Symbol Message Rate Threshold (Equities Only)

The Symbol Message Rate Threshold value is the maximum number of messages that can be sent for a symbol on a single session in a rolling one second window, calculated from the time a non-heartbeat message is received. When the value is exceeded, new orders will be rejected, modifies will be treated as cancels, and cancels will continue to be processed. The default value is 5000 messages per second.

Cboe Titanium U.S. Equities/Options Web Portal Port Controls Specification - Symbol Message Rate Threshold (Equities Only) | Cboe