Cboe BYX Launches Clock Service to Sync Trader Timings
Published Date: 3/17/2026
Notice
Summary
Cboe BYX Exchange just launched a cool new Clock Service that helps traders sync their clocks with the Exchange’s time. This update to Rule 11.22 lets both members and non-members use the service to better track trade timings and reduce confusion. The change is effective immediately, making it easier and faster to measure trade delays without costing extra.
Analyzed Economic Effects
5 provisions identified: 2 benefits, 2 costs, 1 mixed.
Optional sub-nanosecond Clock Service
The Exchange added a voluntary Clock Service that lets subscribers synchronize their primary clocks to the Exchange's primary clock using White Rabbit and Precision Time Protocol for up to sub-nanosecond precision. The service is available to both Members and non-Members and is intended to help latency-sensitive participants more accurately measure message and order traversal times.
Third-Party White Rabbit Devices Required
Some subscribers will need to procure a White Rabbit clock synchronization device and any applicable third-party licenses from vendors in order to use the Exchange's Clock Service. The Exchange notes participants are responsible for procuring applicable licenses as needed.
Nanosecond Timestamps Coming End of March
The Exchange currently provides acknowledgements with microsecond timestamps and intends to update the time-of-receipt timestamping to nanoseconds by the end of March (the year of the filing). This change increases the precision of Exchange-generated timestamps available to participants.
Fees Will Be Filed Separately
The Exchange intends to submit a separate filing under Section 19(b)(1) to propose fees for the Clock Service, meaning subscribers may face charges once that fee filing is approved. The Clock Service is voluntary and no Member or non-Member is required to subscribe.
Dedicated 1 Gbps Port Included
Subscribers to the Clock Service will receive a dedicated 1 gigabit per second (1 Gbps) Physical Port from the Exchange to receive the Exchange's White Rabbit time signal. That 1 Gbps Physical Port must be used solely for the Clock Service and cannot be used for other purposes such as order routing.
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