EP006 – RegNMS Implementation in FIX

This is a narrowly scoped Reg NMS enhancement for block orders. It addresses the case where a broker-dealer routes Intermarket Sweep Orders against protected quotations while the customer elects to receive a single execution at the agreed block price rather than receiving the benefit and operational consequences of the individual ISO fills.

The proposed FIX solution is not a new message. It adds the ExecInst(18) value j, allowing the originating firm to state on the order that a single execution is requested. This provides a standard machine-readable expression of the customer’s preference and supports the broker-dealer’s handling of the Reg NMS block-trade process.