Amendment to the regulation – who can decide on service by the First Mazovian Tax Office (I MUS)?

Monika Bilska

On 20 August, the Journal of Laws published the Regulation of the Minister of Finance and Economy amending the provisions on the catalogue of entities serviced by I MUS (hereinafter: the Regulation). The amendment raises the qualifying income threshold, while allowing certain taxpayers to change the above-mentioned office to a specialised office with local jurisdiction, e.g. – in the case of taxpayers from the Lower Silesian Province – to the Lower Silesian Tax Office in Wrocław.

What exactly is changing?

The Regulation introduces three fundamental changes to the jurisdiction of tax offices, which will come into force on 1 January 2026:

• an increase in the amount of net revenue from the sale of goods, products and services – qualifying for service by I MUS – from EUR 50 million to EUR 100 million;
• clarification of the method of calculating the above amount by indicating that this should be done on the basis of the average exchange rate of the National Bank of Poland on the last working day of the tax year;
• addition to the jurisdiction of the I MUS of taxpayers who have concluded a cooperation agreement with the Head of the National Revenue Administration, regardless of the value of their revenue.

But what about taxpayers who have generated revenues of EUR 50-100 million?

The change in the revenue threshold has particular consequences for entities which, in at least one of the last two tax years (i.e. in 2023 or 2024), generated revenues in the range of EUR 50 to 100 million, without exceeding the upper limit of EUR 100 million in any of those years.

Despite not meeting the new criterion, these entities will, by default, continue to be served by I MUS.

Nevertheless, companies in this group may decide to change the above-mentioned office to a specialised office with local jurisdiction. They may make this change by submitting an appropriate statement to the Head of I MUS by 15 October 2025.

The statement should be made in writing and contain at least:

• the taxpayer’s identification details;
• the legal basis;
• the date of preparation;
• the signature of the authorised person.

Importantly, taxpayers with revenues in the above range may decide to change the I MUS also in subsequent years. For example, if they wish to make this change with effect from 1 January 2027, they should submit the relevant statement by 15 October 2026. In this case, the basis for assessment will be the net income earned in the tax years 2024 and 2025.

Our support

If you need assistance, for example, in determining the appropriate tax office for your company or in preparing a possible declaration of change of I MUS, we will be happy to help.

If you are interested, please contact us.