> Enrich.chat gives AI agents verified work emails and mobiles. To use it from an agent, read https://enrich.chat/agents.md . This is the Markdown version of https://enrich.chat/naics/561621/ # NAICS code 561621: Security Systems Services (Except Locksmiths) The companies classified under NAICS 561621, where they are based, how big they are and how the code maps to SIC. By Enrich.chat Editorial. Updated October 22, 2026. **Short answer:** NAICS 561621 is the code for Security Systems Services (Except Locksmiths), in sector 56: Administrative and Support and Waste Management and Remediation Services. The companies counted under it are mostly very small: 62% have 50 or fewer employees, and 73% are headquartered in the United States. ## What is NAICS 561621? NAICS 561621 is the code for Security Systems Services (Except Locksmiths). It belongs to sector 56: Administrative and Support and Waste Management and Remediation Services. NAICS, the North American Industry Classification System, is the standard U.S. government agencies use to sort businesses by what they mainly do, and each digit narrows the category. Most of the companies counted also carry SIC 7382, Security systems services, in the older SIC system (80%). NAICS is a North American system, so companies outside the US, Canada and Mexico are placed in it by classification. - 62% of the companies counted have 50 or fewer employees, and the middle one is in the 11 to 50 range. - The largest group is headquartered in the United States (73%). Within the US, California is the biggest state (16%). - Most were founded in the 2010s (36%), then the 2000s (26%). **Figure: How NAICS 561621 is built.** The code 561621 split into its parts: sector 56, then subsector, industry group, NAICS industry and U.S. industry. *The six digits of NAICS 561621. Each digit narrows the category.* ## Which companies are classified under NAICS 561621? The biggest by headcount range include Hikvision, Securitas India, Chronicle, Mitie and Seguridad Superior. Names link to a company profile where we have one. | Company | Headquarters | Employees | | --- | --- | --- | | Securitas India | Gurgaon, India | 10,001+ | | Chronicle | Mountain View, CA | 10,001+ | | [Mitie](https://enrich.chat/company/mitie/) | Northampton, United Kingdom | 10,001+ | | Seguridad Superior | Bogota, Colombia | 5,001 to 10,000 | | Sentinelone | Mountain View, CA | 1,001 to 5,000 | | Knowbe4 | Clearwater, FL | 1,001 to 5,000 | | Verkada | San Mateo, CA | 1,001 to 5,000 | | Entrust | Minneapolis, MN | 1,001 to 5,000 | | Par Technology | New Hartford, NY | 1,001 to 5,000 | | Imprivata | Waltham, MA | 1,001 to 5,000 | | Gm Sectec | San Juan, United States | 1,001 to 5,000 | | Vector Security | Warrendale, PA | 1,001 to 5,000 | | Dsi Security Services | Dothan, AL | 1,001 to 5,000 | | Security Alliance | Miami, FL | 1,001 to 5,000 | | Center For Internet Security | East Greenbush, NY | 501 to 1,000 | | Armis | San Francisco, CA | 501 to 1,000 | | Pelco | Fresno, CA | 501 to 1,000 | | Algosec | Ridgefield Park, NJ | 501 to 1,000 | | Vectra Ai | San Jose, CA | 501 to 1,000 | | Onyx-Fire Protection Services | Mississauga, Canada | 501 to 1,000 | | Security 101 | West Palm Beach, FL | 501 to 1,000 | | Affiliated Monitoring | Union, NJ | 501 to 1,000 | | Kastle Systems | Falls Church, VA | 501 to 1,000 | | Zix | Dallas, TX | 501 to 1,000 | | Guardian Protection | Warrendale, PA | 501 to 1,000 | The table shows the 25 biggest by headcount range, with ties broken by audience size. The charts and percentages below cover every company counted for this page, not just these 25, and companies with fewer than 11 employees are not counted. Headquarters is the location on each company's public profile. ## Where are NAICS 561621 companies based? The largest groups are headquartered in the United States (73%), the United Kingdom (14%) and Australia (2%). **Figure: Where companies in NAICS 561621 are based.** Bars for the share of counted companies in NAICS 561621 headquartered in each country: United States 73%, United Kingdom 14%, Australia 2%, Canada 1%, Sweden 1%. *Share of counted companies in NAICS 561621 by headquarters country.* Within the United States, California (16%), Florida (9%) and Texas (8%) lead. **Figure: US headquarters of companies in NAICS 561621, by state.** A tile map of the United States shaded by the share of counted US companies in NAICS 561621 headquartered in each state. The largest are California 16%, Florida 9%, Texas 8%. *Share of counted US companies in NAICS 561621 by headquarters state. The three largest states are outlined.* ## How big are the companies counted for NAICS 561621? 62% of them have 50 or fewer employees, and the middle one is in the 11 to 50 range. Companies with fewer than 11 employees are not counted. **Figure: Size of companies in NAICS 561621.** Seven columns for the share of counted companies in NAICS 561621 in each employee range: 11 to 50 62%, 51 to 200 24%, 201 to 500 8%, 501 to 1,000 4%, 1,001 to 5,000 2%, 5,001 to 10,000 0%, 10,001+ 1%. *Share of counted companies in NAICS 561621 in each employee range.* ## How old are NAICS 561621 companies? Most were founded in the 2010s (36%), then the 2000s (26%). **Figure: When companies in NAICS 561621 were founded.** Eight columns for the share of counted companies in NAICS 561621 founded in each era: Before 1960 3%, 1960s 4%, 1970s 9%, 1980s 8%, 1990s 13%, 2000s 26%, 2010s 36%, 2020s 2%. *Share of counted companies in NAICS 561621 by the era they were founded in, for the ones that list a founding year.* ## How NAICS 561621 compares - 38% were founded in 2010 or later, against 30% across all NAICS codes on this site. ## How do NAICS 561621 companies describe themselves? A code is assigned by classification, and a company does not choose its own, so the label a company uses for itself can differ. The most common labels here are Security and Investigations (52%), Computer and Network Security (12%) and IT Services and IT Consulting (9%). **Figure: How companies in NAICS 561621 describe themselves.** Bars for the share of counted companies in NAICS 561621 that give each industry on their public profile: Security and Investigations 52%, Computer and Network Security 12%, IT Services and IT Consulting 9%, Construction 8%, Security Systems Services 6%. *Share of counted companies in NAICS 561621 by the industry they list on their public profile.* ## NAICS 561621 and the SIC system NAICS replaced SIC in 1997, but the two do not line up one to one: companies filed under one NAICS code can carry several SIC codes. These are the ones seen most. | Code | Title | Share of counted | | --- | --- | --- | | SIC 7382 | Security systems services | 80% | | [SIC 1731](https://enrich.chat/naics/238210/) | Electrical contractor | 10% | | SIC 7381 | Detective and armored car services | 5% | ## Where NAICS codes come from NAICS is maintained by the U.S. Census Bureau with Canada and Mexico and revised every five years; the current edition is NAICS 2022. To check exactly what a code includes, search the [official NAICS index](https://www.census.gov/naics/) or read the Census Bureau's [guide to understanding NAICS](https://www.census.gov/programs-surveys/economic-census/year/2022/guidance/understanding-naics.html). Pick a code by what a company mostly does, not by who it sells to. ## How do you reach the people at NAICS 561621 companies? The people to talk to are usually operations, HR and finance leaders. You can build the list from this code in three prompts to your AI agent. ### 1. Count them (free) Counting who matches never uses credits. ```text Use www.enrich.chat to count the companies with NAICS code 561621 (Security Systems Services (Except Locksmiths)) ``` ### 2. Find the people (5 credits per person) Name the roles you sell to. Each person returned is 5 credits, and name, title and company are included. ```text Use www.enrich.chat to find the operations, HR and finance leaders at companies with NAICS code 561621, with their titles ``` ### 3. Get their work emails (10 credits each) An email is 10 credits only when one is found. Every email comes with a status: verified, catch-all or unknown. ```text Use www.enrich.chat to find the work emails for these people and tell me which ones are verified ``` ## More to explore Codes next to it: [NAICS 561611: Investigation and Personal Background Check](https://enrich.chat/naics/561611/)[NAICS 561612: Security Guards and Patrol Services](https://enrich.chat/naics/561612/)[NAICS 561622: Locksmiths](https://enrich.chat/naics/561622/) Others in sector 56: [NAICS 561311: Employment Placement Agencies](https://enrich.chat/naics/561311/)[NAICS 561510: Travel Agencies](https://enrich.chat/naics/561510/)[NAICS 561730: Landscaping Services](https://enrich.chat/naics/561730/)[NAICS 561720: Janitorial Services](https://enrich.chat/naics/561720/)[NAICS 561312: Executive Search Services](https://enrich.chat/naics/561312/)[NAICS 561320: Temporary Help Services](https://enrich.chat/naics/561320/)[NAICS 561710: Exterminating and Pest Control Services](https://enrich.chat/naics/561710/)[NAICS 561520: Tour Operators](https://enrich.chat/naics/561520/) ## Frequently asked questions ### What is NAICS code 561621? NAICS 561621 is the code for Security Systems Services (Except Locksmiths), in sector 56: Administrative and Support and Waste Management and Remediation Services. ### What is the SIC code for NAICS 561621 (Security Systems Services (Except Locksmiths))? 80% of the companies counted carry SIC 7382 (Security systems services), but the two systems do not map one to one. ### Which companies are classified under NAICS 561621? The biggest by headcount range include Hikvision, Securitas India, Chronicle, Mitie and Seguridad Superior. The page lists 25 with links to their profiles where we have them. ### Where are NAICS 561621 companies based? The largest groups are headquartered in the United States (73%), the United Kingdom (14%) and Australia (2%). ### How big are the companies in NAICS 561621? 62% have 50 or fewer employees, and the middle one is in the 11 to 50 range. Companies with fewer than 11 employees are not counted. ### Is NAICS 561621 the same as a SIC code? No. NAICS replaced SIC as the U.S. federal standard in 1997, and the two do not map one to one. The SIC code seen most among these companies is 7382. ## Try this prompt Find the people at NAICS 561621 companies ```text Use www.enrich.chat to find the operations, HR and finance leaders at companies with NAICS code 561621, with titles and verified work emails ``` ## Related - [Companies using a technology](https://enrich.chat/companies-using/) - [NAICS 561611](https://enrich.chat/naics/561611/) - [NAICS 561612](https://enrich.chat/naics/561612/) - [NAICS 561622](https://enrich.chat/naics/561622/) - [Tech stack lookup](https://enrich.chat/tools/tech-stack-lookup/)