to Do Next

1. Pull your most recent tax return and identify your realized capital gains, marginal rate, and any existing loss carryforwards. That tells you immediately what a harvest this year is worth.
2. Review your taxable accounts for positions currently below cost basis and check whether buying a suitable replacement would avoid the wash-sale window.
3. If you are also considering a Roth conversion this year, model both tactics together before executing either one. The sequencing changes the math.
4. If you want a second set of eyes on the full picture, schedule a conversation about whether your current plan is capturing this.

The information provided is for educational purposes only and does not constitute investment, legal, or tax advice. Tax law changes frequently — verify current rules before acting. Consult with qualified professionals for guidance specific to your situation.