| Name | Exchange | Symbol | Last trade | Change | Mkt cap | |
| ADS Security LP | Private | |||||
| Guardian Protection Services Inc. | Private | |||||
| Interface Security Systems, L.L.C. | Private | |||||
| ADT Security Services, Inc. | Private | |||||
| Protection One, Inc. | Private | |||||
| Slomin's Inc. | Private | |||||
| 3M Cogent, Inc. | Private | |||||
| Benson Systems, Inc. | Private | |||||
| Bellringer Security Patrol, Inc. | Private | |||||
| Cam-Dex Security Corp. | Private | |||||
| Xenotronics Company | Private |