(CBS News) President Obama's re-election campaign continues to raise more money than challenger Mitt Romney's campaign, but a "super PAC" supporting Romney continues to outperform all independent groups supporting a single candidate.
The Obama campaign raised $25.7 million and spent $14.6 million in April and entered May with $115.1 million cash on hand, according to the latest round of reports to the Federal Election Commission. The president's campaign had more than 12 times the cash as Romney's.
Romney's campaign raised $11.7 million and spent $12.6 million in April and entered May with $9.2 million cash on hand, according to its FEC report.
Sunday was the deadline for monthly reports from campaigns and super PACs.Special Section: Election 2012
The reports revealed Republican presidential also-rans beaten by Romney were in varied states of financial shape.
Texas Rep. Ron Paul, who suspended active campaigning only one week ago, entered May with $2.5 million cash on hand and no debt.
By contrast, former House Speaker Newt Gingrich's campaign, which ended May 2, had $800,000 cash on hand but $4.8 million in debt.
Former Sen. Rick Santorum's campaign, which was suspended April 10, had $1 million cash on hand but $2.3 million in debt.
The pro-Romney super PAC Restore Our Future took in another $4.6 million, its lowest monthly fundraising total of the year.
The group spent $2.9 million in April and entered May with $8.2 million cash on hand. The super PAC announced earlier this month it was spending $4.3 million to run a pro-Romney ad in nine battleground states.
Independent expenditure political action committees are known as super PACs because they can raise and spend unlimited sums of money on political advocacy, thanks to a pair of 2010 court decisions.
The Supreme Court's so-called Citizen United case opened the door to unlimited spending by individuals, unions and corporations, which was followed by the Speech Now case in the U.S. Court of Appeals for the District of Columbia, which allowed for unlimited contributions.
Single-candidate presidential super PACs established for seven Republican presidential candidates -- Gingrich, Paul, Romney, Santorum, former businessman Herman Cain, former Utah Gov. Jon Huntsman and Texas Gov. Rick Perry -- and Mr. Obama have now reported spending $89 million on advertising and advocacy through April.
With $48.3 million spent by Restore Our Future, the pro-Romney group alone was responsible for 55 percent of the total, and its roster of big donors continued to grow, with a pair of Texans topping the April donor list.
Homebuilder Bob Perry gave another $750,000 to Restore Our Future, elevating his total to $3.75 million, the most of any donor to the group, while investor John Kleinheinz gave the super PAC $1 million, making him its 16th million-dollar donor.
A number of CEOs opened their checkbooks for Restore Our Future.
Harold Hamm, chairman and CEO of Continental Resources, an Oklahoma oil exploration company, gave $985,000 while the more well-known founder of the Limited retail chain, Leslie Wexner, from Ohio, gave $250,000. Wexner is the 18th billionaire to contribute to the pro-Romney group and the 24th overall to give to a super PAC.
Rocco Ortenzio, co-founder and chairman of Select Medical, a publicly-traded chain of hospitals and outpatient clinics, from Pennsylvania, gave $250,000.
Rodger Crouse and Mark Leder, the co-CEOs of Sun Capital Advisers, from Florida, each gave $100,000 as did Wilbur Ross, CEO of WL Ross & Co., an investment firm that specializes in turnaround of distressed companies, from Florida, and Jack Caveney, the retired founder of Panduit, an Illinois-based provider of physical infrastructure for businesses.
Edmund Kelly, chairman of the board of insurance giant Liberty Mutual, from Massachusetts, and Robert Liggett, the investor and retired chairman of the Big Boy restaurant chain, from Michigan, each gave $25,000.
A friend from Romney's old firm, Bain Capital, Steven Zide, from Connecticut, gave $250,000.
Sam Zell, the billionaire real estate mogul from Illinois, donated another $30,000 to Restore Our Future, bringing his total to $100,000.
C. Boyden Gray, White House counsel to President George H.W. Bush and former ambassador to the European Union, from Washington, D.C., gave $50,000 to the super PAC.
Two oil companies made notable donations in their own name -- Hallador Energy, a publicly traded, Denver-based company, gave $100,000 to the pro-Romney group, while United Refining, a New York-based marketer of petroleum products, gave another $25,000, bringing its total to $50,000.
Pepsi MidAmerica, a distributor of Pepsi beverages in five states owned by the Crisp family of Marion, Ill., gave $5,000.
The main pro-Obama super PAC, Priorities USA Action, raised $1.6 million in April and spent $1.9 million, entering May with $4.7 million cash on hand.
A union, the National Air Traffic Controllers Association, was the group's biggest donor for the month with a $1 million contribution, the second union to give that amount to the pro-Obama group and its fifth million-dollar donor.
Another union, the United Association of Journeymen and Apprentices of the Plumbing and Pipefitting Industry, gave Priorities USA Action $250,000.
Joseph Kiani, the chairman and CEO of the medical technology company Masimo Corp., from California, gave $100,000 to the pro-Obama group.
Michael King, of King World Productions, from California, gave $50,000. King World, the TV syndication company behind "Jeopardy," "Wheel of Fortune," and "Dr. Phil," was acquired by CBS.
John Rogers, CEO of the investment firm Ariel Capital, from Chicago, gave another $50,000, bringing his total to $100,000.
American Crossroads, the leading super PAC backing conservative Republicans, had a relatively quiet month, raising $1.8 million in April, but remains the richest independent group required to disclose its donors, with $25.5 million cash on hand entering May.
Its largest donor was once again Texas tycoon Harold Simmons, who gave another $1 million, raising to $13 million the total donations of this campaign cycle to American Crossroads from him, his wife and his company, Contran.
Simmons, the second-largest donor in the nation behind casino mogul Sheldon Adelson, has now funneled more than $17 million to various Republican super PACs.
The super PAC's sister organization, Crossroads Grassroots Policy Strategies, better known as Crossroads GPS, last week launched a $25 million ad campaign against Mr. Obama in 10 battleground states.
Crossroads GPS, which describes itself as "a policy and grassroots advocacy organization," is classified as a 501(c)4 organization under the tax code, which means it is not required to disclose its donors.
The Crossroads groups were co-founded in 2010 by former top political aide to President George W. Bush Karl Rove and former Republican National Committee chairman Ed Gillespie.
The political director of American Crossroads, Carl Forti, is the executive director of Restore Our Future, and was political director of Romney's 2008 presidential bid.
Club for Growth Action, a like-minded super PAC that opposes higher taxes and government spending, raised $723,000 and spent $2.3 million in April, according to its monthly FEC report.
Team DeMint, the official campaign committee of South Carolina Republican Sen. Jim DeMint, a leader of the Tea Party movement, gave $200,000 to Club for Growth Action, bringing its total donation to $700,000.
Jerry Hayden, the former president of Peacock Engineering, an Arizona packaging company, and his wife gave the group a combined $300,000, bringing their total to $400,000.
The anti-incumbent super PAC Campaign for Primary Accountability raised and spent around $380,000 in April and entered May with $431,000 cash on hand.
Its most notable donor was Leo Linbeck III, president and CEO of Aquinas Enterprises, a Houston-based construction and real estate firm with more than $500 million in annual revenue.
Linbeck gave the group another $130,000 in April, bringing his total to $1.2 million. Counting Linbeck and April donors who reached seven figures, there are now 33 million-dollar donors to super PACs this election cycle.
A previous donor to Campaign for Primary Accountability was Joe Ricketts, the TD Ameritrade CEO who gave the group $500,000 last year.
Ricketts grabbed headlines last week because a proposal for a negative ad campaign reminding voters of Mr. Obama's past ties to the controversial Rev. Jeremiah Wright was submitted to another super PAC that he founded, the Ending Spending Fund. The Ricketts team disavowed the idea.
The Ending Spending super PAC spent $255,000 in a late ad buy to help Nebraska Senate candidate Deb Fischer achieve a surprising win in a Republican primary last week.