Exchange of information requires states to obtain and share tax-relevant information, subject to secrecy and legal limits. Article 28 requires Contracting States to exchange foreseeably relevant tax information and to use information-gathering measures to obtain requested information, even if not needed for their own tax purposes. Information must be treated as secret and disclosed only to authorities concerned with tax assessment, collection, enforcement, appeals or oversight and used solely for those purposes, with permitted disclosure in public court proceedings. States need not act contrary to their laws, supply information unobtainable under their laws, or disclose trade or professional secrets or information contrary to public policy; however, bank, fiduciary or nominee status cannot alone justify refusal to supply information.