11 CFR § 101.1 - Candidate designations (52 U.S.C. 30102(e)(1), (g)).
(a) Principal Campaign Committee. Within 15 days after becoming a candidate under 11 CFR 100.3, each candidate, other than a nominee for the office of Vice President, shall designate in writing, a principal campaign committee in accordance with 11 CFR 102.12. A candidate shall designate his or her principal campaign committee by filing a Statement of Candidacy on FEC Form 2, or, if the candidate is not required to file electronically under 11 CFR 104.18, by filing a letter with the Commission containing the same information (that is, the individual's name and address, party affiliation, and office sought, the District and State in which Federal office is sought, and the name and address of his or her principal campaign committee). Each principal campaign committee shall register, designate a depository, and report in accordance with 11 CFR parts 102, 103, and 104.
(b) Authorized committees. A candidate may designate additional political committees in accordance with 11 CFR 102.13 to serve as committees which will be authorized to accept contributions or make expenditures on behalf of the candidate. For each such authorized committee, other than a principal campaign committee, the candidate shall file a written designation with his or her principal campaign committee. The principal campaign committee shall file such designations with the Commission.