Billionaire and millionaire GOP donors have wasted more than half a billion dollars collectively in trying to take down 2016 Republican presidential frontrunner Donald Trump, a new report from the Center for Public Integrity published by Time Magazine shows.

Just on GOP candidates that have since dropped out of the race against Trump, the report found, donors have wasted a whopping $520 million. That amount doesn’t account for Sen. Ted Cruz (R-TX) or Ohio Gov. John Kasich, the only two remaining out of 16 total candidates against Trump.

The Center for Public Integrity’s Carrie Levine wrote:

So far, donors have funneled more than $520 million collectively into campaigns and outside groups supporting Republican presidential candidates who have now dropped out — and the primaries are far from over. Only U.S. Sen. Ted Cruz of Texas, Ohio Gov. John Kasich and Trump remain in the Republican presidential primary, and they’re aggressively courting those who once wrote checks to their opponents. But some GOP megadonors with millions of dollars to spend haven’t selected a new date to the presidential dance. Others are on the arms of their second and third choices.

While Trump is taking donations, he is not soliciting them, and is largely self-funding his entire presidential campaign. Trump’s highly successful presidential bid has infuriated donors, hence many have tried to hatchet his momentum—and in every case thus far, they have failed.

As Trump continues to succeed, and these donors continue to fail, Levine noted, some of those donors are surrendering to Trump—aiming to “abandon the field for now and instead funnel resources into downballot races.”

“Some key political groups dedicated to promoting Republican congressional candidates say they’re seeing interest from donors who would otherwise be focused on the presidential race,” Levine wrote before quoting Ian Prior—a GOP operative who represents not just a Super PAC backing GOP candidates in U.S. Senate races but also works for Karl Rove’s American Crossroads and Crossroads GPS.

Prior, quoted here in his capacity as the communications director for the GOP Super Pac “Senate Leadership Fund super PAC” and for Senate-focused GOP nonprofit group One Nation, said, “There have certainly been consistent concerns with the tenor and tone of the Republican nominating process.”

As such, Prior added, “The fight to keep the Senate has become one where there has been increased interest, focus, and attention from the donor community.”

Ultimately, according to Levin, most donors who have given big amounts in this presidential campaign have come up empty-handed.

“For instance, members of the Ricketts family, which owns the Chicago Cubs, contributed $5 million to a super PAC supporting Wisconsin Gov. Scott Walker’s presidential bid,” Levine wrote.

“Since Walker withdrew in September, the Ricketts have not thrown substantial support behind another presidential candidate. But since January, members of the Ricketts family have contributed $5 million to an anti-Trump effort, according to campaign finance reports filed with the Federal Election Commission.”

The Ricketts-backed Ending Spending Action Fund’s Brian Baker noted that “Everyone is all over the map” when it comes to whether to shift to backing yet another GOP candidate, and instead the Ricketts’ efforts have shifted more into Senate races like the one brewing in New Hampshire where Sen. Kelly Ayotte (R-NH) is fending off not just primary challenges but a strong general election bid from Democratic Gov. Maggie Hassan.

The Ricketts’ are hardly the only donors in the doldrums. Levine continued:

Another Republican megadonor, billionaire investor Paul Singer, supported U.S. Sen. Marco Rubio until he suspended his campaign earlier this month. Singer is also reportedly boosting anti-Trump efforts; one Rubio fundraiser who attended a meeting of supporters shortly before the Florida primary this month said Singer was outspoken on the subject of Trump, referring to him as a ‘plague.’ Singer did not respond to questions submitted through his lawyer about his political spending plans and his comments about Trump. New campaign finance reports filed Sunday show Singer gave $1 million to the anti-Trump Our Principles PAC.

The story continues by detailing how two mega-donors in Texas who originally backed former Texas Gov. Rick Perry—Welcome Wilson, Sr., and his son Welcome Wilson, Jr.—have shifted to now backing Cruz, with the younger of the two backing his high school classmate former Florida Gov. Jeb Bush in the middle.

“I never support more than one candidate at a time, but I need to be realistic,” the elder Wilson said.

They’ve attended fundraisers for Cruz recently and are still trying to help the Texas senator.

“Wilson said his politically inclined associates are still willing to attend presidential fundraisers he’s hosting,” Levine wrote. “Wilson cites what he described as a well-attended fundraising breakfast he recently conducted for Cruz, which featured the senator’s wife, Heidi Cruz.”

Picking up the defeated candidates’ donors is a constant battle the Cruz campaign is fighting for, Cruz fundraiser Mica Mosbacher told Levine.

“We asked folks in, say, the Bush or Rubio camp to consider Cruz as a second, third, fourth choice,” Mosbacher said. “Money is not drying up for Cruz. His path is still possible.”

Cruz does seem to the establishment’s last hope to stop Trump, as even arch enemies of his like former Massachusetts Gov. Mitt Romney—the 2012 GOP nominee who failed to win the presidential election—and Sen. Lindsey Graham (R-SC), among others, have now aligned behind him. The question is whether this realignment of the Washington establishment behind Cruz is happening too late, or if there will be enough time left to stop Trump heading into the final stages of this presidential primary. Kasich’s lingering in the race is likely to have an effect on the outcome, and it’s unclear at this time whether Kasich remaining helps Cruz or Trump—or hurts both of them—more.

But ultimately, even Cruz’s efforts to get the donor class behind him for one last anti-Trump push isn’t going as well as the Cruz team may hope, Levine rounded out her piece by noting.

“In contrast, two ‘bundlers’ who raised money for Bush’s campaign and subsequently for Rubio’s effort said some donors in their networks are reluctant to support yet another presidential candidate,” Levine wrote. “This is forcing the bundlers to be judicious as they consider their next move. Both men asked not to be named, saying they didn’t want Trump, Cruz or Kasich — or other downballot candidates, for that matter — nagging them for money. One campaign bundler said he will likely support Cruz. Another said that for now, he’s taking a break from presidential fundraising — and may look at supporting Senate candidates, instead.”