Getty Images/Illustration by Emily Bogle/NPR It was a tight race, so a campaign staffer doubted the results of an unreleased poll showing their candidate up — by a lot. The tip about the outside poll didn't match up with the campaign's internal numbers. But accuracy aside, the staffer knew the poll would shake up the prediction markets . One market had their candidate down by double digits. "Myself and others started placing bets before that poll came out," the staffer, who was working on a statewide campaign in the South, told NPR on the condition of anonymity over fear for their future employment. "And then, sure enough as soon as that poll came out, the stock went up and everybody made money." This is one of the first publicly reported instances of a campaign staffer betting and winning thousands on their own candidate on prediction markets — emerging financial exchanges where billions are bet each week on future events like sports, culture and even elections .…