Special VAT return D398 — OSS and IOSS

Prepare transactions and corrections in euros for the selected special scheme, then finalise and submit the return in the ANAF application.

The page lets you choose the Union scheme, non-Union scheme or import scheme and organises each scheme's transactions and corrections separately. Check the Member State of consumption, transaction type, rate, tax base and VAT in euros, without automatically assuming the company is eligible.

Open the page in Accounting

Information tracked on the page

The Member State and supply type determine how the operation is reported.

Report the taxable amount and VAT in euros, and check the rate applied to each transaction.

The row status shows data verification in Fluxe, not submission through the OSS app.

Important! For EU OSS, D398 is filed by the end of the month following the quarter, including quarters without transactions while registration is active. Do not apply this frequency to the IOSS import scheme; check that scheme's instructions separately.

D398 is used only for the OSS/IOSS special regime in which the person is registered and for eligible operations. EU and non-EU OSS are quarterly, IOSS monthly; the deadline is the end of the month following the period and does not move for weekends or holidays.

While registered in the regime, also file a return with no operations as required by OSS instructions. Do not include intra-Community B2B sales simply because the partner is in the EU. Identify the member state of consumption and applicable scheme before calculating.

Supporting documents

Confirmation of registration in the special regime and its effective date.
Orders, invoices, returns and documents for transport or delivery to consumers.
Evidence of the state of consumption, its applicable rate and separate records of eligible operations.
The applicable ECB exchange rate, previous OSS returns and corrections broken down by original period.

Completing and checking data

Check the special regime and registration period. Separate EU OSS, non-EU OSS or IOSS operations from those remaining in the ordinary VAT return.
- Tax profile and registered obligations
Check sales documents and returns together with evidence of the place of consumption. Do not treat all EU sales as OSS.
- Document validation
- Foreign currency sales
In D398, check the taxable base, rate and VAT for each member state. Compare the source currency with the return currency and document the required ECB exchange rate; conversion is not automatic.
- Open this return’s form
Complete the return in the official OSS app, including corrections for previous periods. Check the summary, submit and keep confirmation; pay using the reference and account provided for the special regime.
- Open this return’s form

Records are separated by regime, state, rate and period; the return is submitted through OSS, and confirmation and payment are archived.

Completing and checking the form in Fluxe

In Scheme and period, choose the scheme in which the company is actually registered and the year. For the Union and non-Union schemes, select the Quarter-end month; for the import scheme, select the Month. Confirm the date from which registration takes effect.
Check the OSS identifier and Taxable person. For the import scheme, also check the Intermediary identifier against the registration. Complete the partial period only if it applies to your circumstances.
Check the Member State of consumption, nature of the operation, rate and document for each line item.
Convert the values to euros under the period's rule and keep the exchange rate used.
Separate corrections by original period and reconcile the base and VAT with OSS records.
After the period has ended and all transactions, corrections and confirmations have been checked, use Generate and validate D398 XML. Download the version from Private XML history; generating the file does not submit it to ANAF.

Validation and filing

Open the OSS application in ANAF services and choose the same scheme, year and period — quarter or month, depending on the scheme.
Complete operations and corrections, and compare totals by Member State and rate with Fluxe.
Validate, sign and submit through the OSS application, not the service used for other declarations.
Check the processing status and payment reference, then archive the evidence and the submitted version.

What to check before submission

Confirm eligibility and OSS registration before reporting. Calculate the euro values using the ECB exchange rate applicable to the period and check the amounts entered; conversion is not automatic.

Legal basis and verification date

Article 315 paragraphs (6)–(12) of the Tax Code for the Union scheme and the rules of the selected OSS scheme, together with ANAF's instructions.

Legislative reference: 10 September 2026. Before a later filing, check the software version, instructions and deadline applicable to the period again.

Official sources

Practical example

The company has OSS transactions with buyers in two states. Separate the state of consumption and rate applicable to each transaction and check euro values and corrections. Do not automatically use Romania’s rate for every sale or confuse a store report with the submitted OSS declaration.

Frequently asked questions and solutions

You cannot establish the state of consumption

Gather the evidence required for the operation type and check the place of supply before choosing the rate. The billing address alone does not resolve every situation.

You have a return after the reported period

Link the return to the original operation and period and apply the OSS correction mechanism. Do not deduct the amount globally from another member state.

Euro amounts do not match sales

Check the regime, ECB exchange rate, conversion date and rounding. Keep reconciliation with the original currency without replacing the required rate with an arbitrarily chosen bank rate.