Even Ted Cruz has more money than Trump: $6.8 million, almost three times the billionaire’s campaign savings. Trump’s debt is unprecedented in recent history, blowing away even John McCain, whose money problems in early 2008 threatened his bid.

Trump’s debt comes with a Taj Mahal-sized caveat, however. He owes nearly all of it to himself. Trump’s infusions have funded the majority of his campaign’s $63 million in spending—it started out with drips and drabs in 2015 but recently accelerated to a torrent of cash. (That doesn’t mean he’s footing the whole bill, as he likes to say; outside contributors have donated $17 million.) About one-tenth of that has been plowed back into Trump’s own companies, much of it going to airfare for his own famous jets. Sixteen years ago, Trump told Forbes he could be “the first presidential candidate to run and make money on it.” That’s unlikely, unless you count the free exposure the Trump brand is getting. It is true, though, that depending on how much his companies have marked up the price of their services versus the actual cost, he’s almost certainly getting a deep discount on running for president—presuming he can recoup his loans.

That could be a problem. Trump’s campaign debt may be a mirage for now, but it will become crushingly real soon enough, and his lackluster fundraising will be to blame. Until his acceptance of the nomination at the Republican National Convention, Trump can use campaign funds to pay back loans without limit, replenishing his personal bank account with contributions and proceeds from the “Make America Great Again” hats. But that spigot closes at the conclusion of the convention. At that point, Trump has 20 days to use cash received before his nomination to pay off loans. If he gets any new contributions to his primary campaign, he can only use up to $250,000 to pay himself back. (A similar cap applies for any loans he might make to himself during the general election, the cut-off date being November 8.)

That means the billionaire has a deadline. If he has any hope of seeing his own money paid back, his campaign needs to raise more than $40 million in the next month. That’s on top of the millions he needs per month to actually run for president. In May, Trump raised just $3 million. Momentum is not on his side.

Yes, the Republican National Committee will undoubtedly help the campaign out. And Trump has said before that he wouldn’t try to recoup his loans. Then again, he also wasn’t going to accept outside donations; Tuesday saw the launch of his first fundraising email. Read cynically, his offer to match each donation with a contribution of his own could seem like a clever way to guarantee ready capital to repay his own investment, should he structure his contribution as another self-backed loan.