Who must file
Principal campaign committees
Congressional candidates  (including unopposed candidates and candidates whose names do not appear on the ballot) who seek election in the special election must file the Texas's 6th congressional district special runoff election reports and notices.  Before a committee can stop filing with the FEC, it must file a termination report with the Commission. Committees must continue to file reports until the Commission notifies them in writing that their termination report has been accepted.
Unauthorized committees—Political Action Committees (PACs) and party committees
PACs and party committees not filing monthly in 2021 are subject to special election reporting if they make previously undisclosed contributions or expenditures in connection with a special election by the close of books of the applicable report(s). For more information, consult the Federal Register.
Method of filing
Reports filed electronically must be received and validated by the Commission by 11:59 p.m. Eastern Time on the filing deadline. For additional information, call the FEC's Electronic Filing office at 800-424-9530 (menu option 4) or 202-694-1642.
Under the Commission’s mandatory electronic filing regulations, political committees that receive contributions or make expenditures in excess of $50,000 in a calendar year, or that have reason to expect to do so, must file all reports and statements with the FEC electronically. Other political committees may voluntarily file electronically; however, any entity that files electronically, whether required to do so or not, must comply with the electronic filing rules.
Special note for paper filers
Despite the resumption of limited mail operations at the FEC, the processing of campaign finance reports filed on paper may be delayed. As a result, paper filers may receive non-filer notices during this time. Nevertheless, filers should continue to file their reports on time. More information on FEC operations
Registered & certified mail
Pre-election reports sent by registered or certified mail must be postmarked on or before the mailing deadline to be considered timely filed; other reports must be postmarked by the filing deadline. A committee sending its reports by certified or registered mail should keep its mailing receipt with the U.S. Postal Service (USPS) postmark as proof of mailing because the USPS does not keep complete records of items sent by certified or registered mail.
Reports filed via overnight mail will be considered timely filed if the report is received by the delivery service on or before the mailing deadline. "Overnight mail" includes Priority or Priority Express Mail having a delivery confirmation, or an overnight service with which the report is scheduled for next business day delivery and is recorded in the service’s online tracking system.
Other means of filing
Reports filed by any other means—including first class mail and courier—must be received by the FEC before the Commission's close of business on the prescribed filing date. (If the deadline falls on a weekend or federal holiday, such filers should plan accordingly and file reports by the close of business on the last business day before the filing deadline.) Reports submitted by first-class mail will be considered filed when actually received by Commission staff, subject to delays resulting from the agency’s limited mail processing. The Commission is not accepting courier deliveries at this time. The FEC does not have statutory authority to extend filing deadlines, but it may choose not to pursue administrative fines against filers prevented from filing by reasonably unforeseen circumstances beyond their control.
48-Hour Notices on contributions
The principal campaign committee must file notices if any authorized committees of the candidate receive any contribution (including in-kind gifts or advances of goods or services; loans from the candidate or other non-bank sources; and guarantees or endorsements of bank loans to the candidate or committee) of $1,000 or more per source, during the period of July 8 through July 24, 2021.
The notices, which may be filed using Form 6, or a letter containing the same information, must reach the FEC within 48 hours of the committee’s receipt of the contribution(s). Campaign committees that file electronically MUST submit their 48-Hour Notices electronically. Candidates faxing 48-Hour Notices should transmit them to the Commission by fax at 202-219-0174.
Note for filing post-election report
The reporting period for the Post-Runoff Report spans two election cycles. For this report only, committees should use the Post-Election Detailed Summary Page (Form 3, Pages 5-8) instead of the normal Detailed Summary Page.
Disclosure of lobbyist bundling activity
Principal campaign committees, party committees and Leadership PACs that are otherwise required to file reports in connection with the special elections must simultaneously file Form 3L if they receive two or more bundled contributions from lobbyists/registrants or lobbyist/registrant PACs that aggregate in excess of $19,300 during the special runoff election reporting periods. Learn more about the lobbyist bundling disclosure requirements.
Treasurers of political committees are responsible for both the timeliness and the accuracy of all reports. They may be subject to monetary penalties if reports are inaccurate or are not filed on time.
In addition, political committees that file illegible reports or use non-FEC forms (except for FEC-approved, computer-generated forms) will be required to refile their reports.
Administrative Fine Program
Under the Administrative Fine Program, political committees and their treasurers who fail to file their reports, or who file late, may be subject to civil money penalties up to $23,944 (or more for repeat late- and non-filers). 
Electronic filers must file electronically
Electronic filers who instead file on paper, or who submit an electronic report (either by direct transmission or CD) that does not pass the validation program by 11:59 p.m. Eastern Time on the filing deadline, will be considered non-filers and may be subject to enforcement actions (including administrative fines).
Important filing information—paper filers
The U.S. Postal Service irradiates mail directed to many federal agencies, including the FEC. This process has not only delays mail delivery, it also damages and in some cases destroys pieces of mail. As a result, committees that file reports with the FEC may want to consider submitting their reports by some means other than U.S. mail. Alternative methods include electronic filing, overnight mail service, and hand delivery.
 Generally, an individual becomes a candidate for federal office (and thus triggers registration and reporting obligations) when his or her campaign exceeds $5,000 in either contributions or expenditures. If the campaign has not crossed the $5,000 threshold, it is not required to file reports.
 If a candidate has more than one authorized committee, the principal campaign committee must also file a consolidated report on Form 3Z.
 Penalties for late- and non-filing of 48-Hour Notices are based on the amount of contributions not timely disclosed. As a result, these penalties may exceed $23,944, even for first-time violations.