The one presidential candidate who's staked his reputation on being "really rich" is actually not all that rich, at least, not as far as his campaign is concerned.

On Monday, the Federal Election Commission's monthly report revealed a historic gap between Hillary Clinton and Donald Trump's campaign war chests. Where Clinton ended the month with $42 million in cash on hand, Trump rounded out May with just $1.3 million. To put that in context, that's less than the $1.8 million Ben Carson's campaign still has left, and Carson dropped out of the race in March.

Word traveled fast, and overnight, the hashtag #TrumpSoPoor began trending on Twitter, spawning endless tweets about his business dealings...

His looks...

And of course, making Mexico pay for his campaign...

But while Trump's lack of cash may be shocking compared with Clinton's abundance of it, it's not all that surprising in the context of his campaign. Trump essentially self-funded his primary run and regularly spoke on the stump about why he wasn't seeking money from outside donors. That rhetoric may have worked to sway primary voters, but it's not a realistic strategy to fund an official presidential campaign in the general election.

The FEC report is an early reflection of Trump's initial attempts at true campaign fundraising. It's dismal, but it's important to bear in mind that it reflects only the month of May. The next report, issued in July, will provide a clearer picture of whether Trump is truly struggling to raise money now that he's really trying. The true challenge, however, will be matching Clinton's on-air attacks. Already, reports show Clinton has reserved $117 million in TV ad time. Trump has reserved about zero, which means any ads he does place will come at a premium—a premium it doesn't look like the Trump campaign can quite afford.

What's just as telling as how much money the Trump campaign has raised, however, is where exactly that money is going. The answer: back into Trump's pockets. According to the FEC filing, nearly 20 percent of Trump's campaign expenditures have been spent on Trump-owned venues and airlines, as well as on members of the Trump family.

Talk about a self-funded campaign. Trump is, quite literally, funneling money back to himself. There are, for instance, a number of payroll disbursements to Donald J. Trump himself. There is a $423,000 payout to his Mar-A-Lago golf club and a $349,000 payment to Tag Air, a Trump-owned airline. And that's just from May. There's also a nearly $30,000 rental expense for Trump International Golf Club, and a nearly $36,000 fee for Trump National Golf Club. The list goes on.

The Trump campaign did not respond to WIRED's request for comment, but a spokesperson told NBC News the campaign has "no concerns" about funding. And why should it? With all that money flowing back into Trump's empire, perhaps #TrumpIsn'tSoPoor after all.