Article 19 mandates the exchange of information between Tax Administrations of GCC Member States for implementing the Agreement and local excise laws. Information received is confidential, subject to the recipient state's domestic laws, and its disclosure is strictly limited to authorities involved in tax assessment, collection, enforcement, and related judicial proceedings. Use for other purposes requires mutual legal permission and explicit consent from the providing state. Paragraph 3 outlines specific exceptions, stating a Member State is not obliged to act contrary to its regulations, provide unobtainable information, or disclose commercial secrets. However, a state cannot refuse a request simply because it has no domestic interest in the information or because it is held by a financial institution.