Investment firms which execute transactions in financial instruments must report complete and accurate details of these transactions to the relevant competent authority under Article 26(1) of MiFIR. The current Transaction Reporting regime, as introduced under the Markets in Financial Instruments Regulation (MiFIR), built substantially on the previous Markets in Financial Instruments Directive (MiFID) regime by increasing the number and types of instruments in scope, tripling the number of data fields required and increasing the level of complexity.