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Top AI companies in the United States

Companies building AI products, foundation models, and applied ML platforms. Filtered to companies headquartered in the United States.

Built from a search like: “Top AI companies in the United States”

Ranked by current headcount across AI companies headquartered in the United States. Refreshed daily.

  1. 1
    Thermo Fisher Scientific· Waltham, Massachusetts, United States
    • Post-IPO debt
    • 99.8k employees
    • Founded 1956
  2. 2
    Amgen· Thousand Oaks, California, United States
    • Post-IPO debt
    • 39.9k employees
    • Founded 1980
  3. 3
    The National Institutes of Health· Bethesda, Maryland, United States
    • Grant
    • 28.8k employees
  4. 4
    Syneos Health· Morrisville, North Carolina, United States
    • Private equity
    • 23.3k employees
    • Founded 1985
  5. 5
    PPD· Waltham, Massachusetts, United States
    • Private equity
    • 20.9k employees
    • Founded 1985
  6. 6
    Genentech· South San Francisco, California, United States
    • Series A
    • 18.1k employees
    • Founded 1976
  7. 7
    Agilent Technologies· Santa Clara, California, United States
    • Post-IPO debt
    • 17.7k employees
    • Founded 1999
  8. 8
    Charles River Laboratories· Wilmington, Massachusetts, United States
    • Grant
    • 14.8k employees
    • Founded 1947
  9. 9
    Gilead Sciences· San Mateo, California, United States
    • Post-IPO debt
    • 14.6k employees
    • Founded 1987
  10. 10
    Los Alamos National Laboratory· Los Alamos, New Mexico, United States
    • Grant
    • 13.2k employees
    • Founded 1943
  11. 11
    Avantor· Radnor, Pennsylvania, United States
    • Private equity
    • 12.7k employees
    • Founded 1904
  12. 12
    Fortrea· Triangle, North Carolina, United States
    • 11.3k employees
    • Founded 2023
  13. 13
    Waters Corporation· Milford, Massachusetts, United States
    • Post-IPO debt
    • 10.9k employees
    • Founded 1905
  14. 14
    MilliporeSigma· Burlington, Massachusetts, United States
    • 10.5k employees
    • Founded 1951
  15. 15
    US Department of Agriculture (USDA) Agricultural Research Service (ARS)· Washington, District of Columbia, United States
    • 9.6k employees
    • Founded 1953
  16. 16
    Illumina· San Diego, California, United States
    • Post-IPO debt
    • 9.5k employees
    • Founded 1998
  17. 17
    Lawrence Livermore National Laboratory· Livermore, California, United States
    • Grant
    • 9.3k employees
    • Founded 1952
  18. 18
    Bio-Rad Laboratories· Hercules, California, United States
    • Post-IPO debt
    • 9.3k employees
    • Founded 1952
  19. 19
    MITRE· McLean, Virginia, United States
    • Grant
    • 9.1k employees
    • Founded 1958
  20. 20
    IDEXX· Westbrook, Maine, United States
    • Seed
    • 8.1k employees
    • Founded 1983
  21. 21
    Chief· New York, New York, United States
    • Series B
    • 8k employees
    • Founded 2019
  22. 22
    OpenAI· San Francisco, California, United States
    • Series unknown
    • 7.8k employees
    • Founded 2015
  23. 23
    U.S. Geological Survey (USGS)· Herndon, Virginia, United States
    • 7.8k employees
  24. 24
    Biogen· Cambridge, Massachusetts, United States
    • Post-IPO debt
    • 7.6k employees
    • Founded 1978
  25. 25
    Clario· Philadelphia, Pennsylvania, United States
    • Private equity
    • 7k employees
    • Founded 1972

Find engineers at AI companies in the United States

the United States has long been a hub for AI, and the list above ranks the largest AI companies headquartered there by current headcount, drawn from public LinkedIn and Crunchbase records. With 9,882 matching companies in our index, this is a good map of where the AI talent in the United Stateslives — useful whether you’re recruiting, partnering, or sizing a market.

The biggest AI companies in the United States tend to be the gravitational centres for specialised talent — senior engineers, ML researchers, applied scientists, designers — while the smaller ones compete on speed, equity, and proximity to founders.

Refolk converts this list into a live search. Ask for “AI engineers in the United Stateshiring senior staff” or “founders of AI companies in the United Stateswho left in the last 12 months” and Refolk returns a ranked shortlist with the evidence that earned each person a spot.

How this list is built

Refolk pulled AI companies headquartered in the United States from public LinkedIn and Crunchbase records, ranked them by current employee count, and kept those with at least 10 employees. The list refreshes once a day.

Last refreshed: Thu, 07 May 2026 06:43:00 GMT

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