The New York real estate magnate lagged far behind Clinton in the campaign money stakes in May, raising only $3.1 million to her $26 million, according to federal disclosures filed late on Monday. Trump’s campaign began June with $1.29 million in cash, well-behind Clinton’s $42 million war chest.

The figures underscore the huge cash advantage Clinton is hoping to enjoy leading into the Nov. 8 presidential election, one that could allow her a large staff and millions of dollars of television and digital ads in battleground states.

But Trump has spent much of the race so far breaking the mold of a traditional campaign, defeating a crowded field of primary opponents who vastly outspent him in ads and staff.

“If need be, there could be unlimited ‘cash on hand’ as I would put up my own money,” Trump said in a statement, adding that he had already spent over $50 million dollars on his bid for the White House. “Our campaign is leaner and more efficient, like our government should be.”

Trump donors, allies and other Republican operatives have expressed concerns about his campaign operation, which has been dogged by internal battles, a threadbare campaign infrastructure of about 30 paid staffers, and a barely existent fundraising apparatus.

On Monday, Trump fired his campaign manager, Corey Lewandowski, who had been overseeing the fundraising arm.

Trump has loaned his campaign $46 million since launching last year, federal filings show. He often uses his own plane to travel to campaign events, and also uses his hotels and other properties as venues - expenses he asks his campaign to reimburse.

During the Republican primary race, he shunned donations, often telling his supporters not to contribute money and ridiculing his opponents for accepting cash from special interest groups and wealthy contributors.

UNORTHODOX

“Trump defeated the most talented GOP field in a generation with less staff, less experience and less money in much less time,” said Republican strategist Keith Appell.

“That said, Trump’s campaign needs to transition quickly to a national, general election effort online, on the air and on the ground – his populist, anti-Washington, new leadership message has been muddled by sideshow issues.”

Trump began soliciting donations to his campaign only recently, after largely self-funding his successful bid for the Republican nomination. His first fundraiser was near the end of May, and on Tuesday he sent his first email asking for donations and telling supporters that he will match their contributions up to $2 million.

Trump’s haul in May was about double previous months. The candidate said that his take in June will be more representative of his progress with donors. Trump’s allies have said much more cash is now coming in for the general election.

His campaign finances drew a flurry of taunts on Twitter on Tuesday morning, including a #TrumpSoPoor hashtag mocking the billionaire. One post joked he had listed his Mar-a-Lago estate in Florida as an Airbnb rental, a platform often used by people trying to earn cash off their homes.

The former reality TV star still may have several hurdles to cross before convincing deep-pocketed donors to write the kind of checks that would make him competitive with Clinton’s campaign bank account.

The Republican National Committee, meanwhile, announced it raised $11 million in May, and had $19.9 million in cash at the beginning of June. The RNC will help Trump’s effort to get elected, but also helps fund congressional races.