Top Defense Contractors in 2021 The defense industry is an extremely lucrative sector that is thriving as countries ramp up their military spending amid the changing geopolitical situation. The United States tops the list of the world’s biggest military spenders with a military budget of $940 billion. China, India and Russia are some of the other notable companies that spend a fortune every year on defense. Major countries hire defense contractors for military equipment, services and maintenance of their defense systems. The U.S. Department of Defense has contracts worth billions of dollars with organizations from around the world. The prime contractors of the U.S. Department of Defense include The Boeing Company (NYSE: BA), Northrop Grumman Corporation (NYSE: NOC), and Huntington Ingalls Industries, Inc. (NYSE: HII).