Update - Cboe One U.S. Equities Feed Updates in Support of 23x5 Trading

Reference ID: C2026101503

Applicable Cboe Exchanges: BYX Equities, BZX Equities, EDGA Equities, EDGX Equities

Overview

Effective November 2, 2026, the Cboe One U.S. Equities feed will adjust its restart time and update certain time-related fields in anticipation of Cboe EDGX Equities Exchange transitioning to 23x5 trading for all production symbols on trade date December 7, 2026. For more details, see the related EDGX notice. Corresponding updates will also be made to the Cboe Global Cloud version of the Cboe One U.S. Equities feed. All times outlined in this notice are ET.

Message Field Updates (UPDATED)

Upon the effective date, the Last Update Timestamp, Timestamp, and Transaction Time fields on the Cboe One U.S. Equities feed and the Timestamp field on the Cboe Global Cloud feed will be updated to contain the number of nanoseconds since epoch instead of the number of nanoseconds since midnight.

Additionally, the Timestamp field on the Cboe Global Cloud U.S. Equities TOP messages will be updated to contain the number of nanoseconds since epoch instead of the number of milliseconds since midnight ET.

See the specifications linked below for more details.

Adjusted Restart Times (UPDATED)

Upon the effective date, all Cboe One applications will start on new times as outlined below.
System ApplicationCurrent Start Time RangeNew Start Time Range
System Application Startup (Sunday)N/A. System starts Monday morning between 1:33-1:45 a.m.~1:35-1:50 p.m. on Sunday
System Application Startup (Mon-Thurs)1:33-1:45 a.m.~8:50 p.m. ~8:10-8:22 p.m.

Parallel Production Period

Beginning trade date November 9, 2026, the following test symbols will be supported in the EDGX Production environment for the Overnight Trading Session. Given that the Cboe One U.S. Equities feed will be operating on a 23x5 schedule on this date, market data will appear on the Cboe One U.S. Equities feed for the following test symbols.

  • ZBZX

  • ZTST

EDGX Members are responsible for generating order and trade activity in these symbols in order for Cboe One U.S. Equities feed subscribers to see test data on these symbols.

Testing Opportunities

These changes are currently available to test using the Cboe One Certification feed.