In a reversal from 2012, liberal billionaires top the list of biggest super PAC donors with a little more than two weeks to go before Election Day. Three of the top five givers lean Democrat, while the king of unlimited money mountain — environmental crusader Tom Steyer of California — is lapping the competition, a Sunlight analysis finds.

Taking advantage of the Supreme Court’s ruling in the Citizens United case, which opened the door to political spending by outside groups that can raise funds in unlimited amounts from individuals, corporations and labor unions, Republican billionaire donors and the super PACs they funded dominated the 2010 elections. In 2012, billionaire Democratic donors, many of whom decried the Citizens United ruling, lagged behind mega donors like Sheldon and Miriam Adelson, who combined to give more than $92 million. But in 2014, Democratic billionaires are the biggest givers, and dozens of super PACs have been the beneficiaries.

How much each billionaire really gives is unclear — political nonprofits that can influence elections without disclosing their donors are flush with cash, having spent $120 million on independent expenditures this cycle. While super PACs have no shortage of deep-pocketed donors, 2014’s list of the biggest givers shows the absence of notable players in 2012. Some of the biggest conservative donors in the presidential race are gone or playing lesser roles in the midterms, as newcomers with deep pockets have rocketed to the top spots.

Steyer, who’d never contributed to a super PAC before March 2013, has given $70 million since, making him the largest single contributor to super PACs of all time. The vast majority of the former hedge fund manager’s contributions have gone to NextGen Climate Action, the campaign committee he founded.

Steyer pledged to make climate change a key issue in the mid-terms, but has given to groups like the Senate Majority PAC which has supported Sen. Mary Landrieu, D-La. Landrieu — one of several incumbents in close races that Democrats hope to win in order to preserve their Senate majority — supports the Keystone Pipeline, the controversial project that would transport oil produced from Canadian tar sands to U.S. refineries. At one point, Steyer insisted he would not support candidates who favored building the pipeline.

While Steyer has not insisted on ideological purity, he has more than made good on other promises, including his pledge to give $50 million to NextGen. He gave $5 million to Senate Majority PAC, while NextGen gave Fair Share Action, American Bridge and She’s Changed PAC donations.

The next biggest super PAC donor is former New York City mayor and publishing titan Michael Bloomberg, the Republican turned independent who now directs most of his support to Democrats. He’s donated more than $20 million as of the latest reports. Together, Bloomberg and Steyer gave more than the rest of our top donors combined.

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These figures represent preliminary data from the FEC collected by Sunlight’s Real-Time Federal Campaign Finance tracker. They are subject to change as refunds are processed by the FEC.

An important note: This list only compares individual super PAC donors. Unions, trade associations and corporations all make up other important pieces of the super PAC puzzle. The National Education Association, for example, the nation’s largest teachers’ union that overwhelmingly supports Democrats, contributed at least $17 million for super PACs this cycle. That’s likely a lowball figure since numerous local NEA affiliates have also been funneling money into super PACs.

Conservative donors haven’t abandoned super PACs, with seven giving $3 million or more. But political nonprofits — organizations that can influence elections without disclosing their donors to the Federal Election Commission — appear to be footing the bill for a larger chunk of the ad wars. How many big donors fund these dark money groups is unknown.

The two biggest conservative givers both hail from the financial world.

Paul Singer, a hedge fund manager, has been shoveling money into central players like American Crossroads ($2.6 million) while also venturing in to obscure House races to support pro-gay rights Republicans through his American Unity PAC. Robert Mercer, who serves as a co-CEO of hedge fund Renaissance Technologies, has given more than $8 million this cycle, spread among 13 different committees, the largest benefactor being the Koch-allied Freedom Partners Action Fund, which received $2.5 million from Mercer in September.

One of the biggest differences between our 2012 list and the current iteration is the lesser role of Mr. Super PAC himself, Sheldon Adelson, the conservative casino magnate. He and his wife Miriam spent more than $90 million last cycle to defeat Obama. Recently, Adelson wrote a $5 million check to the Congressional Leadership Fund. And media reports indicate the Las Vegas based Adelson has given hefty sums to groups that don’t disclose their donors.

Ken Vogel of Politico reported in September that the 81 year old had given $10 million to Karl Rove’s Crossroads GPS, a political nonprofit that does not disclose its donors, and had promised millions more to former Republican lobbyist and Sen. Norm Coleman’s American Action Network, another nonprofit organization.

But that’s not the only shakeup among the conservative bench of millionaire donors. Two of 2012’s most prolific givers, developer Bob Perry and Harold Simmons of the multifaceted Contran corporation, died in 2013, though Perry still made our list. Meanwhile TD Ameritrade founder Joe Ricketts remains a prolific force on the campaign trail through Ending Spending Action Fund, a fiscal conservative group focused on the national debt and a major spender in several of this year’s competitive Senate contests.

While media mogul Michael Bloomberg was originally elected as a Republican in New York City, we’ve classified Rudy Giuliani’s successor as a Democratic giver since that’s who the bulk of his money is supporting. Bloomberg made our list last cycle by giving $10 million while still in office, but since his term expired he’s doubled that sum. At publication he had contributed $20 million to super PACs in the 2014 midterms.

Among them is Independence USA, a group Bloomberg started himself. Its website states the PAC “will focus on issues including gun laws, education policy and marriage equality,” but it has been the first item on that list that has defined its electoral work this cycle. Bloomberg has also given $2.25 million to Women Vote!, the super PAC arm of Emily’s List. He’s also doled out $250,000 contributions to former Arizona Rep. Gabby Giffords’ Americans for Responsible Solutions and the League of Conservation Voters Victory Fund.

While he’s tilted heavily to Democrats this cycle, Bloomberg’s political affiliates have come to the aid of some moderate Republicans, including a recent $1.9 million outlay on behalf of GOP Rep. Bob Dold of Ohio and more than $700,000 for Republican Mike Fitzpatrick of Pennsylvania. He also gave $250,000 to the pro-Thad Cochran Mississippi Conservatives.

Rounding out the liberal givers are NewsWeb executive Fred Eychaner and math wiz-cum-hedge fund manager James Simons, who founded Renaissance Technologies and whose multimillion dollar contributions have helped fuel Democratic super PACs House Majority and Senate Majority PAC.

Unfortunately, a large amount of political money remains hidden in nonprofit organizations. The difficulty in tracking the new political beasts is part of their appeal. Defenders of dark money argue that more rigorous disclosure rules would expose donors to harassment and stifle political speech. While Sunlight and other disclosure advocates have called for more transparency of the donors behind these electorally active groups, it doesn’t look they will be going away any time soon.