Tax-Loss Harvesting: How to Turn a Down Market Into Real Tax Savings

A down market is uncomfortable to live through, but it produces something valuable: realized losses. In a taxable brokerage account, those losses can be harvested — sold and reinvested in similar-but-not-identical securities — to generate capital-loss carryforwards that offset future gains and reduce current-year ordinary income. Done well, tax-loss harvesting can save high earners five figures a year in some markets and never expires until used.

This page lives in the Soil stage of the Sporos Doctrine. Soil is the tax architecture beneath the portfolio. Tax-loss harvesting is part of what we call Grafting — the combined-tool strategy that pairs harvested losses with Roth conversions to maximize the after-tax outcome.

What Tax-Loss Harvesting Is

The mechanic is simple. In a taxable brokerage account, when an investment is worth less than what you paid for it (your cost basis), you can sell it to "realize" the loss. The IRS treats that realized loss as a capital loss, which can:

1. Offset realized capital gains in the same year (dollar for dollar).
2. Offset up to $3,000 of ordinary income per year (e.g., wages, interest).
3. Carry forward indefinitely to future years if there are no current gains or ordinary income to offset.

The "harvesting" part is selling the loser, immediately buying a similar (but not "substantially identical") replacement, and keeping the same market exposure with a fresh, lower cost basis going forward.

This only works in taxable brokerage accounts. There is no benefit to harvesting in tax-deferred accounts (401(k), Traditional IRA) or Roth accounts — losses there have no tax consequence either way.

The Wash-Sale Rule (Don't Skip This)

The IRS won't let you sell at a loss and buy the same security back the next day to claim the tax benefit. That is a "wash sale." The rule:

If you sell a security at a loss and buy the "substantially identical" security within 30 days before or after the sale, the loss is disallowed for that year.

The disallowed loss gets added to the cost basis of the replacement security. You don't lose it permanently — it just gets deferred. But the tax-year benefit is gone.

What counts as "substantially identical"?

• Same security, same CUSIP: Wash sale. Don't sell VTI and buy VTI back.
• Different fund tracking the same index: This is the workaround. Sell VTI, buy SCHB or ITOT (different funds, very similar exposure, different CUSIPs). The IRS has not treated different funds tracking the same index as substantially identical.
• The same stock in an IRA: Yes, this triggers wash sale. The IRS reads through account types. Don't sell Apple at a loss in your taxable account if your IRA buys Apple within 30 days.
• Spousal accounts: Treated as your accounts for wash-sale purposes.

The wash sale is the single most-violated rule in DIY tax-loss harvesting. The fix is to have a pre-decided replacement security ready before you harvest.

When Tax-Loss Harvesting Is Worth Doing

Not every loss is worth harvesting. The math depends on a few factors:

It is worth doing when:

• You are in a high marginal tax bracket (24%+) so the deduction is meaningful.
• You have realized gains to offset, or you can use the $3,000/year ordinary-income offset.
• The loss is large enough that the tax savings exceed transaction costs and the friction of the trade.
• You have a clear "substantially not identical" replacement ready.

It is not worth doing when:

• You are in a low bracket (0% LTCG rate) and have no expected high-bracket years ahead. Then the basis reset from holding is more valuable than the loss harvest.
• The position is small (less than a few thousand dollars of loss). Transaction friction can eat the benefit.
• You are about to gift the position to charity or to heirs at death. Both situations reset the basis better than harvesting does.
• The investment is in a non-taxable account.

The $3,000 Ordinary-Income Offset

If your harvested losses exceed your realized gains, you can use the excess to offset up to $3,000 of ordinary income per year. At a 32% marginal bracket, that is $960/year of tax savings, every year, until the carryforward is exhausted.

For high earners with large harvested carryforwards from a 2022-style market drawdown, the $3,000 annual offset can compound to multi-five-figure savings over a decade. This is why carryforwards are valuable even when there are no current gains to offset.

Grafting: Combining TLH with Roth Conversions

This is the highest-leverage version of the strategy. The setup:

1. The market is down. You harvest losses in a taxable brokerage account — say $80,000 of harvested losses on positions you immediately re-buy in similar-but-not-identical funds.
2. The same year, you execute a $50,000 Roth conversion from a Traditional IRA. The conversion is taxable as ordinary income.
3. The capital losses can offset realized capital gains; the $3,000 annual cap on ordinary-income offset still applies to the conversion. But if you also have realized gains elsewhere in the same year, the losses absorb those, and the Roth conversion happens "cheaper" against the rest of the tax picture.

The combined effect: you have converted $50,000 to Roth (taking advantage of the down market's lower share prices for the conversion) AND you have $77,000 of capital-loss carryforward sitting in your basis for future use. The down market produced both opportunities at once.

We call this Grafting in the Doctrine because it is the combined use of two tools that work together better than either alone. The market gives both of these opportunities at the same time. Most retail investors take neither.

Direct Indexing: Tax-Loss Harvesting at Scale

For larger taxable accounts ($500k+), direct indexing — owning the individual stocks of an index rather than an index ETF — allows much more aggressive harvesting. The S&P 500 holds 500 stocks. In any given year, dozens of them are down even when the index is up. Direct indexing lets you harvest each one individually, generating losses even in years when an ETF holder would generate none.

The trade-offs: higher complexity, higher management cost (often via a separately managed account at 0.20-0.40%), and more tax-form pages. For accounts under $250k, the friction usually outweighs the harvest benefit.

How This Fits the Doctrine

Tax-loss harvesting lives in the Soil stage. Soil is where your dollars sit (taxable, tax-deferred, Roth) and how income is sequenced. Harvesting is one of the tools we use to keep the soil productive year over year.

The plant metaphor matters here: harvesting is a form of Grafting — combining tools to produce a yield neither would produce alone. A portfolio is not a houseplant. Active stewardship is the work.

Frequently Asked Questions

How often should I harvest?

Most pre-retiree taxable portfolios are reviewed quarterly for harvest opportunities. Some custodians and direct-indexing platforms run daily or weekly automated checks. The right cadence depends on portfolio size and volatility.

Can I harvest, then re-buy at year-end to lock in basis?

No, that's the wash-sale rule. Wait at least 31 days, or use a different fund.

Do I need to report harvesting on my taxes?

Yes. Realized losses show up on Schedule D and Form 8949. Your custodian sends a 1099-B detailing them. Carryforwards roll year-over-year via your return.

Does TLH work in retirement accounts?

No. There is no tax consequence to gains or losses inside a 401(k), Traditional IRA, or Roth IRA, so harvesting is meaningless. The strategy only applies to taxable brokerage accounts.

What about cryptocurrency?

Crypto positions can be harvested. The wash-sale rule does not currently apply to crypto (as of the 2024 tax year), so you can technically sell BTC at a loss and re-buy immediately. Legislation to extend the wash-sale rule to crypto has been proposed multiple times — verify current law before relying on it.

What to Do This Week

1. Audit your taxable brokerage account for positions trading below cost basis. Most custodians have a "tax lots" view showing unrealized gain/loss per lot.
2. Identify a replacement security for each candidate. Same exposure, different CUSIP. (e.g., VTI → SCHB; IVV → SPLG.)
3. Check for wash-sale risk across all accounts — including your spouse's, including IRAs.
4. Coordinate with any planned Roth conversion for the same year. Grafting is the highest-leverage version of this strategy.
5. Track your carryforward — future-you needs to remember the basis still on the books.

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.