Top Defense Contractors

The Department of Defense (DoD) is by far the largest buyer in the federal government, accounting for roughly two-thirds of all contract spending. In fiscal year 2024, DoD contract obligations exceeded $450 billion. Understanding defense contracting is essential to understanding federal procurement as a whole.

The Big Five

Five companies — often called the Big Five or the primes — dominate defense contracting. Together, they receive well over $100 billion annually in federal contracts:

• Lockheed Martin: The world's largest defense contractor. Major programs include the F-35 Joint Strike Fighter, the Aegis Combat System, and numerous missile defense programs. Lockheed consistently ranks as the top federal contractor by dollar value.
• Boeing: While primarily known as a commercial aircraft manufacturer, Boeing's defense division produces military aircraft (F-15, F/A-18, KC-46), satellites, and weapons systems. Boeing also has substantial contracts with NASA.
• RTX Corporation: Formed from the 2020 merger of Raytheon and United Technologies, RTX produces missiles (Patriot, Tomahawk), radar systems, jet engines (Pratt & Whitney), and aerospace electronics.
• General Dynamics: Produces submarines (Virginia-class, Columbia-class), armored vehicles (Abrams tank, Stryker), and IT services through its GDIT division.
• Northrop Grumman: Specializes in stealth aircraft (B-21 Raider), space systems, unmanned systems (Global Hawk), and cybersecurity.

Defense vs. Civilian Spending

While DoD dominates in total dollars, civilian agencies collectively represent significant contract spending. The Department of Health and Human Services, Department of Energy, NASA, and the Department of Veterans Affairs each manage billions in contracts annually. However, the top civilian agency contract budgets are typically a fraction of DoD's spending. You can compare agency spending on our agencies page.

Industry Concentration

Defense contracting is highly concentrated among a small number of large firms due to the specialized nature of defense products and the high barriers to entry. Building a fighter jet or a nuclear submarine requires decades of investment in facilities, workforce, and intellectual property that new entrants cannot easily replicate. The government has expressed concern about this concentration, particularly after several major mergers reduced the number of prime contractors in the 1990s and 2000s.

The Role of Subcontracting

Despite the concentration at the prime contractor level, thousands of small and mid-sized businesses participate in defense supply chains as subcontractors. Prime contractors are required to submit small business subcontracting plans, and the DoD monitors compliance through the Electronic Subcontracting Reporting System (eSRS). Subcontracting is a common entry point for companies looking to enter the defense market.

Emerging Trends

Several trends are reshaping defense contracting. The Department of Defense is increasingly looking to commercial technology companies for cybersecurity, artificial intelligence, cloud computing, and space launch services. Programs like the Defense Innovation Unit (DIU) and the Air Force's AFWERX aim to bring non-traditional contractors into the defense ecosystem. The rise of Other Transaction Authority (OTA) agreements has also made it easier for innovative companies to work with DoD outside the traditional FAR-based procurement system.

Explore the Data

View the full list of top federal contractors or search for specific companies on our search page. For background on how federal contracting works, see our guide on how government contracts work.

The "Big Five" defense primes: scale and category

The five largest U.S. defense prime contractors consistently capture a large share of total Department of Defense procurement obligations. Each prime specializes in distinct mission areas, which helps explain why their relative rankings shift year to year based on which programs are in active production versus development. The snapshot below summarizes their core specializations and approximate annual federal obligation levels (across all federal agencies, dominated by DoD):

Obligation levels approximated from USAspending.gov annual contractor totals (usaspending.gov/recipient). Exact values shift year to year.

Why concentration persists despite repeated reform efforts

Repeated Department of Defense initiatives over the past 25 years have tried to increase competition by drawing in commercial technology firms, expanding Other Transaction Authority (OTA), and creating fast-track pilot programs. Yet the Big Five maintain durable dominance for structural reasons that procurement reform alone cannot dissolve: (1) the massive engineering workforce required for complex weapon systems is largely captive to existing prime contractors; (2) export-controlled intellectual property accumulates in incumbent firms; (3) the cost-plus contracting environment for development programs favors firms with established cost-accounting compliance; and (4) program-management overhead is itself a barrier to entry that smaller firms cannot absorb without scale.

Why defense contractor rankings often diverge from civilian rankings

Federal contractor rankings reported in business media sometimes blend defense and civilian agency obligations into a single list. This can mask important differences between the two ecosystems. Civilian-agency primes (firms like Booz Allen Hamilton, Leidos, and Accenture Federal Services) have heavier exposure to IT services, consulting, and program management work. Defense primes (Lockheed Martin, Raytheon, Northrop Grumman, General Dynamics, Boeing Defense) dominate platform-development work — aircraft, missiles, ships, and ground vehicles — that civilian agencies rarely purchase. A pure ranking by total federal obligations will mix these two categories; a defense-only ranking using DoD-only obligations isolates the platform-development contractors whose business is most exposed to defense budget cycles.

The tier below the Big Five: specialty integrators and second-tier primes

Below the Big Five sits a tier of specialty integrators and second-tier primes whose federal obligations typically run between $5 billion and $15 billion annually. Firms in this group include Huntington Ingalls Industries (shipbuilding), L3Harris Technologies (communications and electronic warfare), Leidos (IT services), Booz Allen Hamilton (consulting and analytics), CACI International (intelligence and cyber services), and SAIC (engineering services). These firms compete head-to-head with the Big Five for specific contract categories but lack the platform-development portfolios that anchor the largest primes. A meaningful share of this tier's revenue flows from prime contracts where the Big Five themselves are subcontractors — especially in IT services, cyber operations, and intelligence support, where the Big Five increasingly partner with second-tier integrators that hold specialized contract vehicles or socioeconomic-program certifications.

Commercial entrants and the OTA pathway

The most-discussed development in defense contracting over the past decade has been the entry of commercial technology firms into the DoD ecosystem via Other Transaction Authority (OTA) agreements. SpaceX in launch services, Palantir in data platforms, and Anduril in autonomous systems are among the highest-profile commercial entrants. OTA agreements bypass much of the Federal Acquisition Regulation that traditional primes navigate, which makes them faster to negotiate but also harder to scale into long-term sustainment programs. The Defense Innovation Unit and the Air Force's AFWERX continue to expand the pipeline of OTA prototypes, but transitioning those prototypes into production-grade contracts remains the binding constraint on commercial-firm growth inside the defense budget.