11 CFR § 105.2 - Place of filing; Senate candidates, their principal campaign committees, and committees supporting only Senate candidates (52 U.S.C. 30102(g), 30104(g)(3)).
(a)General Rule. Except as provided in paragraph (b) of this section, all designations, statements, reports, and notices as well as any modification(s) or amendment(s) thereto, required to be filed under 11 CFR parts 101, 102, and 104 by a candidate for nomination or election to the office of United States Senator, by his or her principal campaign committee or by any other political committee(s) that supports only candidates for nomination for election or election to the Senate of the United States shall be filed in original form with, and received by, the Secretary of the Senate, as custodian for the Federal Election Commission.
(b)Exceptions. 24-hour and 48-hour reports of independent expenditures must be filed with the Commission and not with the Secretary of the Senate, even if the communication refers to a Senate candidate.