FEC complaints can be filed by any individual, group or political organization alleging that a campaign has violated election laws surrounding fundraising, campaign contribution limits, and coordination between campaigns, political parties or PACs. It is up to the FEC to investigate the complaint and determine if any violations occurred. In this case, the specific complaint is not public knowledge. However, it is possible that the complaint alleges a coordinated campaign of false or misleading information disseminated during the course of Biden’s 2020 presidential campaign. This information may have included false or exaggerated claims about Biden’s policy positions, voting record or connections to certain individuals or organizations. If proven true, such an allegation would be considered a violation of campaign finance laws.