The National Fiscal Service explains

The Main Directorate of the National Fiscal Service in Kyiv accentuates that the validity period of registration of a business entity, pursuant to par. 299.10, article 299 of the Tax Code of Ukraine, is unlimited and can be cancelled by removing an entry record about the single taxpayer from the registry under the decision of the controlling body, in case:

1) an application is filed on refusal to apply a simpler income tax scheme due to necessity to pay other taxes and fees set out in the Tax Code of Ukraine, – on the last day of the quarter in which an application has been submitted;

2) termination of a legal entity (except reorganization) pursuant to the law – on the day of receipt of the notification on suspension of tax simplification by a controlling body from the national registrar;

3) in cases set out in par. 298.2.3, par. 298.2 of article 298 of the Tax Code of Ukraine.

Pursuant to par. 299.11 of article 299 of the Tax Code of Ukraine, in case of violation of the requirements committed by a single taxpayer, which are specified in chapter І The Simplified System of Taxation, Accounting and Reporting, section ХІV of the Tax Code of Ukraine, what has been revealed by the controlling body during audit checks, the cancellation of the single taxpayer registration is conducted under the decision of the said body passed based on the audit report, from the first day of the month following the quarter in which the violation was made.  In this case, the business entity is entitled to choose or move to the simplified tax system after expiry of four successive months from the moment of passing a decision by the controlling body.