Investigation and Security Services (U.S.) — NAICS 5616

An investor's rollup primer for a general audience — relevant to both public-market and private investors. This is an industry group (four-digit level) in the North American Industry Classification System (NAICS), the standard U.S. scheme for classifying businesses by activity [3]. It is synthesized from its two child industries — 56161 and 56162 — plus our ground-truth U.S. federal statistics for NAICS 5616. Reported facts and forward-looking judgments are distinguished in the wording.

1. Overview

This is the industry group where the economy buys protection. It has two halves that share a name but almost nothing else. The first half sends people to watch, investigate, and move things — private detectives and background screeners, uniformed guards, and armored-car crews (child industry 56161). The second half installs machines to do a related job electronically — burglar and fire alarms, cameras, access-control systems, the central stations that monitor them around the clock, and the locksmiths who fit the hardware (child industry 56162). Put crudely: 56161 is humans, 56162 is electronics, and NAICS 5616 is the sum of the two.

Why it matters to an investor: this is a large (~$80.7 billion in federal receipts), recurring-revenue, consolidation-friendly corner of business services that runs on one durable idea — organizations would rather pay a specialist to carry a security burden than carry it themselves [1]. But the single most useful thing this primer can do is show that the two halves are not the same business. One is a labor-driven world of thin margins and headcount (86% of the group's roughly one million jobs sit here); the other is a capital-and-subscription world that earns far more revenue per worker and is where nearly all the group's public stocks live. They grow at different speeds, are owned by different kinds of investors, and are bought in completely different ways.

For public-market investors, exposure is uneven and mostly indirect: the cleanest U.S.-listed pure-plays (ADT, Alarm.com) sit in the smaller electronic-systems half, while the larger people half offers only scattered windows — one clean cash-logistics large-cap (Brink's), one listed screening pure-play (First Advantage), and no U.S.-listed pure-play in guarding at all. For private investors, the whole group is a rich, fragmented hunting ground — 21,000-plus firms across guards, detectives, armored routes, alarm dealers, and locksmiths — that private equity (PE, firms that buy companies with pooled money and debt), search funds, and independent operators actively roll up.

2. What's inside — the two child industries and how they differ

NAICS 5616 contains two five-digit child industries [3], and the contrast between them is the whole story:

• 56161 — Investigation, Guard, and Armored Car Services: private detectives and employment background screeners; contract security guards and patrols; and armored-car cash-in-transit and cash-processing. The people half.
• 56162 — Security Systems Services: selling, installing, and above all monitoring electronic alarms, video, and access control (child 561621), plus locksmiths (child 561622). The electronics half.

"CR4" = the combined revenue share of the four largest firms. "HHI" (Herfindahl-Hirschman Index) is a 0–10,000 concentration gauge that squares and sums each firm's market share; it is withheld by the Census Bureau for both children (see Section 3). Revenue and concentration figures are 2022 Economic Census; employment is 2023 County Business Patterns — internally consistent but drawn from different survey years [1][2].

How to read the table. Three contrasts do most of the work:

1. Humans on one side, machines on the other — and the revenue-per-worker gap is enormous. 56161 holds ~86% of the group's jobs but only ~58% of its revenue, because guarding especially is a low-revenue-per-head labor business. 56162 earns ~42% of the revenue on ~14% of the jobs, because a monitoring subscription and a truckload of installed electronics generate roughly four times the revenue per employee (~$235k vs. ~$54k) [1][2]. A dollar of "security services" revenue is a very different thing depending on which half you buy.
2. The cleaner public window is in the smaller half. The two U.S.-listed near-pure-plays in the whole group — ADT and Alarm.com — both sit in electronic systems (56162). The larger people half (56161) has only a clean cash-logistics large-cap (Brink's) and one listed screener (First Advantage); its biggest slice by far, contract guarding, has no U.S.-listed pure-play. Size is a poor guide to what you can actually own on an exchange.
3. Both halves are the same shape: a scaled head on a long fragmented tail. Each child is a handful of capitalized leaders sitting atop thousands of small firms — national screeners and guard giants over ~3,800 one-person detective shops in 56161; ADT, Vivint, and PE integrators over thousands of independent alarm dealers and locksmiths in 56162. That shape is exactly what fuels the roll-up activity in Section 8.

A fourth, cross-cutting fact matters for anyone mapping the group: the biggest names straddle the two children. Securitas runs both a huge U.S. contract-guard arm (56161) and Securitas Technology, a major electronic-security integrator (56162); GardaWorld spans guarding and cash logistics; Johnson Controls sits in systems. A layer of global "integrated security" companies is deliberately blurring the people/electronics line — selling officers plus cameras plus monitoring as one bundle — even though the underlying economics stay distinct [4][5][10].

3. How big it is (the rollup)

U.S. federal ground-truth figures for NAICS 5616 (the datasets use different survey years — do not treat them as one synchronized financial year):

The concentration paradox — the group looks more fragmented than either of its halves. This is the most counterintuitive number in the file and worth pausing on. Each child industry has a CR4 around 32–33%, yet the group's CR4 is only 25.6%, and its HHI of 215.5 is very low (a level below 1,500 is conventionally "unconcentrated") [1]. How can combining two moderately concentrated industries produce a less concentrated whole? Because their leaders barely overlap: the top firms in guarding and cash logistics (Allied Universal, GardaWorld, Brink's) are almost entirely different companies from the top firms in alarm monitoring (ADT, Vivint). Pooling two separate pyramids into one ranking dilutes the top-four share. The top 50 firms account for just half the group's revenue — the other half is spread across 21,000-plus firms [1]. Note also that, unusually, the HHI is published for the group but suppressed for each child; we state the group value and do not reproduce a suppressed one.

Sanity check — the children add up. The two child industries reconcile almost exactly to the group: receipts $46.80B + $33.94B = $80.74B; establishments 15,880 + 11,112 = 26,992; employees 866,822 + 144,585 = 1,011,407; annual payroll $29.02B + $9.83B ≈ $38.85B [1][2]. Firm counts sum to 21,624 versus the group's 21,607 — a difference of just 17, consistent with a handful of firms (the straddlers in Section 2) being counted in both children but once at the group level. That tight reconciliation is a good sign the pieces and the whole are consistent — but it also means the group inherits every one of the children's blind spots.

Undercount and scope caveats — read before quoting the number. The $80.7B / ~1.0-million-employee figures are the outsourced, employer-firm slice of a much larger security economy, and they understate it in several ways:

• In-house (proprietary) security is invisible here. The federal count captures only contract firms. Hospitals, casinos, universities, retailers, and manufacturers that employ their own guards, camera operators, and corporate investigators are counted under their industry, not 5616 — so the true security workforce is well above one million [7].
• Solo operators (nonemployers) are excluded. County Business Patterns (CBP) counts only establishments with payroll. Both children have a large fringe of one-person, no-payroll shops — private detectives (56161) and mobile locksmiths (56162) especially. Commercial databases list on the order of 14,000+ locksmith locations against ~3,900 employer establishments, for example [5]. Our data set contains no 5616 nonemployer total, so none is estimated here [20].
• Adjacent revenue is booked elsewhere. Credit reports (Credit Bureaus, NAICS 561450), drug/health testing (medical labs), do-it-yourself (DIY) alarm hardware (retail/manufacturing), install-only electrical work (NAICS 238210), and much fast-growing cash-management revenue land outside these codes even though the same companies sell them [3].
• These are U.S. figures only. The multinationals that dominate — Securitas, Allied Universal, GardaWorld, Brink's, Loomis — earn most of their revenue abroad. The federal number is the domestic footprint, not company scale.
• The federal file provides no group-wide profit, margin, pricing, or customer-concentration data; none is asserted here.

4. The investable universe — where value concentrates across the children

Because the two halves are so different, "where the value is" depends on which one you mean — and public availability is thin on the larger side and cleaner on the smaller side.

Public companies (uneven, and inverted vs. size).

Public screening exposure actually shrank in 2024 (Sterling Check was absorbed by First Advantage; HireRight was taken private), and there is no U.S.-listed pure-play locksmith or guarding company at all [4][5]. "OTC" is the U.S. over-the-counter market.

Major private platforms and owners (where most of the group lives).

• In the people half (56161): Allied Universal — U.S. #1 in guarding (~$20B global revenue, ~800,000 employees), PE-backed, built by merging AlliedBarton + Universal and buying most of G4S; management has floated a possible 2026 initial public offering (IPO) [11]. GardaWorld — private, Canada-based, spanning guarding and cash logistics, recapitalized in 2024–25 at roughly C$13.5–14B [12]. Screening platforms Checkr (venture-capital-backed), Accurate Background, HireRight, Cisive, DISA, Kroll; plus thousands of regional guard firms and detective agencies [9][13].
• In the electronics half (56162): Brinks Home (Monitronics), SimpliSafe and Everon (both PE firm GTCR), and integrator platforms Convergint, Pavion, Vector Security, Pye-Barker; on the locksmith side, franchises (Pop-A-Lock, FlyLock) and a PE commercial-access consolidator (Cobalt Service Partners) [5].

Bottom line for value concentration: in electronic systems, value is concentrated in scaled monitoring and two of those firms (ADT, Alarm.com) are publicly buyable; in cash logistics, value concentrates in a global oligopoly and one member (Brink's) is listed; in guarding — the single biggest activity by revenue and jobs — value sits overwhelmingly in private hands. The part of the group that matters most to the labor economy is the hardest to own on a public exchange.

5. How the money works

There is no single business model here. The group splits into two capital archetypes, and telling them apart is the core analytical task.

Labor and route businesses (most of 56161, plus locksmiths). These are priced on cash flow and contracts, not on a subscription multiple.

• Guards run on labor arbitrage, cost-plus: revenue ≈ billable guard-hours × bill rate, from which the firm pays the guard's wage plus "burden" (payroll taxes, insurance, training) plus overhead. Labor consumes ~55–65% of revenue and net margins are commonly mid-single digits; the decisive lever is retention, because industry turnover routinely exceeds 50% [4].
• Armored car is route-and-network logistics: recurring per-stop contracts where route density — stops per route-hour, customers per vault — is the master variable, topped by higher-margin cash processing and "smart-safe" technology services [8].
• Investigation/screening is a per-transaction data business: revenue ≈ screens run × price, where automation is everything (a check that clears instantly against a database is high-margin; one needing a person to pull a court record is not). High operating leverage; retention in the mid-to-high-90s% [9].
• Locksmiths run on billable technician hours, where high-margin automotive-key programming and commercial access-control work subsidize commodity key cutting [5].

The subscription annuity (the monitoring core of 56162). Forget one-time hardware margins — this business is valued on Recurring Monthly Revenue (RMR), the sum of all contracted monthly monitoring fees at a point in time. Firms grow by creating RMR (signing accounts) and buying RMR (acquiring account books), and a book trades at a multiple of monthly RMR — typically 25× to 50× in market practice. The multiple is driven mostly by attrition (customer churn): low churn supports high multiples and rich cash flow; high churn destroys both at once. Unit economics run roughly $1,200 to acquire a residential account, ~$40–60/month at a monitoring gross margin near 80%, then keep churn low enough that lifetime value clears the upfront cost [14].

The common thread: every activity in 5616 is a recurring-revenue service business with real switching friction, which is why the entire group consolidates (Section 8). But the two archetypes reward different things and are priced differently — labor/route businesses on enterprise value to earnings before interest, taxes, depreciation, and amortization (EV/EBITDA) and on contract quality; monitoring on RMR multiples and attrition. Metrics an investor watches therefore differ by segment: fill rate, turnover, and bill-vs-pay spread (guards); stops per route and managed-services mix (armored car); screen volume and retention (screening); RMR growth, attrition, and payback (monitoring).

6. What drives demand

Demand across the group is broadly resilient — fear of crime, compliance mandates, and insurance requirements do not take a year off — but each half answers to a different meter.

Shared drivers: crime and the perception of crime (lifts guards, alarms, cameras, and investigations alike); commercial construction and the artificial-intelligence-driven data-center build-out (access control, guarding, monitored fire-and-security systems); insurance and compliance mandates; and, above all, the multi-decade shift from in-house to outsourced security.

Divergent drivers:

• People half (56161) tracks hiring volume and labor-market churn (more hires = more background checks), the paradox that cash in circulation keeps rising (~$2.3 trillion) even as cash's share of payments falls (so there is still cash to move and safeguard), and critical-infrastructure and event security for guards [7][8][9].
• Electronics half (56162) tracks housing turnover and moves (a move is both a prime install moment and a top churn risk, making the half sensitive to mortgage rates), the smart-home wave (cameras, video doorbells, smart locks, app control, AI video verification), and — for locksmiths — the vehicle fleet and ever-more-electronic car keys [15][17].

The cross-cutting mega-trend is the substitution of technology for people. AI video analytics, remote monitoring, and access automation let one monitored camera network do work that once needed guards on posts — shifting value at the margin from the people half toward the electronics half, and simultaneously pushing the two halves to converge into blended "officers-plus-technology" offerings. Federal employment projections for the people half are muted (the guard occupation is roughly flat through 2034); these are occupational indicators, not revenue forecasts for the group [7].

7. Regulation

There is no single federal licensor for NAICS 5616; each activity carries its own regulatory backbone, mostly at the state level.

• Screening lives under the Fair Credit Reporting Act (FCRA): screeners are legally consumer reporting agencies, so covered reports require applicant consent, a permissible purpose, maximum-possible accuracy, and a two-step adverse-action process — enforced by the Federal Trade Commission (FTC) and Consumer Financial Protection Bureau (CFPB), with statutory-damages class actions a live financial risk [18].
• Guards are licensed state by state (often both firm and individual officer), with federal-contract work adding the Service Contract Act (prevailing wages); the Private Security Officer Employment Authorization Act (2004) allows FBI criminal-history checks [3].
• Armored car is heavily licensed — state licensing of carriers and armed crews, the Armored Car Industry Reciprocity Act of 1993 (so armed crews can cross state lines), heavy insurance, and Department of Transportation / Federal Motor Carrier Safety Administration vehicle rules — with a live anti-money-laundering (AML) exposure: in 2025 Treasury's Financial Crimes Enforcement Network (FinCEN) assessed a $37 million penalty against Brink's Global Services USA in its first enforcement action against an armored-car company [8].
• Alarm monitoring is state-licensed at the operator/installer level, with municipal alarm permits per premises, monitoring stations certified against UL 827 (the central-station standard), and a distinctive false-alarm problem — cities charge per-response fines or impose "verified response" (no police dispatch unless independently confirmed), which degrades the core value proposition [14].
• Locksmiths are lightly and unevenly licensed (only a minority of states require a statewide license); the one hard national gate is automotive — programming late-model car keys requires registration through the National Automotive Service Task Force, which controls access to manufacturer immobilizer data [5].

Investor implication: compliance is simultaneously a moat (it keeps sub-scale entrants out) and an uncapped liability (FCRA class actions, AML penalties, use-of-force claims, false-alarm ordinances). And the data-holding activities — screeners and monitoring firms — carry existential data-breach exposure. A firm's licensing, insurance, audit history, and data-security controls deserve as much diligence as its revenue growth.

8. Competitive dynamics and consolidation

Every activity in the group is consolidating, each from a head-over-long-tail starting point — which is why the group's blended CR4 of 25.6% understates how concentrated the top of each pocket really is.

• People half (56161): armored car is a near-oligopoly (Brink's rolled up Dunbar and most of G4S's cash operations; GardaWorld and Loomis run steady tuck-ins); guarding is fragmented but roll-up-driven (Allied Universal is the archetype); screening consolidated fast into ~5 platforms atop ~3,800 detective agencies [4].
• Electronics half (56162): monitoring is a roll-up industry by design — because value is quantified as RMR and account books are portable, contracts trade continuously through bulk purchases, dealer programs, and PE integrator platforms (Convergint, Everon, Pavion, Pye-Barker). Locksmithing consolidates only at the commercial-access edge, via franchising and PE roll-ups of commercial door/access-control service; the residential/mobile core resists national roll-up [5].

The distinctive rollup dynamic is that consolidation now runs across the two children, not just within them. The former G4S empire was split between Allied Universal (guards) and Brink's (cash). Securitas owns both a guard arm and a technology integrator; guarding firms are buying monitoring and analytics capability; the enterprise buyer increasingly wants a single vendor for officers, cameras, access control, and a monitoring center. So the competitive map is less "two industries" than a set of global platforms assembling integrated people-plus-technology security portfolios that cut across the NAICS boundary — while below them, thousands of local guard firms, detective agencies, alarm dealers, and locksmiths remain classic acquisition fodder.

9. Risks

Group-wide, then archetype-specific:

• Labor is the shared operational risk of the people half — turnover above 50% in guarding, wage inflation across all its activities, and thin margins that a mispriced contract or a lagging wage pass-through can erase [4].
• Attrition/churn is the core risk of the subscription half — a small rise in monitoring churn simultaneously shrinks cash flow and compresses the RMR multiple a buyer will pay [14].
• Cyclicality — screening volumes fall immediately when hiring cools; guard-hours, installs, and cash volumes soften with construction, housing, and consumer spending [4][17].
• Compliance and litigation — FCRA statutory-damages class actions (screening), AML/FinCEN and firearms exposure (armored car), negligent-hiring and use-of-force claims (guards), and false-alarm/verified-response ordinances (monitoring) [8][14][18].
• Technology as a double-edged sword — AI video, remote monitoring, and robots can cap guard headcount; DIY kits and Big Tech (Amazon's Ring, Google's Nest) can commoditize monitoring pricing; API-first entrants commoditize routine background searches — even as AI-era fraud makes identity verification more valuable [15][17].
• Data and physical security — screeners and monitoring firms hold highly sensitive personal data (breach = existential); armored carriers face robbery, insider collusion, and vault loss.
• Leverage and opacity — the private, PE-owned leaders across both halves carry meaningful acquisition debt and disclose little, making downside harder to underwrite; growth also consumes working capital (guards pay staff before clients pay; armored car and monitoring account-buying are capital-heavy) [11][14].
• Measurement risk — employer-only statistics undercount both halves (heavily for detectives and locksmiths), so both the true size and the true fragmentation of the group are hard to pin down [2][5].

10. How to invest and outlook

Public-market routes (segment-picked, not group-wide). There is no fund or ticker that cleanly buys "NAICS 5616." The practical menu, by child:

• Electronic systems (56162) — the cleanest public window. ADT (NYSE: ADT) is the direct large-cap bet on U.S. residential/small-business monitoring (watch RMR growth, gross attrition ~13%, payback, leverage); Alarm.com (Nasdaq: ALRM) is the capital-light "arm-the-dealer" SaaS play (watch renewal rate ~95%, dealer count). Lock/hardware makers (ASSA ABLOY, Allegion, Fortune Brands, dormakaba, Hillman) are the only way to touch locksmithing, and only as a hardware proxy [5][14][15].
• People (56161) — thin and scattered. Brink's (NYSE: BCO) is the one genuine U.S.-listed large-cap (cash logistics); First Advantage (Nasdaq: FA) is the one listed screening pure-play; Securitas (Stockholm/OTC) is the closest guard exposure and a straddler into electronic systems. The marquee catalyst is a possible Allied Universal IPO (management has floated 2026), which would finally give U.S. investors a scaled listed guard vehicle [8][9][10][11].

Because most listed names are diversified, foreign, or straddle both halves, do not compare valuation multiples mechanically across them — judge U.S.-segment growth, retention/attrition, wage-route-technology mix, cash generation, leverage, and litigation/insurance reserves. Tickers, yields, and multiples should be checked at the time of investment.

Private-market routes (where most of the group lives). Every activity here is fragmented, recurring-revenue, and roll-up-friendly, which is why PE, search funds, and independent sponsors are active buyers: regional guard firms and detective agencies at modest EBITDA multiples; underutilized armored-car routes with density upside; RMR account books priced at 25–50× monthly recurring revenue (attrition discipline is the whole game); and commercial door/access-control service — the one locksmith segment with recurring contracts. Because private disclosure is limited, diligence must go deeper: contract assignability and customer concentration, licensing and compliance history (FCRA/AML/wage-and-hour), turnover and fill rates, attrition and RMR quality, insurance reserves, working capital, and owner succession.

Outlook (analytical judgment). Expect the group to keep growing in dollar terms at a modest pace, driven more by wage inflation, higher-value services, technology mix, and continued outsourcing than by rising headcount — which federal projections show as roughly flat [7]. The two halves diverge on trajectory: electronic systems (56162) is the structurally faster grower, carried by recurring monitoring, cloud video, AI verification, and smart-building integration; the people half (56161) grows mostly in dollars, as guarding shifts from commodity "warm-body" staffing toward "guarding + technology," screening becomes a continuous identity-and-fraud service, and armored car races to convert "moving cash" into recurring "managing cash." The defining structural theme is convergence: technology substituting for labor at the margin, and global platforms (Securitas, Allied Universal, GardaWorld, Brink's, ADT) assembling integrated people-plus-electronics portfolios that erode the boundary between the two children. The swing factors to watch are labor costs and minimum-wage policy (people half), U.S. hiring volume (screening), whether DIY and Big Tech commoditize the monitoring fee faster than smart-home complexity re-professionalizes it (electronics half), the slope of cash's decline (armored car), and whether Allied Universal comes public and reprices the group's visibility. Our federal data set provides no market-growth rate or total-addressable-market estimate for this group, so none is stated here.

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Sources

1. U.S. Census Bureau, 2022 Economic Census — Concentration of Largest Firms (EC2200SIZECONCEN), NAICS 5616 and children 56161 / 56162 (receipts, firm counts, CR4/CR8/CR20/CR50, HHI). https://data.census.gov/table/ECNSIZE2022
2. U.S. Census Bureau, County Business Patterns 2023 — NAICS 5616 and children (establishments, employment, annual and first-quarter payroll). https://www.census.gov/programs-surveys/cbp.html
3. U.S. Census Bureau, 2022 NAICS Manual — 5616 Investigation and Security Services, and definitions/exclusions for 56161 and 56162. https://www.census.gov/naics/
4. Child primer 56161 — Investigation, Guard, and Armored Car Services, synthesizing: 2022 Economic Census concentration; guard labor economics (labor 55–65% of revenue, mid-single-digit margins, turnover >50%); Securitas/Pinkerton and GardaWorld straddle; screening platform consolidation. (See that primer's Sources 1–3, 10–13, 16–17.)
5. Child primer 56162 — Security Systems Services, synthesizing: 2022 Economic Census concentration (CR4 34.7% monitoring, ~6.5% locksmiths); ADT/Alarm.com; RMR-multiple practice; UL 827 and false-alarm ordinances; lock/hardware makers (ASSA ABLOY, Allegion, Fortune Brands, dormakaba, Hillman); NASTF automotive-key regime; ~14,000+ locksmith establishment estimate; IBISWorld ~$2.9B locksmith market. (See that primer's Sources 1–12.)
6. U.S. Small Business Administration, Table of Small Business Size Standards (56161 children $25M–$43M; 56162 children $25M average annual receipts), 2023. https://www.sba.gov/document/support-table-size-standards
7. U.S. Bureau of Labor Statistics, Occupational Outlook Handbook / Occupational Employment and Wage Statistics — Security Guards (33-9032) and Private Detectives and Investigators, 2024–2025. https://www.bls.gov/ooh/protective-service/
8. The Brink's Company, Form 10-K FY2024 and results (~$5B revenue; cash-in-transit vs. managed-services mix); FinCEN, $37M civil penalty against Brink's Global Services USA (first armored-car AML action), 2025; Armored Car Industry Reciprocity Act of 1993 (15 U.S.C. ch. 85). https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0000078890 · https://www.fincen.gov/
9. First Advantage Corporation, Acquisition of Sterling Check ($2.2B, 2024) and FY2025 results (~$1.6B revenue); background-screening market research (IBISWorld / Mordor Intelligence), 2025–2026. https://investors.fadv.com/
10. Securitas AB, Annual and Sustainability Report 2024 (~$16B revenue; U.S. guard arm plus Securitas Technology electronic-security integrator; Pinkerton). https://www.securitas.com/
11. Allied Universal Newsroom, Allied Universal M&A and possible 2026 IPO consideration; Security Info Watch, Allied Universal acquisition of G4S ($5.3B, 2021). https://ausnewsroom.aus.com/
12. GardaWorld, Recapitalization led by founder Stephan Crétier and HPS Investment Partners (~C$13.5–14B), 2024–2025. https://www.gardaworld.com/news/
13. Forbes / Checkr, venture-backed gig-economy background screening (120,000+ customers; peak valuation ~$5B), 2025–2026. https://checkr.com/
14. U.S. Securities and Exchange Commission, ADT Inc. 2025 Form 10-K (RMR ~$359M/month; gross customer revenue attrition ~13%; revenue payback ~2.3 yrs; RMR-multiple and account-acquisition economics). https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=ADT&type=10-K
15. U.S. Securities and Exchange Commission, Alarm.com Holdings 2025 Form 10-K (SaaS & license ~68% of revenue; SaaS renewal rate ~95%; dealer-channel model). https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0001459200&type=10-K
16. IBISWorld, Locksmiths in the US — Market Size (~$2.9bn; fragmented, no firm >5% share), 2025. https://www.ibisworld.com/united-states/market-size/locksmiths/4833/
17. Global Growth Insights / Market Research Future, Alarm Monitoring / Home Security Systems Market — size and growth estimates, 2025 (third-party estimate; not official statistics). https://www.globalgrowthinsights.com/market-reports/alarm-monitoring-market-121074
18. U.S. Federal Trade Commission, Equal Employment Opportunity Commission, and Consumer Financial Protection Bureau, Background Checks / FCRA guidance for employment screening; CFPB Circular 2024-06, 2014–2024. https://www.ftc.gov/business-guidance/resources/background-checks-what-employers-need-know
19. Loomis AB / Prosegur Cash, S.A., Annual reports and company information (foreign-listed cash-logistics alternatives). https://www.loomis.com/ · https://www.prosegur.com/en/investors-shareholders
20. U.S. Census Bureau, Nonemployer Statistics (solo, no-payroll firms excluded from employer-based counts). https://www.census.gov/programs-surveys/nonemployer-statistics.html