TLH + Roth Conversion = Grafting

A down market is uncomfortable. It is also, if you are positioned to act, one of the most productive tax planning windows of the year. This page answers a specific question: can you harvest losses in your taxable account and do a Roth conversion in the same calendar year, and if so, does each move make the other more valuable? The answer is yes, and understanding exactly why is worth your time.

How the Two Moves Work Together

Tax-loss harvesting (TLH) means selling a depreciated position in your taxable account, locking in a capital loss, and immediately reinvesting in something similar enough to maintain your market exposure. The loss goes on your tax return. Capital losses offset capital gains dollar for dollar. Beyond that, up to $3,000 per year offsets ordinary income, and anything left rolls forward as a carryforward loss.

A Roth conversion means moving pre-tax dollars from a traditional IRA (or old 401(k)) into a Roth IRA. That amount is added to your ordinary income in the year of the conversion. You pay the tax now, and the money grows tax-free permanently.

Here is why the combination works. When you harvest losses in the same year you convert, those losses sit on your return alongside the conversion income. Capital losses reduce your net capital gain exposure, which can keep you out of a higher bracket or at least reduce the effective rate on the conversion itself. More precisely: a large conversion in a year with significant realized losses may allow you to convert a larger dollar amount while staying within your target bracket than you could in a clean year with no losses on the books.

The market, in a down year, hands you both opportunities at the same moment. Asset values are lower, so the conversion costs less in absolute terms. And the embedded losses in your taxable account are available to harvest.

The Rules and the Traps

A few things to get right before you act.

Capital losses do not directly offset Roth conversion income. This is the most common misconception. Ordinary income from a conversion is not capital income. The losses reduce your net capital gains, not the conversion amount itself. The indirect benefit comes from how reducing your total taxable picture affects your marginal bracket and potentially your exposure to the 3.8% Net Investment Income Tax (NIIT).

The wash-sale rule applies to the taxable account losses. If you sell a position at a loss and buy the same or substantially identical security within 30 days before or after the sale, the loss is disallowed. Reinvest in something correlated but not identical. Swapping one S&P 500 index fund for a total market fund typically satisfies this, but get specific guidance on your holdings.

IRMAA look-back matters for clients near Medicare age. A large Roth conversion in the current year shows up in your income two years later for Medicare premium surcharges. If you are 61 or 62, this deserves a projection before you act. For younger HENRYs, it is less of an immediate concern but worth knowing about.

Carryforward losses are a durable asset. If losses exceed what you can use this year, the excess carries forward indefinitely. I tell clients to think of a large carryforward balance as a tax coupon book. Future capital gains events, including asset sales, a business exit, or a concentrated position liquidation, can be offset against it.

A Worked Example

Consider an illustrative client: a 42-year-old with a household income of $480,000, a $900,000 taxable brokerage account, and $600,000 in a rollover IRA. In a year when equity markets are down 18%, this client has positions in the taxable account that are sitting on roughly $85,000 in unrealized losses.

She harvests $85,000 in losses by selling the depreciated positions and reinvesting in comparable funds the same day. Net capital gains for the year are now zero (she had some gains earlier in the year from a position sale). The $3,000 ordinary income offset is applied. The remaining $82,000 stays on the books as a carryforward.

At the same time, because the IRA balance has also declined with the market, converting $120,000 from the rollover IRA costs her a smaller percentage of the portfolio's future value than it would have at peak valuations. She pays ordinary income tax on the $120,000. The harvested losses do not directly reduce this, but her overall taxable income picture is cleaner, the gains offset means she is not also paying tax on capital gains, and she is buying permanently tax-free growth on assets that are, in a real sense, on sale.

Five years from now, if she sells a concentrated equity position, that $82,000 carryforward is ready to absorb the gain.

How This Connects to Tax-Loss Harvesting

This strategy lives inside what we call the Grafting layer of the Sporos Doctrine: the deliberate combining of Roth conversions and tax-loss harvesting to reshape the tax character of a portfolio over time. Neither move in isolation produces what both moves together produce.

For the broader mechanics of how TLH works, the wash-sale rules that catch people off guard, and how to think about when harvesting is worth doing at all, the parent pillar Tax-Loss Harvesting: How to Turn a Down Market Into Real Tax Savings covers the full picture. This page assumes you have the basics and want to know how the combination works.

Frequently Asked Questions

Do harvested capital losses reduce my Roth conversion tax bill directly?

No. Capital losses offset capital gains, not ordinary income. The conversion amount is treated as ordinary income. The indirect benefit is that eliminating capital gain tax liability in the same year can keep more of your bracket available for the conversion.

What is the right conversion amount if I am also harvesting losses?

Run a bracket projection before you act. The goal is usually to fill up a bracket, not cross into the next one. Your CPA or advisor should model the combined picture: wages, any other ordinary income, the conversion amount, and remaining capital gain exposure after harvesting.

Can I harvest losses in a 401(k) or IRA?

No. Tax-loss harvesting only applies to taxable brokerage accounts. Losses inside tax-deferred accounts have no tax consequence because you are not paying tax on gains inside them either.

How long do carryforward losses last?

They carry forward indefinitely under current law. There is no expiration. They pass through on your tax return each year until fully used.

Is there a minimum loss threshold that makes this worth doing?

Transaction costs are low enough today that the threshold is mostly about your time and the cost of tracking. As a practical matter, I focus on losses of $10,000 or more per position. Smaller losses are worth harvesting if the trade is clean, but the planning effort starts to exceed the benefit below that level.

Does this strategy work in every down market year?

The math works whenever you have unrealized losses available to harvest and taxable IRA or 401(k) dollars worth converting. The question is whether converting makes sense in your specific income year. A year with unusually high W-2 income may not be the right conversion year even if losses are available.

What to Do Next

1. Pull your taxable account and identify positions with unrealized losses before year-end. Your custodian's gain/loss report will show this.
2. Run a bracket projection with your advisor or CPA showing your total ordinary income, current capital gain exposure, and the conversion amount that keeps you within your target bracket.
3. Confirm your replacement securities in advance so you can reinvest immediately after the sale without violating the wash-sale rule.
4. After the year closes, record your carryforward loss balance and factor it into your planning for future liquidity events.

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.