For every presidential hopeful, a $1 million donor

—Other rich executives who gave at least $1 million to help Romney's campaign include Paul Edgerly, a managing director at Bain Capital, and his wife Sandra; Edward Conard, a former Bain executive; Mormon businessman Frank VanderSloot; Paul Singer, founder and CEO of Elliott Management Corp., a top New York-based hedge fund; John Paulson, head of Paulson and Company, another major hedge fund; Bob Perry, a Houston real estate developer; Tulsa businessman Francis Rooney; Robert Mercer, co-chief of Renaissance Technologies, a New York hedge fund; and William Koch, head of Oxbow Carbon, LLC, a fossil fuel processor and mining firm.

—The group supporting former Pennsylvania Sen. Santorum — the Red, White and Blue Fund — collected nearly all its $2.8 million so far from just two major, $1 million contributions. Foster S. Friess, a mutual fund entrepreneur and conservative advocate, is a major funder behind the Daily Caller, a conservative web news aggregator, and has his own website advocating free enterprise and warning about militant Islam. Friess opposed the Obama administration's health care program and gave $100,000 to statewide Republican races and causes in 2008.

—The pro-Santorum group's other $1 million contribution came from William J. Dore, president of a Louisiana energy and real estate firm. Dore backed New Orleans Mayor Mitch Landrieu and other state Democrats, but he has also funded Republican politicians, as well as charities in Louisiana and Texas.

—The pro-Gingrich super PAC Winning Our Future also gained $1 million from Texas billionaire Harold Simmons, a longtime Republican donor. Simmons also donated $12 million — both personally and through his firm, Contran — to American Crossroads, the Republican-leaning super PAC co-founded by longtime Republican strategist Karl Rove.