I think that is what I was trying to say.
Odds are set to make sure bets on both sides are covered. Bookies don’t want risk having to pay their own money out.
Maybe Trump made a large bet on McAuliff, willing to lose the money.
Predictit isn’t even a bookie, they are just facilitators. They provide a marketplace for people who want to wager against each other. They charge the winners 10% of their “profits”. There has been a surge in volume in the past couple of hours, accompanied by surge in price for McAuliffe, who had only been trailing on Predictit for the past few days.