Exchange of information obligations expanded under the tax treaty, mandating mutual information sharing while protecting confidentiality. The Protocol replaces Article 26 to require competent authorities to exchange information foreseeably relevant for administering or enforcing taxes, applying to federal taxes in Brazil; information must be kept secret and used only for tax assessment, collection, enforcement, prosecution, appeals or oversight unless both States' laws permit other uses and the supplying State authorises such use. Requests must be met using available information gathering measures even absent domestic interest, and bank or fiduciary holding of information does not alone permit refusal, subject to limits preserving domestic law, unobtainable information, trade secrets and public policy.