Lot-Level Tax-Loss Harvesting: A Pre-Sale Records Checklist

Tax-loss harvesting happens at the share level, not at the position-summary level. A brokerage screen can show one total gain or loss for an ETF while the actual holdings contain separate purchases with different bases, dates, and tax results.

This guide is the pre-sale records checklist: identify the exact lot, document the instruction, and test the loss against the rest of the tax picture before placing the order. For choosing between FIFO and specific identification, use the FIFO versus specific-identification guide. For the broader decision framework, start with tax-lot optimization.

Start With the Exact Lot, Not the Blended Return

A tax lot is a distinct purchase. Its shares, acquisition date, adjusted basis, and holding period can differ from every other purchase of the same security. A loss lot can exist inside a position whose aggregate value is up.

For example, suppose an investor owns 300 shares in three 100-share lots and the current price is $70:

| Lot | Basis per share | Unrealized result | | --- | ---: | ---: | | January purchase | $48 | +$2,200 | | September purchase | $65 | +$500 | | Recent purchase | $82 | -$1,200 |

The position is up $1,500 in total, but the recent lot has a $1,200 unrealized loss. Selling that lot may realize a loss; selling a different lot could realize a gain instead. The illustration ignores commissions, state tax, other income, and every other transaction in the return.

Confirm How the Shares Will Be Identified

The IRS says that when shares bought at different times cannot be adequately identified, the shares acquired first generally determine basis. To use a specific-lot instruction through a broker, identify the particular shares at the time of the sale and obtain written confirmation within a reasonable time. Keep the order confirmation with the lot record. IRS Publication 550 explains the identification and FIFO rules.

Before submitting a sale, record:

• The account and security.
• The exact share quantity and acquisition date for each selected lot.
• Adjusted basis per share and total adjusted basis, including known adjustments.
• The broker's selected cost-basis method and the specific-lot instruction shown on the order.
• The order confirmation and any later correction to it.

Do not assume an account-level setting applies to a particular trade. Review the order ticket and the confirmation, especially after transfers, dividend reinvestments, stock splits, equity compensation, or a brokerage migration.

Check Whether the Loss Has a Current Use

A realized capital loss first enters the capital-gain and loss netting calculation. If total capital losses exceed total capital gains, the current federal ordinary-income deduction is generally limited to the lesser of the net loss or $3,000 ($1,500 for married filing separately); remaining net capital loss can carry forward. IRS Topic 409 summarizes the rule and reporting path.

That means a visible loss is a candidate, not an automatic tax saving. Ask whether it will offset a current or planned gain, become a carryforward, or consume a loss that could be more valuable against a different transaction. A loss used against an intentional gain is not free: it may change the basis and future tax profile of the position retained or replaced.

Review the 61-Day Purchase Window

For stock or securities, a loss can be disallowed under the wash-sale rule when substantially identical property is acquired during the 30 days before or after the loss sale. The review should include dividend reinvestments, recurring purchases, options, spouse accounts, and IRA purchases where relevant. A disallowed loss is generally added to the basis of replacement shares; an IRA replacement can have a different basis consequence. See the IRS wash-sale discussion in Publication 550 and the wash-sale rules guide.

If the sale needs continued market exposure, compare a potential replacement's benchmark, holdings, concentration, fees, liquidity, and expected tracking behavior. A different ticker is not a legal conclusion that two investments are not substantially identical.

A Lot-Level Sale Checklist

Use this sequence before placing a taxable sale:

1. Export or review the broker's lot table rather than relying on the position card.
2. Identify the shares and confirm the expected gain or loss from the adjusted basis and current sale price.
3. Compare holding period and character with other gains and losses for the year.
4. Check purchases during the 30 days before the sale and planned purchases during the 30 days after it.
5. Decide whether the loss has a current use, a likely carryforward, or a better use in a planned transaction.
6. Choose a suitable replacement only after checking investment fit and wash-sale risk.
7. Enter the specific-lot instruction where available and save the broker's written confirmation.
8. Reconcile the later Form 1099-B and Form 8949 reporting with the saved lot records.

This is general education, not individualized tax or investment advice. Complex basis adjustments, transferred shares, employer stock, options, or material sales may warrant a qualified tax professional's review.

Bottom Line

Lot-level review makes the tax result of a sale visible. It does not guarantee that a sale will improve lifetime after-tax wealth. The useful discipline is to identify the shares, confirm the broker's record, check the loss against gains and wash-sale activity, and preserve the documentation needed to report the transaction accurately.