This study conducts a normative legal evaluation of the authority of the Directorate General of Taxes (DGT) to freeze taxpayer assets, focusing on a concrete case study involving the freezing of assets belonging to PT Intan Karya Mandiri, domiciled in Sumbawa, West Nusa Tenggara Province, by the Banjarbaru Tax Office (KPP) in South Kalimantan Province. The primary objective is to analyze two main issues: the ratio legis underlying the asset-freezing authority within the Indonesian tax law framework, and the legal implications of exercising this authority on taxpayers and the national tax system—specifically concerning alleged territorial overreach (ultra vires ratione loci) and errors in legal identity (error in persona). Adopting a normative legal (doctrinal) research methodology, this study employs statute, conceptual, case, and deductive approaches. Findings reveal that while the ratio legis under Law No. 19 of 2000 on Tax Collection by Warrant and its implementing regulations aims to safeguard state receivables, this power is inherently constrained by three cumulative boundaries: material limits, territorial limits, and personal limits (correct legal subjects). In the case of PT Intan Karya Mandiri, strong evidence indicates a dual violation of territorial and personal limits. Consequently, the asset-freezing action by KPP Banjarbaru constitutes an ultra vires act compromised by both procedural authority defects and substantive errors in identifying the legal subject. The legal implications encompass the infringement of the taxpayer’s economic and legal rights, structural weaknesses in inter-tax office coordination, the urgent need to enhance the single identity system, and potential institutional and personal legal liabilities for the officials involved. This study recommends mandating a dual-verification mechanism combining the Tax Identification Number (NPWP) and Business Identification Number (NIB) prior to asset freezing, along with drafting explicit regulations codifying a Taxpayer’s Bill of Rights within Indonesia’s legal tax system.