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Industry Primers

Bottom-up NAICS industry primers written for both public-market and private investors. Leaf industries are researched from the ground up; every group, subsector, and sector above them reads as a contrast across the industries beneath it.

2122 industries · 24 sectors · NAICS 2022

Researched with AI assistance from official U.S. statistics and independent sources, with citations on every page. Figures are not individually verified against pinned evidence — primers marked Evidence-verified are. Industry research, not investment advice. Methodology.

IndustryNAICS 33612

Heavy Duty Truck Manufacturing (United States) — NAICS 33612

An investor's primer. NAICS (North American Industry Classification System) code 33612 is a five-digit "industry" level that sits one rung above the individual industry 336120. It contains exactly one child — 336120, Heavy Duty Truck Manufacturing — so this level and that child are, for all practical purposes, the same thing: the factories that build America's big rigs (the Class 8 tractors that pull freight trailers) plus heavy vocational trucks and heavy chassis.

1. Overview

NAICS 33612 is a rollup code with a single occupant. In the census classification, the five-digit "industry" 33612 and the six-digit "national industry" 336120 cover an identical set of factories, so every figure and every company described for 336120 applies here without change [1][3]. The reason to have a separate five-digit code at all is bookkeeping symmetry — most NAICS families split into several six-digit children, and heavy-duty trucks simply do not.

The output of these plants carries most of the American economy. The American Trucking Associations estimates trucks moved 11.27 billion tons of U.S. freight in 2024 — 72.7% of national freight tonnage, against an estimated $906 billion freight bill — and projects 13.99 billion tons by 2035 [4].

Because the two levels coincide, this page stays short: it confirms that 33612 equals its one child, gives this level's own ground-truth federal statistics, and then points you to the full 336120 primer for the detail — the four-group oligopoly, the aftermarket-and-financing profit model, the emissions-rule demand cycle, and how to actually own the industry.

One-line takeaway. This is a small, extremely concentrated, deeply cyclical capital-goods business: four corporate groups build roughly 98% of the heavy trucks sold in North America, and orders can double or halve in a single year [5][6][19].

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

NAICS 33612 has a single child industry:

Child code Name Relationship to 33612
336120 Heavy Duty Truck Manufacturing The only child; identical scope, identical statistics

The U.S. Census Bureau defines the underlying industry as establishments primarily engaged in manufacturing heavy-duty truck chassis and assembling complete heavy-duty trucks, buses, heavy motor homes, and special-purpose highway vehicles — or making heavy-duty chassis alone [3]. The economic center of gravity is the Class 8 tractor (over 33,000 lb gross vehicle weight rating, "GVWR"), with heavy vocational trucks (dump, refuse, cement mixer, utility) alongside.

Because there is only one child, there is no allocation to make across sub-industries and no "mix" to analyze — a point that distinguishes this page from a normal rollup. What 33612 excludes is therefore the useful part: light trucks and SUVs (NAICS 336112), truck bodies built onto a purchased chassis (336211), truck trailers (336212), and motor homes (336213) are all separate codes, as are the engines, transmissions, and axles that go into a heavy truck [3]. That last exclusion matters more than it sounds: PACCAR reports that bought-in raw materials, processed materials, and finished components are roughly 85% of a new truck's cost, so most of the physical value of a heavy truck is counted outside this code [5].

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

Federal statistics for NAICS 33612 are, by construction, the same as for 336120:

Metric Value Source (year)
Receipts / product shipments $33.1 billion Economic Census (2022) [1]
Employment 40,522 workers County Business Patterns (2023) [2]
Annual payroll $2.85 billion (≈ $70,000 average pay) County Business Patterns (2023) [2]
First-quarter payroll $701 million County Business Patterns (2023) [2]
Establishments (plants) 109 County Business Patterns (2023) [2]
Firms 84 Economic Census (2022) [1]
SBA small-business threshold 1,500 employees SBA size standards (2023) [10]

Concentration. The largest 4 firms account for 76% of industry receipts, the top 8 for 86.2%, the top 20 for 96.1%, and the top 50 for 99.7% [1]. (The Herfindahl-Hirschman Index, a standard concentration measure, is suppressed in the federal data, so we do not state a value [1].) The mirror image is worth holding in mind: the customer base is not concentrated at all. ATA counted almost 580,000 active U.S. motor carriers as of June 2025, of which 91.5% ran ten or fewer trucks and 99.3% ran a hundred or fewer [4].

Reading the numbers honestly. Unlike restaurants or construction, this industry is not meaningfully undercounted — there are few tiny operators and essentially no government producers to miss, so small/individual ownership is not a gap here. If anything the $33.1 billion domestic figure understates the "truck business," because much North American assembly happens in Mexico (outside U.S. counts) and the biggest profit pools — aftermarket parts and captive financing — are booked under other industry codes. The cleaner way to size the market is by units, and here the child page is careful about scope: PACCAR reported 232,800 U.S.-and-Canada heavy-duty retail sales in 2025, down from 268,100 in 2024 (about −13%) [5], while U.S.-only Class 8 retail sales ran roughly 240,000 trucks in 2024 [11][12]. The two are different geographies, not competing estimates — do not net them against each other.

4. Investable universe (where value concentrates)

With a single child, all of the industry's value sits in the same handful of names described in the 336120 primer. In brief:

  • PACCAR (Nasdaq: PCAR) — the one large, liquid, U.S.-listed truck maker (Kenworth, Peterbilt, DAF); $33.7 billion of revenue, $4.16 billion of net income and 185,300 trucks delivered worldwide in 2024, followed by severe margin compression in 2025 (see §5). The cleanest direct way to own a heavy-truck OEM ("original equipment manufacturer") [5][13].

  • Daimler Truck (ADR DTRUY), Volvo Group (ADR VLVLY), Traton (8TRA) — the other three of the four groups, foreign-listed, carrying currency exposure. Traton is 87.52% Volkswagen-owned with only a 12.5% free float, which belongs in any governance or liquidity analysis [6][8][9].

  • Cummins (NYSE: CMI) — supplier-side exposure to engines and emissions aftertreatment; its engine segment took in $3.49 billion from heavy-duty trucks in 2025 (down 18%) on 101,900 HD engines shipped (down 23%) [14].

  • Allison Transmission (NYSE: ALSN) — automatic transmissions, weighted to vocational and medium/heavy rather than Class 8 line-haul; $1.54 billion of North American on-highway sales in 2025, down 12% [15].

  • Rush Enterprises (RUSHA/RUSHB) — the dealer/service/aftermarket angle; the largest U.S. commercial-truck dealer, which sold 12,770 new Class 8 trucks in 2025, about 5.8% of U.S. Class 8 sales [16].

  • Tesla (Nasdaq: TSLA) — a small optional electric-Semi angle inside a far larger company [17].

There is no dedicated Class 8 ETF; PCAR and CMI are the common holdings inside broad industrial/transport funds. For private investors, most capital touches the industry around the OEM — dealership and service groups, body/up-fit builders, leasing and rental fleets (Ryder, Penske), and privately held vocational specialists such as Autocar and Battle Motors. See §4 of the 336120 primer for the full table and scale figures.

5. How the money works (in brief)

A heavy-truck OEM is a build-to-order capital-goods maker. Revenue is units × price (a new Class 8 sleeper runs roughly $170,000–$200,000; the Tesla Semi is quoted around $290,000) [17][18]. Building the truck earns thin margins; the durable profit comes from replacement parts sold over a truck's 10–15-year life — high-margin and counter-cyclical, worth $6.67 billion at PACCAR Parts in 2024, roughly 24% of company revenue — plus captive financing (PACCAR Financial financed 27.0% of new PACCAR truck sales in 2025) and increasingly proprietary powertrain [5][13][29].

Because fixed factory costs are high, capacity utilization is the swing factor, and the revised child page now quantifies just how violent that leverage is. PACCAR's worldwide truck gross margin fell from 13.9% in 2024 to 7.5% in 2025; truck pretax return on revenue went from 11.5% to 4.5%, and its U.S.-and-Canada truck revenue from $15.39 billion to $11.35 billion, on lower deliveries, weaker pricing, higher regulatory content and tariffs [5]. That is the best-run operator in the group: at International Motors, adjusted operating return on sales fell from 6.5% to 0.1% as truck sales dropped from 79,300 to 50,112 units [9]. PACCAR's 12.4% after-tax return on revenue in 2024 [13] and its 2025 result are the two ends of the same cycle. Full mechanics are in §5 of the 336120 primer.

6. Demand drivers

Demand tracks freight volumes and carrier profitability (ACT Research describes 2025 as a prolonged downcycle of weak freight demand, poor carrier margins, high operating costs and defensive, replacement-only buying), the replacement cycle (when retail sales run below replacement need the active truck population shrinks and pent-up demand builds), and regulatory pre-buys (fleets rushing to order ahead of a costly new emissions rule) [12][19][20][21]. One caution the child adds: the order board is not a clean leading indicator — it has to be decomposed into regulatory pull-forward, cancellations, and genuine fleet expansion. Vocational demand (construction, refuse, utility) is steadier than long-haul freight, and buses and specialty chassis inside the code run on different procurement cycles again. See §6 of the 336120 primer.

7. Regulation

Emissions rules are the single biggest external force — they dictate product design, cost, and the timing of demand — and the landscape is now unusually fluid. The key items: the EPA 2027 NOx rule (U.S. Environmental Protection Agency; a 0.035 g/hp-hr oxides-of-nitrogen limit from model-year 2027), whose start date and limit remain intact even though EPA published proposed amendments on July 14, 2026 to useful life, warranty, testing, nonconformance penalties and diesel-exhaust-fluid inducements (comments closed August 29, 2026, so the proposal is not final) [21][22][24]; EPA's rescission of the greenhouse-gas endangerment finding on February 12, 2026 and repeal of the federal GHG standards for highway vehicles, which EPA says does not disturb traditional-air-pollutant rules [23]; the 2025 revocation by Congress of the EPA waivers behind California's Advanced Clean Trucks and Omnibus low-NOx rules, after California had already withdrawn its Advanced Clean Fleets waiver request in January 2025 [25][26]; and a 2025 proclamation imposing a 25% tariff on covered imported medium- and heavy-duty trucks and parts, with an offset tied to U.S. assembly [27]. The practical takeaway is that regulatory whiplash is itself a risk, and that surviving state mandates and waiver litigation may still force makers to support several compliance architectures at once. Full detail in §7 of the 336120 primer.

8. Consolidation

This level is a four-group oligopoly: Daimler Truck (Freightliner, Western Star), PACCAR (Peterbilt, Kenworth), Volvo Group (Volvo, Mack), and Traton's International — together roughly 98% of North American Class 8 [5][6]. Approximate 2025 U.S./Canada Class 8 retail share is Daimler ~39.6%, PACCAR ~29.9%, Volvo plus Mack ~17.8%, and International ~11–13% [7][8][9]. The federal concentration ratios in §3 confirm the picture from the U.S. side. Decades of mergers produced this structure — most recently Volkswagen's Traton acquiring Navistar (International) in 2021 for ~$3.7 billion ($44.50/share), now rebranded International Motors [29][30]. High barriers to entry (capital, dealer and service networks, emissions R&D) explain why well-funded EV startups such as Nikola failed [17][31]. The one independent chokepoint is the supplier layer, above all Cummins for engines and aftertreatment [14]. See §8 of the 336120 primer.

9. Risks

The main risks are the child's risks: severe cyclicality (2025 sat near the bottom of a multi-year freight recession, and 2026 is forecast lower still), the pre-buy hangover (an air-pocket once the EPA-2027 pull-forward passes), regulatory reversals, stranded EV investment, tariffs and cross-border trade, customer concentration among a few large fleets, and the foreign ownership of three of the four groups [5][6][19][21][27][31]. The revised child adds two that this page previously omitted: input and supply-chain risk — a missing engine, semiconductor, transmission, axle or emissions component stops a line, and steel, aluminium, copper, batteries and rare-earth inputs drive cost [32] — and labor risk, from collective bargaining and work stoppages to shortages of skilled electrical, software and service technicians. On electrification, the grid is the binding constraint as much as the truck: a January 2025 Department of Energy assessment put an 80% recharge in twenty minutes at up to 3.5 megawatts per truck and 25–125 megawatts for a full site [33], which is why adoption concentrates in return-to-base duty cycles. Longer term, truck autonomy remains an unquantified structural uncertainty, though it is likelier to change a truck's content than to remove the need to build trucks. See §9 of the 336120 primer.

10. How to invest & outlook

Because 33612 is its one child, the how-to-invest map is identical: the cleanest public route is PACCAR (PCAR), with Cummins (CMI) and Allison (ALSN) for supplier exposure and Daimler Truck / Volvo / Traton via ADRs or European listings for the rest of the oligopoly; Rush Enterprises for the dealer/aftermarket angle; Tesla only as a marginal EV-Semi option; no dedicated Class 8 ETF exists [5][6][9][14][15][16][17]. Private capital more often sits around manufacturing — dealerships, body builders, leasing, used-truck remarketing, and vocational OEMs — where the underwriting turns on installed-base service revenue, technician capacity, floor-plan financing, residual values, and who funds the diesel-to-electric transition.

Outlook (forward-looking judgment, not a forecast of record). The industry is emerging from one of its deepest downcycles: ACT Research projects roughly 171,000 units in 2026 (down ~18%) before a recovery, even as December 2025 order boards hit a three-year high on EPA 2027 pre-buying [19][28]. The likely shape is soft deliveries into 2026, a pre-buy bump around 2027, then an air-pocket, with a more durable recovery tied to freight rates and carrier profitability. Through it all the structural story holds — a stable four-way oligopoly whose aftermarket-parts and captive-finance profits cushion the brutal new-truck cycle, with electric-truck adoption slow and, after the 2025–2026 rollbacks, markedly less policy-driven than it looked two years ago.

For everything in full detail, read the 336120 primer — this page is a thin wrapper over it.

Sources

  1. U.S. Census Bureau, 2022 Economic Census — Concentration ratios & receipts, NAICS 336120 (2022). https://data.census.gov/
  2. U.S. Census Bureau, County Business Patterns 2023, NAICS 336120 (2023). https://www.census.gov/programs-surveys/cbp.html
  3. NAICS Association / U.S. Census Bureau, NAICS Code 336120 — Heavy Duty Truck Manufacturing (definition & exclusions) (2022). https://www.naics.com/naics-code-description/?code=336120
  4. American Trucking Associations, Economics and Industry Data / Freight Forecast (2025). https://www.trucking.org/economics-and-industry-data
  5. PACCAR Inc, Form 10-K (FY2025) (2026). https://www.sec.gov/Archives/edgar/data/75362/000119312526057025/pcar-20251231.htm
  6. Yahoo Finance, Daimler Truck sustains Class 8 market dominance despite weak demand in North America (2026). https://finance.yahoo.com/news/daimler-truck-sustains-class-8-094600356.html
  7. Trucking Dive, Daimler Truck Q4 2025 Earnings — Class 8 Market Share (2026). https://www.truckingdive.com/news/daimler-truck-q42025-earnings/814714/
  8. Transport Topics, PACCAR and Volvo/Mack Truck Market Share (2026). https://www.ttnews.com/articles/paccar-truck-market-share
  9. TRATON SE, TOGETHER 2025 Annual Report (2026). https://annualreport.traton.com/2025/en/assets/downloads/TRA_GB25_EN.pdf
  10. U.S. Small Business Administration, Table of Small Business Size Standards (NAICS 336120 = 1,500 employees) (2023). https://www.sba.gov/document/support-table-size-standards
  11. NADA/ATD, December 2024 Truck Beat: New Commercial Truck Sales Down 4.8% to End 2024 (2025). https://www.nada.org/atd/atd-insider/december-2024-truck-beat-new-commercial-truck-sales-down-48-end-2024
  12. Transport Topics, US Class 8 Sales Fall in 10th Straight Month of Declines (2024). https://www.ttnews.com/articles/us-class-8-sales-decline-0524
  13. PACCAR Inc, PACCAR Achieves Strong Annual Revenues and Net Income (2025). https://www.paccar.com/news/current-news/2025/paccar-achieves-strong-annual-revenues-and-net-income/
  14. Cummins Inc, 2025 Annual Report (2026). https://www.sec.gov/Archives/edgar/data/26172/000110465926039182/tm261336d7_ars.pdf
  15. Allison Transmission Holdings Inc, Form 10-K (FY2025) (2026). https://www.sec.gov/Archives/edgar/data/1411207/000119312526065627/alsn-20251231.htm
  16. Rush Enterprises Inc, Form 10-K (FY2025) (2026). https://www.sec.gov/Archives/edgar/data/1012019/000143774926005424/rusha20251231_10k.htm
  17. Electrek, Tesla is quoting $290,000 for its 500-mile electric semi truck (2026). https://electrek.co/2026/02/10/tesla-quoting-price-500-miles-electric-semi-truck/
  18. Charter Trucks, How Much Does a Semi Truck Cost in 2025–2026? (2026). https://chartertrucks.com/blog/how-much-does-a-semi-truck-cost-in-2025-2026/
  19. ACT Research, 2026 Class 8 Truck Sales Forecast & Trucking Industry 2025 in Review (2026). https://www.actresearch.net/resources/blog/class-8-truck-sales-forecast-2026
  20. ACT Research, Trucking Industry 2025 Review (2025). https://www.actresearch.net/resources/blog/class-8-truck-sales-forecast-2025
  21. Commercial Carrier Journal, EPA Rejects Trucking Industry Plea, Will Keep 2027 NOx Rule Timeline (2025). https://www.ccjdigital.com/regulations/emissions/article/15771994/epa-rejects-trucking-industry-plea-will-keep-2027-nox-rule-timeline
  22. U.S. EPA, Final Rule and Related Materials — Heavy-Duty Engine and Vehicle Standards (2022). https://www.epa.gov/regulations-emissions-vehicles-and-engines/final-rule-and-related-materials-control-air-pollution
  23. U.S. EPA, Final Rule: Rescission of Greenhouse Gas Endangerment and Repeal of GHG Standards (2026). https://www.epa.gov/regulations-emissions-vehicles-and-engines/final-rule-rescission-greenhouse-gas-endangerment
  24. U.S. EPA, Proposed Rule: Amendments and Nonconformance Penalties for Heavy-Duty Criteria Pollutant Standards (2026). https://www.epa.gov/regulations-emissions-vehicles-and-engines/proposed-rule-amendments-and-nonconformance-penalties
  25. Heavy Duty Trucking (Truckinginfo), Congress Revokes EPA Waivers for California's Clean Truck, NOx Rules (2025). https://www.truckinginfo.com/news/congress-revokes-epa-waivers-for-californias-clean-truck-nox-rules
  26. Sidley Austin LLP, California Withdraws EPA Waiver Request for Advanced Clean Fleets Regulations (2025). https://www.sidley.com/en/insights/newsupdates/2025/01/california-withdraws-epa-waiver-request-for-advanced-clean-fleets-regulations
  27. White House, Fact Sheet: President Donald J. Trump Addresses the Threat to National Security from Imports of Medium- and Heavy-Duty Vehicles, Parts, and Buses (2025). https://www.whitehouse.gov/fact-sheets/2025/10/fact-sheet-president-donald-j-trump-addresses-the-threat-to-national-security-from-imports-of-medium-and-heavy-duty-vehicles-parts-and-buses/
  28. Commercial Carrier Journal, December Class 8 orders hit 3-year high amid regulatory clarity (2026). https://www.ccjdigital.com/economic-trends/article/15800938/december-class-8-orders-hit-3year-high-amid-regulatory-clarity
  29. FleetOwner, Fleets Explained: History of the 7 major heavy-duty truck manufacturers in the U.S. (2024). https://www.fleetowner.com/fleets-explained/article/55127030/
  30. FreightWaves, Traton takeover brings changes to Navistar (2022). https://www.freightwaves.com/news/whats-changed-at-navistar-a-year-after-tratons-3-7b-takeover
  31. Yahoo Finance, Electric truck startup Nikola files for bankruptcy (2025). https://finance.yahoo.com/news/electric-truck-startup-nikola-files-215430304.html
  32. TRATON SE, 2025 Annual Report — Report on Expected Developments, Opportunities, and Risks (2026). https://annualreport.traton.com/2025/en/combined-management-report/report-on-expected-developments-opportunities-and-risks/index.html
  33. U.S. Department of Energy, Vehicle-to-Grid Integration Assessment Report (2025). https://www.energy.gov/sites/default/files/2025-01/Vehicle_Grid_Integration_Asseessment_Report_01162025.pdf