Specific Share Identification: IRS Rules, Records, and Form 8949

Specific share identification is the IRS-sanctioned method that lets you pick exactly which lot of a stock or fund is sold when you own multiple purchases of the same security, so you control the cost basis and holding period applied to the sale. Treasury Regulation 1.1012-1(c) allows it, but only if you tell your broker which shares to sell at the time of the trade and receive written confirmation of that choice within a reasonable time afterward.¹ Skip either step and the IRS treats the sale as first-in, first-out (FIFO), which usually means selling your oldest, lowest-basis shares and paying the largest possible tax.²

Why the Choice Matters

Every purchase of the same security creates a separate tax lot with its own basis and holding period. Say you bought 100 shares at $30 in 2020, another 100 at $50 in 2022, and another 100 at $70 in 2024. If you sell 100 shares today at $75, the $30 lot produces a $45-per-share gain, the $70 lot produces a $5-per-share gain, and the difference is entirely your choice — if you make it correctly.

The character of the gain matters as much as the size. Shares held more than a year qualify for long-term capital gains rates of 0%, 15%, or 20% depending on income, while shares held one year or less are taxed as ordinary income, reaching 37% at the top bracket in 2026.³ Higher earners may also owe the 3.8% net investment income tax on capital gains.⁴ Picking a lot that flips a short-term sale into a long-term one, or a high-basis lot into a loss you can use, can change the tax bill dramatically on the same trade.

The Two IRS Requirements

Under Treasury Regulation 1.1012-1(c)(3), an adequate identification of shares held by a broker takes two steps.¹

First, you specify to the broker which shares you want sold at the time of the sale. There are no required magic words; you identify the lot by its purchase date, price paid, and number of shares — enough detail to isolate it from the rest of the position. On most brokerage platforms, a lot-selection screen appears during the order process; clicking the exact lot satisfies this step.

Second, the broker must send you written confirmation of the specification within a reasonable time. The regulation treats electronic documents the same as paper, so a trade confirmation showing the identified lot generally works.¹ If you placed the order by phone, state the lot details clearly to the representative and ask for written confirmation. If it does not arrive within a few days, follow up. That confirmation is your primary defense if the IRS ever questions which shares were sold.

Both steps are mandatory. Telling your broker which lot to sell but never receiving written confirmation means you do not have a valid identification.

Do It By Settlement Date

The identification deadline is the earlier of the actual settlement date or the settlement date required by SEC rules.¹ Since May 2024, the standard cycle for most securities is T+1, one business day after the trade. For a stock trade, that realistically means selecting the lot when you place the order; waiting until the next day is cutting it dangerously close.

You cannot decide which lots to assign after the fact, at tax time. Once the settlement window closes without a valid identification, FIFO applies and the tax result is whatever FIFO produces.

Standing Instructions

You do not have to select lots manually on every trade. The regulation treats a standing order or instruction for specific identification as an adequate identification made at the time of sale.¹ Most brokers let you set a default lot-selection method in your account preferences:

FIFO sells the oldest shares first. This is usually the broker’s own fallback if you never choose anything.
LIFO sells the most recently purchased shares first.
HIFO sells the highest-cost shares first, which minimizes the taxable gain on each sale.
Specific lot leaves the choice to you at the time of each trade.

HIFO as a standing default is a common approach in taxable accounts because it minimizes realized gains automatically. You can still override the default on any individual trade by selecting a different lot at order time.

Records You Need to Keep

The IRS expects records showing the basis and adjusted basis of your investments, which for specific identification means the purchase date, purchase price, and share count for every lot in the position.⁵ You also need records of adjustments — stock splits, reinvested dividends, return-of-capital distributions — that change basis over time.

Brokers now track basis for covered securities (generally stocks acquired after 2010 and mutual fund shares acquired after 2011) and report it to the IRS on Form 1099-B.⁶ For older positions, transferred securities, or shares received through corporate actions, the 1099-B basis data may be incomplete, and the burden of reconstructing it from original trade confirmations, statements, or transfer records falls on you.

Keep the broker’s written confirmation of each lot selection with your trade records. Without it, the IRS can treat the sale as FIFO and recalculate your tax accordingly.²

Mutual Funds, DRIPs, and the Average Cost Method

Mutual fund shares and shares acquired through dividend reinvestment plans (DRIPs) add complexity. Each reinvested dividend creates a new tax lot with its own purchase date and price, even though you never placed a buy order. Over years, you can accumulate dozens of small lots at different prices.⁷ Specific identification works the same way for these shares as for any other stock, but tracking them takes more effort.

Many mutual fund investors use the average cost method instead, which lumps all shares together and divides total cost by total shares to produce a single per-share basis. It is simpler but less flexible. Switching from average cost to specific identification requires electing out of average cost before making the trade, not after. Publication 550 describes the requirements for adequate identification of mutual fund shares, which mirror the stock rules: specify the shares to your broker at the time of sale and receive written confirmation.⁸ Some brokerages require a one-business-day lead time after you change methods before specific lot data becomes available, so check with them before assuming you can cherry-pick lots on the next sale.

Watch the Wash Sale Rule When Harvesting Losses

Specific identification is most powerful when you are selling high-cost lots at a loss to offset gains elsewhere. But under IRC Section 1091, any loss you claim is disallowed if you buy substantially identical securities within 30 days before or after the sale.⁹

The disallowed loss is not permanently gone; it is added to the basis of the replacement shares, deferring the tax benefit until those shares are sold.⁹ The trap is common with automatic dividend reinvestment: if you sell specific high-cost lots at a loss and your DRIP buys new shares of the same fund two weeks later, that reinvestment triggers the rule. When planning a tax-loss harvest, consider pausing reinvestment for at least 31 days around the sale. One important exception: if the replacement shares land in an IRA or Roth IRA, the disallowed loss is gone for good, because the basis adjustment does not apply to retirement accounts.⁸

Reporting the Sale on Form 8949

Sales where you used specific identification are reported on Form 8949, which feeds into Schedule D. For each transaction, report the acquisition date of the specific lot you identified, the sale date, the gross proceeds, and the cost basis of those shares.⁵ Totals flow to Schedule D, where your overall gain or loss for the year is calculated.¹⁰

For covered securities, the broker reports basis to the IRS on Form 1099-B. If the broker’s reported basis matches the lot you identified, the numbers line up. When they do not (transferred accounts, corporate actions, older shares with incomplete records), enter adjustment code “B” in column (f) of Form 8949 and the correcting amount in column (g).⁵ That signals you are not ignoring the 1099-B; you are correcting it with better information.

What Happens If You Get It Wrong

Reporting the wrong basis is not just an administrative problem. If the error produces an underpayment of tax, the IRS can assess an accuracy-related penalty of 20% of the underpaid amount under IRC Section 6662, plus interest from the original due date.¹¹ The penalty applies whether the error was intentional or careless, though it can be avoided by showing reasonable cause and good faith.

The most common misstep is picking a lot on the tax return without ever making a valid identification with the broker before settlement. The IRS can reclassify the sale as FIFO, which changes the basis, changes the gain, and creates the underpayment that triggers the penalty. The prevention is simple: select the lot through the broker’s system before the trade settles, and keep the confirmation.

Inherited and Gifted Shares

The identification procedure works the same for inherited or gifted shares, but the starting basis behaves differently and is worth flagging. Inherited property generally receives a stepped-up basis equal to the fair market value at the date of death, so multiple inherited lots of the same stock share the same per-share basis regardless of when the decedent originally bought them.¹² Gifted shares carry over the donor’s basis for figuring a gain, but use the lower fair market value at the date of the gift for figuring a loss, which can create a range where neither gain nor loss is recognized.¹³ If you received gifted shares from multiple lots, keep the donor’s original purchase records; you will need them to identify lots correctly at sale.

1
eCFR. 26 CFR 1.1012-1 – Basis of Property
2
Internal Revenue Service. Frequently Asked Questions – Stocks (Options, Splits, Traders) 1
3
Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
4
Internal Revenue Service. Topic No. 559, Net Investment Income Tax
5
Internal Revenue Service. Instructions for Form 8949 – Sales and Other Dispositions of Capital Assets
6
Internal Revenue Service. Instructions for Form 1099-B (2026)
7
Office of the Law Revision Counsel. 26 USC 1012 Basis of Property – Cost
8
Internal Revenue Service. Publication 550, Investment Income and Expenses
9
Office of the Law Revision Counsel. 26 USC 1091 Loss From Wash Sales of Stock or Securities
10
Internal Revenue Service. About Form 8949, Sales and Other Dispositions of Capital Assets
11
Office of the Law Revision Counsel. 26 USC 6662 – Imposition of Accuracy-Related Penalty on Underpayments
12
Internal Revenue Service. Publication 551, Basis of Assets
13
Internal Revenue Service. Property (Basis, Sale of Home, Etc.)