Form 1099-B

Form 1099-B is the information return a broker or a barter exchange files to report a customer's dispositions during the year. Its title, printed on the form itself and repeated on its instructions, is "Proceeds From Broker and Barter Exchange Transactions". A broker files one for each sale, redemption or short sale of stock, commodities, regulated futures contracts, foreign currency contracts, forward contracts, debt instruments, options and securities futures contracts; a barter exchange files one for the value a member received in trade.

The form's design reflects a rule that changed in stages rather than at once. Brokers have always reported proceeds. Reporting the customer's cost basis was phased in by acquisition date, which is why the form has a box for basis, a checkbox saying the security is noncovered, and a separate checkbox saying whether the basis was reported to the IRS. Those three fields together, not the dollar amounts, are what a reader needs to understand first.

Covered and noncovered is an acquisition test, not a holding-period test. A covered security is broadly stock acquired for cash in an account after 2010; stock for which the average basis method is available, meaning mutual fund and dividend reinvestment plan shares, acquired for cash in an account after 2011; certain debt instruments and options acquired for cash in an account after 2013, and a further group after 2015; a securities futures contract entered into in an account after 2013; a security received in a stock split, reorganization, redemption or similar action whose basis derives from a covered security; and a security transferred into an account with a transfer statement reporting it as covered. A noncovered security is anything else. Note what is not on that list: nothing turns on when you sold, and nothing turns on the broker you sold through. Moving an account does not make a covered position noncovered, because the transfer statement carries the status along with the basis.

What the boxes carry. Box 1a describes the property and box 1b and 1c give the acquisition and sale dates, though 1b may be blank where the lot was built over many dates. Box 1d is proceeds, which the instructions require the broker to reduce by the commissions and transfer taxes on the sale. Box 1e is cost or other basis, blank where the security is noncovered and the broker chose not to report it. Box 1f is accrued market discount and box 1g is the wash sale loss disallowed. Box 2 marks the gain as short-term, long-term or ordinary. Box 3 flags collectibles or a qualified opportunity fund. Box 4 is federal income tax withheld, which here means backup withholding. Box 5 is the noncovered checkbox and box 12 is the "basis reported to IRS" checkbox. Boxes 8 through 11 are the separate regime for regulated futures and section 1256 contracts, which are marked to market rather than reported trade by trade. Box 13 is bartering.

The wash sale box has a narrow mandate, and reading it as complete is the most expensive mistake on the form. The instructions require a broker to report a loss disallowed under section 1091 only where the sale and the purchase both occur "in the same account with respect to covered securities with the same CUSIP number". A broker is permitted to report more, and some do, but nothing obliges it to. It also does not have to apply the rule where the replacement security was purchased in another account, or transferred in or out around the sale. The rule itself follows the taxpayer rather than the account, so the reporting is narrower than the law. Whether a loss is disallowed, and what happens to it, belongs to the wash sale rule; what belongs here is that box 1g answers a smaller question than the one a reader is asking.

The correction path depends on the box 12 checkbox, and the asymmetry is counterintuitive. Where basis was not reported to the IRS, you simply enter the correct basis on Form 8949 and make no adjustment. Where basis was reported to the IRS and is wrong, the Form 8949 instructions require you to enter the broker's incorrect figure anyway, then enter code B in column (f) and correct the error with an adjustment in column (g). The return has to reproduce the number the IRS already holds and then visibly move it, because a silent substitution looks like a discrepancy to a matching program. This is the mechanism behind the most common real-world basis correction, which is stock acquired through an employer equity plan where the compensation element was already taxed as wages and the broker's basis does not include it. That case is the disqualifying disposition page's territory.

Not everything on Form 8949 needs to be on Form 8949. Where a transaction appears on a Form 1099-B with basis reported to the IRS and needs no adjustment at all, Schedule D lets you enter the totals directly on line 1a for short-term or line 8a for long-term and skip the detail form. Everything else runs through Form 8949, sorted into the boxes that record whether basis was reported, which is why Schedule D has so many total lines. Capital gain distributions from funds are a separate case again: they arrive on Form 1099-DIV, not Form 1099-B, and go straight to Schedule D line 13.

Digital assets moved to a form of their own. Sales of digital assets effected by a broker are reported on Form 1099-DA, "Digital Asset Proceeds From Broker Transactions", rather than on Form 1099-B. Schedule D and Form 8949 accommodate both, which is why the boxes on Form 8949 run from A to L rather than A to F.

The February packet is one envelope, not one form. Most brokerage customers never receive a bare Form 1099-B. They receive a composite statement combining it with Forms 1099-DIV, 1099-INT and others, which is permitted and is why the arrival dates and the correction rate differ from what the individual form's deadline suggests.

Reading the form for a return is a four-step sort.

1. Split the transactions by the box 12 checkbox, meaning by whether basis was reported to the IRS. That split, crossed with short-term and long-term, is exactly the set of boxes at the top of Form 8949.

2. Check the basis on every lot the broker did report. A covered lot with a wrong basis has to be corrected with an adjustment rather than by typing the right number in its place.

3. Supply the basis on every lot the broker did not report. This is your own record-keeping problem, and old transfer statements and confirmations are the evidence.

4. Look for the wash sales the broker could not see, meaning replacement purchases in another account, in a spouse's account, or in a retirement account.

A hypothetical example. Devon sells 200 shares of one company in a single trade for $9,400, or $4,700 per hundred. The shares came from two lots. Lot A is 100 shares bought through this same broker in 2015 for $3,000; it is a covered security, so box 1e reports the basis and box 12 is checked. Lot B is 100 shares transferred in from a different firm long before basis reporting began, with a cost of $1,200 that Devon can prove from an old confirmation; box 5 is checked and box 1e is blank.

Lot A produces a gain of $1,700, which is $4,700 minus $3,000. Lot B produces a gain of $3,500, which is $4,700 minus $1,200. The total gain is $5,200. Both lots are long-term, and on Form 8949 they sit in different parts of Part II: Lot A with box D checked, Lot B with box E checked, where Devon simply enters $1,200 in the basis column.

Now change one fact. Suppose the broker had reported Lot A's basis as $3,600, because a corporate action was mishandled. Devon cannot enter $3,000 in the basis column, because box 12 says $3,600 went to the IRS. Instead he enters $3,600, puts code B in column (f), and enters a $600 adjustment in column (g), which restores the correct $1,700 gain by a route the matching program can follow.

What the form does well

• Basis reporting on covered securities removed most of the guesswork from the single hardest number on an investor's return, and it did so at the one point in the chain where the information actually exists.
• The covered and noncovered split is visible on the form itself, so a reader can see immediately which lots require their own records.
• The correction mechanism preserves the audit trail: a corrected basis shows as an adjustment rather than as an unexplained difference.
• Reporting proceeds net of commissions and transfer taxes removes a reconciliation step that used to be done by hand.

Where it causes trouble

• The wash sale box is narrower than the wash sale rule, and nothing on the form says so, so a clean box 1g reads as a clearance it is not.
• Positions held for decades are exactly the ones with no reported basis, so the largest gains are the ones with the weakest records.
• Basis reported on covered employer stock is predictably too low, and the error runs against the taxpayer.
• Corrected forms are common, often arriving after a return has been filed, because brokers reclassify fund distributions and corporate actions late.
• The form's arithmetic is per transaction, so an active trader's composite statement can run to hundreds of pages that no one reads carefully.