Introduction

Note that this specification will be the standard Multicast Top specification to be used for the BZX Options, Cboe Options (C1), C2 Options and EDGX Options Exchange platforms. This specification is for the Simple book only, see the Cboe Titanium U.S. Options Complex Multicast TOP Specification for complex book information.

Options participants may use the Multicast Top protocol to receive real-time top of book quotations direct from each exchange. Market data received through Multicast Top is less timely than receiving the same data from the Multicast PITCH Depth of Book feed. The Top protocol offers a significant reduction in the number of events and number of bytes of application data sent, compared to the US Options Multicast PITCH protocol.

The quotations received via Multicast Top provide an aggregated size and do not indicate the size or number of individual orders at the best bid or ask. The Multicast Top protocol also provides last trade price and size and cumulative volume data.

Complete depth of book market data can be received via the US Options Multicast PITCH protocol.

Top cannot be used to enter orders. For order entry, refer to the appropriate US Options FIX or BOE Specification.

All versions of the Multicast Top feed will be Gig-shaped (current maximum 2Gb/s) and will be available from one or both of Cboe’s datacenters. Participants may choose to take one or more of the following Multicast Top feeds depending on their location and connectivity to Cboe.