Oil mogul Harold Hamm gushed in his speech at the Republican convention Wednesday night, “President Trump will fuel America’s future, and he will be the first president to achieve American energy independence.”

But Hamm, the chief executive of the shale oil exploration company Continental Resources, hasn’t spoken as loudly on behalf of the Republican presidential nominee with his wallet. By April of the 2012 presidential election, Hamm had already had donated $985,000 to Mitt Romney’s Super PAC. In contrast, as of June 30, Hamm had made only a $5,000 contribution in June from Continental’s PAC, the same amount the PAC gave to several Congressional candidates.

Six weeks after Donald Trump appeared before petroleum producers in North Dakota and made a speech that seemed tailor-made to win their support, the fossil fuel industry appears to remain on the sidelines in the presidential campaign.

Trump promised to scrap the Obama administration’s climate plan and environmental regulations, open up federal lands to drilling, and revive the Keystone XL pipeline project—themes echoed in the GOP platform. Still, the oil and gas industry, historically a top backer of GOP presidential candidates, had forked over relatively little by the end of June to Trump’s campaign or to the Super PACs that support him, financial disclosures filed late Wednesday night show.

Of the $63.5 million raised in June by Trump and the Super PACS, about $580,000 came from people connected to the fossil fuel industry—80 percent of it flowing from one fundraiser in West Virginia hosted by coal magnate Bob Murray. The Murray Energy PAC and a regional insurance agent who underwrites the coal and gas industry wrote the largest checks: $100,000 and $150,000, respectively. The rest came in small donations from Murray employees, including coal miners, and companies that service or supply the mines.

Only about $106,000 came from individual donors who reported some connection to the oil and gas industry, in checks that ranged from as little as $5 up to the legal limit of $5,400.

Missing from Trump’s roster of donors are oil industry stalwarts of campaign finance, like ExxonMobil chief executive Rex Tillerson, who together with his wife gave $80,000 to Romney and thousands more to the Republican Party in 2012. Tillerson gave $2,700 to Jeb Bush’s campaign last fall, and has since given $35,000 to the Republican National Committee.

Similarly missing from Trump’s donations is Trevor Rees-Jones, chairman of Chief Oil and Gas, who gave $100,000 to Mitt Romney’s Super PAC in 2012, and donated more than $1 million to Bush’s Super PAC last year. The Koch brothers’ PAC has focused its more than $1 million in donations this campaign cycle on House, Senate and state races. Charles Koch told a business conference that a contest between Trump and Clinton would be like a “choice between cancer and a heart attack.”

It’s not that energy producers don’t like Trump’s stated plans. “Trump provides hope that some of the regulatory overreach can be overturned,” said Kathleen Sgamma, vice president of government and public affairs for the Western Energy Alliance, an oil producers’ group. But some mistrust his shifting positions; although he has promised to undo the Paris accord and once said on Twitter that climate change is a hoax invented by the Chinese, he also signed an open letter calling for climate action in 2009 before the international negotiations in Copenhagen.

One indication that the Trump campaign isn’t reading from a single energy playbook is a speech Donald Trump Jr., the candidate’s 38-year-old son, gave on June 24 in Fort Collins, Colo. The younger Trump, an avid hunter, touted the need for preservation. The candidate, too, has endorsed “protecting nature,” but contradicting his father’s public stance, he described as “very reasonable” the Obama administration’s rules restricting fracking on federal lands—regulations that the oil industry had just succeeded in having blocked in federal court. The GOP platform adopted this week would go even further, undoing the federal lands management policy of the past 40 years and giving states oversight of energy development on the federal lands that lie within their borders.

Another factor dampening giving: They don’t think he’s going to win. They don’t want to be seen pouring money into Trump’s campaign, and then be left with Hillary Clinton in charge.

“Nothing against either candidate, but we all wish there were better candidates,” Scott Sheffield, chairman and chief executive of Pioneer Natural Resources said at an energy security forum in Washington, D.C. on Tuesday. (Sheffield personally gave $2,000 to Bush’s campaign last fall.)

Of course, it is too early to tell whether the fossil fuel industry will stay out of the presidential race entirely. Although Trump had said he would not use a SuperPAC, one of his real estate industry friends set up something close to an official SuperPAC last month. SuperPACs are the only vehicles for mega-donations without campaign limits and a few claim to support Trump. At least one—the Great American PAC, which raised about $2 million last month—was in favor and then disavowed by the candidate; Whiting Petroleum chief executive James Volker was among its contributors in June.

Trump’s selection of Indiana Gov. Mike Pence as his running mate may inspire donors to come forward. Pence raised $7 million in his  gubernatorial campaign before he was tapped for vice president. He has strong ties to the big energy donors; David Koch is his third-largest all-time individual contributor, and Koch Industries’ general counsel, Mark Holden, is his sixth biggest,  the New York Times reported. Pence’s deputy chief of staff, Mike Lloyd, was also communications director for Koch Industries, and Mark Short, formerly president of the Koch-backed Freedom Partners, is his new communications chief.

Some political observers also believe that fossil fuel industry support for the campaign may simply be rerouted to “social welfare” nonprofit organizations that don’t have to disclose their donors. One of these, the American Energy Alliance (AEA), came out in favor of Trump on July 12, in what the eight-year-old group said was its first-ever presidential endorsement.

AEA president Thomas Pyle said the group, which ran advertising against Obama’s policies in the 2012 presidential race, will educate the public on the differences between Trump and Clinton on energy by using platforms like Facebook.

Pyle is a former lobbyist for Koch Industries, and the AEA is one of a large number of nonprofit advocacy groups that have gotten support from Freedom Partners, the Koch organization that helps raise and dispense contributions.

“He’s been very clear that he recognizes the harmful impacts of the president’s climate agenda on American families,” Pyle said. “He’s been very straightforward on what he wants to do, which is to get the government out of the way.”

Tyson Slocum, who heads up the energy program at the watchdog group, Public Citizen, said secretive groups will be especially attractive because many big corporations see Trump as “too toxic” to be openly associated with.

“The money is going to be going into the dark pools, which are going to be bigger than ever,” he said.

When asked how much support there was for Trump in the oil industry, Sheffield, the Pioneer chief executive, said it was important to remember how much doubt there was about Ronald Reagan’s ability as a leader during his campaign. “He turned out to be one of our greatest presidents,” Sheffield said at a forum of the Center for Strategic & International Studies, a Washington D.C. think tank. Sheffield added that either Trump or Clinton “may end up doing a great job.”

“The industry historically has actually done better under Democrats during my 42 years going back than under Republican presidents,” he said, noting Pioneer’s stock was one of the five best in the Standard & Poor’s 500 during the early years of the Obama administration. He said it will be important for the industry to reach out to both sides: “Our goal is to educate them well on the importance of a strong domestic oil and gas industry.”

“I think the industry will get behind whoever’s president,” Sheffield added.  “I can’t tell you if the industry’s going to support Trump in the next four or five months.”