An Electronic Communication Network (ECN) is a type of trading system that allows buyers and sellers to trade securities directly without the need for a traditional stock exchange. ECNs match orders electronically, providing a platform for market participants to execute trades efficiently and transparently. They are particularly popular in the foreign exchange and stock markets. ECNs operate by connecting various market participants, including institutional investors, brokers, and individual traders. By facilitating direct trading, they help reduce costs and improve market liquidity. Notable examples of ECNs include Instinet and Archipelago, which have transformed how trading occurs in financial markets.