Trade Monopoly is a way to win a game in Age of Empires III. It occurs when a player or team of players controls more than half of the Trading Post sites on a map. Once enough Trading Posts are under control, a countdown starts to count down, and all the others players have five minutes to stop the monopoly by making the defending team or player lose control of so many Trading Posts that they have less than half left under their control. A trade monopoly can be attempted multiple times, but every time the countdown starts at five minutes.