Effective September 8, 2025, all Cboe-affiliated U.S. Options Exchanges will update the DateTime and Time Offset data types to provide nanosecond precision transaction time in market data feeds.

Additionally, a “Send Nanoseconds” port attribute will be added to allow customers to select nanosecond or microsecond transaction times.

Currently, the DateTime and Time Offset data types are populated to microsecond precision.

Upon the effective date, all fields using these two data types will be populated to nanosecond precision. A new “Send Nanoseconds” port attribute will be added to FIX, FIX Drop, ODROP, and FIX Purge ports to allow for the return of nanosecond transaction times.

The “Send Nanoseconds” port attribute will be set to false by default. Nanosecond precision transaction times will automatically be sent on BOE, BOE Quote, and BOE Purge ports. BOE users cannot opt out of the automatic nanosecond precision transaction time notifications.

To support this new functionality, TransactTime (FIX Tag 60) and OrigTime (FIX Tag 43) will be updated to allow the GMT date-time to be available in nanoseconds.

A nanosecond time of 1,737,580,407,123,456,789 (Wednesday, January 22, 2025 9:13:27.123456789) will return value = 123456789.

This functionality will be available to test in the U.S. Options certification environments beginning July 28, 2025.