Any person, partnership, or corporation under investigation compelled or requested to furnish information or documentary material shall be advised of the purpose and scope of the investigation, the nature of the acts or practices under investigation, and the applicable provisions of law. A copy of a Commission resolution, as prescribed under § 2.7(a), shall be sufficient to give persons, partnerships, or corporations notice of the purpose of the investigation. While investigations are generally nonpublic, Commission staff may disclose the existence of an investigation to potential witnesses or other third parties to the extent necessary to advance the investigation.