Grafting: How Roth Conversions and Tax-Loss Harvesting Work Together

Grafting is the Sporos term for running a Roth conversion and tax-loss harvesting together in the same year, ideally a down year. Paired correctly, the harvested losses trim the tax bill on the conversion while depressed prices let you move the same shares into the Roth at a lower taxable value, so the recovery compounds tax-free. Most high earners run the two separately and leave that pairing on the table.

The Mechanic: How the Two Tools Interact

Tax-loss harvesting means selling a position in your taxable account at a loss, then immediately buying a similar (but not substantially identical) replacement so you stay invested. Harvested losses first offset any realized capital gains in the same year, up to $3,000 of the excess offsets ordinary income each year, and everything left carries forward indefinitely.

A Roth conversion is treated as ordinary income, so the $3,000 annual offset chips away at the taxable amount of a conversion. Not a dollar-for-dollar wipeout, but it reduces what you owe.

The real opportunity arrives in a down market. Falling equities let you harvest larger losses, and the assets you plan to convert are also worth less, so you convert fewer dollars to move the same number of shares. Both effects compress the tax bill.

The Rules and Watchouts

The wash-sale rule (IRC Section 1091) disallows the loss if you repurchase the same or substantially identical security within 30 days before or after the sale. A different fund in the same asset class is generally fine; so is buying the same fund back in 31 days. Buying it in your IRA or your spouse's account still triggers the rule, a trap many miss.

The $3,000 offset reduces taxable income, not tax. At a 32% marginal rate, that is $960 of actual savings per year. The capital-gain offsets can be far larger, because there is no annual cap on using carryforwards against realized gains.

Conversions add to adjusted gross income for the year. A large one can push you into a higher bracket, trigger the 3.8% Net Investment Income Tax on investment income, or affect Medicare IRMAA surcharges if you are approaching 63. Size the conversion carefully, and only harvest into a replacement you are willing to hold.

Worked Example: $50k Conversion in a Down Year

Say equities have dropped 20%. You hold a $75,000 sector ETF position now worth $25,000, a $50,000 unrealized loss. You sell it and immediately buy a different ETF covering a similar (not identical) index, locking in the $50,000 capital loss. With no realized gains this year, you use $3,000 against ordinary income per the IRS limit and carry the rest forward.

You also convert $50,000 from your traditional IRA to your Roth. The $3,000 offset brings the net taxable conversion to $47,000, saving $960 at a 32% marginal rate this year. The remaining $47,000 rolls forward to absorb future realized gains, where the larger value lives. The conversion itself moved into the Roth at a depressed value, and when markets recover, all of that growth is permanently tax-free.

How This Connects to The Sporos Doctrine

In The Sporos Doctrine: A Life-Centered Framework for Retirement, grafting lives in the Soil layer, the tax architecture built early enough to affect decades of compounding. We pair these tools deliberately because of what the Doctrine calls Tax-Location Alpha: a 7% return is not a 7% return if half of it eventually belongs to the IRS. Coordinating the harvest and the conversion in one down year is that principle in practice.

Frequently Asked Questions

Can I harvest losses in my IRA to help offset the conversion tax?

No. Losses inside an IRA or 401(k) are not deductible and cannot be carried forward; harvesting only works in taxable accounts.

Is there a limit on how much I can convert in a single year?

There is no IRS dollar cap on Roth conversions. The limit is practical: your marginal rate, IRMAA exposure, and what you can pay in taxes without drawing from the converted funds themselves.

What happens to my carryforward if I do not use it all?

It rolls forward indefinitely during your lifetime. Unused carryforwards generally do not transfer to heirs, so using them while living matters.

Can the loss carryforward offset NIIT as well?

Capital losses reduce your net investment income, which can reduce or eliminate the 3.8% NIIT on investment income. They do not directly offset the NIIT on the conversion amount, which is ordinary income, not investment income.

What to Do Next

1. Pull your current unrealized gain/loss report from your taxable accounts and identify positions that have declined since purchase.
2. Check your existing capital-loss carryforward balance on Schedule D of your most recent tax return.
3. Model what bracket a $25,000 to $75,000 conversion would put you in this year, including IRMAA look-back implications if you are within a decade of Medicare.
4. Coordinate the timing with your advisor before December 31, since both the harvest and the conversion need to settle in the same tax year to work together.

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.