Why are there multiple exchanges for the same papers to begin with? Because it allows the exchanges to compete on features (latency, order types) and pricing (

Why are there multiple exchanges for the same papers to begin with? Because it allows the exchanges to compete on features (latency, order types) and pricing (transaction fees, connectivity costs). In the case of stocks, for example, there has to be one ultimately authoritative copy of who owns which stocks anyway. So why not just do all the trading in the place where the authoritative copy is stored? For equities, trading and settlement are two separate steps. Trading occurs on the exchanges and, for U.S. equities, settlement is handled by the DTCC, the central counterparty for all U.S. equities trading. Handling all the specifics and details of what happens after a trade is executed is a massive industry. For some products, trading does occur only on one exchange. Typically in futures trading, an exchange will develop a product (a contract) and that contract can only be traded on that exchange which also handles settlement.