Lockheed Martin is an American aerospace, defense, security, and advanced technology company formed in 1995 by the merger of Lockheed Corporation and Martin Marietta. Headquartered in Bethesda, Maryland, Lockheed Martin employs over 123,000 people worldwide and generates most of its revenue from military contracts with the US government. Robert J. Stevens serves as the current Chairman and CEO, leading the company's four business segments of Aeronautics, Electronic Systems, Information Systems & Global Solutions, and Space Systems.