Industrial Supplies Merchant Wholesalers (U.S.) — NAICS 42384

A Histometrics industry primer for public- and private-market investors

Read this first — it's a short "rollup" page. In the North American Industry Classification System (NAICS), the five-digit industry 42384 contains exactly one six-digit national industry, 423840 (also called Industrial Supplies Merchant Wholesalers). Because there is only one child, this level and that child describe the same set of businesses and carry the same statistics. This page gives you the essentials and this level's own federal figures; for the full treatment — product scope, company-by-company detail, economics, and the investment case — see the primer for NAICS 423840.

1. Overview

NAICS 42384 is the federal statistical box for distributors that specialize in industrial supplies — the low-cost, high-turnover consumables that keep factories, refineries, mines, and warehouses running: abrasives, bearings, welding rods (the consumables, not the gas), cutting tools, adhesives, industrial containers, power-transmission supplies, printing inks, and thousands of similar items. These distributors are merchant wholesalers: they buy goods on their own account, hold inventory, and resell to other businesses (as opposed to agents or brokers, who never take ownership of the product and belong in NAICS 425). [1]

For an investor, the appeal is that this is the connective tissue of the physical economy. Demand tracks manufacturing output and the recurring "keep the lights on" maintenance spending of industrial facilities — spending that is hard to defer for long, because a stalled production line costs far more than the part that fixes it. The industry is also unusually fragmented, with a Herfindahl-Hirschman Index of about 139 and the top 50 firms holding barely half the market, which makes it a decades-long consolidation story that both public-market and private-equity investors have been playing. [2]

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

A five-digit NAICS industry can hold several six-digit national industries. This one holds just one:

When a five-digit industry has a single child, the two levels are effectively the same thing: the United States did not split the category any finer, so the national industry (423840) and the industry group's five-digit line (42384) cover the exact same establishments, revenue, and employment. There is no aggregation to do and no sibling industries to weigh against each other. Everything specific — the product lines in scope (and the adjacent codes that are excluded, such as industrial machinery and fluid power in 423830, welding gases in 424690, electrical supplies in 423610, plumbing and heating supplies in 423720, and construction and mining machinery in 423810), the mix of private independents versus listed consolidators, and the detailed economics — lives in the child primer. [1]

Bottom line: treat 42384 and 423840 as interchangeable, and go to the 423840 primer for anything beyond the summary below.

3. Size (this level's rollup figures)

Because there is one child, this level's federal statistics are simply that child's statistics.

Two revenue vintages, not a revision. The 2022 Economic Census put receipts for this code at $94.6 billion; the Census Bureau's Annual Integrated Economic Survey (AIES) for 2023 reports $92.743 billion of U.S. employer-business sales. These come from different surveys covering different years, so they should be read side by side rather than as a correction — the AIES figure is the more current reading, and the table above carries it. [2][4] The same applies to payroll: County Business Patterns puts 2023 annual payroll at $9.99 billion, while AIES for the same year reads lower, which is why the child primer carries a range. [3][4]

The AIES detail also shows something the parent page previously could not: of the $92.7 billion, $78.1 billion came from merchant wholesalers excluding manufacturers' sales branches and offices, while $14.7 billion came from manufacturers' branches and offices — so independent merchant wholesalers are roughly 84% of the code, and captive manufacturer-owned distribution is the remaining sixth. [4]

The firm, establishment, employment, and payroll counts are drawn from our ingested ground-truth federal statistics for NAICS 42384; none is suppressed. They imply an average of roughly $9.7 million in revenue per establishment and about 12 employees per location — a portrait of mid-sized, branch-based businesses rather than a few mega-warehouses. Most of the 5,526 firms run just one or two locations, and by the U.S. Small Business Administration (SBA) threshold of 125 employees, the overwhelming majority qualify as "small." [3][5] One statistic is published natively at this five-digit level rather than the six: Bureau of Labor Statistics data for the 42384 series show average hourly earnings of about $39.75 and average weekly earnings of approximately $1,606 as of mid-2026 — a reminder that this is skilled, better-paid warehouse and counter work, not minimum-wage fulfillment. [6]

Undercount and scope caveat. These figures likely understate the true footprint of industrial-supply distribution. Broad-line distributors are classified by their single primary line of business, so industrial-supply sales that spill into adjacent codes are counted elsewhere — and conversely, a firm coded 42384 may sell electrical or plumbing goods that are captured here under its single primary code. And County Business Patterns excludes non-employer businesses (sole proprietors with no payroll), so the smallest one-person distributors and brokers are missing from the establishment and employment counts — a meaningful omission in an industry where small, individually owned firms are common. Read the $92.7 billion as the receipts of establishments whose main business is industrial supplies, not the total U.S. market for these products, which private research firms — using much broader "maintenance, repair, and operations" (MRO) definitions — size in the hundreds of billions. Those third-party estimates vary widely and are not directly comparable to the federal code. [7][8]

4. Investable universe — where the value sits

All of the investable value at this level is the value described in the child primer; nothing is added by the five-digit rollup. Value concentrates at the top of a fragmented pyramid: a handful of large, publicly traded broad-line MRO distributors that span 423840 and adjacent codes, sitting atop thousands of small private independents. None of the public names is a pure play on the census code — their combined reported revenue exceeds the entire 42384 receipts figure precisely because their business is wider than this one code. The listed tier spans roughly an order of magnitude, from W.W. Grainger (NYSE: GWW) at about $17.9 billion in FY2025 revenue [9] down to Global Industrial (NYSE: GIC) at about $1.31 billion in FY2024. Genuine Parts' Motion segment (about 37% of GPC revenue in FY2025) is the other large industrial distributor in the group, and its planned spin-off into a standalone public company — targeted for roughly Q1 2027 — will add a large, focused pure-play to the menu. [10][11] The rest of the roster runs Fastenal (NASDAQ: FAST, about $8.2 billion in FY2025) [12], Applied Industrial Technologies (NYSE: AIT), MSC Industrial Direct (NYSE: MSM, about $3.77 billion in FY2025) [13], and DXP Enterprises (NASDAQ: DXPE). [14] Beneath them sits a large private tier: Germany's family-controlled Würth Group, McMaster-Carr (which does not disclose revenue), SBP Holdings, and numerous regional independents — many owned by founding families or by private-equity platforms pursuing buy-and-build roll-ups, as when Sonepar sold its North American Vallen MRO and integrated-supply business to Nautic Partners. [15][16][17] See 423840, Section 4 for the full roster, revenue figures, and ownership tiers.

5. How the money works

Distribution is a spread-and-turns business, not a manufacturing-margin business: owners earn the gap between what they pay suppliers and what they charge customers, multiplied by how many times a year they cycle their inventory. Gross margins for the larger public distributors run in the high-30s to mid-40s percent — in fiscal 2025, Grainger reported 39.1%, MSC Industrial 40.8%, and Fastenal 45.0%. [9][12][13] Because those margins are thin, inventory velocity (turns) is what converts them into an attractive return on invested capital.

The more useful rollup observation is how wide the operating-margin spread is inside a single census code: in 2025 Fastenal earned 20.2%, Grainger 13.9%, and MSC 8.0%. [9][12][13] That range reflects product mix, customer concentration, and service model — Fastenal's localized, vending-intensive fastener business versus MSC's metalworking-heavy, national-account-weighted one — not an industry-wide norm. Investors underwriting this code should price the business model, not the label.

The balance sheet is the business — inventory and accounts receivable are the biggest assets — so working-capital discipline and high fill rates (having the right stock-keeping unit, or SKU, in stock for same- or next-day delivery) are the core skills. Supplier rebates and volume discounts are a genuine profit source, and vendor-managed inventory — on-site bins, vending machines, automated replenishment — converts transactional sales into stickier revenue; Fastenal finished 2025 with roughly 124,000 FASTVend devices installed at customer sites. [12] Despite the digitization, the model stays labor-intensive: Fastenal reported that employee-related costs were 70–75% of its 2025 selling, general, and administrative (SG&A) expense. [12] Roughly two-thirds of sales are recurring consumable MRO items, which cushions downturns. The full mechanics are in 423840, Section 5.

6. Demand drivers

Demand at this level is identical to the child's: it is driven above all by industrial production and manufacturing activity (purchasing-manager surveys and factory capacity utilization are leading indicators), by recurring maintenance, repair, and operations spending that has a floor because deferred maintenance eventually becomes non-deferrable, and by reshoring and industrial capital investment expanding the installed base of U.S. factories that must be supplied. The customer base is concentrated in manufacturing — MSC reported 67% of fiscal-2025 revenue from manufacturing customers, and Fastenal estimated 71–76% of its 2025 business was with manufacturers — so the industrial cycle transmits almost directly into distributor volumes. [12][13] Energy, mining, and construction cycles and inflation pass-through round out the list. Two structural shifts now matter as much as the cycle: procurement digitization (MSC reported that e-commerce channels were 63.8% of fiscal-2025 sales) and the move from transactional selling toward embedded inventory at the point of use, which raises transaction frequency and switching costs but also increases price transparency. [12][13] See 423840, Section 6.

7. Regulation

Industrial-supplies distribution is lightly regulated at the industry level — there is no sector-specific federal price or entry regulation as there is in utilities or finance. The applicable rules are the general ones for handling and shipping physical goods: Occupational Safety and Health Administration (OSHA) workplace and hazard-communication rules, Department of Transportation (DOT) rules for shipping hazardous materials, and Environmental Protection Agency (EPA) rules for certain chemical products. Trade policy (tariffs on steel, fasteners, and tools) is a growing swing factor on product costs. One rule does have direct commercial force: the SBA's 125-employee size standard determines which firms in this code qualify for federal small-business set-asides, which matters to any distributor selling to government agencies. [5] None of this creates a regulatory moat; barriers to entry come from scale, inventory, and customer relationships. See 423840, Section 7.

8. Consolidation

The defining structural fact is fragmentation, and this level's federal concentration data make it concrete:

Source: Economic Census concentration, 2022. [2]

An HHI (a standard antitrust measure of market concentration) of about 139 is extraordinarily low — U.S. antitrust guidelines treat anything below 1,500 as unconcentrated, and this industry sits an order of magnitude below that. The top 50 firms together hold barely half the market; the rest is spread across thousands of small independents. That fragmentation is the engine of a long-running consolidation story, in which scaled distributors and private-equity buy-and-build platforms acquire regional players to gain better supplier pricing and denser logistics. Genuine Parts' Motion was itself built through decades of acquisitions, and its February 2026 decision to spin the segment into a standalone public industrial distributor is the clearest recent signal that investors want focused exposure to this business. [10][11] Customers are consolidating their supplier lists in parallel — national contracts, one invoice, standardized safety programs — which favors scale and turns sub-scale independents into acquisition targets. Competition is fought on availability, service, and total cost rather than price alone, which is also the main defense against Amazon Business and other digital entrants. [13][15] See 423840, Section 8.

9. Risks

The risks are those of the child industry: cyclicality (a manufacturing slowdown or destocking cuts volumes quickly, starting with the project-sensitive portion of demand); thin margins and high working capital (poor inventory or receivables management can erase free cash flow even when sales hold); digital disintermediation by Amazon Business and manufacturer-direct e-commerce; tariffs and supply-chain disruption raising product costs, with contracted prices that often reset more slowly than supplier costs — both Fastenal and MSC flag the inability to pass costs through synchronously as a margin risk; deflation compressing revenue and gross-profit dollars at stable volumes while high-cost inventory sits on hand; labor and freight inflation, which bites hard in a branch- and delivery-heavy model where employee-related costs run 70–75% of SG&A; and integration/overpayment risk for acquirers rolling up the fragmented tail. Operational exposures — dead inventory, carrier disruption, cyberattacks on procurement integrations, and customer credit losses in a downturn — round out the list. [12][13] See 423840, Section 9.

10. How to invest & outlook

Because 42384 equals 423840, the investment approach is the same. Public route: the roster of listed broad-line distributors in Section 4 is the cleanest way in; there is no dedicated pure-play exchange-traded fund (ETF), though industrial-sector and total-market funds hold the larger names. Bear in mind that none of them is a U.S. 42384 tracker — Grainger pairs a high-touch North American model with international and endless-assortment operations, Fastenal carries meaningful fastener, construction, and international activity, and MSC is concentrated in metalworking — so product and customer mix drive returns more than the "industrial distributor" label does. Investors typically judge these companies on organic sales growth versus industrial production, gross- and operating-margin durability, cash conversion, and acquisition track record, with valuation multiples and dividend yields assessed against those fundamentals. Private route: because the industry is so fragmented, most of it is not on any exchange — private-equity platforms and family buyers consolidate regional and specialty distributors, earning returns by improving procurement and inventory turns and adding branches. Underwriting there centers on customer concentration, gross-margin quality, supplier authorizations, SKU-level turns and obsolescence, branch density, salesperson retention, receivable quality, tariff exposure, and how much of the business is embedded through onsite, vending, or procurement integration. The structural draw through cycles — a large, recurring stream of must-have maintenance spending distributed across a fragmented market ripe for consolidation — is unlikely to change; how much of it the scaled operators capture, and at what margin, is the judgment each investor must make. For the complete investment case and outlook, go to 423840, Section 10. [11][15]

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Sources

This rollup synthesizes the child primer for NAICS 423840 plus our ingested federal statistics for NAICS 42384. The sources below are those cited above, drawn from the child primer.

1. U.S. Census Bureau, "2022 NAICS Definition — 423840 Industrial Supplies Merchant Wholesalers," 2022. https://www.census.gov/naics/?chart=2022&details=423840
2. U.S. Census Bureau, "2022 Economic Census — Concentration by Largest Firms (NAICS 423840): firm count, receipts, CR4/CR8/CR20/CR50, HHI," 2022. https://data.census.gov/table/ECNSIZE2022.EC2200SIZECONCEN (Matches our ingested federal statistics for NAICS 42384.)
3. U.S. Census Bureau, "County Business Patterns 2023 (NAICS 423840): establishments, employment, annual payroll," 2023. https://data.census.gov/table/CBP2023.CB2300CBP (Matches our ingested federal statistics for NAICS 42384.)
4. U.S. Census Bureau, "Annual Integrated Economic Survey 2023 (NAICS 423840): sales, payroll," 2023. https://data.census.gov/table/AIESBASICTIMESERIES.AIES42BASIC?codeset=naics~423840
5. U.S. Small Business Administration, "Table of Small Business Size Standards (NAICS 423840 = 125 employees)," 2023. https://www.sba.gov/document/support-table-size-standards
6. U.S. Bureau of Labor Statistics, "Employment and Earnings by Industry (NAICS 42384)," 2026. https://www.bls.gov/web/empsit/ceseeb1b.htm
7. Precedence Research, "MRO Distribution Market Size," 2025. https://www.precedenceresearch.com/mro-distribution-market
8. SkyQuest Technology, "MRO Distribution Market Size, Share, and Long-Term Growth Outlook," 2024. https://www.skyquestt.com/report/mro-distribution-market
9. W.W. Grainger, 2025 Form 10-K (fiscal year ended December 31, 2025). https://www.sec.gov/Archives/edgar/data/277135/000027713526000011/gww-20251231.htm
10. Genuine Parts Company, 2025 Form 10-K (fiscal year ended December 31, 2025). https://www.sec.gov/Archives/edgar/data/40987/000004098726000003/gpc-20251231.htm
11. Genuine Parts Company, "Genuine Parts Company Announces Plan to Separate Automotive and Industrial Businesses," Feb 17, 2026. https://www.genpt.com/2026-02-17-Genuine-Parts-Company-Announces-Plan-to-Separate-Automotive-and-Industrial-Businesses-Into-Two-Industry-Leading-Public-Companies
12. Fastenal Company, 2025 Form 10-K (fiscal year ended December 31, 2025). https://www.sec.gov/Archives/edgar/data/815556/000081555626000009/fast-20251231.htm
13. MSC Industrial Direct, 2025 Form 10-K (fiscal year ended August 30, 2025). https://www.sec.gov/Archives/edgar/data/1003078/000100307825000123/msm-20250830.htm
14. Global Industrial Company, "Full Year 2024 Financial Results," 2025. https://investors.globalindustrial.com/
15. Mordor Intelligence, "United States Maintenance, Repair, and Operations (MRO) Market — Key Players," 2024–2026. https://www.mordorintelligence.com/industry-reports/united-states-maintenance-repair-and-operations-mro-market/companies
16. Modern Distribution Management, "Industrial Supplies Top Distributors Ranking," 2026. https://www.mdm.com/top_distributors/distributor_categories/industrial/
17. Sonepar, "Sonepar enters into an agreement to sell Vallen North America," 2025. https://www.sonepar.com/en/newsroom/sonepar-enters-into-an-agreement-to-sell-vallen-north-america-35010