Austria KESt & CARF, The Complete Guide for CASPs

Why Austria is different

Most EU member states have one crypto-tax obligation: report user information under DAC8 starting CY2026. Austria has three. CASPs serving Austrian residents must withhold capital gains tax (KESt) on every disposal, file a separate domestic report under the Krypto-Meldepflichtgesetz (Krypto-MPfG), and comply with DAC8/CARF for the same population.

The three regimes overlap but do not substitute for each other. A CASP that builds for DAC8 alone, ignoring KESt and the Krypto-MPfG, will be non-compliant in Austria from day one.

KESt: the 27.5% withholding

Since 1 January 2024, Austrian-resident CASPs (and foreign CASPs that elect to act as withholding agents) must withhold 27.5% capital gains tax, Kapitalertragsteuer or KESt: on every realised crypto-asset gain by an Austrian resident. The withholding settles the user's annual income-tax obligation for the gain ("Abgeltungswirkung"), so users do not need to declare it separately.

Two consequences for system design:

Withhold per disposal, not per year. The KESt amount is calculated and deducted at the moment of disposal, in EUR.
Refund mechanism for losses. Within the same calendar year, realised losses can offset earlier gains; the CASP refunds previously withheld KESt up to that amount.

Cost basis and moving average

Austria mandates the moving-average cost method (gleitender Durchschnittspreis) for cost basis, not FIFO. Every buy of a given crypto-asset updates the user's weighted average cost; every sell is realised against that average. This was a 2023 change, code written to a FIFO model is now wrong.

Crypto-to-crypto swaps are non-taxable as long as both assets are Neuvermögen (acquired on or after 1 March 2021, see below). Crypto-to-fiat and fiat-to-crypto conversions are taxable events.

Altbestand vs Neubestand

Austria splits a user's crypto holdings into two pools based on acquisition date:

Altvermögen: acquired before 1 March 2021. Outside the new regime; disposals are not subject to KESt.
Neuvermögen: acquired on or after 1 March 2021. Fully in scope.

The two pools are tracked separately per user per asset. A complication: if Altvermögen is swapped for a different crypto-asset, the new asset enters Neuvermögen at fair-market value at the moment of the swap. This is a one-time transition; the original Altvermögen characterisation does not transfer.

UX implication

Austrian users expect their CASP to show them the Altbestand / Neubestand split per asset in real time. A user who can't see how much of their BTC pool is Altvermögen has a hard time making informed disposal decisions.

Ka1Y FinanzOnline filing

Annually, by 15 February: Austrian withholding agents file a Ka1Y report through the BMF FinanzOnline portal. The report aggregates KESt withheld, refunds issued, and the underlying transactions, in a BMF-defined XSD schema. This filing is separate from CARF/DAC8 and from the Krypto-MPfG report.

Krypto-MPfG domestic reporting

Even where KESt is being withheld, Austria has introduced a domestic CARF-style reporting obligation (Krypto-Meldepflichtgesetz) effective from CY2026. The Krypto-MPfG captures CASPs that the EU DAC8 nexus rules might not, most notably non-EU CASPs that accept Austrian users via passive marketing only, and acts as a domestic backstop.

Reporting is to the Austrian Finanzamt in a Krypto-MPfG-specific schema closely modelled on CARFxml. Deadline aligns with DAC8 (30 September following the reporting year).

How CARF and DAC8 interact with all of this

For an Austrian-resident CASP, the practical stack looks like this:

Real-time: withhold KESt per disposal, track Altbestand/Neubestand, apply moving-average cost basis.
By 15 February: file Ka1Y for the prior year's KESt aggregates via FinanzOnline.
By 30 September (from 2027): file under DAC8 to the Finanzamt for all Austrian users, AND under the Krypto-MPfG for any users not in DAC8 scope.
By 30 September (from 2027): if the CASP is the single-MS registration for other EU users, file under DAC8 for those populations in the same window.

SteuerreportingVO additionally requires CASPs to provide each user with an annual per-user tax certificate, in a defined format, by 31 January following the reporting year (effective from 2025).

Bottom line

Austria is the most operationally complex single jurisdiction in the EU for crypto-tax reporting. A CASP that gets Austria right has, by construction, built most of what is needed for the rest of the EU.