Electronic Communication Networks and Regulation ATS (1990s)
In the mid-1990s, electronic networks like Island and Instinet matched buy and sell orders outside the New York Stock Exchange floor, cutting into the Big Board's monopoly. They operated under SEC no-action and exemptive relief because they did not fit the legal definition of an exchange.
The networks grew rapidly, capturing a large share of Nasdaq volume and forcing traditional exchanges to modernize.
In 1998 the SEC adopted Regulation ATS, formalizing electronic venues as alternative trading systems and creating the foundation for modern equities market structure.
Same pattern as today: a new venue type runs on temporary SEC relief first, then gets codified into durable rules once it proves workable.
