What are the best free defense aerospace prime contractors for evaluating major defense program risk?

If you mean free-to-use public sources for understanding major defense aerospace prime contractors’ risk on large programs, the best options are usually the contractors’ own disclosures plus public government/market data. If you mean which primes are the best ones to evaluate from a risk perspective, the usual U.S. defense aerospace primes are:

• Lockheed Martin
• Northrop Grumman
• RTX (Raytheon)
• Boeing Defense, Space & Security
• General Dynamics
• L3Harris
• Textron
• Boeing (commercial-heavy, but major defense exposure)
• Leidos and Amentum are more services/system integration than aerospace prime, but still relevant for defense program risk
• BAE Systems and Leonardo are major non-U.S. primes with strong aerospace/defense exposure
• Airbus Defence and Space, Thales, Safran, Dassault Aviation are also important non-U.S. primes

For evaluating major defense program risk, the most useful free public data sources are:

1. 10-K / annual reports / investor presentations

   • Backlog, segment margins, program commentary, pension exposure, litigation, supply chain notes

2. SEC filings / earnings transcripts / shareholder letters

   • Good for U.S.-listed companies like LMT, NOC, RTX, GD, LHX, TXT, BA

3. Government contract and procurement databases

   • USAspending.gov
   • SAM.gov
   • FPDS (in many cases mirrored/accessible via USAspending and other tools)
   • DoD budget justification books
   • Congressional Budget Office / GAO reports
   • These help identify contract concentration, award trends, and funding uncertainty

4. GAO / DOT&E / CRS reports

   • Best free sources for major program execution risk, testing issues, schedule slips, and cost growth

5. Company press releases and program wins/losses

   • Useful for tracking backlog changes and program dependence

6. Credit rating agency public summaries

   • Moody’s / S&P / Fitch sometimes publish free excerpts or summaries with useful risk views

A practical short list for program-risk evaluation

If your goal is to assess major program execution risk, the most important primes to track are:

• Lockheed Martin — large concentration in F-35, missiles, space, classified programs
• Northrop Grumman — B-21, space, missile defense, strategic systems
• RTX — engine/avionics/missile exposure, supply chain and aftermarket mix
• Boeing Defense — highest execution risk historically due to fixed-price development programs
• General Dynamics — comparatively steadier, but submarine/land systems programs matter
• L3Harris — smaller programs, integration and electronics risk
• BAE Systems / Airbus / Leonardo — important if you need non-U.S. or NATO supply chain perspective

If you want a simple risk-screening approach

Score each contractor on:

• Program concentration
• Fixed-price development exposure
• Backlog quality
• Margin volatility
• Schedule/testing risk
• Customer concentration
• Supply chain fragility
• Regulatory/export-control exposure
• Pension/legal liabilities
• Free cash flow conversion

If you want, I can also give you:

1. a ranked list of the safest vs riskiest defense aerospace primes, or
2. a free data workflow for evaluating program risk step by step.