A mercantile exchange
A mercantile exchange was a type of organized marketplace in the late 32nd century. They were operated by, and emblematic of, the Emerald Chain, to the extent that its leader Osyraa defined it as "a federation of mercantile exchanges". The exchanges were guarded by regulators and employed couriers for transporting goods in exchange for dilithium. The exchanges often dealt in goods used in the slave trade, and some had open slave markets. (DIS: "That Hope Is You, Part 1", "People of Earth", "Scavengers", "There Is A Tide...")