Photo Credit: Gage Skidmore. Image Credit: Kevin Kreneck

“Technically known as independent expenditure-only committees, super PACs may raise unlimited sums of money from corporations, unions, associations and individuals, then spend unlimited sums to overtly advocate for or against political candidates,” according to campaign finance watchdog OpenSecrets.org. They are prohibited by federal law from donating to or coordinating with candidates.

Former Florida Governor Jeb Bush in super PAC support leads the pack—his Right to Rise PAC has raised $103,167,845.

Texas Senator Ted Cruz is a distant second. His 10 PACs, several of which have yet to raise any money, have reported a total $38,719,516.

Florida Senator Marco Rubio comes in third; so far, his Conservative Solutions PAC has raised $16,057,755. Super PAC fundraising for Bush has so outpaced the other Republican presidential candidates that going into the Iowa caucuses he had spent $64,178,404—more than the $61,138,179 raised by all the other candidates.

Republican candidate super PACs have raised much more than their Democratic counterparts. Six Hillary Clinton super PACs have raised a total of $16,278,542, with most of the money raised by Priorities USA Action ($15,654,457). A Bernie Sanders super PAC reported that it had raised $8,785.

Ten super PACs have been set up to oppose Clinton, though none have yet disclosed any funds raised to the Federal Elections Commission. All are directed by conservative Republicans, who will surely begin fundraising if Clinton wins the Democratic nomination. Two anti-Clinton super PACs—Just Say No to Her! and Just Say No to Hillary PAC—are run by former Bill Clinton political advisor Dick Morris, now a conservative political consultant.

The only other presidential candidate opposed by a super PAC is New Jersey Governor Chris Christie.

These sums do not include money raised by the individual campaigns. Eleven Donald Trump super PACs have filed with the FEC, although only one, Patriots for Trump, has reported any fundraising activity: $131,622. Trump’s campaign is largely self-funded.