Fredreka Schouten and Christopher Schnaars

USA TODAY

WASHINGTON — Nearly half the money pouring into all federal super PACs came from just 107 people or groups that each gave $1 million or more to influence the outcome of this year’s presidential and congressional races, a USA TODAY analysis of new campaign finance reports shows.

Robert Mercer, a publicity-averse hedge fund magnate backing Texas Sen. Ted Cruz’s bid for the Republican presidential nomination, has topped giving, contributing $14.1 million to super PACs that can raise and spend unlimited amounts.

Close behind: Tom Steyer, another billionaire who made his fortune running a hedge fund but now uses his money to push an environmental agenda that largely aids Democrats in federal and state elections. Steyer donated $13 million to his own super PAC, NextGen Climate Action Committee.

Meet the mega-donors

Republican donors dominate the giving, accounting for 70% of $253.1 million that the mega-donors sent to all super PACs during 2015. Only three Democrats — Steyer and financiers George Soros and S. Donald Sussman — rank among the top 20 super PAC donors so far in 2016 contests.

Most donations from the super-rich are aimed at the presidential race — the first wide-open contest for the White House since 2008. In all, 93 of the mega-donors — many with ties to energy companies or Wall Street — directed $183 million to super PACs specifically aligned with presidential contenders.

Toby Neugebauer, an energy investor who donated $10 million to a pro-Cruz super PAC, called Cruz the “most accomplished conservative in the country.” He said more “checks are fixing to come in” from other donors impressed by Cruz’s big win over Donald Trump in the Iowa caucuses.

This year marks the second presidential election since a pair of federal court rulings, including the Supreme Court’s 2010 Citizens United decision, allowed corporations, unions and wealthy individuals to band together and spend unlimited amounts in candidate elections.

The analysis, which examined super PAC donations in 2015, shows a presidential contest fast racing toward the $1 billion mark in fundraising as super PAC donors seek to boost their favorite candidates.

The cash-rich super PACs are fueling record outside spending. Super PACs and other groups active in the White House contest reported pumping $176 million into advertising, mailers and other independent expenditures reported to the Federal Election Commission as of Friday, a tally by the non-partisan Campaign Finance Institute shows. That’s up from $45 million during the same period in the last presidential race.

Right to Rise, a super PAC supporting former Florida governor Jeb Bush had spent the most — more than $70 million. Despite Right to Rise's relentless advertising, Bush finished sixth in the Iowa caucuses and ranks fifth in RealClearPolitics average of recent New Hampshire polls.

A group backing Bush’s former protégé, Florida Sen. Marco Rubio, ranked second in independent spending through Friday, spending $25.3 million. In third place: America Leads, a super PAC working to boost New Jersey Gov. Chris Christie ahead of Tuesday’s primary in New Hampshire.

America's richest pick sides in '16 contests

Other super PACs still are sitting on huge stockpiles. Three families — Neugebauer, Mercer and Texas energy billionaires Farris and Dan Wilks and their wives — collaborated to donate a combined $36 million to a network of pro-Cruz super PACs early last year.

That family of Cruz super PACs — all of which bear the name Keep the Promise — had nearly $30 million in cash reserves at the start of 2016, on top of the $18.7 million Cruz’s campaign still had in the bank.

Neugebauer, whose money has funded Keep the Promise II, would not discuss future spending or strategy but said the plan never was to spend money heavily and early the way the Bush super PAC has. Cruz’s win in Iowa, he said, is the result of a carefully developed and sophisticated strategy to draw in small donors and turn out voters.

“This is deliberate,” he said. “This has been planned, and it’s working.”

Meet the people who give campaign money to billionaire Donald Trump

New campaign finance reports show some wealthy Democrats have stepped up their super PAC giving during the final half of 2015.

Priorities USA Action, a super PAC aligned with Hillary Clinton’s bid for the Democratic presidential nomination, saw its donations increase by more than 60% during the second half of the year — fueled by a $6 million infusion from Soros, and $1.5 million each from several other donors, including Sussman and Haim Saban, a Hollywood mogul best known for his hawkish pro-Israel stance and for creating the Power Rangers children’s TV series.

Priorities has spent little on Clinton’s behalf so far, as it marshals its resources for a general-election battle if Clinton wins the Democratic nomination.

Steyer, despite his enormous wealth and influence in Democratic politics, has refrained from unleashing his money to favor either Clinton or her rival, Vermont Sen. Bernie Sanders. Steyer, who runs his own super PAC and political organization, was the biggest individual donor of the 2014 midterms and spent more than $70 million of his hedge-fund fortune in that election to influence Senate races with mixed results.

In the 2016 election, Steyer said his goal is to advance climate change as a top issue, rather than provide an early boost to individual candidates.

"We truly think that our job in this campaign is to elevate the awareness and the significance of clean energy and climate," Steyer told USA TODAY on Monday.

His NextGen Climate group announced Monday that Sanders had joined Clinton in signing its pledge to commit to a goal of 50% clean energy powering the country by 2030.

Steyer would not talk about how much he intends to spend in the months ahead but his team is building field operations in four states important to the presidential election: Iowa, New Hampshire, Ohio and Florida.

The group established 10 offices Iowa ahead of the recent caucuses in the state, where Steyer said his team persuaded more than 30,000 voters to agree to caucus for candidates based on their energy policies. He said NextGen has seven field offices in New Hampshire and a presence on 14 college campuses.