1099-B, 1099-DA and Form 8949: reporting investment sales

Selling investments in the US produces a paper trail with exactly three stations, and knowing which does what removes most of the fear. Checked 2026-08-22 against the IRS Form 8949 page; general information, not tax advice.

Station 1: what the broker reports

Each broker where you sold sends you (and the IRS) a 1099-B: proceeds, dates and, for covered shares, cost basis. Crypto got its own sibling: the 1099-DA. Digital-asset brokers report gross proceeds from the 2025 tax year on; basis arrives only for covered assets acquired on or after January 1, 2026 and held at the same broker (IRS final regulations). The key mental shift: the IRS already has this document, so your return is reconciling against it, not revealing anything.

Station 2: Form 8949, lot by lot

Form 8949 lists each sale: acquired date, sold date, proceeds, basis, gain or loss. It is sorted into boxes by whether the broker reported basis (A/B/C short term, D/E/F long term). Where basis is missing (old shares, transferred crypto, exchanges that only report proceeds), YOU reconstruct it, which is where a FIFO computation earns its keep. Missing basis reported as zero means taxing the whole proceeds: the classic expensive laziness.

Station 3: Schedule D and the two speeds

Schedule D takes the 8949 totals and applies the two-speed system: positions held one year or less are short-term gains at ordinary income rates; over a year, long-term rates of 0/15/20% by income. Losses offset gains without limit, then up to $3,000 of ordinary income a year, and the rest carries forward indefinitely.

The freelancer note

None of this touches self-employment tax: investment gains are not SE income, and they do not belong on Schedule C. But large gains DO raise your quarterly estimated payments picture: a big realized gain in June without an adjusted September payment is how safe-harbor penalties happen to people who did everything else right.