§ 10.27 Fees.

(a) In general. A practitioner may not charge an unconscionable fee in connection with any matter before the Internal Revenue Service.

(b) Contingent fees. (1) Except as provided in paragraphs (b)(2), (3), and (4) of this section, a practitioner may not charge a contingent fee for services rendered in connection with any matter before the Internal Revenue Service.

(2) A practitioner may charge a contingent fee for services rendered in connection with the Service's examination of, or challenge to—

(i) An original tax return; or

(ii) An amended return or claim for refund or credit where the amended return or claim for refund or credit was filed within 120 days of the taxpayer receiving a written notice of the examination of, or a written challenge to the original tax return.