Donald Trump's company charges the Secret Service for the rooms agents use while protecting him at his luxury properties.
US taxpayers pick up the tab at rates as high as $650 (€593) per night, according to federal records and people who have seen receipts.
Those charges, revealed for the first time, show Mr Trump has an unprecedented - and largely hidden - business relationship with his own government. When he visits his clubs in Palm Beach, Florida, and Bedminster, New Jersey, the service needs space to post guards and store equipment.
His company says it charges only minimal fees. Secret Service records do not show that.
At Mr Trump's Mar-a-Lago Club, the Secret Service was charged the $650 rate dozens of times in 2017, and a different rate - $396.15 - dozens more times in 2018.
And at the Trump National Golf Club Bedminster, the Secret Service was charged $17,000 a month to use a three-bedroom cottage on the property, an unusually high rent for homes in that area, according to receipts from 2017. Mr Trump's company billed the government even for days when he wasn't there.
These payments appear to contradict the Trump Organisation's own statements about what it charges members of his government entourage. "If my father travels, they stay at our properties for free - meaning, like, cost for housekeeping," Mr Trump's son Eric said last year.
The full extent of the Secret Service's payments is not known. The Secret Service has not listed them in public databases of federal spending, as is usually required for payments of more than $10,000 (€9,130).
'The Washington Post' compiled available records and found 103 payments from the Secret Service to Trump's company dated between January 2017 and April 2018.
The records show more than $471,000 in payments from taxpayers. But - because these records cover only a fraction of Mr Trump's travel during a fraction of his term - the total is likely to be higher.
"It is more than a little disconcerting, knowing this is going on, and not knowing what the actual numbers are," said Jordan Libowitz, of the watchdog group Citizens for Responsibility and Ethics in Washington. "That's kind of crazy that we know the president is benefiting from the presidency, and we do not know how." (© Washington Post)