bilateral system
6a system that brings together buying and selling interests in the way described in the definition of an alternative trading system, where a single person enters into one side of every transaction effected using the system, on his own account and not merely as a central counterparty interposed between a buyer and seller, or would enter into every trade in that way but for client orders that are crossed occasionally. This definition includes such a system where, rather than a single person, it is one of a number of persons in the same group that enters into one side of every transaction effected using the system.