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

What backup withholding is

In the US, if a payee doesn't provide a correct taxpayer identification number, the payer can be required to withhold a flat 24% and remit it to the IRS. It's a long-standing rule across reportable payments, and as crypto brokers come into the 1099 world, their reportable transactions come with it. The withholding isn't a penalty on the user; it's an obligation on the broker.

Why it connects to reporting

The trigger is a missing or incorrect TIN, the same data point that drives reporting. That's the important link: the TIN validation you do to file a clean 1099-DA is the same check that keeps you out of backup withholding. Fail it and you have both a reporting problem and a withholding liability. It mirrors the TIN validation logic in CARF onboarding, just under a different regime.

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 doesn't cover. Both run off the same customer and transaction data, which is the argument for not treating them as separate projects.

Handling both from one place

The clean setup validates TINs once, at onboarding, and uses that result for both the 1099-DA filing and the backup-withholding decision. 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. The IRS digital assets guidance is the primary source for the US rules.