How does presidential campaign finance work?

Presidential campaign finance is regulated by the Federal Election Commission (FEC) under the Federal Election Campaign Act and subsequent legislation. Individual donors may give a limited amount directly to a candidate's campaign committee per election cycle. These limits are adjusted for inflation periodically.

Super PACs - political action committees that operate independently of campaigns - may raise and spend unlimited amounts from individuals, corporations, and unions, but are prohibited from coordinating directly with campaigns. In practice, super PACs supporting a candidate's message have become essential to modern presidential campaigns.

A federal public financing system exists for presidential campaigns, providing matching funds to candidates who agree to spending limits. Since Barack Obama declined public financing in 2008 and raised far more private money, major-party nominees have routinely opted out of public financing, choosing to raise and spend without the caps.

Donors and expenditures above certain thresholds must be reported to the FEC and are publicly available at fec.gov. This disclosure allows the public and press to see who is funding which candidates and how campaigns are spending their money.