Although Donald Trump has boasted about self-funding his presidential campaign with up to $100 million of his own money, it turns out that his campaign has actually been financed more by grassroots donors than the famous billionaire himself.

According to the Federal Election Commission (FEC), the GOP front-runner's campaign has spent slightly more money from Trump supporters than from his personal bank account in the third quarter. While Trump has invested $1.9 million of his own money into running for president, his campaign spent $4.2 million.

The FEC filings also show that the former reality TV star managed to raise $3.9 million from nearly 75,000 "unsolicited donations." Meanwhile, he spent $500,000 on paraphernalia, including his famous "Make America Great Again" hats and T-shirts, according to MSNBC.

Compared to his Republican rivals, Trump's $4.2 million spending is much lower than other 2016 hopefuls like Ben Carson, who spent $14.2 million this quarter, and Jeb Bush, who spent $11.5 million. In comparison, Democratic front-runner Hillary Clinton spent a whopping $25 million.

"To be No. 1 in every poll and to have spent the least amount of dollars of any serious candidate is a testament to what I can do for America," Trump said in a statement, according to NBC News. He added that he initially planned a "substantially higher" budget, but "good business practices" have kept costs down.

The filings also reveal Trump has not actually directed any of his own money to the campaign since June, when he invested a $1,081,647 interest-free loan. He began funding the campaign in April with a modest $292,650 through two loans, and then invested another $430,540 loan in May.

According to some Republican operatives, the FEC filing revealed a new picture of the Trump campaign.

"We don't know if Donald Trump is willing to open his pocketbook" until he "demonstrates he's willing to actually spend significant dollars," said Kate Packer, former deputy campaign manager for presidential candidate Mitt Romney.

"Just because someone's rich," she told NBC, "doesn't mean they're completely liquid, and it also doesn't mean that they're willing to write a blank check to support their campaign. So we just don't know."