In politics, money talks. When millionaires and billionaires open their wallets to support candidates, there’s much to consider. At the top of the list of curiosities is major donors’ motivation for giving in the first place. While the more skeptical will claim that the sole factor igniting these actions is that money buys political power, others contend that major donors give because they simply believe in a specific platform (perhaps it’s a mix of both for some). Either way, knowledge of who’s financially backing the candidates — and how much they’re doling out — is worth knowing.

After all, political donations can open doors that are closed to most people. Big-dollar donors are often invited to state dinners at the White House and other events with the president. They also may be asked to weigh in on public policy, especially if it affects their own financial interests. And the ranks of ambassadors, advisory panels and other government jobs traditionally are filled with those who have been unusually generous during the campaign (hence the original point made: In politics, money talks).

Meet Obama & Romneys Top 5 2012 Presidential Campaign Donors

Credit: AFP/Getty Images

Based on campaign finance reports, the Associated Press has put together top five lists of the biggest donors in the 2012 presidential campaign. The first list focuses upon Republican candidate Mitt Romney and the second explores the biggest contributors to President Barack Obama’s re-election bid. All stated, the lists are based upon reports that were submitted to the Federal Election Commission and include monies given through super PACs, some bundlers’ efforts, campaigns, parties and joint-fundraising committees.

What is not included, according to the AP, are potentially-secretive contributions. These legal donations may be given to non-profit groups that put out issue ads. While these efforts don’t advocate for or against a candidate, they do tackle issues that are likely present in specific party platforms (and, thus, they do tend to support a candidate along these lines). These numbers are not included, as the aforementioned groups are not required to disclose giving.

Below, learn more about the biggest players bankrolling both Romney and Obama this election cycle.

Romney’s Top 5 Presidential Campaign Donors

No. 1: Sheldon Adelson, 79, owner of the Las Vegas Sands casino empire.

Total: $34.2 million

Adelson is the largest declared donor to the Romney campaign and supporting political committees, providing more than $34.2 million this election season. He and his wife, Miriam, a physician who heads the Nevada-based Adelson Drug Clinic, have given $10 million to the Restore Our Future, a super PAC backing Romney. Adelson also joined relatives to give $24 million to committees backing former GOP presidential candidate Newt Gingrich. And he has made public pledges vowing to give $10 million to Karl Rove’s American Crossroads super PAC and as much as $100 million this election more broadly to the GOP.

Meet Obama & Romneys Top 5 2012 Presidential Campaign Donors

US business magnate Sheldon Adelson speaks on the phone after attending the first presidential debate between US President Barack Obama and Republican challenger Mitt Romney in Denver,Colorado on October 3, 2012. Credit: AFP/Getty Images

Worth an estimated $25 billion, Adelson oversees the Las Vegas Sands Corp., which runs casino and resort interests in Las Vegas, Singapore and Bethlehem, Pa., and Sands China Ltd., a cluster of casinos in the Chinese territory of Macau. He would benefit from loosened trade restrictions and a rise in the Chinese currency rate against the dollar. His company devoted $60,000 this year to lobby on tax issues, foreign tourist visas, travel and Internet gambling issues – and has spent $1.86 million lobbying on legislation dealing with China trade, gambling and travel since 2002.

A staunch supporter of Israel, he also is a contributor to the Republican Jewish Coalition, which spent $920,000 since 2002 backing bills aimed at pressuring Iran and enhancing U.S. security cooperation with Israel. Adelson’s casino company has advised shareholders that it was under investigation by the Justice Department and the Securities and Exchange Commission. Investigators were said to be focusing on the Macau casinos and reports of missing money and possible violations of the Foreign Corrupt Practices Act.

No. 2: Harold Simmons, 81, owner of Contran Corp., a Dallas-based conglomerate worth an estimated $9 billion that specializes in metals and chemical production and waste management.

Total: $16 million

Simmons is a longtime backer of GOP and conservative causes. He has donated $16 million to the party’s efforts this year, including more than $11 million to American Crossroads and $800,000 to Restore Our Future. Simmons and his wife, Annette, also gave $2.2 million to Super PACs backing former GOP presidential candidates Gingrich, Rick Santorum and Rick Perry. Simmons has been active in political fundraising since the 1990s and in 2004 was a $4 million backer of the Swift Vets campaign, the GOP-backed effort to discredit Democratic presidential nominee John Kerry’s military record in the Vietnam War. Simmons’ Titanium Metals Corp.

reportedly is a top producer of titanium for weapons and other industrial uses. He also owns a majority stake in Valhi Inc., a Texas-based waste management company, and could benefit from a proposed Nuclear Regulatory Commission rule change that would allow the company’s Texas facility to store spent uranium from nuclear power and weapons plants. Contran’s subsidiaries have spent $200,000 this year lobbying the NRC, Energy Department, the Senate and House on metals and waste issues, and $4.3 over the past decade, including efforts to protect a Pentagon rule limiting titanium purchases to U.S. producers.

Simmons was fined $19,800 by the Federal Election Commission in 1993 for exceeding the then-annual $25,000 limit on individual campaign contributions, which has since been lowered.

No. 3: Bob J. Perry, 80, head of a Houston real estate empire worth an estimated $650 million.

Total: $15.3 million

Perry has given about $15.3 million to aid the Romney campaign and allied causes so far this election season. Long active in Texas and national GOP politics, Perry donated nearly $9 million to Restore Our Future and a total of $6.5 million to American Crossroads. Before backing Romney this year, Perry gave $100,000 to the super PAC backing Texas Gov. Rick Perry (no relation).

This combo image of file photos shows biggest Republican presidential campaign donors, from left, Sheldon Adelson, owner of the Las Vegas Sands casino empire; Harold Simmons, owner of Contran Corp.; Bob J. Perry, head of a Houston real estate empire; Robert T. Rowling, head of Dallas-based TRT Holdings; and William Koch, an industrialist. Credit: AP

Bob Perry has been a fixture of GOP fundraising in Texas and nationally dating back to former President George W. Bush’s Texas gubernatorial races in the mid-1990s. Perry was a top Bush presidential “bundler” and also gave big to the Swift Vets and POWs for Truth campaign in 2004, donating $4.4 million to the effort to discredit Kerry.

No. 4: Robert Rowling, 58, head of Dallas-based TRT Holdings.

Total: $4.1 million

Rowling has given at least $4.1 million to Republican Party and candidates this election. Most of his donations, $4 million, went to Rove’s American Crossroads, both through personal donations and through his firm. Rowling also has given $100,000 to the pro-Romney Restore Our Future super PAC.

Rowling’s holdings are worth an estimated $4.8 billion and include Omni Hotels, Gold’s Gym and Tana Exploration, his family’s oil company. Rowling once told the Texas Tribune he prefers political donations to lobbying efforts. Rowling has been a big donor in Texas political circles, winning a role for Omni as operator of Dallas’ convention center hotel after a 2009 city referendum fight.

No. 5: William Koch, 72, an industrialist whose South Florida-based energy and mining conglomerate is worth an estimated $4 billion.

Total: $3 million

Koch has given $3 million to the Restore Our Future, including a $250,000 personal donation and $2.75 million through his corporation, Oxbow Carbon LLC, and a subsidiary, Huron Carbon.  Unlike his brothers, Charles and David Koch, who are longtime supporters of Republican and conservative causes, Bill Koch has funded both GOP and Democratic Party candidates in the past. Koch’s corporate interests have repeatedly battled against what company officials have decried as government interference.

Oxbow spent $570,000 last year on lobbying in Washington, mostly aimed at mining, safety issues and climate change. The company has complained in federal filings about government delays on permits and has raised concerns about administration changes in regulations that would aid collective bargaining. Koch also has pushed for approval of the Central Rockies Land Exchange, a proposed swap of land tracts in Colorado and Utah to enlarge his 4,500-acre Bear Ranch. The proposal, which requires congressional approval, has sparked local opposition.

Obama’s Top 5 Presidential Campaign Donors

No. 1: Jeffrey Katzenberg, 61, Hollywood film producer and chief executive of DreamWorks Animation.

Total: $2.566 million

Katzenberg is President Barack Obama’s top donor when tallying his contributions to a “super” political committee, money to Obama’s campaign and the money he arranged for others to write for the president. The biggest contributions include $2 million to the Priorities USA Action super PAC. It was founded by former White House advisers and is the key pro-Obama PAC this election cycle.

Robert Kyncl, left, and Jeffrey Katzenberg pose backstage at the CoachArt Gala of Champions at The Beverly Hilton on Thursday Oct. 18, 2012, in Beverly Hills, Calif. Credit: Invision for CoachArt

Katzenberg has helped “bundle” more than $500,000 for the president’s second term, making him among the campaign’s top volunteer fundraisers. He’s also given more than $66,000 to Obama’s campaign and the Democratic Party. The Hollywood icon has been invited to White House events, including a state dinner. Such high-profile soirées put him in proximity earlier this year to Chinese Vice President Xi Jinping, who signed off on an overseas deal benefiting Katzenberg’s studio.

No. 2: Irwin Jacobs, 78, the founder and former chairman of Qualcomm.

Total: $2.122 million

Jacobs has given more than $2 million to pro-Obama super PACs and about $23,000 directly to Obama’s campaign and the Democrats. But he’s no newcomer to political giving: The La Jolla, Calif., billionaire has routinely backed San Diego-area politicians, including those in City Hall.

Some of his local proposals have caused dust-ups in town, including one backed by San Diego’s mayor that would have changed the name of Qualcomm Stadium for 10 days to reflect the cellphone-maker’s new computer chip. Another proposal wanted to alter automobile traffic and parking in the city’s historic Balboa Park; that plan that was overwhelming approved by city officials, although a firm tied to Jacobs spent $34,000 to lobby the San Diego government for the change.

No. 3 (tie): Fred Eychaner, founder of Chicago-based alternative-newspaper publisher Newsweb Corp.

Total: $2.066 million

Eychaner has given $1.5 million to the Priorities USA Action super PAC. He’s also given more than $60,000 to the president’s re-election committees, and he’s listed as a major “bundler” for Obama, having raised at least $500,000 for the president. Eychaner, a gay-rights activist, also has donated millions to other nonprofit groups, including more than $1 million to the progressive EMILY’s List organization.

Meet Obama & Romneys Top 5 2012 Presidential Campaign Donors

This combo image of file photos shows 4 of the 5 biggest Democrat presidential campaign donors, from left, Jeffrey Katzenberg, Hollywood film producer and chief executive of DreamWorks Animation; Irwin Jacobs, the founder and former chairman of Qualcomm; Fred Eychaner, founder of Chicago-based alternative-newspaper publisher Newsweb Corp.; and Steve Mostyn, 41, a Houston-based personal injury attorney. (AP Photo/File)

He’s visited the White House several times since early 2009, according to records, and Obama appointed Eychaner to the board of trustees of the John F. Kennedy Center for the Performing Arts. During the 2008 election cycle, Newsweb spent more than $1.7 million on Illinois elections and about $200,000 on the federal level, according to the Center for Responsive Politics.

No. 3 (tie): Jon Stryker, 54, a Michigan philanthropist.

Total: $2.066 million

Stryker has given $2 million to the Priorities USA Action super PAC and has given $66,000 in contributions to Obama and the Democratic Party. Stryker is the heir to namesake Stryker Corp., the major medical-device and equipment manufacturer. Stryker has been active in politics before the 2012 election; he contributed millions to help Democratic candidates statewide. And he also has given nearly $250 million of his personal wealth to groups supporting gay rights and the conservation of apes.

No. 5: Steve Mostyn, 41, a Houston-based personal injury attorney.

Total: $2.003 million

Mostyn has given more than $2 million to the Priorities USA Action super PAC that’s helping Obama. Mostyn, the former head of the Texas Trial Lawyers Association, is a major backer of Democratic candidates in the state. He’s also sank cash into a Texas political committee that tried unsuccessfully to unseat Gov. Rick Perry two years ago.

Most famously, in 2009, Mostyn demanded tens of millions of dollars for property owners affected by Hurricane Ike in claims against the Texas Windstorm Insurance Association.

Based on the numbers, Romney’s top donors have given substantially more than Obama’s. While Adelson, Romney’s top donor, gave $34.2 million, Obama’s top donor, Katzenberg gave just $2.566 million. All of the president’s top five donors were somewhere in or around the $2 million range, while Romney’s top five gave a minimum of $3 million.

Be sure to use Wired’s “Influence Tracker” tool as well to see who’s funding presidential and congressional candidates.

The Associated Press contributed to this report.

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