This rule, pursuant to Article 17 of the Executive Regulations, establishes a mandatory notification requirement for all competent bodies. Entities responsible for certifying documents, registering incorporated bodies, issuing or renewing activity licenses, or authenticating customs data must notify the Tax Administration. This notification is required within thirty days of conducting such procedures for a taxpayer. The submission must include detailed statements of concluded contracts, specifying the incorporated body's name, address, tax card number, contract specifics, and any income tax retentions made.