6 Cash equities were traded in New York on the New York Stock Exchange, equity futures were traded and cleared in Chicago by the Chicago Mercantile Exchange, while stock options were traded on the Chicago Board Options Exchange and cleared by the Options Clearing Corporation. 8  The next slide helps to represent the ensuing payment flows.
7 Calls requesting payment are on the left in red. When making a margin call, a CCP requests payment from its clearing members. Clearing members in turn request margin payments from the customers for whom they are clearing, and those customers must then direct their bank to make the payment. If everything works as it should, payments (in green, on the right) will ensue.