BAE Systems plc (LSE: BA.) is a British defence, security and aerospace company headquartered in Farnborough, Hampshire, England, that has global interests, particularly in North America through its subsidiary BAE Systems Inc. BAE is the world's largest defence contractor by sales revenue as of 2008. It was formed on 30 November 1999 by the £7.7 billion merger of two British companies, Marconi Electronic Systems (MES), the defence electronics and naval shipbuilding subsidiary of the General Electric Company plc (GEC), and aircraft, munitions and naval systems manufacturer British Aerospace (BAe). It is listed on the London Stock Exchange, where it is a constituent of the FTSE 100 Index.

BAE is the successor to various aircraft and defence electronics companies, including The Marconi Company, the first commercial company devoted to the development and use of radio; A.V. Roe and Company, one of the world's first aircraft companies; de Havilland, manufacturer of the world's first commercial jet airliner; British Aircraft Corporation, co-manufacturer of the Concorde supersonic transport; and Supermarine, manufacturer of the Spitfire. It has increasingly disengaged from its businesses in continental Europe in favour of investing in the United States. Since its formation it has sold its shares in Airbus, Astrium, AMS and Atlas Elektronik.

BAE Systems is involved in several major defence projects, including the F-35 Lightning II, the Eurofighter Typhoon, the Astute class submarines and the Queen Elizabeth class aircraft carriers. The company has been the subject of criticism, in terms of general opposition to the arms trade and particularly specific allegations of unethical and corrupt practices, including the Al Yamamah contracts with Saudi Arabia that have earned BAE and its predecessor £43 billion in twenty years. In February 2010 BAE Systems agreed to pay £286 million in criminal fines to the Serious Fraud Office and the US Department of Justice for failure to keep "reasonably accurate accounting records" with regard to activities in Tanzania and for "conspiring to make false statements to the US government."

Source: Wikipedia