When sending orders to CAT, are Options Market Makers required to mark such orders with an open or close indicator?
Options Market Makers generally are not required to report open/close indicators on orders represented on/sent to an exchange. The CAT NMS Plan states that the open/close indicator does not need to be reported to CAT as part of the material terms of an order for Options Market Makers quotations. However, if exchange rules require an options market maker to include an open/close indicator when submitting orders to the exchange, Options Market Makers should submit the indicator for their orders to CAT as well.