The Master Registration Agreement (or MRA) was the industry code setting out obligations on Electricity Suppliers and Distribution Network Operators, primarily to facilitate the effective customer switching arrangements in the electricity market.

It was established in 1998 to facilitate the creation of a competitive energy supply market across Great Britain. It was overseen by the MRA Service Company (MRASCo) and the MRASCo Board of Directors.

The obligations in the MRA were no longer effective from 01 September 2021, as the Retail Energy Code V2.0 came into force. REC incorporated the MRA obligations alongside those within the Supply Point Administration Agreement and a number of other operational codes.