Donald Trump has forgiven $50 million in loans he made to his campaign, and fundraising efforts have kicked into high gear, his national finance chairman told CNBC on Thursday.

"[Trump] loaned $50 million to the campaign. He's now forgiven that loan. So that is a contribution," said Steve Mnuchin. "[Trump] has also said he will contribute significantly more money."

"We just forgave the loan this week," Mnuchin added in a "Squawk Box" interview.

Trump was severely lagging last month in efforts to raise money compared with Democratic rival Hillary Clinton, according to the latest filings with Federal Election Commission made public this week.

The New York tycoon and the Republican National Committee brought in about $18.6 million in May, including another loan from Trump. Clinton and the Democratic National Committee raised more than double that amount.

Trump's campaign started June with just $1.3 million in the bank, while Clinton's campaign began this month flush with $42 million, according to the filings.

Mnuchin told CNBC those numbers are "irrelevant," because the joint fundraising agreement with RNC was only signed in the last week in May. "Donald financed the campaign ahead of time, so there was no reason to have extra cash in the bank," he said.



"We've really ramped up the effort this month," said Mnuchin, who is also chief executive of hedge fund Dune Capital Management. "We've had some successful events in New York ... [and] those events have raised approximately $10 million in conjunction with the RNC."

Mnuchin said online fundraising began this week. "We've done about $6 million," he said. "[In] the first email that went out Monday, Donald matched $2 million online."

Overall, Trump does not need nearly as much money in the general election as Clinton, Mnuchin said. "He's proven in the primary that he's been able to be very efficient," he said.

"[Trump] has a huge online presence with over 20 million followers. This is going to be a nontraditional campaign," the finance chairman added. "This is going to be a campaign driven by social media and driven by free TV."

The May fundraising totals were double whammy in the headlines for Trump on Monday, which also saw the departure of two high-profile campaign staffers.

First, Trump fired his campaign manager Corey Lewandowski, following long-simmering disputes with chief Trump strategist Paul Manafort.

Second, Trump's New York campaign director Michael Caputo — who reveled in Lewandowski's dismissal by tweeting, "Ding dong the witch is dead" — stepped down on Monday.



"They're not going to replace [Lewandowski], per se. Paul is overall managing the strategy of the campaign," Mnuchin said. "The campaign is in transition and growing."

Addressing the issues, Mnuchin said: "This campaign and this election is all going to come down to two things: national security and the economy."

"I'm absolutely convinced he has plans on both to make this country great," he said, such as plans to reform the tax code, reduce regulations for businesses, and make sure fair trade.