European Union (Tax Dispute Resolution Mechanisms) Regulations 2019 (S.I. No. 306 of 2019)
9. Mutual agreement procedure
(1) Where Regulation 8(6) does not apply and the Commissioners and the competent authority of each relevant Member State decide to accept a complaint, the Commissioners shall, with the competent authority of each relevant Member State, endeavour to resolve the question in dispute by mutual agreement, subject to paragraph (5), not later than -
(a) subject to subparagraph (b), 2 years from the date of the last notification of a decision to accept the complaint, whether that decision is made by the Commissioners or a competent authority of a relevant Member State, as the case may be, or
(b) the end of any extension of the period referred to in subparagraph (a), where the Commissioners or the competent authority of a relevant Member State, as the case may be, make a request to the competent authorities of the other relevant Member States (including the State, as the case may be) for an extension of not more than 1 year of that period and provide written justification for such an extension.
(2) For the purposes of paragraph (1), the Commissioners may, during the period referred to in subparagraph (a) or (b), as the case may be, of that paragraph, by notice in writing to the affected person, request the affected person to provide such additional information, specified in the notice, as the Commissioners consider necessary to undertake the substantive consideration of the case.
(3) (a) Where a mutual agreement is reached in accordance with paragraph (1), the Commissioners shall, without delay give notice in writing to the affected person of the mutual agreement.
(b) Subject to -
(i) subparagraph (d), and
(ii) the affected person accepting the mutual agreement and renouncing any right to any other remedy that may be available under the law of the State or of a relevant Member State relating to the question in dispute,
the Commissioners shall implement the mutual agreement in accordance with its terms as a decision that is binding on them and enforceable by the affected person, irrespective of any time limits provided for by or under the Act of 1997.
(c) The Act of 1997 and any instrument made thereunder shall apply with any necessary modifications for the purpose of giving effect to subparagraph (b).
(d) Where proceedings have already commenced in the State, or in a relevant Member State, in respect of any remedy referred to in subparagraph (b), the mutual agreement shall only become binding on the Commissioners and enforceable by the affected person when the affected person provides evidence to the Commissioners and the competent authority of each relevant Member State, not later than 60 days from the date on which notice of the mutual agreement was given to the affected person under subparagraph (a), that action has been taken by the affected person to discontinue those proceedings.
(4) Where a mutual agreement is not reached within the period specified in subparagraph (a) or (b), as the case may be, of paragraph (1), the Commissioners shall, without delay, give notice in writing to the affected person accordingly and the notice shall set out the general reasons for the failure to reach such an agreement.
(5) Where the question in dispute is the subject of proceedings by the affected person in the State or in a relevant Member State, with respect to any remedy that may be available under the law of the State or that relevant Member State, as the case may be, other than under the Directive, the period of 2 years referred to in paragraph (1)(a) shall commence on the date on which a final judgment, order or decree is delivered in those proceedings or on the date on which those proceedings are suspended, discontinued or otherwise disposed of.