§ 10.63 Service of complaint; service of other papers; service of evidence in support of complaint; filing of papers.

(a) Service of complaint—(1) In general. The complaint or a copy of the complaint must be served on the respondent by any manner described in paragraphs (a)(2) or (3) of this section.

(2) Service by certified or first class mail. (i) Service of the complaint may be made on the respondent by mailing the complaint by certified mail to the last known address (as determined under section 6212 of the Internal Revenue Code and the regulations thereunder) of the respondent. Where service is by certified mail, the returned post office receipt duly signed by the respondent will be proof of service.

(ii) If the certified mail is not claimed or accepted by the respondent, or is returned undelivered, service may be made on the respondent, by mailing the complaint to the respondent by first class mail. Service by this method will be considered complete upon mailing, provided the complaint is addressed to the respondent at the respondent's last known address as determined under section 6212 of the Internal Revenue Code and the regulations thereunder.

(3) Service by other than certified or first class mail. (i) Service of the complaint may be made on the respondent by delivery by a private delivery service designated pursuant to section 7502(f) of the Internal Revenue Code to the last known address (as determined under section 6212 of the Internal Revenue Code and the regulations thereunder) of the respondent. Service by this method will be considered complete, provided the complaint is addressed to the respondent at the respondent's last known address as determined under section 6212 of the Internal Revenue Code and the regulations thereunder.