Through the first half of 2012, the pro-Mitt Romney Restore Our Future, was the most active super PAC, raising $81 million and spending $60 million through June 30. Two-thirds of its spending, or $40 million, went to negative ads attacking Republican primary opponents Newt Gingrich and Rick Santorum.
Super PACs established for six also-ran Republicans -- Gingrich, Santorum, Ron Paul, Rick Perry, Jon Huntsman, Herman Cain -- spent a combined $36 million dollars on advertising and advocacy during the primaries, which effectively ended when Santorum dropped out in April.
The pro-President Obama super PAC Priorities USA Action raised $20.8 million and spent $18.3 million through June and entered July with $2.8 million cash on hand. American Bridge 21st Century, another pro-Obama super PAC, raised $10.6 million and spent $8.4 million.
Super PACs are permitted to spend unlimited sums raised from individuals, companies, and unions due to a pair of 2010 court decisions, most notably the "Citizens United" case adjudicated by the Supreme Court.
Through June, at least 22 people or companies contributed $1 million or more to pro-Romney Restore Our Future. Together, they provided 48 percent of the funds collected by the super PAC since its inception in 2011.
Casino mogul Sheldon Adelson leapfrogged to the top of the Restore Our Future donor list in June with a $10 million gift from him and his wife, Miriam. Houston homebuilder Bob Perry was next, with $5 million given to the group, including $2 million last month. Florida energy company president William Koch, a brother of the better known Charles and David Koch, gave $3 million by himself or through his business, including $1 million last month.
Adelson and Koch are among 20 billionaires who contributed to Restore Our Future by themselves or through their companies. Half the billionaire donors earned their fortune, like Romney, in the financial sector, such as Charles Schwab, Warren Stephens, and. The list included a pair of Marriott brothers and Walton siblings, a trio of real estate moguls, and one retail clothing chain founder.