Donald Trump's campaign is cash poor, but he's finding ways to cycle money from his White House bid back to his companies.

Fundraising reports show Trump has used about $6 million in campaign money to pay his companies and family members. The campaign paid for products and services that went back to Trump’s companies, to the tune of nearly 10 percent of his expenditures.

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Looking closely at the numbers, Trump donated $400,000 in campaign office space and salaries of some employees who are now working on his campaign. His campaign spent $423,000 on access to Mar-a-Lago, the private club in Florida that serves as Trump’s vacation home. His companies also charged the campaign for goods and services.

The biggest payment to a Trump company is the $4.6 million bill to TAG Air, the holding company of his airplanes. The campaign paid about $520,000 in rent and utilities to Trump Tower, another $26,000 to rent Trump National Doral, his Miami golf course, and $400 for Trump-branded water. About $5,000 in campaign funds went to Trump’s son’s wine company. Campaign shirts and hats were made by a company owned by a board member of Eric Trump’s charity, to the tune of $4.7 million.

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According to the Associated Press, there’s nothing illegal about the payments. Regulations require companies — even ones owned by the candidate — to charge fair-market value. But it could prove a tricky practice in the eyes of donors, who may wonder why should they donate to a candidate who will pay himself first with their donations.

News of Trump's spending practices caught Hillary Clinton's eye on Twitter.

CNN reports Trump-linked businesses account for 17 percent of all campaign expenses so far.

Trump began this month with $1.3 million in the bank. He raised about one-tenth what Clinton raised in May. He’s since vowed to match up to $2 million in campaign contributions.

– The Associated Press contributed to this report.

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