Exchange of information: competent authorities must obtain and share bank, ownership and fiduciary records for tax purposes. Article 5 requires the requested Party to provide, upon written request demonstrating foreseeable relevance, all information necessary for tax purposes and to use all relevant information gathering measures within its law to obtain such information, including witness depositions and authenticated originals where permissible. Competent authorities must be able to access bank and fiduciary records and legal and beneficial ownership information across ownership chains for companies, partnerships, investment schemes, trusts and foundations, subject to a proportionality exception for publicly traded entities. The requested authority must acknowledge receipt, notify deficiencies within sixty days, and report inability or refusal within ninety days, then forward information promptly.