Reverse line movement occurs when the betting line shifts contrary to the expected direction based on public betting percentages, often indicating that sharp money or experienced bettors (often referred to as "smart money") are placing bets on the less popular side. For instance, if a team opens as a 3-point favorite and, despite the majority of bets being placed on them, the line moves to favor the opposing team, this suggests that significant amounts of money are being wagered on the underdog, signaling confidence from well-informed bettors.