The RTS 2025/1155 specifies that the timestamp fields to be transmitted to the CTP must follow the ISO 8601 date‑time format with six decimal places (i.e. ss.dddddd) representing fractions of a second in microseconds, as set out in Table 1 of Annex III, where timestamps must be provided in the format YYYY‑MM‑DDThh:mm:ss.ddddddZ.

ESMA confirms that a data contributor will be considered compliant with the timestamp requirements of Articles 5 and 6 of Commission Delegated Regulation (EU) 2025/1155 if it transmits timestamps with at least six decimal (microsecond) digits and follows the ISO 8601 format.