Administrative and Support and Waste Management and Remediation Services (U.S.) — NAICS 56

A Histometrics rollup primer for a general investing audience — relevant to both public-market and private investors. NAICS (the North American Industry Classification System) is the U.S. government's standard scheme for grouping businesses by activity. Code 56 is a two-digit sector — the broadest tier in the system — and its very name is a conjunction of two unrelated things: 561, Administrative and Support Services and 562, Waste Management and Remediation Services. This page synthesizes the two already-written subsector primers plus our ground-truth federal statistics for the sector level; it does not re-research from scratch. Figures are reported facts unless the wording marks them as projections or judgments.[1][2][3]

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1. Overview

Sector 56 is the part of the economy that does the work other organizations would rather not do themselves — and then, at the very end, hauls away what's left over. Read the awkward, stapled-together name literally: this is two different service economies filed under one roof. One is the outsourced back office, front desk, loading dock, and security post of American business (561). The other is the trucks, permitted landfills, and cleanup crews that manage the nation's waste and contamination (562). They share a filing bucket and almost nothing else.[4]

At the sector level the federal statistics are enormous: roughly $1.35 trillion in 2022 receipts, about 13.5 million paid employees — one of the largest employment footprints of any sector in the economy — 381,490 firms, and ~$763 billion of annual payroll.[1] But an aggregate this broad hides more than it reveals, because the sector is overwhelmingly one subsector with a much smaller, economically opposite tail: Administrative and Support (561) is about 90% of the receipts and 96% of the jobs; Waste Management and Remediation (562) is the remaining ~10% and ~4%.[1][2][3] The distinctive value of a sector-56 rollup is not a single number — it is the contrast between these two halves, which is the subject of Section 2.

Three facts frame everything below. First, the sector is lopsided: to a first approximation, "56" is administrative-and-support services, with a waste business one-tenth its size attached. Second, the two halves have opposite economic DNA — 561 is capital-light, labor-heavy, fragmented, and cyclical-to-defensive by turns; 562 is capital-heavy, infrastructure-like, permit-protected, and uniformly defensive. Third, they answer to different swing factors — artificial intelligence (AI) is the force reshaping the labor-based admin half, while PFAS regulation (per- and polyfluoroalkyl substances, the "forever chemicals") is the force reshaping the waste half. No single valuation lens, demand story, or investment vehicle fits the sector as a whole.

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

NAICS is a nested hierarchy: sector 56 splits into two three-digit subsectors, each of which drills down into industry groups (561 has eight; 562 has three). The single most useful thing this rollup adds is the side-by-side. All figures below are from our ground-truth federal files; receipts, firm counts, and concentration are 2022 Economic Census ("EC"), while establishments, employment, and payroll are 2023 County Business Patterns ("CBP") — two programs from different years, so do not divide one across the other to derive a true margin. "Direction of travel" is a qualitative read from the subsector primers, not an official statistic.[1][2][3]

(CR4 = combined revenue share of the four largest firms; HHI = Herfindahl-Hirschman Index, a standard 0–10,000 concentration gauge where U.S. antitrust agencies treat anything under ~1,000–1,500 as "unconcentrated." Both are defined here on first use.[5][6] Revenue-per-worker mixes 2022 receipts with 2023 headcount and, for 561, is inflated by wage pass-through — treat it as an order-of-magnitude contrast, not a precise ratio.)

Reading the contrast — five things stand out:

1. The sector is ~90% one subsector. Administrative and Support (561) dwarfs Waste (562) roughly nine-to-one on revenue and twenty-six-to-one on jobs. "NAICS 56" as a single figure is almost entirely a story about outsourced business support; the waste economy is a distinct, much smaller appendix. Anyone quoting a sector-56 total is really quoting 561 with a rounding-error's worth of garbage trucks attached.[1][2][3]

2. The two halves have opposite economic DNA. 561 sells the billed human hour — a staffing shift, a cleaned square foot, a guard post, an answered call — and is capital-light, labor-heavy, and structurally fragmented; its top line is swollen by pass-through wages. 562 sells access to a scarce physical asset — a truck route, a permitted landfill's tipping capacity — is capital-heavy and infrastructure-like, and earns near-pure margin on every extra ton. They are about as different as two service subsectors can be.[2][3]

3. Revenue-per-worker and pay-per-worker both flag the split. Waste books roughly three times the revenue per employee of admin support (~$280k vs ~$93k), the signature of asset- and commodity-heavy sites rather than a labor pool. It also pays more per worker (~$72,100 vs ~$56,100), reflecting capital-adjacent, hazmat-skilled, often unionized or municipal-adjacent work versus a vast low-wage service labor force.[1][2][3]

4. Concentration runs backwards from the headline — the pooling illusion, doubled. The sector HHI is just 23 and its CR4 only 7.5%, statistically "unconcentrated" to the point of near-perfect competition.[1] But 23 is lower than both children — below 561's own diluted 25 and far below 562's 293. Combining two subsectors that never compete mechanically shrinks every firm's measured share. Real competitive concentration lives deep inside the niches — a three-firm credit-bureau oligopoly (inside 561), a local landfill that behaves as a metro monopoly (inside 562) — not at "56," which is not a market anyone competes in.[2][3][6]

5. They answer to different swing factors, so a shock to one need not touch the other. The story reshaping 561 is AI, which threatens the children that sell commodity human hours (call centers, temp, routine admin) while helping the data and platform assets (credit bureaus, monitoring analytics). The story reshaping 562 is PFAS regulation, a two-sided force that expands cleanup and hazardous-treatment demand while creating new liability for landfills. Neither force meaningfully moves the other half of the sector.[2][3]

What actually unites them. The only genuine through-line is that both subsectors are things organizations outsource rather than do in-house — support functions and waste handling alike are jobs a company can either perform itself or pay a specialist to do. That shared "make-versus-buy" character has three investing consequences that do travel across the whole sector: (a) employer-only federal data undercount both, because in-house ("captive") operations and government provision are excluded by definition (Section 3); (b) both are consolidation fields — fragmented tails of small operators with scaled leaders rolling them up (Section 8); and (c) in both, the top line overstates the money actually kept — pass-through wages and commissions in 561, cross-code integrated revenue in 562 — so revenue is a poor proxy for value.[2][3]

Where the boundaries sit. Sector 56 excludes the work organizations do for themselves (a bank's own collections, a city's own sanitation crew, a hospital's own guards are booked in their industry, not here) and everything outside these two subsectors.[4] The federal figures below count only what the codes narrowly capture.

3. Size — the sector as a whole

Our ground-truth federal statistics for the combined sector, NAICS 56. Receipts, firm counts, and concentration are 2022 Economic Census; establishments, employment, and payroll are 2023 County Business Patterns — two snapshots from different years, not one income statement.[1]

The rollup reconciles almost to the unit — a strong confidence check. The two subsectors sum to this level essentially exactly: establishments (421,777 + 29,237 = 451,014) and employment (12,960,998 + 493,864 = 13,454,862) match the sector file precisely; receipts (~$1,209.2B + ~$138.4B = ~$1,347.7B) and annual payroll (~$727.4B + ~$35.6B = ~$763.0B) each reconcile to within rounding.[1][2][3] The only line that does not add up is the firm count: the two subsectors sum to 381,612 versus the sector's 381,490, because ~122 companies operate in both subsectors and are counted once at the sector level but in each subsector they touch (~0.03%). That tight additivity confirms the sector file and the subsector files come from the same underlying census.

What the numbers reveal — read carefully:

• A labor-driven sector, but the headline overstates it. Payroll is ~57% of receipts at face value — the mark of a wage-based service economy. But that ratio is dominated by 561 (payroll ~60% of its receipts, itself inflated by the pass-through wages of ~7.8 million placed and co-employed staffing workers who physically work elsewhere), while 562 is far less labor-intensive (payroll ~26% of its receipts).[2][3] Read the sector as a giant low-to-mid-wage service labor pool with a small, capital-heavy waste-infrastructure business bolted on.

• Concentration is lower at the sector than in either subsector. The sector HHI of 23 sits below both children — arithmetic, not a market fact. No one dominates "56" because "56" is not something anyone competes in; it is two separate markets pooled into one denominator.[1][6]

• Overwhelmingly a small-business sector. Average receipts per firm are ~$3.53 million and the median firm is far smaller; the great majority of the 381,490 firms qualify as small businesses under U.S. Small Business Administration (SBA) size standards.[2][3] The scaled, investable operators are a thin layer on top of a vast base of local firms.

Undercount caveat — the ~$1.35 trillion is an employer-only floor. These are employer statistics: CBP and the Economic Census largely omit nonemployer businesses (the self-employed and firms with no paid staff), and small/individual ownership is heavy in both halves — hundreds of thousands of solo landscapers, one-truck haulers and septic pumpers, home-based travel advisors, solo private detectives, and one-person admin shops. Two further scope effects push the same way: in-house ("captive") operations are excluded by definition (a company's own cleaners, guards, and collections; a city's own sanitation crews), and government does an enormous share of the waste work directly — municipal collection, publicly owned landfills and waste-to-energy plants, and the U.S. Department of Energy's ~$8-billion-a-year cleanup program all sit largely outside these figures.[2][3] Our ground-truth file for this level carries no nonemployer total, so none is stated here. And the top line is not apples-to-apples across the two halves: 561 books gross revenue swollen by pass-through (temp wages, professional-employer-organization billings) and commission-only lines (travel), while 562's integrated majors book revenue across adjacent codes. Treat ~$1.35 trillion as the visible employer core of a materially larger services economy, not its full weight.

4. Investable universe — where value concentrates across the two halves

The defining sector-level fact for a public-market investor: there is no pure-play, no fund, and no clean ticker for sector 56 as a whole, and the two halves are almost mirror images of one another on how you actually gain exposure. Paradoxically, the smaller subsector is the more investable one for a generalist.

(Company names below are thematic orientation, not quotes or recommendations. Most listed names report diversified segments, not a clean NAICS line — treat them as proxies and underwrite the relevant net economics, not consolidated revenue swollen by pass-through or unrelated businesses.)

Waste (562) — the cleaner, more concentrated public vehicle. A handful of integrated solid-waste majors — Waste Management (NYSE: WM), Republic Services (NYSE: RSG), Waste Connections (NYSE/TSX: WCN), GFL Environmental (NYSE/TSX: GFL), and Casella Waste Systems (Nasdaq: CWST) — straddle collection, the landfill profit core, and recycling, so one name is a bet on "environmental services" broadly. Clean Harbors (NYSE: CLH) is the nearest hazardous-and-cleanup pure-play; Tetra Tech (Nasdaq: TTEK) and the federal engineers reach the remediation end; and a real sector ETF exists — VanEck Environmental Services (NYSE Arca: EVX), an exchange-traded fund (ETF) — bundling the listed waste names into one ticket.[3]

Administrative & Support (561) — no ETF, no pure-play, assembled corner-by-corner. Here public quality concentrates in a scattered few children, and access runs partly inverse to size — the two largest children (employment and building services) are dominated by private ownership. The cleanest listed exposure sits in: credit bureaus — Equifax (NYSE: EFX), TransUnion (NYSE: TRU), FICO (NYSE: FICO), Experian (London: EXPN), the sector's single cleanest quality play; pest control — Rollins (NYSE: ROL), Rentokil; alarm monitoring and cash logistics — ADT (NYSE: ADT), Alarm.com (Nasdaq: ALRM), Brink's (NYSE: BCO); and professional employer organizations (PEOs) — TriNet (NYSE: TNET), Insperity (NYSE: NSP), with ADP and Paychex as lower-volatility payroll/PEO giants. Higher-beta or diversified exposure runs through cyclical staffing (ManpowerGroup, Robert Half, Korn Ferry), depressed call-center operators (Nasdaq: CNXC and peers) and debt buyers (Nasdaq: ECPG, PRAA), facilities and landscaping (NYSE: ABM, EME, BV), and travel distribution (NYSE: BKNG; Nasdaq: EXPE, SABR; NYSE: LYV).[2]

Where value is private or non-buyable. In both halves the bulk of the money changes hands privately — contract guarding, healthcare management-services organizations, and tour operators in 561; family haulers, materials-recovery-facility operators, and field-service platforms in 562 — plus the government operations (municipal sanitation, civic visitor bureaus) you cannot invest in at all except through municipal bonds.[2][3]

Bottom line: for a public investor, 562 offers concentrated, one-ticket access to a defensive compounder theme, while 561 offers a handful of high-quality corners and a lot of cyclical or diversified optionality — but no way to buy "administrative services" as a whole.

5. How the money works

Strip away the two labels and the sector runs on a short list of distinct engines. Knowing which one you are looking at tells you the cyclicality, the capital intensity, and the right valuation lens.

• Sell the billed hour (labor arbitrage) — the dominant model in 561. Most of the admin half bills a unit of human work — a staffing hour, a cleaned square foot, a guard-shift, an answered call — above the fully-loaded cost of the person doing it, times how busy they are kept. The levers are utilization, attrition and re-hiring cost (turnover routinely tops 50% in guarding and cleaning), billable-hour mix, and route/branch density. Margins are thin — low-single-digit net is common.[2]
• Route density and scarce permitted assets — the model in 562. Waste collection earns money by packing more stops into each truck-route (an incumbent serves a new customer on an existing route at almost pure margin), while disposal earns a tipping fee per ton on a permitted landfill or incinerator, where every ton above breakeven is nearly pure margin and the permit itself is the moat. Integrated majors run roughly 28–32% EBITDA margins (earnings before interest, taxes, depreciation, and amortization) — a different order of profitability from the labor half.[3]
• The recurring annuity (subscription). Both halves have contracted, renew-for-years revenue: alarm monitoring priced on Recurring Monthly Revenue (RMR — the sum of contracted monthly fees), pest and cleaning routes, and auto-club memberships in 561; municipal collection contracts with price escalators in 562. Switching friction makes these the assets buyers pay up for.[2][3]
• Sell the same data twice (the toll booth) — the outlier. Credit bureaus (inside 561) collect borrower data for free, sell it back per report at near-zero marginal cost, and earn incremental margins in the high tens of percent. This is the one durable pricing-power model in the sector.[2]
• Fee, spread, float, and engineering services. Placement agencies earn a one-time fee; PEOs add an insurance spread; debt buyers collect charged-off receivables for their own account (all 561). Remediation firms earn on backlog and contract type (time-and-materials, cost-plus, fixed-price); recycling plants earn a per-ton fee plus a volatile commodity leg (562).[2][3]

The unifying trait is that most of the sector is capital-light-to-moderate, contract- or route-based service work whose top line overstates the money actually kept, and whose returns come from scale, density, retention, and buy-and-build consolidation rather than organic pricing power. The exceptions that do have pricing power — credit bureaus and dominant trade shows in 561, scarce permitted landfills in 562 — are precisely where durable value concentrates. Standard regulated-utility "rate base," real-estate "funds from operations," and mining "all-in sustaining cost" lenses do not fit this sector; revenue-per-productive-hour, RMR multiples, tipping-fee-per-ton utilization, and enterprise-value-to-EBITDA do. Our federal file reports no sector-wide margin, growth rate, or total addressable market, so none is stated.[1]

6. Demand drivers

Because the two halves answer to different forces, the sector has no single demand driver — but a few themes cut across it.

• The make-versus-buy (outsourcing) decision — the master driver for 561. Nearly every admin child exists because organizations decide a support function is non-core and cheaper to buy than build. Corporate cost pressure and recessions often push more volume out the door, making parts of the subsector counter-cyclical to their clients' budgets.[2]
• Regulation and mandated waste flows — the master driver for 562. Waste must move through a documented, permitted chain and contamination must be cleaned up by law, which makes demand unusually non-cyclical; regulation is effectively the waste half's sales force.[3]
• The labor market and business cycle. Employment services is a leveraged bet on hiring confidence (temp help is a classic leading indicator) and travel rides discretionary and corporate spend; waste collection tracks population, households, construction, and industrial output more steadily.[2][3]
• The credit cycle. Collections, credit bureaus, and repossession (inside 561) track lending and delinquency.[2]
• Government funding. Federal appropriations (Superfund, Brownfields, DOE cleanup) and municipal budgets move waste and remediation demand directly.[3]
• AI and PFAS — the two structural wild cards. AI destroys demand where it deflects calls and drafts documents but is additive for the data assets (561); PFAS regulation expands hazardous-treatment and cleanup demand while creating landfill liability (562). Each is largely confined to its own half.[2][3]

7. Regulation

There is no single regulator or license for NAICS 56 — oversight follows the activity, and the two halves face different regimes. A common base of employment law (the Fair Labor Standards Act; Equal Employment Opportunity Commission anti-discrimination rules; Occupational Safety and Health Administration standards) runs under all of it.

• The admin half (561) is governed by whatever it administers on clients' behalf: consumer-finance rules (the Fair Debt Collection Practices Act and Fair Credit Reporting Act, or FCRA, over collections, credit bureaus, and screening), co-employment and PEO rules, federal service-contract wage law, pesticide law for pest control, and the H-2B visa cap for seasonal labor. Firms here are typically more exposed to the rules attached to the data and functions they handle than to any single license on themselves.[2]
• The waste half (562) is governed by environmental law that is simultaneously its demand engine and its barrier to entry: the Resource Conservation and Recovery Act (RCRA, cradle-to-grave waste control), the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, or "Superfund," which drives remediation), and the Clean Air Act, plus the state permitting and local "not-in-my-backyard" opposition that keeps new disposal capacity scarce — a curse for entrants and a gift to whoever already owns permitted sites.[3]

The two live regulatory stories are different. For 561 the swing factor is emerging AI-hiring and data-privacy rules layered on top of long-standing consumer-finance regimes; for 562 it is PFAS — the EPA's designation of two forever chemicals as CERCLA hazardous substances — a genuinely two-sided force that expands the cleanup market while creating landfill liability, alongside Extended Producer Responsibility (EPR) laws reshaping recycling economics.[2][3] Common thread across the sector: compliance quality is at once a competitive moat (it keeps sub-scale entrants out) and an uncapped liability (an FCRA class action or a Superfund cleanup order can be existential for a small operator), and tightening rules generally favor scaled operators who can absorb the cost.

8. Consolidation

The sector's structural signature is a barbell: extreme fragmentation at the base (381,490 firms, CR4 7.5%, HHI 23) with durable value consolidating at the top of each niche.[1] That gap — between fragmented supply and the scale advantages available to leaders (route/network density, purchasing power, software, data, compliance capacity, and a valuation premium on recurring revenue) — fuels relentless private-equity buy-and-build across both halves. The mechanics rhyme but differ:

• In 561, roll-ups cluster by route density (pest, landscaping, monitoring account-books) and by capability (staffing/PEO, call-center outsourcing, healthcare management-services organizations), while cross-boundary bundling assembles integrated facilities management and integrated security.[2]
• In 562, collection has been rolled up for decades (fold a nearby hauler's stops into existing routes and internalize volume through owned disposal); disposal grows by buying scarce permitted capacity because new sites almost never get permitted; and remediation-and-other is a textbook fragmented roll-up field.[3]

Public consolidators exist in a few corners — the credit-bureau oligopoly, ADT in monitoring, Rollins/Rentokil in pest (561); the integrated waste majors (562) — but most consolidation happens privately and will keep showing up as niche platforms rather than as rising concentration at the "56" level, because pooling two non-competing subsectors can never raise the sector's measured HHI no matter how much roll-up occurs within a niche. One caution travels across the whole sector: capital structure, not demand, is the binding constraint on roll-ups — an over-leveraged consolidator can fail even on steady demand (the December 2025 Chapter 11 of a large portable-sanitation platform in 562 is a live example), and the private platforms that own the best assets in both halves carry meaningful, often undisclosed debt.[3]

9. Risks

• AI substitution — the defining risk for the labor half (561). Live deployments already replace agents, drafters, and routine admin at scale (public markets have repriced call centers severely), and commodity recruiting, temp, and clerical work sit directly in the path. The data, annuity, and franchise assets are largely insulated and may benefit — but a subsector that is ~60% labor by payroll has real exposure.[2]
• Environmental liability — the defining long-tail risk for the waste half (562). PFAS/CERCLA exposure, landfill leachate and methane, and Superfund-style cleanup obligations are heaviest where operators own disposal assets, and PFAS designation remains in active litigation — a two-sided risk.[3]
• Cyclicality and end-market concentration. Employment services and travel (561) are high-beta bets on hiring and discretionary spend; the rest of 561 and most of 562 are more defensive. Losing or repricing one large contract can strand facilities and trained staff in either half.[2][3]
• Confusing revenue with value. Much of 561's top line is wage-and-insurance pass-through or commission, and 562's majors book revenue across adjacent codes — so firms can grow gross revenue while net economics stagnate. This is the single most common analytical trap in the sector.[2][3]
• Labor cost, turnover, and immigration exposure. Wage inflation, chronic turnover, and enforcement risk (E-Verify, the H-2B cap) hit the people-heavy children hard, on thin margins with little cushion.[2]
• Roll-up and leverage risk. The PE platforms that own the best private assets in both halves carry meaningful debt; integration missteps or rising rates strain the most levered operators — proven, not hypothetical.[3]
• Data-security and privacy liability. Screeners, credit bureaus, monitoring firms, and payroll/PEO operators (561) hold highly sensitive data; a serious breach is existential.[2]
• Measurement risk. Employer-only federal data understate the nonemployer-, in-house-, and government-heavy reality, and mix gross and net receipts across the two halves — so both the true size and the true fragmentation of the sector are hard to pin down, and third-party "market size" figures routinely blur these codes with adjacent ones.[1]

10. How to invest, and the outlook

Public routes — two different vehicles for two different halves. There is no listed pure-play, ETF, or REIT for NAICS 56; you build exposure to the half (and the corner) you want. For the waste half (562), the integrated majors (WM, RSG, WCN, plus GFL and CWST) are the cleanest way to own the collection-plus-landfill core — prized as defensive compounders with price-led growth and strong free cash flow — Clean Harbors (CLH) is the hazardous/cleanup read, and the VanEck EVX ETF gives one-ticket access. For the admin half (561), there is no equivalent one-ticket vehicle; the highest-quality listed exposure is assembled corner-by-corner — credit bureaus (EFX, TRU, FICO, Experian), pest control (ROL, Rentokil), monitoring and cash (ADT, ALRM, BCO), and PEOs (TNET, NSP, ADP, Paychex) — with cyclical staffing, depressed call-center names, facilities/landscaping (ABM, EME, BV), and travel distribution (BKNG, EXPE, SABR, LYV) for higher-beta or contrarian exposure. Because most of these are diversified, foreign, or straddle sub-industries, do not compare multiples mechanically — judge each on the net economics attributable to the activity, on recurring-revenue quality and retention, and on utilization, leverage, and litigation reserves.

Private routes — where most of the sector actually trades. Both halves are among the largest small-business M&A pools in the country. The mainstream paths: in 561, buy or operate an SBA-financeable local business (a staffing branch, a cleaning or landscaping route, a pest or security firm, a collection agency) or back a PE roll-up; in 562, buy or build a local hauling company, acquire a disposal asset (or lend via municipal bonds), or own a field-service, remediation, or recycling operator. Prize recurring revenue, low churn, route/branch or disposal density, documented compliance and licensing, and — for 561 especially — AI wrapped around the workflow rather than competing with it on price. Diligence centers on verified net cash flow, contract and customer concentration, utilization/attrition, insurance and environmental reserves, working capital, and leverage.

Outlook (forward-looking judgment; the federal data contain no growth forecast). Do not underwrite sector 56 as one number — it is two theses running on different clocks. The waste half (562) looks durable and infrastructure-like: mandated, recession-resistant demand, pricing above inflation in collection, scarce permit-protected disposal, and a multi-year consolidation runway, with PFAS the main two-sided overhang. The admin half (561) splits internally: a data, annuity, and franchise core (credit bureaus, alarm monitoring, pest and route services, PEOs, dominant trade shows and ticketing, facilities riding the data-center build-out) that looks durable and even favored, against a commodity-labor core (call centers, document prep, low-skill placement, routine admin, undifferentiated guarding) facing a structural, AI-driven squeeze. Across the whole sector, value is created less by markets expanding than by operators improving mix and consolidators rolling up small units — the durable tailwinds are outsourcing (561) and regulation (562); the durable headwinds are labor-plus-technology (561) and environmental liability (562). Public investors get concentrated quality in a few corners of a very broad field; private investors get two vast, cash-generative roll-up pools — provided they underwrite each subsector, and each niche within it, on its own economics and treat the two-digit code as a filing convenience, not a market. For the full, industry-by-industry analysis — company rosters, unit economics, regulation, and diligence checklists — read the two subsector primers (561 and 562) and, beneath them, the eleven industry-group primers.

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Sources

This rollup synthesizes our ground-truth federal statistics for NAICS 56 and the two already-written subsector primers, each of which carries its own complete numbered Sources list (Census, SEC filings, and sector-specific regulators and trade bodies).

1. Histometrics ground-truth federal file — NAICS 56, Administrative and Support and Waste Management and Remediation Services: U.S. Census Bureau, 2022 Economic Census — Concentration of Largest Firms (receipts $1,347,672,352K; firms 381,490; CR4 7.5% / CR8 10.8% / CR20 17.2% / CR50 25.2%; HHI 23) and 2023 County Business Patterns (establishments 451,014; employees 13,454,862; annual payroll $762,956,356K; Q1 payroll $190,952,059K). No nonemployer counts or per-firm operating metrics supplied at this level. https://www.census.gov/programs-surveys/economic-census.html; https://www.census.gov/programs-surveys/cbp.html
2. Histometrics subsector primer — NAICS 561 Administrative and Support Services (receipts ~$1,209.2B; 12,960,998 employees; 359,824 firms; CR4 7.8%, HHI 25.1; eight industry groups; labor-arbitrage / data-toll / annuity economics; AI as the defining swing factor; credit bureaus, pest control, monitoring, PEOs as the cleanest listed corners). primer-561-DRAFT.md
3. Histometrics subsector primer — NAICS 562 Waste Management and Remediation Services (receipts ~$138.4B; 493,864 employees; 21,788 firms; CR4 29.1%, HHI 293.3; three industry groups — collection, treatment & disposal, remediation & other; route-density and scarce-permitted-asset economics; PFAS as the two-sided swing factor; integrated waste majors, Clean Harbors, and the EVX ETF). primer-562-DRAFT.md
4. U.S. Census Bureau — 2022 NAICS Manual: Sector 56, Administrative and Support and Waste Management and Remediation Services, and its subsectors 561 and 562 (definitions, structure, and scope exclusions including in-house/captive operations and government provision). https://www.census.gov/naics/
5. U.S. Census Bureau — About the Economic Census and County Business Patterns (concentration ratios, HHI methodology, and employer-only coverage that excludes nonemployers and most government). https://www.census.gov/programs-surveys/cbp/about.html
6. U.S. Department of Justice and Federal Trade Commission — 2023 Merger Guidelines (HHI and concentration-ratio thresholds; "unconcentrated" below ~1,000–1,500). https://www.justice.gov/atr/2023-merger-guidelines