According to Article 12 of Commission Delegated Regulation (EU) 2017/580, operators of Trading Venues should maintain an individual "Trading venue transaction identification code" (TVTIC) for each transaction resulting from the full or partial execution of an order as specified in Field 48.
Consequently operators of a Trading Venue should always generate a "Trading venue transaction identification code" (TVTIC) for each transaction executed on their Trading Venue that arises from an order in a financial instrument advertised through their systems. In the above circumstances, the operator of the Trading Venue should report accordingly the revevant TVTIC by populating Field 48.