The rumors are true: Democrats have learned to love the super PAC.

Sunlight’s review of year end filings finds that, in a reversal of last cycle’s trend, the top two individual donors to super PACs in 2013 (by a long shot) both lean Democratic. Former NYC Mayor Michael Bloomberg, who ran as an Independent, and California billionaire hedge fund  manager-turned-environmentalist Tom Steyer combined to account for nearly $20 million in donations to groups pushing their respective policy agendas nationwide. The next closest individual on our list? The deceased Bob Perry, who spent $3.1 million on conservative causes before he passed away in April of last year. Another prolific GOP donor, Howard Simmons, also died last year; his Contran corporation and individual contributions in 2013 amounted to $1.2 million.

As Mother Jones notes, President Obama and Democratic leaders in Congress initially took an aggressive stance against the Supreme Court’s Citizens United decision that allows unlimited spending by outside groups as long as it was not coordinated with candidates. The president publicly worried the ruling would “open the floodgate for special interests — including foreign corporations — to spend without limits in our elections.” The latest filings show there is plenty of money from inside our borders.

While some liberal leaders simultaneously deride the outsized role of single donors in elections while capitalizing on the rule, thus far in 2014 elite donors on the left are not shying away from spending millions to help Democrats win in places like Massachusetts.

Here are the top five individual donors to outside spending groups in 2013 with summaries of their super PAC giving. Note that this analysis is based on electronic filings at the Federal Election Commission (FEC) and depend on their accuracy. Also, by definition, these amounts do not include contributions by these individuals to so-called “dark money” groups that are not required to report their donors, nor does it include all spending at the state level.

Thomas Steyer, $11.1 million

A long-time donor to Democratic causes, Thomas Steyer’s contributions to federal and state elections have topped $40 million over the years, according to Influence Explorer. He contributed a whopping $32 million to California’s Proposition 39, a tax initiative that won approval from voters in 2012, The Californian is a billionaire hedge fund maestro turned environmentalist who poured some $11.1 million into Super PACs in 2013.  All of this went to his own Super PACs, NextGen Climate Action Committee and CE Action (formerly known as NextGen Committee). CE Action spent more than $1 million supporting longtime House Democrat Ed Markey’s successful bid for the U.S. Senate. The Super PAC also gave $250,000 to the League of Conservation Voters Super PAC, which was supporting Markey in the race.

CE Action has also given contributions to other groups of environmental or liberal bent: $125,000 for the The National Wildlife Federation Action Fund; $75,000 for the American Values Network, a Christian progressive group; as well as $30,000 apiece for the Chesapeake Climate Leadership Alliance and the Virginia New Majority. And NextGen Climate Action was a top donor in the Virginia’s governor’s race, spending $1.7 million to support Democrat Terry McAuliffe’s successful campaign, according to the Virginia Public Access Project.

Steyer, who stepped down from leadership of Farallon Capital Management to devote himself to environmental causes, has centered his efforts on climate change and the Keystone pipeline. Along with some other environmentally inclined donors, he has been pressuring President Barack Obama to oppose the pipeline, including running an anti-Keystone ad during Obama’s recent State of the Union address. Last April he hosted a fundraiser for the DCCC featuring the president at his house in San Francisco, where he reportedly pressed him on the issue.

Michael Bloomberg, $8.7 million

The now-ex mayor of New York City and Republican-turned-Independent has poured more than $622,000 into Independence USA, the super PAC he founded to “support moderates on both sides of the aisle” who favor gun control, marriage equality and education reform. The PAC, in turn, spent $2.2 million to eliminate Debbie Halvorson, a pro-gun, former one-term House member who was running in a special election in Illinois 2nd Congressional District. Kelly lost the race to Robin Kelly, who went on to win the election. The PAC also spent heavily — $732,000 — to help elect Democrat Cory Booker to the Senate in an October special election.

Bloomberg also contributed to $250,000 to Americans for Responsible Solutions, the pro-gun control super PAC founded by former Rep. Gabrielle Giffords, D-Ariz., and her husband, former astronaut Mark Kelly. The super PAC appears to be hoarding money to spend this election year: It raised more cash than any other issue-based super PAC last year but spent nothing on independent expenditures, and is sitting on $6 million cash on hand. Another $2.5 million went to the Senate Majority PAC, a Democratic super PAC that spent cash last year helping elect Ed Markey as the Democratic senator from Massachusetts; defending Sen. Kay Hagan, D-N.C., from attacks by Americans for Prosperity, and opposing Sen. Mitch McConnell, R-Ky. He also spent some $3.1 million in independent expenditures as well as direct contributions to help elect Democrat Terry McAuliffe win the Virginia governor’s race, according to the Virginia Public Access Project.

We also know that the money Bloomberg spent on super PACs is only part of his giving strategy. Mayors Against Illegal Guns, a nonprofit founded by Bloomberg and other big city mayors in 2006, waged an air war for gun control legislation last year. A review by Sunlight of ads captured by Political Ad Sleuth, the Sunlight tool that tracks media buys across the country, showed that the group was active in 17 states, with the ads peaking around a key Senate vote in April, in which senators voted against strengthening the background check system for gun buyers. The ads also synched state level debates over gun legislation in Colorado, Nevada and New York. Because the group is registered as a 501(c)4 group under IRS regulations, it does not disclose its donors. And Bloomberg has also given cash directly at the state level, including $350,000 to help defend two Colorado state senators facing recall elections last September, who lost, as well as more than $1 million from his philanthropies for an education ballot initiative.

Bob Perry, $3.1 million

The Republican party lost one of its most prolific donors with the passing of Houston-based homebuilder Bob Perry, who died in April of last year. Perry made more than $50 million in political contributions during his lifetime and the waves of cash did not abate in his final year, in which he gave more than $3 million to super PACs.

Though Perry was known as a major financial backer of the “establishment” wing of the Republican party (he contributed more than $15 million to Karl Rove’s American Crossroads and backed former Lt. Gov. David Dewhurst over Tea Party darling Ted Cruz), in his final year he gave generously to both camps: $2 million to Texans for a Conservative Majority (affiliated with Sen. John Cornyn), a $1 million check to Senate Conservatives Action (the super PAC associated with former senator and current president of the Heritage Foundation, Jim DeMint, R-S.C.) and $100,000 to Kentuckians for Strong Leadership.

Senate Conservatives Action has blasted Senate Minority Leader Mitch McConnell, R-Ky., in ads and is supporting his Republican challenger — political newcomer Matt Bevin. Perry’s support for Senate Conservatives Action seems to clash with his giving to Kentuckians, whose stated goal on its website is “to ensure that Kentucky’s own Senator Mitch McConnell is reelected.” As reported by the Center for Public Integrity, the Kentucky super PAC originally listed the receipt of the $100,000 as taking place after the Houston homebuilder’s death, though this has since been amended. Before his death, Perry also made contributions to the campaigns of Rep. Paul Ryan, R-Wisc., and incumbent Sens. Ted Cruz and John Cornyn, R-Texas.

John Thomas Jordan, $1.7 million

Jordan is a California vintner who poured some $1.7 million of his own money into the special Senate election in Massachusetts. The winery executive was the sole benefactor of Americans for Progressive Action, a counterintuitively named super PAC that developed ads for moderate Republican Gabriel Gomez, a Navy veteran who ultimately lost to Ed Markey. The special election was held to fill the seat left vacant by former Sen. John Kerry, D-Mass., who was appointed to Secretary of State.

Although the California winemaker is not new to GOP circles — he contributed $94,100 to Republican committees during the 2012 cycle — his massive spending in a race on the other side of the country raised some eyebrows. “I couldn’t just sit by and watch and leave him alone while the establishment Republican groups decided to just sit on their hands and leave him on the beach,” Jordan, who described himself as a centrist, told the Wall Street Journal in March. Gomez supporters were vastly outspent by Democratic donors who poured millions into the race. Thomas Steyer, another Californian who made Sunlight’s 2014 list of top super PAC donors, also diverted some of his personal fortune into the Bay State Senate race in support of Markey.

Americans for Progressive Action ceased its spending after the unfavorable result in Massachusetts. It was officially terminated on Jan. 21.

Jonathan Soros, $1.02 million

The son of Democratic mega donor George Soros (who spent tens of millions of dollars against George Bush in his 2004 reelection campaign), CEO of investment firm JS Capital Management and Senior Fellow at the liberal Roosevelt Institute, the younger Soros has put $1,000,000 in the “anti-super PAC super PAC” he co-founded: Friends of Democracy, which ironically “seeks to build the political power necessary to force meaningful change in the way money flows in and around politics and the influence it wields.” The younger Soros accounted for more than half of the group’s receipts in 2013. Friends of Democracy, which ended the year with just over $1.9 million in cash on hand. Napster founder and former Facebook executive Sean Parker donated $250,000 while Google’s Matt Cutts contributed $200,000.

Soros has also donated old-fashioned hard money as well, including maximum contributions to would-be congressman Sean Eldridge (husband of Facebook co-founder Chris Hughes) as well as Democratic incumbents like Reps. Pete Gallego, Texas, and Dan Maffei, N.Y., and Planned Parenthood for a total of $18,000.