FOP and Undeclared Activity: Risks, Restrictions, and Legal Consequences 2025

The issue of restrictions on activities of sole proprietors (FOPs) on the single tax is connected to clearly designating business activities in the Unified State Register (USR) and the Single Taxpayer Register. Can an FOP conduct activities not listed there? This is one of the most pressing legal questions for small businesses wishing to expand their profile or try a new business direction without formal registration changes.

Legal framework: basic principles
According to Ukraine’s Constitution (Art. 42), everyone has the right to entrepreneurial activity unless prohibited by law. However, Laws No. 755-IV (“On State Registration of Legal Entities, Individual Entrepreneurs and Civic Organizations”) and Chapter V of the Tax Code specify: all FOP business activities must be listed in the USR; this information is automatically passed to the Tax Service for tax accounting.

For single-tax FOPs, point 299.7 of the Tax Code states that the Single Taxpayer Register must list the business activities the entrepreneur intends to carry out. The law is clear: if an activity is not registered, the FOP must switch to the general taxation system starting from the month after the income from such activity is received.

“Off-register” activity: risks for single-tax entrepreneurs
The Tax Authority and Ministry of Justice clarify: a single-tax FOP may not carry out activities not included in their registration (USR and Single Taxpayer Register). For example, a second-group entrepreneur who provides new services without updating registration data violates single tax requirements.

Financial consequences:

• All income from such “unregistered” activity is taxed at the 18% general income tax rate, the 1.5% military levy, and possibly the social contribution.
• The entrepreneur is automatically removed from the Single Tax Register.
• The obligation to pay taxes under the general regime arises from the first day of the month following the infraction.
• Tax penalties and fines apply for late declaration of income and incorrect tax regime application.

Updating the activity code (KVED) and registration procedure
To legalize a new line of business, the entrepreneur must update the USR with the proper KVED code. The process is simple: submit a request electronically or through a registrar, receive an updated extract. Changes are automatically reported to the Tax Service – from the following month, the new activity can officially be performed under the single tax.

Note: systems integration is not instantaneous — before starting new operations, verify the new KVED is in your taxpayer extract.

Court practice and tax clarifications
Ukrainian courts adhere to Tax Service and Justice Ministry guidance: income from unregistered activity leads to transfer to the general system and tax surcharges. Agreements and acts with counterparties for “unregistered” activities are not void for the counterparty, but they create tax risk for the FOP.

A common issue: income received “by mistake” (e.g., by not updating the KVED, due to accountant error). In such cases, courts consider the actual commencement date, the moment tax obligations arise, and the date the request to update the KVED was filed.

Special features of switching to the general system
A FOP who breaks the rule and receives off-register income must:

• File a general system declaration the next month,
• Use the new “Standard Income and Expenses Logbook,”
• Pay taxes according to general system rules: PIT, military levy, SSC, VAT.

Note: Return to the single tax is only possible after resolving all formalities and closing past tax issues.

Liability and risks for FOPs:

• Automatic transition to the general system — substantial increase in tax burden.
• No right to operate under the single tax alongside “off-KVED” activities.
• Fines for late KVED changes, incorrect declarations and tax payments.
• Problems with banks (transaction denials, account blocks) if the activity in the registry mismatches actual activity.

Are there exceptions?
Some sectors (licensed, financial, medical, educational, legal services) require mandatory KVED updates — failure may entail additional administrative or even criminal liability.

In other cases, if no income is generated under ancillary KVEDs, there are no violations. But to avoid risk, always update USR and taxpayer registry data before starting new lines of business.

Practical tips for single-tax FOPs:

1. Check current KVED in USR and Single Taxpayer Register before expanding or changing activity.
2. Promptly update the registry and obtain an extract with new data.
3. Don’t accept any payments for new activities until all registries are updated.
4. Document and confirm all changes with the tax authority.
5. Use “Diia” or the Tax website to track status for risk minimization.

Conclusions:
A single-tax FOP may only engage in activities included in the USR and Single Taxpayer Register. Violations result in a switch to the general regime, higher taxes, and administrative fines. Legal security for small business in 2025 means transparency, registry compliance, and expert advice before any changes.
Professional support and timely registration issue resolution guarantee peace of mind and risk avoidance for entrepreneurs.

Author – Yulia Popadyn, attorney specializing in tax and customs law at the “WINNER” Law Firm. If you have questions or issues with code updates, registry activity reporting, switching tax systems or tax disputes, seek expert legal help to minimize risks and protect your business.