Commercial & Industrial Machinery Repair and Maintenance (U.S.)

NAICS 2022 code 81131 — Commercial and Industrial Machinery and Equipment (except Automotive and Electronic) Repair and Maintenance. NAICS is the North American Industry Classification System, the U.S. government's standard scheme for grouping businesses. [4]

This is a roll-up page. NAICS 81131 is a NAICS industry (5-digit) that contains exactly one national industry (6-digit): 811310. Because the two levels cover the identical set of businesses, the numbers on this page and the numbers for 811310 are the same figures. This page gives the top-line picture and the federal stats for the level; for the full treatment — economics, metrics, named companies, regulation, and how-to-invest detail — read the 811310 primer.

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1. Overview

This is the industry that keeps America's heavy machines running: the independent shops and field-service crews that repair, rebuild, and maintain forklifts, machine tools, construction and mining equipment, industrial pumps, motors and compressors, commercial refrigeration, agricultural machinery, and factory production lines. [4] It sells skilled technician hours, replacement parts, and maintenance contracts — it is an uptime service business, not a manufacturing one.

Two things make it worth an investor's attention: it is counter-cyclical at the margin (when new equipment gets pricey, owners fix what they have), and it is enormously fragmented (roughly 22,000 mostly small employer firms, no dominant player) — a classic private "roll-up" hunting ground. Public-market investors have no pure play; exposure is indirect through equipment dealers, distributors, flow-equipment makers, and rental companies whose parts-and-service arms do this work.

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2. What's inside — and why this level equals its one child

A NAICS industry (5-digit) can hold several national industries (6-digit). This one holds a single 6-digit child:

When a NAICS industry has only one child, the two codes are a pass-through: the 5-digit "81131" and the 6-digit "811310" describe exactly the same establishments, so every establishment count, dollar of receipts, and concentration ratio is identical at both levels. There is nothing at 81131 that isn't also at 811310. The rest of this page therefore stays short and hands off to the child primer for detail.

The scope covers repair and maintenance of agricultural, construction, and mining machinery; forklifts and material-handling gear; machine tools; industrial motors, pumps and compressors; commercial refrigeration; and industrial welding repair. It explicitly excludes automotive repair (NAICS 8111), electronic and precision-equipment repair (811210), household/appliance repair (8114), HVAC construction trades (238), and equipment rental (5324). [4]

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3. How big it is (this level's rollup figures)

Federal figures for the employer side of NAICS 81131 — identical to 811310 because it is the sole child:

That is roughly $2.5 million of revenue per firm and about 10 employees per establishment [1][2] — a small-business industry by any measure, with payroll near $73,000 per employee [1] reflecting skilled trades (millwrights, welders, industrial mechanics, refrigeration techs).

Undercount caveat (real and large). These figures count only employer establishments, and only work bought from an outside repair shop. They exclude (a) non-employer sole proprietors — one-person mobile mechanics with no payroll, which private research firm IBISWorld estimates lift the field toward ~56,000 businesses and ~$60 billion in 2025–26 revenue once counted [5]; and (b) the enormous volume of in-house maintenance that factories, utilities, mines, and government fleets perform on their own equipment, which is classified in their industries, not here. Read $54.6 billion as the measured, outsourced, employer slice — not the total economic activity of fixing industrial machines.

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4. Investable universe (where value concentrates)

With a single child, there is no cross-child allocation to make — all of the value sits in 811310, and none of it is a listed pure play. Public exposure is indirect, through larger businesses that carry a substantial parts-and-service (aftermarket) operation: flow/rotating-equipment repairers and MRO (maintenance, repair, and operations) distributors such as Flowserve (NYSE: FLS), DXP Enterprises (Nasdaq: DXPE), and Applied Industrial Technologies (NYSE: AIT) [15][16][17]; equipment dealers with big parts-and-service departments such as Alta Equipment Group (NYSE: ALTG) and Titan Machinery (Nasdaq: TITN) [18][19]; aftermarket-heavy OEMs (original equipment manufacturers) like Caterpillar (NYSE: CAT) and Deere (NYSE: DE) ; and rental/field-service names such as United Rentals (NYSE: URI) and Herc Holdings (NYSE: HRI) [22][23]. Every ticker is an exposure proxy, not a clean match. The real industry is private — thousands of independent shops, privately held OEM dealer groups, and PE-backed service platforms. See the 811310 primer for the full list and the exposure-quality caveats.

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5. How the money works

Owners make money on four levers that all rest on billable technician time: (1) labor billed at a marked-up shop or field rate, measured by technician utilization and first-time-fix rate; (2) parts, which carry a markup and often out-earn labor on gross-profit dollars; (3) preventive-maintenance contracts, which convert unpredictable break-fix work into recurring, higher-margin revenue; and (4) rebuilds, modernization, inspections, and warranty work. For dealer-attached service, the key figure is the absorption rate — the share of a dealer's fixed overhead covered by parts-and-service gross profit alone, which is why parts and service typically generate the majority of dealer gross profit even when machine sales go cold. [19] The binding constraint is skilled labor: revenue is effectively capped by how many good technicians you can hire and keep utilized. (Full metric set in the 811310 primer.)

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6. Demand drivers

Demand tracks how hard the installed base is worked and how old it is: industrial activity and machinery utilization (manufacturing capacity utilization ran about 75.7% in mid-2026 against a long-run average near 78% [7]), an aging installed base with a deferred-maintenance backlog [14], outsourcing of upkeep, repair-vs-replace economics (higher new-machine prices, rates, or tariffs tip toward fixing), and reshoring converting announced factory investment into maintenance demand [13]. Maintenance is more resilient than new-equipment sales because customers must keep existing assets running, but it is still cyclical — noncritical rebuilds and modernization get deferred when industrial profits weaken. Labor is both a driver and a ceiling: BLS (the Bureau of Labor Statistics) projects 13% employment growth for industrial machinery mechanics and millwrights from 2024 to 2034, well above average. [8]

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7. Regulation

Lightly licensed but heavily safety- and environmentally regulated at the technician and job-site level. OSHA (the Occupational Safety and Health Administration) governs lockout-tagout for de-energizing machines (29 CFR 1910.147) [9] and powered-industrial-truck/forklift maintenance (29 CFR 1910.178) [10], plus welding, confined-space, and machine-guarding rules. EPA (the Environmental Protection Agency) requires Section 608 certification for technicians handling refrigerants under the Clean Air Act [11]. The regulation to watch is right to repair — laws (led by Colorado's 2023 agricultural-equipment statute [12]) that determine how much repair work independents can capture versus OEM dealer networks as machines fill with proprietary electronics and locked software.

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8. Consolidation

The federal concentration data confirm an unusually fragmented market — identical at 81131 and 811310 because they are the same establishments:

A CR4 of just 10.6% means the four biggest players together hold barely a tenth of the market. (The Herfindahl-Hirschman Index, or HHI, a standard concentration gauge, is suppressed for this industry in the federal data, so none is shown. [2]) What's consolidating it: distributor and private-equity roll-ups of independent shops [16][23], OEMs pushing into recurring aftermarket/telematics service , and scale concentrating in equipment rental (e.g., the 2025 Herc–H&E deal, ~$5.3 billion [23]). Integration risk is high, though, because local relationships and technician talent are hard to standardize.

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9. Risks

The child-level risks apply unchanged: cyclicality tied to industrial capital spending, farm income, construction, mining, and energy; skilled-labor scarcity (an aging technician workforce is the binding constraint) [8]; input-cost inflation and tariffs squeezing parts margins [5]; parts and supply-chain delays that idle billable technicians; OEM encroachment and proprietary lock-out, with right-to-repair policy as the swing factor [12]; customer insourcing; safety and environmental liability [9][10][11]; technology transition to electric, automated, and connected equipment; and small-business fragility — succession risk, key-person dependence, and roll-ups that overpay or lose technicians.

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10. How to invest & outlook

Because 81131 is a single-child pass-through, the investment playbook is exactly that of 811310 — see that primer for the detailed routes. In brief: public investors buy the aftermarket inside larger businesses (favor disclosures that separate recurring service from equipment sales and rentals — Flowserve, DXP, and Applied on the service-heavy end; dealers and rental names for lower-purity exposure) and reserve valuation multiples for the portion of a name's repair/service segment that actually drives the thesis, adjusting for capital intensity. Private investors — where the industry really lives — buy an established shop (most fall under the SBA's $12.5 million size standard [3], financeable with SBA 7(a) loans) or build a regional platform via bolt-on acquisitions, underwriting contract-vs-break-fix mix, technician utilization and retention, parts-margin capture, and customer concentration.

Near-term outlook: steady, low-single-digit growth — IBISWorld models roughly $60 billion in 2025–26 [5] — with upside from reshoring [13] and a deferred-maintenance backlog [14], and swing factors in skilled-technician supply (a hard growth ceiling), tariff-driven parts inflation, and the direction of right-to-repair policy. Net: a defensive, cash-generative, deeply fragmented service industry — modest as a public-equity theme, rich as a field for private ownership and consolidation.

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Sources

Drawn from the 811310 child primer; numbering matches that source.

1. U.S. Census Bureau, County Business Patterns (CBP), 2023 — NAICS 811310 establishments, employment, and payroll. https://www.census.gov/data/datasets/2023/econ/cbp/2023-cbp.html
2. U.S. Census Bureau, 2022 Economic Census, EC2200SIZECONCEN — Concentration of Largest Firms — NAICS 811310 firms, receipts, CR4/CR8/CR20/CR50 (HHI suppressed). https://data.census.gov/table/ECNSIZE2022.EC2200SIZECONCEN
3. U.S. Small Business Administration, Table of Size Standards, 2023 — NAICS 811310 ($12.5 million average annual receipts). https://www.sba.gov/document/support-table-size-standards
4. U.S. Census Bureau, 2022 NAICS Manual — code 811310, Commercial and Industrial Machinery and Equipment (except Automotive and Electronic) Repair and Maintenance. https://www.census.gov/naics/reference_files_tools/2022_NAICS_Manual.pdf
5. IBISWorld, Machinery Maintenance & Heavy Equipment Repair Services in the US — Industry Report and Market Size (NAICS 811310), 2025–2026. https://www.ibisworld.com/united-states/industry/machinery-repair-maintenance/1708/
6. U.S. Bureau of Labor Statistics, Producer Price Index Introduced for Commercial and Industrial Machinery and Equipment Repair and Maintenance — NAICS 811310. https://www.bls.gov/ppi/factsheets/producer-price-index-introduced-for-commercial-and-industrial-machinery-and-equipment-except-automotive-and-electronic-repair-and-maintenance-naics-811310.htm
7. Federal Reserve Board, Industrial Production and Capacity Utilization (G.17), Table 7. https://www.federalreserve.gov/releases/g17/Current/table7.htm
8. U.S. Bureau of Labor Statistics, Industrial Machinery Mechanics, Machinery Maintenance Workers, and Millwrights — Occupational Outlook Handbook (13% projected growth, 2024–2034). https://www.bls.gov/ooh/installation-maintenance-and-repair/industrial-machinery-mechanics-and-maintenance-workers-and-millwrights.htm
9. Occupational Safety and Health Administration, 29 CFR 1910.147 — The Control of Hazardous Energy (Lockout/Tagout). https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.147
10. Occupational Safety and Health Administration, 29 CFR 1910.178 — Powered Industrial Trucks. https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.178
11. U.S. Environmental Protection Agency, Section 608 Technician Certification Requirements (Clean Air Act, 40 CFR Part 82, Subpart F). https://www.epa.gov/section608/section-608-technician-certification-requirements
12. National Conference of State Legislatures, Right to Repair 2023 Legislation (incl. Colorado agricultural-equipment right-to-repair law). https://www.ncsl.org/technology-and-communication/right-to-repair-2023-legislation
13. Reshoring Initiative, 2024 / Q1-2025 Data Report — announced U.S. manufacturing reshoring and investment. https://reshorenow.org/content/pdf/2024-1Q2025_RI_DATA_Report.pdf
14. Manufacturing Today, Why Predictive Maintenance Is Manufacturing's Next Big Advantage — prevalence of reactive/time-based maintenance and deferred-upkeep backlog. https://manufacturing-today.com/news/why-predictive-maintenance-is-manufacturings-next-big-advantage/
15. Flowserve Corporation, Quick Response Centers / Aftermarket Services and FY2024 results (~$4.6B revenue; services/aftermarket 40%+ of sales). https://www.flowserve.com/services/quick-response-centers/
16. DXP Enterprises, Inc., Form 10-K, Fiscal Year 2024 — total sales ~$1.8B; Service Centers, Innovative Pumping Solutions, Supply Chain Services segments. https://www.sec.gov/Archives/edgar/data/1020710/000102071025000036/dxpe-20241231.htm
17. Applied Industrial Technologies, Inc., Fiscal 2024 Full-Year Results — net sales ~$4.5B; Service Center Based Distribution and Engineered Solutions segments. https://www.sec.gov/Archives/edgar/data/109563/000010956324000063/a8k8152024releaseexhibit991.htm
18. Alta Equipment Group Inc., 2025 Form 10-K / Annual Report — total revenue ~$1.84B; parts $291.0M, service $256.7M, new/used equipment $999.3M. https://www.sec.gov/Archives/edgar/data/1759824/000119312526076932/altg-20251231.htm
19. Titan Machinery Inc., Quarterly Results (Form 8-K) — parts and service as roughly half of dealer gross profit. https://www.sec.gov/Archives/edgar/data/0001409171/000110465913088507/a13-25691_1ex99d1.htm
20. United Rentals, Customer Equipment Solutions / Equipment Service & Maintenance. https://www.unitedrentals.com/services/equipment-service-maintenance
21. Herc Holdings Inc., Acquisition of H&E Equipment Services (~$5.3 billion, completed 2025); 2025 Form 10-K. https://www.sec.gov/Archives/edgar/data/1364479/000136447926000050/hri-20251231.htm
22. Caterpillar Inc., 2025 Form 10-K — construction/mining/power OEM with independent dealer service network and recurring aftermarket. https://www.sec.gov/Archives/edgar/data/18230/000001823026000008/cat-20251231.htm
23. Rotunda Capital Partners, Rotunda Acquires and Combines American Equipment, Pacific Crane & Hoist and Allied Crane — overhead-crane service roll-up (American Equipment Holdings). https://www.rotundacapital.com/rotundacapitalpartnersacquiresandcombinesamericanequipment/