26 CFR § 301.6103(h)(4)-1 - Disclosure of returns and return information in whistleblower administrative proceedings.
(a) In general. A whistleblower administrative proceeding (as described in § 301.7623-3) is an administrative proceeding pertaining to tax administration within the meaning of section 6103(h)(4).
(b) Disclosures in whistleblower administrative proceedings. Pursuant to section 6103(h)(4) and paragraph (a) of this section, the Director, officers, and employees of the Whistleblower Office may disclose returns and return information (as defined by section 6103(b)) to a whistleblower (or the whistleblower's legal representative, if any) to the extent necessary to conduct a whistleblower administrative proceeding (as described in § 301.7623-3), including but not limited to -
(1) By communicating a preliminary award recommendation or preliminary denial letter to the whistleblower;
(2) By providing the whistleblower with an award report package;
(3) By conducting a meeting with the whistleblower to review documents supporting the preliminary award recommendation; and
(4) By sending an award decision letter, award determination letter, or award denial letter to the whistleblower.
(c) Effective/applicability date. This rule is effective on August 12, 2014. This rule applies to information submitted on or after August 12, 2014, and to claims for award under sections 7623(a) and 7623(b) that are open as of August 12, 2014.