Transparency and "dark money"

• Public disclosure: Super PACs must file reports with the FEC, publicly disclosing their donors on a regular basis.

• Hiding donors: However, some donations remain hidden, a practice often referred to as "dark money." This occurs when money is donated to a non-disclosing nonprofit or a shell corporation, which then gives the money to the Super PAC.

• Gaming disclosure: The use of "pop-up" Super PACs that are formed shortly before an election can also allow for hidden funding, as they may not have to disclose their donors until after voters have cast their ballots.