Mark Errington

Here’s the list of the top 30 security companies in the USA, organized by the year they were founded:

1800s
1. Brinks Home Security
- Founded: 1859
- Employees: ~5,000

2. ADT
- Founded: 1874
- Employees: ~20,000

3. Stanley Security (now part of Securitas AB)
- Founded: 1843 (originally Stanley Works)
- Employees: ~5,000 (prior to acquisition)

1900s
4. Securitas AB
- Founded: 1934 (Sweden), expanded to the USA in 1999
- Employees: ~350,000

5. Guardian Protection Services
- Founded: 1950
- Employees: ~1,300

6. Per Mar Security Services
- Founded: 1953
- Employees: ~2,500

7. US Security Associates (now part of Allied Universal)
- Founded: 1955
- Employees: ~50,000 (prior to acquisition)

8. Allied Universal
- Founded: 1957
- Employees: ~800,000

9. First Alarm Security & Patrol
- Founded: 1966
- Employees: ~1,000

10. SOS Security
- Founded: 1969
- Employees: ~17,000

11. Vector Security
- Founded: 1970
- Employees: ~2,000

12. Central Security Group
- Founded: 1978
- Employees: ~500

13. Akal Security
- Founded: 1980
- Employees: ~12,000

14. Paragon Systems
- Founded: 1983
- Employees: ~12,000

15. Andrews International (now part of Allied Universal)
- Founded: 1988
- Employees: ~10,000 (prior to acquisition)

16. CPI Security Systems
- Founded: 1991
- Employees: ~1,200

17. Protect America
- Founded: 1992
- Employees: ~1,000

18. Monitronics International
- Founded: 1994
- Employees: ~1,100

19. GardaWorld
- Founded: 1995
- Employees: ~120,000

20. PalAmerican Security
- Founded: 1997
- Employees: ~10,000

21. Vivint Smart Home
- Founded: 1999
- Employees: ~11,000

22. Security Industry Specialists (SIS)
- Founded: 1999
- Employees: ~5,000

2000s
23. G4S (now part of Allied Universal)
- Founded: 2004 (merged from Group 4 Falck and Securicor)
- Employees: ~150,000 (prior to acquisition)

24. Alarm.com
- Founded: 2000
- Employees: ~1,000

25. Convergint Technologies
- Founded: 2001
- Employees: ~7,500

26. Covenant Aviation Security
- Founded: 2002
- Employees: ~3,000

27. Triple Canopy (now part of Constellis)
- Founded: 2003
- Employees: ~5,000

28. Constellis
- Founded: 2010 (formed from several security companies including Triple Canopy)
- Employees: ~21,000

2010s
29. Asylon Robotics
- Founded: 2014
- Employees: ~100

30. Universal Protection Service (part of Allied Universal)
- Founded: 1965
- Employees: ~200,000 (prior to merger with Allied Barton)