Selex ES was a subsidiary of Finmeccanica S.p.A. (today Leonardo), active in the electronics and information technology business, based in Italy and the UK, and formed in January 2013, following Finmeccanica's decision to combine its existing SELEX Galileo, SELEX Elsag and SELEX Sistemi Integrati businesses. From 1 January 2016, the activities of Selex ES merged into Leonardo-Finmeccanica’s Electronics, Defence and Security Systems Sector. In particular, Selex ES’s activities have been organised in three Divisions within the sector: Airborne & Space Systems, Land and Naval Defence Electronics and Security and Information Systems.
In July 2003 Finmeccanica and BAE Systems signed a joint venture agreement with the intention merging their avionics, C4ISR and communications businesses to create three joint venture partnerships under the name Eurosystems. The difficulties of integrating the companies in this way however led to a re-evaluation of the proposal. BAE's 2004 Annual Report states that "recognising the complexity of the earlier proposed ... transaction with Finmeccanica we have moved to a simpler model."
This revised agreement was signed on January 27, 2005. Finmeccanica and BAE announced the intention to dissolve their partnership in the Alenia Marconi Systems (AMS) joint venture with AMS' UK and Italian operations to be taken over by the respective partners.
On May 3, 2005, the Eurosystems Transaction was finalised with: