The Financial Conduct Authority has finalized rules streamlining the United Kingdom’s transaction reporting regime while retaining the data needed for market abuse detection, market monitoring and firm supervision. The changes are expected to reduce the industry’s annual MiFID transaction reporting costs from GBP 493 million to about GBP 385 million, a net saving of GBP 108 million. The rules reduce reporting fields from 65 to 52 and remove foreign exchange derivatives from the requirements, cutting costs for more than 400 firms. They also exclude 7 million financial instruments traded only on European Union venues, generating estimated annual savings of GBP 32 million, and shorten the period for correcting historical errors from five years to three, reducing report resubmissions by one-third. The changes take effect on April 3, 2028, although the FCA will take a flexible supervisory approach for firms ready to implement certain measures earlier. It will continue working with the Bank of England and the Treasury to harmonize transaction and post-trade reporting rules.