Each candidate's super PACs, which can accept unlimited donations as long as they don't coordinate spending with the campaign, will file their first finance reports of 2015 by Friday. These reports will show just how much each allied group has in the bank to launch negative advertisements against their opponents, organize field programs in early states and march through what could be a slog of a nomination fight.
Most super PACs have already released top-line figures for the amount of money they raised in the first half of the year. But on Friday, the actual reports will reveal which of the nation's mega-donors have chosen to back their campaigns, a particularly important indicator of strength in the fractured Republican field.
Political observers are looking to if any surprise names who have cut million-dollar checks to their favorite candidate turn up and to see how split is the powerful Koch Brothers network of donors, which meets this weekend in California.
Here's what we've learned so far:
Ted Cruz's super PAC supports ... Carly Fiorina's?
CNN's MJ Lee picks up
an unusual tidbit in the report for Carly Fiorina's super PAC, which has been outsourced many functions by the official campaign.
Carly for America -- which is the super PAC, not the campaign -- received $500,000 from Keep the Promise I, the super PAC funded by Robert Mercer to support Ted Cruz. It's unclear if Mercer -- who has given $11 million to that super PAC, sources say -- has repurposed some of that money to support Fiorina, or if there is something else afoot. Mercer at least supports Fiorina personally -- he gave $2,700, the legal maximum, to her official campaign.
That Cruz super PAC received $11 million from Mercer, the New York hedge fund magnate, the largest individual donation we've seen so far.
Bobby Jindal wins only one million-dollar donor
The Louisiana governor's sole million-dollar check comes from Gary Chouest, who owns a company that specializes in shipping. He only raised $3.6 million total, trailing other Republicans solidly in fundraising, just as he does in the polls.
Norman Braman only sinks $5 million into Rubio's super PAC
Marco Rubio's longtime Miami mentor, Norman Braman, has reportedly been willing to send up to $10 million to his super PAC. But a filing obtained by CNN shows that he's only in for $5 million so far.
Two other donors are opening their wallets wide to back Rubio: former Oracle CEO Larry Ellison, who gave $3 million to Rubio's group, Conservative Solutions PAC, and Floridian Laura Perlmutter, who is married to the head of Marvel Entertainment, Ike. Perlmutter gave $2 million.
Together, Braman, Ellison and Perlmutter gave $11 million of the $16 million raised by the group. Rubio also has a political nonprofit group -- which isn't required to disclose its donors -- that raised another $16 million.
Mike Huckabee is very, very dependent on Ron Cameron
The independent group supporting Mike Huckabee raised $3.6 million. $3 million of that came from one man: Ron Cameron.
The chairman of an Arkansas poultry producing business, Mountaire Corp., Cameron has ties to the Koch Brothers' political network. Huckabee, who has strong support among evangelicals in Iowa but has never been a particularly strong fundraiser, only collected checks for his super PAC from five other donors -- including one operative, Nick Ryan, who runs it.
A $10 million donation to Ted Cruz
Ted Cruz's four super PACs are designed to give donors maximum control over their donations, and Toby Neugebauer certainly has control. Neugebauer, a Houston oil investor and the son of a congressman, gave a $10 million donation to Keep the Promise II -- the largest single contribution we've seen so far.
The other three Keep the Promise groups supporting Cruz haven't yet filed as of early afternoon.
Cubs owner Ricketts gives $5 million to Walker
The powerful Ricketts family -- who have been spending increasingly large amounts of their personal fortune on politics in recent elections -- is backing Scott Walker.
As CNN's Tom LoBianco reports
, Joe and Marlene Ricketts gave his super PAC, Unintimidated PAC, $5 million -- which accounts for a quarter of the Walker group's haul. Joe's son, Todd, is the Walker campaign's finance director, but he isn't legally allowed to coordinate with the outside spending group.
The Ricketts run a super PAC and a political nonprofit, both called Ending Spending, that combined to spend nearly $30 million in the 2014 midterm elections.
Also giving $5 million to Walker is Wisconsin roofing billionaire Diane Hendricks.
Steve Cohen and his wife give $2 million to support Chris Christie
Hedge funder Steve Cohen, one of the wealthiest people in the United States and a longtime Chris Christie supporter, and his wife have given the New Jersey governor's super PAC $2 million, according to a filing obtained by CNN.
Also giving $1 million to America Leads, Christie's super PAC, is a corporation linked to Reebok founder Paul Fireman.
Ken Langone, a co-founder of Home Depot and one of the New Jersey governor's most outspoken backers, gave $250,000 to Christie. Also pitching in are professional wrestling executive Linda McMahon and Arkansas businessman Warren Stephens, two of the biggest Republican donors in the 2014 midterms.
The group has $10.7 million on hand as of June 30.
Jeb Bush's historic super PAC haul is historically deep
What is perhaps most impressive about Jeb Bush's super PAC — beyond its record-setting haul of $103 million — is how deep that support runs. Unlike many of his competitors, who are dependent on a few names, Bush collected about two dozen donations of more than $1 million, which altogether only accounted for about 25% of the money his super PAC raised.
No donor gave more than $3 million to Bush's group, which he fundraised for aggressively
throughout the first half of 2015. More than a dozen of his $1 million donors hail from one of the states Bush has called home: Texas and Florida.
Many of the top donations come from donors with ties to the previous two Bush administrations, including contributions from the former presidents themselves. George H.W. Bush gave $125,000 to his son's super PAC, but George W. Bush only gave $95,000 to his brother's.
Original Ted Cruz super PAC supplanted — only raises $250,000
The creation of Stand for Principle, a super PAC dedicated to electing Ted Cruz, right after Election Day was read as the clearest signal yet that Cruz allies were gearing up for a presidential run.
But now, that group — which has indicated it would focus more on grass-roots engagement — seems to be faltering, having only raised $250,000 in the first half of 2015. A constellation of four other super PACs, Keep the Promise, have elbowed out the original Cruz groups and raised $38 million.
All of that $250,000, save $500, came from a New Jersey limited liability corporation.
John Kasich's 527 committee got four seven-digit gifts
Ohio Gov. John Kasich is drawing on some of his state's top givers to bankroll his new presidential campaign.
Three individuals or companies from Ohio wrote him more than $1 million between April and June: Philanthropist Abigail Wexner, real estate firm Schottenstein Management Company, and Ohio donor Tom Rastin, who is married to a woman who has donated to organizations in Koch Brothers' network, Karen Wright. A California family trust also gave another $1 million.
"Gov. Kasich has built a strong base in Ohio and has attracted donors nationally because supporters have seen, many firsthand, how his policies and leadership are working in Ohio," said Connie Wehrkamp, a spokeswoman for Kasich's group.
The group, which raised a total of $11.1 million, filed its report with the Internal Revenue Service -- and not the Federal Election Commission -- because it was a tax-exempt organization and not yet a super PAC at the time of the filing.
Jeff Yass: Rand Paul's sugar daddy
The Kentucky senator has three separate super PACs financing his independent spending: America's Liberty PAC, run by a longtime family aide, Concerned American Voters, a grassroots organization, and Purple PAC, a libertarian advocacy group repurposing itself as a Paul group.
Behind all those groups is Philadelphia investor Jeff Yass, who gave $2.25 million of the $6 million that the three groups raised. Yass -- who gave $250,000 to Concerned American Voters and $1 million to each of the other two groups -- runs Susquehanna International and reportedly learned about options trading as a brilliant poker player
Other big donors to Paul's super PACs are Paypal board member Scott Banister ($1.25 million) and George Macricostas ($1.1 million.)
Lindsey Graham has three $500,000 donors
The South Carolina senator's super PAC, Security is Strength, raised 50% of its $3 million from three donors: Houston Texans owner Bob McNair, philanthropist Ron Perelman and a New York holding company founded by investor Len Blavatnik.
Other prominent donors include Marlene Ricketts, the wife of one of the Republican Party's most prominent donors, Joe Ricketts, who gave $10,000, and General Electric chief and former Obama administration official Jeff Immelt, who gave $25,000.
The group had $2.75 million on hand as of June 30.