Already, at least 15 states ban prop betting in collegiate sports, according to data maintained by the American Gaming Association, a trade group. Last month, ESPN reported the NBA and its players union supported further limits on certain prop bets. This summer, MLB Commissioner Rob Manfred told reporters he would like to see some limits on prop bets. In an interview, Maloney said eliminating legal prop betting will only move that activity into unregulated markets with no transparency. He said prop bets are a reflection of sports fandom: Bettors like to wager on their favorite players notching touchdowns or 3-pointers.