Presumptive Republican presidential nominee Donald Trump often boasts about his wealth, but he may end up with a money problem ahead of November's general election.
Trump loaned his campaign most of its cash for the GOP primary, which he all but won last week when his last remaining rivals suspended their campaigns. But facing higher spending demands in a likely contest with former Secretary of State Hillary Clinton, the billionaire businessman has started to set up a more traditional fundraising organization.
Trump faces a tough task in quickly establishing a fundraising structure and securing the support of deep-pocketed Republican donors.
"I believe it's going to be hard. He's starting at a substantial organizational disadvantage to Hillary Clinton," said Michael Malbin, executive director of the nonpartisan Campaign Finance Institute.
The 2012 contest shows the huge financial demands of a general election. Both the Democratic and Republican sides shelled out more than $1.1 billion supporting President Barack Obama and Mitt Romney, respectively, according to the Center for Responsive Politics. Those figures include candidate committee, national party and outside group spending.
Despite his wealth, Trump likely cannot front that type of money. Last week, he appointed Steven Mnuchin, a former Goldman Sachs partner who is chairman and CEO of Dune Capital Management, as his national finance chairman.
Mnuchin told CNBC last week that the campaign has started to work with the Republican Party, which has had a strained relationship with Trump, to raise money. He added it is "in the process" of signing a joint fundraising agreement, which allows Trump and the party to combine fundraising efforts.
Mnuchin said they plan to raise more than $1 billion in pro-Trump cash. The Trump campaign is so far confident in its ability to raise money.
"Mr. Trump will be raising money for the party and has begun building a world-class team to execute a top-tier fundraising operation that will enable Republicans to take back the White House in the fall," campaign spokeswoman Hope Hicks said.
Trump may already face an organizational disadvantage to Clinton. He raised only about $12 million in individual contributions through the end of March, the most recent federal data available, instead loaning about $36 million to his campaign.
Outside groups supporting Trump have raised less than $3 million so far, according to the Center for Responsive Politics.
Through the end of March, Clinton's campaign committee had taken in more than $180 million. Outside groups supporting Clinton, meanwhile, racked up another $76 million, the center said.
"He's absolutely at a disadvantage because it takes time to build an organization," Malbin said.
Some top Republican donors have signaled they could back Trump. Casino magnate Sheldon Adelson, who previously donated to Sen. Marco Rubio of Florida, told The New York Times he will support Trump.
Home Depot co-founder Ken Langone, who had backed Ohio Gov. John Kasich, told CNBC he thinks Trump will "do a hell of a good job."
It remains to be seen if those comments translate to donations. Malbin noted that "at least some" of the traditional Republican donors may be reluctant to give to Trump.
Mobilizing small donors may be the best route for Trump, added Elaine Kamarck, senior fellow in the governance studies program at the Brookings Institution and author of "Primary Politics." In the primaries, Trump relied on the narrative that he did not need donor money and was not beholden to any special interests. That appealed to many of his supporters.
Relying on large donors may "create some problems for some of his supporters," Kamarck said.