A trade repository is an institution that is notified of and maintains electronic records of transactions.
It is a concept developed as part of the (re-)regulation of derivatives in wake of the financial crisis early in the 21st century in order that the authorities are better able to assess the positions and associated risks of institutions and to the financial system overall.
Provision of data to repositories is mandatory for financial institutions and their business customers and for derivatives entered into between non-financial businesses (including internal transactions between members in the same group of companies). Partial information is likely to be misleading of course, so gathering of information was conceived as global.
Early indications were that the lack of a detailed definition of the required systems and allowing of multiple repositories using their own, would make it likely that no global information on the position of institutions would ever be made available to any authority.
Trade repositories initially expected to be registered by ESMA for the purposes of EMIR included Regis-TR, CME Group, DTCC Derivative Repository, UnaVista (LSE), IntercontinentalExchange (ICE), Trade Vault, Harmony TR Connect and KDPW.