The 2027 Basis Detonation

Your first crypto tax form shows what you sold for, not what you paid. That makes your gains look bigger than they are, and the real collision is still a year out.

Real numbers. No hype. Receipts.

Home Did It Actually Pay?Did It Actually Ship?

The 2025 form reports proceeds with no cost basis. That is a blank you fill in, not a tax you owe.

Form 1099-DA phase-in · basis added on 2026 forms, furnished early 2027

The rule

Form 1099-DA (Digital Asset Proceeds From Broker Transactions) phases in over two tax years:

Tax year 2025 (furnished early 2026): brokers report gross proceeds only. No cost basis.

Tax year 2026 (furnished early 2027): brokers add cost basis, but only for covered assets acquired on or after January 1, 2026. This is the detonation.

The basis mechanics underneath are already in force: wallet-by-wallet (per-account) tracking has been mandatory since January 1, 2025, and the old universal, pooled method is gone. The one-time safe harbor to allocate unused basis to specific wallets under Rev. Proc. 2024-28 had to be locked in by December 31, 2024, and that window has closed. Absent a specific-identification election made at the time of sale, FIFO applies, the earliest units are treated as sold first. There is no general small-transaction exemption; every ordinary crypto disposal is a taxable event. And the DeFi broker rule was repealed (Public Law 119-5, signed April 10, 2025), so decentralized platforms file no 1099-DA at all, leaving that basis burden entirely on the individual.

The receipt

On the 2025 forms already in hand, holders see gross proceeds with the cost-basis fields blank or showing $0. That makes the raw numbers look like almost pure gain, because the amount you paid is missing.

Read this carefully: a blank or $0 basis box is not a statement that you owe tax on the full proceeds. It means the broker did not report what you paid, so you supply your own basis on Form 8949 and Schedule D. The real collision lands in early 2027, when 2026 forms start carrying broker-reported basis, but only for assets bought in 2026 or later. Anything you moved between wallets, or bought before 2026, can still arrive with gaps, and IRS matching runs against whatever the broker reported.

Why it is early, and what to do

We are in the gap year. For 2025 returns the burden of proving basis is entirely on you; for 2026 returns only newly acquired covered assets will carry reliable broker basis.

Pull your own acquisition records now, dates, amounts paid, transfer history, for every wallet and exchange, before the trail goes cold.
Confirm you are tracking per-wallet, as required since January 1, 2025.
If you sell, make any specific-identification election at or before the time of sale. Without it, FIFO applies and can inflate your reported gain.
Do not treat a blank or $0 basis box as the tax you owe. Treat it as a field you must fill in with your records.

Sources

IRS 2026 Instructions for Form 1099-DA: irs.gov/instructions/i1099da · About Form 1099-DA: irs.gov · Final broker regulations: irs.gov newsroom · Rev. Proc. 2024-28: irs.gov/pub/irs-drop/rp-24-28.pdf · DeFi rule repeal, Public Law 119-5: congress.gov

Educational record only, not tax or legal advice, and not a substitute for a qualified tax professional. Rules and dates are sourced to IRS materials as of July 12, 2026 and may change; confirm against the linked primary sources and your own records before filing. The Receipts Index takes no compensation from any party named here.