US 1099-DA backup withholding: the 24% rule crypto brokers face

Form 1099-DA is usually described as a reporting form: US crypto brokers report customer disposals of digital assets to the IRS. That is right, but there is a second obligation next to it that is easy to miss and can cost the broker real money, backup withholding. This guide explains what it is, what triggers it, and why the cleanest way to avoid it is the same TIN discipline that produces a clean 1099-DA.

What backup withholding is

In the US, if a payee does not provide a correct taxpayer identification number, or the IRS notifies the payer of a mismatch, the payer can be required to withhold a flat 24% of reportable payments and remit it to the IRS. It is a long-standing rule across many kinds of reportable income, and as crypto brokers enter the 1099 world, their reportable transactions come with it. The withholding is not a penalty on the user; it is an obligation on the broker, and a broker that fails to withhold when required can end up liable for the amount.

What actually triggers it

The trigger is a TIN problem: a missing TIN, an obviously incorrect one, or a mismatch the IRS flags through a B-notice. You collect the TIN on a Form W-9 and, in a robust setup, run it through TIN matching before you rely on it. That is the same data point that drives reporting, which is the important link: the TIN validation you do for CARF onboarding is conceptually the same check that keeps you out of backup withholding, just under a different regime. Fail it and you have both a reporting problem and a withholding liability.

Two layers, one dataset

For a broker serving US users, this is a domestic layer that sits underneath the global one. CARF and DAC8 handle cross-border reporting; the US 1099-DA obligation, including backup withholding, is the American piece CARF does not cover. Both run off the same customer and transaction data, which is the argument for not treating them as separate projects with separate vendors.

Avoiding it by design

The clean setup validates TINs once, at onboarding, and uses that result for both the 1099-DA filing and the backup-withholding decision, so a bad or missing TIN is caught while the user can still fix it rather than at year end when 24% starts coming off payments. It also handles the B-notice flow, applying and later lifting withholding as the IRS status changes.

Handling both from one place

Our platform runs 1099-DA reporting and CARF and DAC8 on one data layer, and the same withholding engine behind Austrian KESt generalises to a rule like the 24% backup rate, so US brokers meet the reporting and the withholding obligation from a single integration. The IRS digital assets guidance is the primary source for the US rules.

About the author

Sukesh Tedla

Founder & CEO