The check was written by the mayor himself – to cover what Reed described as potentially "troublesome" expenses.
Reed showed an image of the 2016 check to 11Alive on July 27. After he was sworn in for his second term in 2014, Reed’s campaign treasury stayed active – spending campaign money to upgrade his airfare and hotel expenses as mayor, among other things.
During the July interview in which he was questioned about campaign expenses, Reed said that he'd written the $15,500 check to his campaign from his personal account "just in case there were any expenses that were troublesome."
"It was to cover any de minimis items because, at the time, I was in consideration for a cabinet position," he added.
The date on the check was December 20, 2016 -- one month before the end of President Barack Obama's second term and six weeks after Democrat Hillary Clinton lost her presidential campaign to Donald Trump.
"With large campaigns, sometimes (improper expenditures) can slip through cracks," said Marc Hershovitz, an attorney who advises Democratic campaigns on financial issues and has no client in the mayor's race.
However, concerning Reed's check Hershovitz said, "where someone is writing a check 'just in case,' that is not normal. It raises a whole bunch of legitimate questions that deserve answers."
Reed's campaign filed a disclosure report in February 2017 that did not mention the check from Reed. The disclosure reported no contributions during the previous year.
"The check that the candidate writes should be disclosed on the report," Hershovitz explained.
Reed’s campaign sent a statement, but it didn’t address that question or what "troublesome" expenses they were trying to reimburse.
"It is routine for candidates to reimburse campaigns for expenses for any number of reasons, including a later determination that the expense would more appropriately be borne by the candidate and not the campaign," Reed's campaign spokeswoman, Anne Torres, wrote in a statement. "We also have a campaign attorney who regularly reviews our disclosures to correct mistakes."