Last Updated Saturday 12:39 p.m. ET
(CBS News) NEW YORK - As the presidential campaign turned toward the general election last month, the super PAC supporting Mitt Romney raised three times more money than the super PAC supporting Barack Obama. But the president's campaign committee ended the first quarter of 2012 with ten times the cash on hand as the Republican challenger's.
During March, the pro-Mitt Romney super PAC raised $8.7 million and spent $12.7 million, according to its required monthly fundraising report with the Federal Election Commission. Some of its biggest givers were a Koch brother, investor Charles Schwab, tycoon Harold Simmons, and the hotel-running Marriott brothers.
Restore Our Future bumped up its donations by $2 million compared to the month before, and the pro-Romney group continued to out-pace the pro-Obama Priorities USA Action. Priorities USA raised $2.5 million in March, leaving it with $5 million entering April. It has already spent close to $1 million this month to run a pair of anti-Romney ads in general election battleground states - Colorado, Florida, Iowa, New Mexico, Ohio, and Virginia.
The pro-Romney super PAC came into March with $10 million cash on hand but reported having only $6.454 million coming into April. So far this month, Restore Our Future has spent at least $1.6 million on ads in Wisconsin - which held its primary April 3 - and in New York, Pennsylvania, Rhode Island, Connecticut, and Delaware, which all hold primaries on Tuesday.
In a strategic switch reflecting rival Rick Santorum's exit from the presidential race, 83% of the pro-Romney super PAC's spending in April has been on positive pro-Romney ads.
Over a 15 month period starting in January 2011 and through March, Restore Our Future has raised $51.9 million and spent $45.4 million, far more than all the other presidential super PACs combined.
By comparison, the Romney for President campaign raised $12.6 million in March, bringing its total for the past 12 months to $87 million in primary funds. The campaign had $10.1 million cash on hand entering April.
The president's campaign, Obama For America, raised $35 million in March and spent $15.6 million, leaving it with $104 million cash on hand.
Unlike campaigns, which can accept a maximum of $2,500 per individual for the primaries and another $2,500 for the general election, there is no limit on what super PACs can receive and spend, thanks to a 2010 Supreme Court decision upholding expansive free speech rights of individuals, corporations, and unions in political campaigns.
The biggest giver last month to pro-Romney Restore Our Future was a company -- $1 million on March 5 from Huron Carbon, which is run by billionaire William Koch, a brother of Charles and David Koch, who run Koch Industries and are prolific conservative political donors.
Huron Carbon has the same Palm Beach, Florida, address as William Koch's Oxbow Carbon. Brad Goldstein, a Koch spokesman, told CBS News Huron is a subsidiary of Oxbow Carbon that specializes in "calcining," or making a calcine petroleum coke, a primary ingredient, for making aluminum.
Koch, worth as estimated $4 billion, and his company, Oxbow Carbon, previously gave a combined $1 million to Restore Our Future last year.
The second biggest March gift to the pro-Romney super PAC was from billionaire Chicago investor Ken Griffin, CEO of Citadel LLC, who gave $850,000 on March 12. Griffin had previously given Restore Our Future $200,000. Griffin has now given Restore Our Future $1,050,000, making him the 13th individual or company to cross the million dollar donor threshold for the pro-Romney super PAC.
With another $700,000 donation, Griffin was also the top giver in March to American Crossroads, the pro-Republican super PAC co-founded by Karl Rove, which raised just $1.2 million in March, but entered April with $24.4 million cash on hand.
The third biggest gift to the pro-Romney Restore Our Future in March was from a familiar name -- Texas tycoon and billionaire Harold Simmons, who gave Restore Our Future the group another $600,000 in two chunks: $100,000 on March 9 and $500,000 on March 19.The third biggest gift in March was from a familiar name - Texas tycoon and billionaire Harold Simmons, who gave Restore Our Future another $600,000 in two chunks: $100,000 on March 9 and $500,000 on March 19.
Simmons, CEO of Dallas-based holding company Contran, had previously given the pro-Romney super PAC $200,000, for $800,000 overall. He has been more generous with super PACs, supporting Rick Perry, Rick Santorum and Newt Gingrich - giving them each at least $1 million - and at least $12 million to American Crossroads, the pro-Republican super PAC co-founded by Karl Rove.
James Davis, the chairman of New Balance sneakers, from outside Boston, Massachusetts, gave Restore Our Future $500,000 on March 8. Steven Webster, a Houston equity fund manager, gave $500,000 on March 1.
Billionaire investment adviser Charles Schwab and his wife, Helen, who live in San Francisco, gave a combined $250,000, or $125,000 each, on March 13. Schwab, worth an estimated $3.5 billion according to Forbes, is the 17th billionaire to donate to the pro-Romney super PAC.
In addition, a Hamilton, Montana company, Fair Oaks Finance LLC, with an address apparently linked to the Schwabs, gave Restore Our Future $250,000 on March 21. The company's registered agent with Montana's Secretary of State is "Charles R. Schwab," and its address and the Schwabs are listed on a 2004 Federal Communications Commission radio service application for a working ranch in Montana, according to documents reviewed by CBS News. A representative for Mr. Schwab did not reply for comment.
The billionaire Marriott brothers - J. W. "Bill" and Richard -- each gave another $250,000 to Restore Our Future, on March 7 and 23, respectively. The hotel chain heirs and bosses both gave the super PAC $500,000 last June and another $250,000 in January, making them the 14th and 15th million dollar donors to ROF.
A Palm Beach company called Seaspray Partners, run by investor Scott Desano, gave Restore Our Future $400,000 on March 1. The firm is inactive, according to the Florida Secretary of State.
The Fox family of St. Louis - Jeffrey, Marilyn, and Sam -- gave a combined $300,000 -- three $100,000 gifts last month. Jeffrey Fox is CEO of the Harbour Group, a buyout firm, according to its website.
Los Angeles real estate developer Geoff Palmer gave $250,000 to the pro-Romney group on March 9, bringing his total to $500,000. A new giver, Betty Brown Casey, President of Casey Management, a real estate management company in Maryland, gave it $200,000 on March 29.
There were 16 other $100,000 donors to Restore Our Future in March.
Investor John Griffin, President of Blue Ridge Capital, in Florida, gave $100,000. Griffin is a "Tiger cub" apprentice of billionaire hedge fund legend Julian Robertson, CEO of Tiger Management, in New York, who previously gave $1.25 million.
The Linder family of Cincinnati, a family with a history of big Republican giving, now led by Carl Linder III, co-CEO of the American Financial Group, gave a combined $100,000.
Kelly Loeffler, owner of the WNBA franchise Atlanta Dream, gave Restore Our Future $100,000 on March 5. She listed herself as the VP of International Exchange. Her husband, Jeffrey Sprecher, Chairman of International Exchange, previously gave the super PAC $230,000 last year.
Smaller but substantial donors to the pro-Romney group included Rod Aycox, Owner and President of Select Management Resource, a Georgia-based pay day lender, who gave Restore Our Future $50,000 in March. Similarly, Axcess Financial, which specializes in prepaid MasterCards and debt recovery, gave it $35,000.
Billionaire Sam Zell, who previously gave the super PAC $50,000 last year, gave another $20,000 last month.
There were ten donors who gave Restore Our Future only $25. The smallest of the 135 donors in March was a New York City probation officer from Brooklyn, James Bennett, who gave $5 twice, for a total of $10.
The pro-Romney group did return at least one donation -- a $5,000 gift from last year from M.C. Dean, a government defense contractor based in Dulles, Virginia who was listed hosting at least one super PAC event at Bloomfield Hills Country Club in Michigan.
Endorse Liberty, the leading super PAC supporting Republican presidential candidate Ron Paul, has taken a serious dive in donations, receiving only $13,000 in March while spending $114,000. Its cash on hand coming into April was $53,984. For the second month in a row, the group's biggest benefactor, Silicon Valley billionaire Peter Thiel, did not contribute. Thiel, CEO of Clarium Capital Management, previously gave the group $2.6 million.
On the other hand, the Paul campaign raised $2.6 million in March, leaving it with $1.8 million cash on hand and zero debt entering April. The campaign raised another $1.4 million April 15 in a Tax Day internet-fundraising drive, and is eyeing the May 29 Texas primary. Campaign Chairman Jess Benton said in a written statement, "These ample funds also will help us compete even harder in Texas, where Ron Paul is the only Texan, veteran, and authentic conservative running."
Editor's Note: An editing error in the 1Q numbers' totals of Restore Our Future has been corrected.