Exchange of information: tax authorities must share relevant data subject to confidentiality and limited-use safeguards. Article 25 requires competent authorities to exchange information foreseeably relevant for implementing the Agreement or administering and enforcing domestic tax laws, subject to a confidentiality obligation treating received information as secret and limiting disclosure and use to tax assessment, collection, enforcement, prosecution, appeals and oversight. Exceptions disallow requests that would contravene a State's laws or administrative practice, require unattainable information, or force disclosure of trade secrets or information contrary to public policy, while obliging States to use their information-gathering measures even without a domestic interest and preventing bank or fiduciary status from being a blanket bar to disclosure.