The definition of automated trading (AT) is much discussed. For the purposes of AT 9000, the defining characteristic of an AT system is neither the duration of its trades nor the volume of its order requests routed to the exchange, but rather the risks a given system poses to the marketplace. Any automated or algorithmic trading system that enters computer-generated order requests into the market gives rise to immediate risks in the event of its strategic or technological failure. Such systems, broadly defined, may engage in market making, index arbitrage, statistical arbitrage, or any number of other strategies that provide liquidity by way of automated decision-making. This definition also intends to include automated systems that take liquidity as well.