Meet the Midterm's Top Ten Donors

The overwhelming number of Americans who will vote in the mid-term elections on Nov. 5 won't have contributed a penny to their candidates' campaigns.

But a handful of people will have given more. A lot more.

More than a quarter of the $6 billion contributed to campaigns in 2012 came from about 31,500 individual donors, according to the Sunlight Foundation, which found that not a single candidate won two years ago without the help of the group dubbed the "one percent of the one percent."

As politics becomes more expensive with every election cycle, these super donors have never been more important.

Here are the top 10 individual donors of the 2014 election cycle, compiled for ABC News by the Center for Responsive Politics from a study of the most recent publicly available campaign financial disclosure reports.

(This ranking does not take into account unreported donations made to 501(c) 4 nonprofit organizations, which are not required to disclose their donors. According to the Center for Responsive Politics, spending by these "dark money" groups in the midterm elections could hit $1 billion.)

1. Tom and Kathryn Steyer, $42.95 million, Democrat

The San Francisco billionaire made a splash on the political scene when he pledged $100 million to turn climate change into marquee political priority. After spending big in the Massachusetts Senate race and Virginia governor's race in 2013, Steyer, 57, has been active in seven midterm races across the country, opposing candidates skeptical of climate change in North Carolina, Iowa and Colorado. For now, Steyer is focused on helping others, but he's rumored to be eying a future bid for governor or U.S. Senate in California.

2. Michael Bloomberg, $12.2 million, Independent

The former mayor of New York City is still working to shape the national political agenda. His anti-gun group Everytown for Gun Safety has endorsed candidates in 28 states, and is supporting a Washington ballot initiative to expand background checks for firearm purchases. Through his Independence USA PAC, Bloomberg, 72, will also spend $25 million in support of centrists in statewide and national races, including Massachusetts Republican Charlie Baker, who is running for governor, and Democratic Rep. Gary Peters, who is running for Senate in Michigan, according to the New York Times.

3. Fred Eychaner, $7.84 million, Democrat

Self-effacing and press-shy, Eychaner is at odds with his outsized footprint in Democratic politics. He's described himself as a "basic social activist with small-business experience," but the Chicago media mogul was the top individual liberal donor in the 2012 election cycle, pumping $14 million into liberal Super PACs. In 2013, he bankrolled successful efforts to legalize same-sex marriage in Illinois. This cycle, he's cut checks for the Senate Majority PAC in hopes of protecting Democrats' control of the Senate, and contributed to the Senate campaigns of Democratic Sens. Mark Pryor of Arkansas, Mark Begich of Alaska, and Kentucky Senate candidate Alison Lundergan Grimes.

4. Paul Singer, $5.3 million, Republican

Singer, a New York hedge fund manager pejoratively called a "vulture capitalist" for his firm's ownership of Argentine debt, is the top individual Republican political donor of the cycle. He was the driving force behind New York's legalization of gay marriage, and has spent millions on legalization efforts in other states, including Maryland and New Hampshire. This cycle, he's also supporting Republicans opposed to same-sex marriage, such as Rep. Tom Cotton in Arkansas, Alaska Senate candidate Dan Sullivan and South Carolina Sen. Lindsay Graham.

5. Richard and Elizabeth Uihlein, $5 million, Republican

Since 2010, the Uihleins, owners of the Wisconsin-based packaging supply company Uline, have given millions to local and national tea party organizations and Republican candidates. In 2012, they supported Wisconsin Gov. Scott Walker's campaign to fight a recall and Texas Sen. Ted Cruz's Senate bid. This year, they've given to the Senate campaigns of Rep. Tom Cotton in Arkansas and Col. Rob Maness in Louisiana. "I'm a conservative Republican, and I'm trying to help people who believe as I do in limited government and free markets," Richard Uihlein told Crain's Chicago Business. "I'm not one to hide from that."

6. Robert and Diana Mercer, $3.71 million, Republican

Robert Mercer, a New York hedge fund manager, spent millions in 2012 contributing to GOP establishment groups like American Crossroads. This cycle, he's also spent big on tea party Republicans. According to disclosure records, Mercer, 67, and his wife Diana have contributed to the Senate campaigns of Chris McDaniel in Mississippi, Greg Brannon in North Carolina, Joni Ernst in Iowa and Rep. David Vitter in Louisiana.

7. James and Marilyn Simons, $3.41 million, Democrat

At 23, James Simons had earned his PhD in mathematics. Three years later, he was a code breaker for the National Security Agency. In the half century since, Simons, 76, has made billions revolutionizing investment banking -- Robert Mercer, who appears on this list, runs the firm Simons founded -- and establishing himself as a leading political and philanthropic donor. This cycle, he's given $3 million to Democrats' House and Senate Super PACs. His wife, an economist, has contributed to Planned Parenthood's political arm and Ready for Hillary. The couple has also contributed to the campaigns of New York Reps. Steve Israel and Tim Bishop.

8. John "Joe" and Marlene Ricketts, $3.2 million, Republican

John, the billionaire founder of online brokerage TD Ameritrade and head of the family that owns the Chicago Cubs, is best known in political circles for spending millions to defeat and discredit President Obama in 2012, including efforts to design an ad campaign that would have connected Obama to incendiary comments made by former spiritual adviser Rev. Jeremiah Wright, and financing the controversial film "2016: Obama's America." This cycle, his wife Marlene has contributed millions to the Ricketts' Ending Spending Action Fund, and supported the campaigns of Republicans like Michigan Senate candidate Terri Lyn Land, Arizona Congressional candidate Martha McSally and Virginia Congressional candidate Barbara Comstock.

9. Robert and Doylene Perry, $3.12 million, Republican

Robert Perry, the late Houston development magnate and longtime Bush supporter who passed away in April 2013, made headlines for bankrolling Swift Boat Veterans for Truth, the conservative veterans' organization that discredited John Kerry's Vietnam War service record during his presidential bid in 2004. In 2013, Perry 's wife, Doylene, wrote checks to Senate Conservatives Action and the reelection campaign of Texas Sen. John Cornyn.

10. George Soros, $2.5 million, Democrat

Soros, the dean of liberal mega-donors, famously told the Washington Post that defeating President George W. Bush in 2004 was the "central focus of my life," and backed up his words with $24 million in 2003 and 2004. This cycle, Soros, 84, has given more than $2 million to American Bridge, a Democratic opposition research firm, and Democrats including New York Rep. Tim Bishop, Delaware Sen. Chris Coons, and at-risk Sens. Kay Hagan of North Carolina, Mark Udall of Colorado and Jeanne Shaheen of New Hampshire.