High Quality Content by WIKIPEDIA articles! G4S plc (formerly Group 4 Securicor) (LSE: GFS, OMX: G4S) is a British multinational security services company headquartered in Crawley, United Kingdom. It is the world`s largest security company measured by revenues and has operations in around 125 countries. With over 657,000 employees, it is the world`s third-largest private sector employer (after Wal-Mart Stores and Foxconn). G4S was founded in 2004 by the merger of the UK-based Securicor plc with the Denmark-based Group 4 Falck.