a scenario in which the likelihood of a particular outcome is roughly 50-50, as in “We don’t have a good sense of which banker they’re going to pick, it’s pretty much a jump ball”; from the mechanism used to start or restart play in basketball, in which the referee tosses the ball upwards in between opposing players who then attempt to win possession by tipping it in the direction of their teammates, with the assumption that both teams have roughly equal chances of succeeding; the phrase is not necessarily limited to circumstances with binary options; similar to toss-up