Ministerial Decision No. 55 of 2025 establishes Kuwait's DMTT framework under Decree-Law No. 157 of 2024. Article 78 mandates the tax registration mechanism for all entities subject to the Top-up Tax. It requires that registration must be conducted on a group basis with the Tax Administration, which then issues a tax card and a Tax Registration Number (TRN). The TRN is mandatory on all correspondence. Crucially, the provisions of the law apply from the date an entity becomes subject to the tax, regardless of its actual registration date, ensuring retroactive compliance.