Motor Vehicle Steering and Suspension Components (except Spring) Manufacturing — U.S. Industry Primer

NAICS 2022 code 33633. This is a NAICS industry (the 5-digit level). Figures below are the most recent U.S. federal statistics available for this level; forward-looking statements are worded as judgments, not facts.

1. Overview

This level makes the parts that let a vehicle turn and absorb the road — steering gears, columns, racks, electric power-steering (EPS) units, shock absorbers, struts, control arms, ball joints, tie rods, and stabilizer (sway) bars — everything in the steering and suspension systems except springs, which are counted separately [1][2].

The one thing to know up front: this 5-digit industry is a pass-through. In the North American Industry Classification System (NAICS), the U.S. detail industry 336330 is the only child underneath it, and the two are defined identically. So 33633 and 336330 describe the same set of factories, the same products, and the same companies. This page gives the rollup's own ground-truth stats and the short version of the story; for the full treatment — economics, company tables, demand drivers, regulation, and outlook — read the 336330 primer.

The short version of why the level is worth a look at all: these are wear-and-safety parts fitted to essentially every one of the ~289 million light vehicles on U.S. roads, so demand has two legs — new-vehicle production and replacement [12] — and the category is powertrain-agnostic, which makes it a relative safe harbor in the electric-vehicle (EV) transition compared with engine-parts suppliers [10].

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

NAICS is a nested system: a 5-digit industry normally rolls up two or more 6-digit U.S. detail industries. Here it rolls up exactly one:

• 336330 — Motor Vehicle Steering and Suspension Components (except Spring) Manufacturing.

Because 33633 has a single child that carries the same scope, there is nothing to "add up" and no mix to weigh — the parent simply is 336330. The "(except Spring)" tag in the name reflects the one boundary that matters: leaf, coil, and torsion springs are excluded and counted in Spring Manufacturing (NAICS 33261 / 332613) [1][2]. Related driveline, brake, engine, and electrical parts sit in their own neighboring industries (336350, 336340, 336310, 336320), with anything left over falling to 336390, so this level is a clean "steering-and-suspension mechanical hardware" bucket [1][2].

That boundary matters when reading company financials: names routinely described as chassis or suspension suppliers — American Axle, Dana — actually earn most of their revenue in driveline (336350), with only a slice of genuine 33633 content.

3. How big it is (U.S. federal figures for this level)

Ground-truth statistics for NAICS 33633. Because the level equals its one child, these are identical to 336330's numbers:

Average pay works out to roughly $62,000 per worker (annual payroll ÷ employment) — typical of skilled U.S. manufacturing. For trend, receipts were about $15.8 billion in 2017, so the domestic base grew only modestly over five years [4].

Undercount caveat — it's about imports, not tiny operators. This industry is made up of mid-size to large Tier 1 and Tier 2 plants, not owner-operators, so federal business statistics capture U.S. production well. But the United States installs far more steering and suspension content than it makes: imports of these parts run higher than the domestic figure, and the country is a net importer [4]. Read the ~$17 billion as the domestic manufacturing base, not total U.S. demand.

Concentration. By the standard federal yardstick the industry looks unconcentrated — the Herfindahl-Hirschman Index (HHI, a market-concentration score where below 1,500 is "unconcentrated") is just 487 [3]. The top four firms hold 34.5% of revenue, the top eight 54.6%, the top twenty 76%, and the top fifty 91.9% [3]. The long tail of specialist shops is real, but within any single original-equipment (OE) product line the practical field is a handful of global Tier 1 suppliers — so the headline HHI understates how narrow any one automaker's choice actually is.

4. Investable universe (where value concentrates)

With only one child industry, all of the value sits in that one bucket — there is no second sub-industry to compare it against. The key fact for investors: there is no large, U.S.-listed pure play in steering and suspension. Exposure comes three ways — (a) diversified U.S. suppliers that carry partial chassis content (mostly driveline businesses), (b) U.S.-listed aftermarket names, and (c) foreign-listed or privately held Tier 1 leaders that actually dominate OE steering and suspension. The 336330 primer carries the full company tables; a few names by route: Dana (NYSE: DAN, ~$10.3B sales in 2024) and American Axle/Dauch (NYSE: AXL, ~$6.1B) on the diversified-supplier side; Dorman (Nasdaq: DORM, ~$2.15B), Standard Motor Products (NYSE: SMP, ~$1.4B), and MotorCar Parts of America (Nasdaq: MPAA, ~$0.7B) on the aftermarket side; and Bosch, ZF, Nexteer (HKEX: 1316), JTEKT/NSK/KYB and Hitachi Astemo (Japan), thyssenkrupp (Germany), and HL Mando (Korea) among the foreign-listed or foreign-parent Tier 1 leaders [5][6][7][8][9][10].

Nexteer is the closest thing to a listed proxy for this level's core product — ~$4.6 billion of revenue and ~12,600 employees in 2025, with 68% of revenue from EPS and 36 of 57 program launches that year on EV platforms [15]. Two of the largest players in the level, Tenneco (Monroe shocks, DRiV aftermarket; Apollo) and Marelli (KKR), are private-equity-owned and not investable in public markets at all [4].

5. How the money works

Same economics as any auto Tier 1, and covered in full in the child primer. The levers that matter are program awards (a supplier wins a "platform award" to supply a part for a 5–7-year vehicle program; un-booked awards are reported as backlog), content per vehicle (the shift from hydraulic to electric power steering, plus adaptive dampers and steer-by-wire, lifts this industry's dollars per car even when total production is flat [10]), capacity utilization (high-fixed-cost stamping/forging/machining lines, so margins swing with build rates), and the two-channel split — lower-margin, cyclical OE sales versus higher-margin, counter-cyclical aftermarket (replacement) demand. Margins are thin, balance sheets are often levered, and automakers demand annual price reductions.

How thin: Nexteer, a steering-focused Tier 1 and a reasonable stand-in for the level's OE economics, reported an 11.4% gross margin, roughly 10% adjusted EBITDA margin, and a 2.2% net margin in 2025, with raw materials consuming about 65% of revenue [15]. Material costs (steel, aluminum, plus motors, magnets, bearings, sensors, and semiconductors on the EPS side) do pass through to automakers, but with a lag [15].

6. Demand drivers

• Light-vehicle production (the cycle). OE volume follows automaker build rates; U.S./North American output topped 16.06 million units in 2024, with 2025 tracking lower at roughly 15.3–15.6 million [11]. Regional mix can diverge from the global picture: global OEM output rose 3.7% in 2025 while North American production fell 1.0% [15].
• Content growth (the structural tailwind). EPS is already in more than ~70% of North American new vehicles and rising, and over 85% of battery-electric vehicles use electric steering; steer-by-wire and advanced driver-assistance systems (ADAS) add electronics and redundancy, lifting revenue per car [10]. The U.S. electric-power-steering market alone was about $5.5 billion in 2024 [9].
• Fleet size and age (the aftermarket). The U.S. light-vehicle fleet reached 289 million vehicles at a record average age of 12.8 years in 2025; older vehicles need more steering and suspension repairs, and the large 2015–2019 model-year cohort is now entering its heavy-repair window [12].
• Vehicle mix. Trucks and SUVs carry more (and larger) steering/suspension content than small cars.

7. Regulation

Steering and suspension are safety-critical, so the National Highway Traffic Safety Administration (NHTSA) writes and enforces the Federal Motor Vehicle Safety Standards (FMVSS) that govern them — steering-column rearward displacement and energy absorption (FMVSS 203 and 204) and electronic stability control (FMVSS 126), which interacts with steering inputs [14][16]. These are performance requirements rather than mandates for one steering design, which matters as steer-by-wire spreads [16]. Defects trigger high-severity safety recalls, and warranty/liability reserves are a real line item: Nexteer alone carried $84.1 million of estimated warranty and product-liability provisions at year-end 2025 [15]. Trade policy also bites: in 2025 the U.S. applied Section 232 tariffs of 25% on imported automobiles and certain auto parts, and because this industry is a net importer with cross-border (U.S.–Mexico–Canada) supply chains, tariffs and regional-content rules directly affect costs [13]. USMCA requires 75% regional value content for qualifying passenger vehicles and light trucks, treats steering and suspension as core parts, and imposes North American steel and aluminum sourcing rules [17]. Full detail is in the 336330 primer.

8. Consolidation

Consolidation is the dominant theme: Apollo Global Management took Tenneco (owner of the Monroe shocks brand) private in a ~$7.1 billion deal completed November 2022, has roughly doubled its EBITDA since, and an eventual IPO has been discussed [4]; American Axle combined with Dowlais (GKN) in a ~$1.4 billion deal that closed February 2026 to form a ~$12 billion group [5]; Dana sold its off-highway business to Allison for $2.7 billion (2026) to focus on light and commercial vehicles [6]; and on the aftermarket side roll-ups continue [8]. Bargaining power sits with the automaker customers, and concentration on that side is severe — General Motors and affiliates accounted for 34% of Nexteer's 2025 revenue [15]. Chinese ownership is a live factor: Nexteer, a leading U.S.-operating steering supplier, is majority-controlled by a Chinese state group [9].

9. Risks

Cyclicality (OE volume tracks auto production); customer concentration and annual price-downs from a handful of automakers [15]; steel/aluminum and labor cost inflation ahead of pass-throughs; the 25% Section 232 parts tariff and cross-border disruption [13]; import penetration from lower-cost foreign producers already supplying a large share of U.S. demand [4]; outsized recall and product-liability exposure on safety-critical parts [14]; and leverage at the private-equity-owned names [4]. The child research adds three operating risks the parent previously understated: cyber and software risk as mechanical systems become electronically controlled (production stoppages, data compromise, manipulation), supply-chain and environmental-compliance concentration in sole-source electronics and forging plus plating, coating, and heat-treatment permitting, and footprint rationalization — Nexteer disclosed shifting column and intermediate-shaft work from a U.S. site to Mexico as part of a profitability program [15]. The electric-vehicle transition is mostly a tailwind here — a car needs to steer and absorb the road whatever powers it — but the move to EPS and steer-by-wire rewards scaled, well-capitalized suppliers and could strand sub-scale, hydraulic-era shops.

10. How to invest and the outlook

Routes. Because there is no U.S.-listed pure play, public-market exposure is indirect: diversified suppliers (DAN, AXL) for partial chassis content, aftermarket names (DORM, SMP, MPAA) for the steadier replacement side, foreign-listed Tier 1 leaders (Nexteer, JTEKT/NSK/KYB, thyssenkrupp, HL Mando) to own the OE leaders directly, or broad auto-parts baskets [5][6][7][8][9][10]. Private-market ownership is arguably the primary model — private equity already controls Tenneco (Apollo) and Marelli (KKR), and middle-market machining/forging shops are frequent roll-up targets [4]. Diligence on a private target should separate OE from aftermarket revenue, measure platform and customer concentration, identify customer-owned versus supplier-owned tooling, test commodity pass-through clauses, quantify warranty history, and check whether capitalized engineering is recoverable if a program slips or is cancelled [15].

Outlook (forward-looking judgment). The central tension is flat-to-lower unit volumes against rising content per vehicle. Softer 2025–26 North American build rates (~15.3–15.6 million versus 16.06 million in 2024) and the 25% tariff are near-term headwinds [11][13]; structurally, EPS, steer-by-wire, and adaptive suspension should keep lifting content per car, and the record 12.8-year fleet age underpins a durable aftermarket floor [10][12]. Likely winners are scaled suppliers that can fund the electronics and software content.

For everything on this page in depth — full company tables, detailed economics, and sourcing — see the 336330 primer, which this level mirrors exactly.

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Sources

1. U.S. Census Bureau, "North American Industry Classification System — 336330," 2022. https://www.census.gov/naics/?input=336330
2. NAICS Association, "NAICS Code 336330 — Motor Vehicle Steering and Suspension Components (except Spring) Manufacturing," 2024. https://www.naics.com/naics-code-description/?code=336330
3. U.S. Census Bureau, County Business Patterns 2023 and 2022 Economic Census (Comparative Statistics / Concentration), NAICS 336330 / 33633. https://data.census.gov
4. Apollo Global Management, "Apollo Funds Complete Acquisition of Tenneco," 2022; and industry trade/receipts references. https://www.apollo.com/insights-news/pressreleases/2022/11/apollo-funds-complete-acquisition-of-tenneco-134627289
5. American Axle & Manufacturing, "AAM Announces Combination with Dowlais for $1.44 Billion in Cash and Stock," 2025; completed Feb 2026. https://www.aam.com/media/story/aam-announces-combination-with-dowlais
6. Dana Incorporated, "Full-Year 2024 Financial Results" and "Dana Completes Sale of Off-Highway Business," 2024–2026. https://www.dana.com/newsroom/press-releases/dana-incorporated-completes-sale-of-off-highway-business/
7. Forbes / Yahoo Finance, "Dorman Products (DORM) — Company Overview," 2026. https://finance.yahoo.com/quote/DORM/
8. Standard Motor Products, "SMP Completes Acquisition of European Aftermarket Supplier Nissens Automotive," 2024. https://www.prnewswire.com/news-releases/standard-motor-products-inc-completes-acquisition-of-european-aftermarket-supplier-nissens-automotive-302293368.html
9. Expert Market Research, "United States Electric Power Steering Market" (US EPS market ~$5.51B, 2024); Nexteer profile. https://www.expertmarketresearch.com/reports/united-states-electric-power-steering-market
10. Fortune Business Insights / Future Market Insights / IndexBox, "Automotive Electric Power Steering and Steer-by-Wire Market," 2025. https://www.fortunebusinessinsights.com/automotive-electric-power-steering-market-105808
11. S&P Global Mobility, "2025 Light Vehicle Production Forecast," 2025. https://www.spglobal.com/automotive-insights/en/blogs/2025-light-vehicle-production-forecast
12. S&P Global Mobility, "U.S. Vehicle Age Rises Again to 12.8 Years in 2025," 2025. https://press.spglobal.com/2025-05-21-U-S-Vehicle-Age-Rises-Again-to-12-8-Years-in-2025,-According-to-S-P-Global-Mobility
13. U.S. Customs and Border Protection, "Section 232 Additional FAQs — Automobiles and Auto Parts," 2025. https://www.cbp.gov/trade/programs-administration/entry-summary/section-232-additional-faqs-autos
14. National Highway Traffic Safety Administration, "Laws, Regulations & FMVSS," 2025. https://www.nhtsa.gov/laws-regulations
15. Nexteer Automotive Group Limited, 2025 Annual Report, Hong Kong Stock Exchange. https://www1.hkexnews.hk/listedco/listconews/sehk/2026/0424/2026042402166.pdf
16. National Highway Traffic Safety Administration, "NHTSA Interpretation 1982-326 (Steering Systems)," 1982. https://www.nhtsa.gov/interpretations/1982-326
17. Office of the United States Trade Representative, "USMCA Economic Impact Report," 2019. https://ustr.gov/sites/default/files/files/agreements/FTA/USMCA/USMCA%20EIR.pdf