Other Motor Vehicle Parts Manufacturing (United States)

NAICS 2022 code 336390 — an investor's primer

1. Overview

This is the "everything else" bin of the car-parts factory world. When U.S. statisticians divide up companies that build the pieces of a motor vehicle, they carve out engines, electronics, steering, brakes, transmissions, seats, and body stampings into their own categories — and sweep the rest into 336390. What's left is a surprisingly large and varied group: the makers of airbags and seatbelts, catalytic converters and exhaust systems, radiators and other cooling ("thermal management") parts, air-conditioning compressors, air filters, wheels (the metal rims), windshield wipers, and bumpers [4].

Why should an investor care? Two reasons. First, this is real, physical, cash-generating manufacturing tied to one of the economy's biggest end markets — roughly 289 million vehicles are on U.S. roads and the average one is now a record 12.8 years old, which keeps a steady replacement business humming even when new-car sales slump [16]. Second, the sector sits squarely in the crosscurrents that dominate today's headlines: the shift to electric vehicles (EVs), tariffs, and precious-metal prices. Some product lines in this bucket (exhaust, catalytic converters) shrink as cars electrify; others (battery cooling, airbags, wheels) grow. That split makes it a place where picking the right sub-segment matters more than betting on "auto parts" as a whole.

Public vs. private ways in. A handful of these companies trade on U.S. exchanges — the airbag leader Autoliv, the thermal-management maker Modine, the wheel maker Superior Industries, mirrors and vision specialist Gentex, and aftermarket parts sellers Standard Motor Products and Dorman. But much of the industry is private: family-owned Tier-2 machine shops, private-equity-owned platforms (Tenneco, taken private by Apollo in 2022), and the U.S. plants of foreign giants (Japan's Denso, France's Forvia and Valeo, Germany's Mahle). So public-market investors see only a slice; private-market and credit investors reach the rest.

2. What it is and how it's structured

Scope. NAICS (the North American Industry Classification System) code 336390 covers establishments that manufacture or rebuild motor-vehicle parts and accessories not captured by the more specific parts codes [5]. In plain terms, its main product families are [4]:

• Occupant safety / restraints — airbag assemblies and seatbelt systems
• Emissions and exhaust — catalytic converters, mufflers, resonators, exhaust systems
• Thermal / climate — radiators and cores, air-conditioning compressors and condensers
• Wheels — steel and aluminum road wheels (rims), for cars, trucks, and buses
• Miscellaneous — air filters, windshield wipers, bumpers, fuel tanks, frames, convertible tops, jacks

What it explicitly excludes (each lives in an adjacent NAICS code) [4]:

Tires (rubber, NAICS 326211) and automotive glass (NAICS 327215) sit outside the 3363xx family entirely. Note the practical catch: a big supplier such as Denso or Forvia makes products spanning several of these codes at once, so no single code captures a whole company — 336390 counts only the qualifying establishments.

Ownership mix. The supply chain is tiered. "Tier-1" firms sell finished systems directly to automakers (the OEMs, or original-equipment manufacturers); Tier-2 and Tier-3 firms sell components to the Tier-1s. Ownership runs from a few U.S.-listed public companies, through large private and private-equity-held platforms, to hundreds of small independent job shops. Many of the largest names are foreign-headquartered multinationals operating U.S. factories.

3. How big it is

Our ground-truth federal figures for NAICS 336390 in the United States:

That works out to roughly $50 million of shipments and about 109 workers per establishment, and an average wage near $57,700 [1][2] — mid-scale, capital-intensive factories rather than mom-and-pop shops. The Small Business Administration (SBA) treats a firm here as "small" up to 1,000 employees, a high bar that reflects how equipment-heavy the work is [3].

Two caveats on the number. First, $66.5 billion is only one of eight motor-vehicle-parts codes; the full U.S. auto-parts manufacturing base across all 3363xx codes is several times larger (industry trackers put total U.S. auto-parts output in the hundreds of billions) [18]. Do not confuse this slice with the whole. Second, unlike industries dominated by tiny sole proprietors or by government, this one is not badly undercounted by federal business statistics — the establishments are established firms that file. The bigger distortion is the opposite: because 336390 is a residual "other" bucket, it blends genuinely different product markets (a wheel plant and an airbag plant have little in common), so any single industry-wide average blurs more than it reveals. And because many leaders are foreign-owned, the domestic data captures their U.S. plants but not the global company behind them. NAICS is establishment-based and measures U.S. production rather than U.S. consumption — exports are included, imports are not. Adding shipment values across supplier tiers can also double-count components embedded in other components.

4. The investable universe

There is no pure-play public company for "336390" — it's too broad. But several U.S.-listed firms derive most of their revenue from products in this bucket, plus a wider set of private and foreign owners. Scale figures are company-wide (these firms also touch adjacent parts codes).

U.S.-listed companies with meaningful 336390 exposure

*Superior was delisted from the NYSE in June 2025 for falling below the minimum-market-value rule and now trades over-the-counter [11] — a reminder that a "public" plumbing does not guarantee a liquid or healthy one. Gentex's classification straddles 336390 and the excluded automotive-electronics category.

Major private and foreign-owned players (reachable via private-equity funds, private credit, or foreign-listed shares):

• Tenneco — exhaust and clean-air (Walker brand) plus ride control; taken private by Apollo Global Management in November 2022. At acquisition, the company disclosed 2021 revenue of approximately $18 billion, 71,000 employees and more than 260 sites worldwide [12]. A leader in vehicle exhaust and catalytic converters.
• Flex-N-Gate — a significant bumper, structural and component supplier, privately held with more than 27,000 employees and 78 manufacturing facilities and product-development sites globally [13].
• Denso (Japan), Forvia/Faurecia and Valeo (France), Mahle and Eberspächer (Germany), Hanon Systems (Korea) — global Tier-1s dominating thermal, A/C, and exhaust, with large U.S. footprints. Forvia reported 2025 sales of €26.2 billion and a 5.6% operating margin, but only part of the group falls economically within 336390 [14].
• Joyson Safety Systems (owned by China's Ningbo Joyson; built from the former Takata assets) — the #2 airbag and seatbelt maker behind Autoliv [17].
• Wheels: Maxion Wheels (owned by Brazil's Iochpe-Maxion, the world's largest wheel maker), Accuride (commercial-vehicle wheels), Ronal (Switzerland) [20].
• First Brands Group — a private aftermarket roll-up (Fram filters, Trico wipers, Autolite plugs) that filed for Chapter 11 bankruptcy in September 2025 with more than $10 billion in liabilities; its executives were later charged with multibillion-dollar fraud [15]. A cautionary tale for private-credit investors, discussed below.

For the emissions niche, the precious-metal coating inside catalytic converters is supplied by specialty-chemical firms (BASF, Umicore, Johnson Matthey), a related but separately classified business.

5. How the money works

Owners in this industry make money on volume, mix, and cost discipline — the classic economics of cyclical manufacturing. There is no defensible single "industry margin" because product differentiation, aftermarket exposure, customer concentration, manufacturing intensity, and pass-through accounting produce radically different results. The key levers:

Two channels, two margin profiles.

• OEM (original equipment): selling parts to automakers for new vehicles. This is the larger channel — roughly two-thirds of parts demand by value [18] — but margins are thin. Automakers award multi-year programs (Autoliv says a typical vehicle-platform contract lasts approximately five to seven years [6]) and typically write in annual price give-backs (the supplier must cut its price a few percent each year). Contracts are large and sticky, but pricing power flows to the automaker.
• Aftermarket (replacement): selling parts to fix vehicles already on the road, through distributors and retailers. Margins are higher and far steadier, because repairs are largely non-discretionary and track the installed base, not new-car sales. This is why aftermarket-tilted names (Dorman, Standard Motor Products) are prized as recession-resilient, while OEM-heavy names swing with the auto cycle. Dorman reported a 42.1% gross margin and 14.1% operating margin in 2025, but it outsources much of its manufacturing and combines product design, offshore sourcing and distribution — approximately 77% of its purchases came from outside the United States, including 38% from China [9].

Capacity utilization is the profit dial. These are high-fixed-cost plants — stamping presses, welding lines, casting furnaces. When factories run full, incremental units drop straight to profit; when volumes fall, fixed costs crush margins. So operating profit is highly operating-leveraged to vehicle-production volumes. The contrast across firms is stark: Autoliv posted a 10.1% operating margin in 2025 [6], Gentex approximately 18.7% [8], Forvia 5.6% [14], while Superior Industries' gross margin was only 8.7% with operating income around 2.3% of sales [11].

Input costs and pass-through. Steel, aluminum, plastics, and — for catalytic converters — platinum-group metals (PGMs: platinum, palladium, rhodium) are the main raw materials. A catalytic converter's value is dominated by a few grams of PGMs; rhodium alone traded above $11,000 per ounce in 2026 [19]. Suppliers generally index or pass through metal costs to customers, so PGM swings hit revenue more than margin — but they inflate working capital and, notoriously, make converters a theft target (Section 7). Autoliv's direct materials were approximately 54% of sales in 2025, with steel, textiles, plastics and non-ferrous metals among the principal inputs [6]. Superior's customer arrangements pass through aluminum and some other input costs, but the timing of customer price adjustments rarely matches the timing of cost changes, creating gross-profit volatility [11].

Content per vehicle. Even when U.S. vehicle production is flat, a supplier can grow by putting more of its product in each car: more airbags per vehicle (front, side, curtain, knee, center), larger-diameter wheels, and — the biggest structural tailwind — far more cooling hardware in an EV to manage battery and motor heat. Rising content-per-vehicle is the main organic growth story in an otherwise mature market.

Customer concentration. A few automakers buy most OEM output and extract annual price cuts, capping margins. Superior says customer concentration, supplier fragmentation and product commoditization create continuing OEM demands for cost reductions; in 2024, GM, Ford, Volkswagen and Toyota accounted for 24%, 16%, 12% and 12% of its sales, respectively [11]. Autoliv's five largest customers represented approximately 44% of 2025 sales and its ten largest approximately 70% [6].

What to watch in the financials: capacity utilization, OEM vs. aftermarket revenue mix, gross margin net of metal pass-through, "book-to-bill" or new-program awards (future OEM revenue), and free cash flow versus debt — leverage is the industry's recurring undoing.

6. What drives demand

• New-vehicle production (the auto cycle). OEM parts demand tracks the number of vehicles built. U.S. automobile and light-truck assemblies averaged a seasonally adjusted annual rate of approximately 10.0 million in 2025, versus 10.2 million in 2024 [21]. U.S. new-vehicle registrations topped 16 million in 2024 for the first time since 2019 [16]. This is the cyclical, volatile driver; a supplier's actual exposure depends on the specific platforms it serves.
• The installed base and vehicle age (the aftermarket). With about 289 million vehicles in operation and an average age of a record 12.8 years, older cars need more repairs — a large, stable demand pool that grows regardless of new-car sales [16]. Miles driven and scrappage rates fine-tune it.
• Rising content per vehicle. Safety regulation, consumer preference for bigger wheels, and electrification all push more of this bucket's dollars into each vehicle (Section 5).
• Electrification — a two-sided force. EVs eliminate the tailpipe: demand for exhaust systems, mufflers, catalytic converters, and fuel tanks is in structural decline, with forecasts of roughly –3% per year through 2030, accelerating toward –8% by 2035 [22]. But EVs add battery and power-electronics cooling, expanding the thermal-management market that firms like Modine, Denso, and Valeo serve. Wheels, airbags, and cabin A/C are broadly neutral-to-positive. U.S. EVs represented 9.4% of new light-vehicle sales in 2025, down from 9.8% in 2024, demonstrating that the transition is material but neither linear nor complete [23].
• Trade policy. Tariffs (Section 7) reshape where parts are sourced and can pull production back to U.S. and USMCA (United States–Mexico–Canada Agreement) plants.

7. Regulation

Regulation is unusually load-bearing here because several of these products exist because the law requires them.

• Vehicle safety (NHTSA). The National Highway Traffic Safety Administration mandates occupant crash protection under Federal Motor Vehicle Safety Standard (FMVSS) 208, which effectively requires airbags and seatbelts — creating and steadily expanding the restraint market [4][17][24]. NHTSA's defect-reporting obligations support demand for validated safety systems but create recall, notification and remedy exposure for equipment manufacturers. Autoliv states that it faces product-liability and warranty claims where products allegedly cause bodily injury or property damage [6].
• Emissions (EPA and CARB). The catalytic converter exists to meet Clean Air Act tailpipe limits enforced by the Environmental Protection Agency (EPA) and, in California, the Air Resources Board (CARB), which certifies aftermarket converters separately. Removing or defeating a converter is illegal "tampering," and 2025 enforcement pursued fines of up to $50,000 per vehicle [25]. Exhaust and catalytic-converter suppliers remain subject to traditional-pollutant and anti-tampering rules even after EPA's February 2026 rescission of federal motor-vehicle greenhouse-gas standards; EPA expressly said that rescission did not affect traditional air-pollutant regulation [26]. Regulatory reversals can strand capacity as readily as new mandates can create demand.
• Converter theft rules. Because converters hold valuable metals, theft became a national problem; federal proposals (e.g., the Preventing Auto Recycling Theft Act) would require converters on new vehicles to be marked and traceable in a law-enforcement database [25].
• Tariffs (Section 232). In 2025 the U.S. imposed 25% tariffs on imported automobiles and many auto parts under Section 232 of the Trade Expansion Act; the parts tariff took effect May 3, 2025. Parts qualifying under the USMCA are largely exempt (as of early 2026 most Canada/Mexico imports claimed the exemption, keeping effective rates low), and a "Commerce inclusions process" can add more parts over time [27]. USMCA generally requires 75% North American regional value content for qualifying passenger vehicles and light trucks; complementary parts, including catalytic converters, have a 65% threshold, while principal parts have a 70% threshold [28]. In a March 2025 MEMA survey of 139 suppliers, more than 80% reported exposure to steel or aluminum derivative tariffs, and more than one-third were exposed through both imported inputs and delivered products; Gentex said unrecovered tariffs reduced its 2025 gross margin by approximately 110 basis points [8][29]. Net effect: an incentive to make parts in North America, and a cost shock for import-reliant suppliers.
• Product liability and recalls. Safety parts carry outsized recall risk. The Takata airbag-inflator scandal — the largest auto recall in history — bankrupted the maker and reshaped the airbag industry, a permanent reminder of the tail risk in this segment.

8. Competitive dynamics and consolidation

The federal data paint 336390 as fragmented: the top four firms hold only 13.6% of receipts, the top 50 hold 65.3%, and the Herfindahl-Hirschman Index (HHI, a standard concentration gauge where under 1,500 is "unconcentrated") is just 125.4 — extraordinarily low [2].

But that low number is partly an artifact of the "other" bucket lumping unrelated products together. Within each real product market, concentration is high: airbags and seatbelts are effectively an oligopoly (Autoliv plus Joyson and ZF hold the lion's share) [17]; exhaust and clean-air are led by Forvia, Tenneco, and Eberspächer [30]; wheels by Maxion, Superior, Accuride, and Ronal [20]. So the industry is "fragmented in aggregate, concentrated in the aisle you actually shop."

Consolidation is the through-line. Automakers prefer fewer, larger, better-capitalized Tier-1 partners, which pushes scale. Recent moves: Apollo took Tenneco private (2022) [12]; Standard Motor Products bought Europe's Nissens engine-cooling business for about $390 million in 2024 to expand its temperature-control line [10]; and private equity owns large swaths of the aftermarket. The counter-example — First Brands' debt-fueled roll-up that collapsed into bankruptcy and fraud charges in 2025 — shows how consolidation financed with too much leverage can end [15].

9. Risks

• Cyclicality. OEM revenue rises and falls with vehicle production; a downturn hits high-fixed-cost plants hard.
• Customer power and concentration. A few automakers buy most OEM output and extract annual price cuts, capping margins.
• Electrification stranding. Exhaust and catalytic-converter product lines face structural, permanent decline as EVs spread [22]; firms that fail to pivot to thermal management or other growth parts will shrink.
• Commodity and PGM volatility. Steel, aluminum, and especially platinum-group-metal prices swing hard, inflating working capital and (for converters) inviting theft [19].
• Leverage. Debt-heavy, private-equity-owned structures are common; First Brands' failure — with more than $10 billion in liabilities and fraud allegations — is the industry's cautionary tale for equity and credit investors alike [15].
• Tariffs and supply-chain shocks. Section 232 tariffs, plus dependence on imported steel, aluminum, semiconductors, and rare earths, can whipsaw costs and output [27][29].
• Recall and liability tail. Safety-critical parts carry catastrophic recall exposure (see Takata).
• Capital allocation under uncertainty. Suppliers face a difficult problem: maintaining legacy capacity while funding uncertain EV-related programs can depress returns under either a faster- or slower-than-expected transition.

10. How to invest, and the outlook

Public-market routes. There is no single ticker for this industry; investors assemble exposure by theme:

• Safety / secular content growth: Autoliv (ALV) — the dominant airbag and seatbelt maker, largely insulated from the EV-vs-ICE debate because every vehicle needs restraints [6][17].
• EV-thermal winner: Modine (MOD) — repositioned around data-center and EV cooling; its market value has re-rated sharply on that story [7].
• Higher-margin vision systems: Gentex (GNTX) — auto-dimming mirrors and connected-car systems with a 79% global share in its core product and operating margins near 19% [8].
• Aftermarket resilience: Dorman (DORM) and Standard Motor Products (SMP) — geared to the aging vehicle fleet rather than the new-car cycle [9][10].
• Deep-cyclical / turnaround: Superior Industries (SSUP), now over-the-counter and highly leveraged — a distressed situation, not a core holding [11].
• Diversified proxies: broad auto-supplier or industrial ETFs give indirect exposure without single-name risk; most hold automakers, semiconductor companies and technology vendors rather than pure 336390 exposure. Reserve valuation work (price-to-earnings, EV/EBITDA, dividend yield, leverage) for these names specifically; the OEM-heavy ones trade at low multiples reflecting thin margins and cyclicality, the aftermarket and thermal names at richer ones.

Private-market routes. Because most of the industry is private, this is fertile ground for private equity (platform roll-ups of aftermarket brands and Tier-2 suppliers) and private credit (lending to those platforms). Apollo's ownership of Tenneco shows that large global suppliers are viable buyout targets, while Flex-N-Gate demonstrates the continuing importance of large family- or founder-controlled suppliers [12][13]. Smaller opportunities include specialist manufacturers, rebuilders, tooling businesses and aftermarket brands. The First Brands collapse [15] is a live warning that returns here depend as much on capital structure and disclosure quality as on the parts themselves — private investors need unusually careful diligence on program-level profitability, customer recovery mechanisms, tooling ownership, environmental liabilities, pension obligations, recall indemnities and the amount of capital required before a new program reaches positive cash flow.

Near-term drivers and outlook (forward-looking). The base case: a large, mature industry growing slowly in aggregate but bifurcating underneath. Aftermarket demand should stay firm, underpinned by a record-old, 289-million-vehicle fleet [16]. The clearest structural loser is internal-combustion exhaust and catalytic converters, which fade as electrification advances [22]; the clearest structural winner is thermal management, expanding with EVs and hybrids. Cross-cutting all of it, 2025's Section 232 tariffs [27] are nudging production toward North American plants — a potential tailwind for U.S.-based capacity but a cost headwind for import-dependent suppliers. For investors, the durable lesson is that "auto parts" is not one bet: the sub-segment, the OEM/aftermarket mix, and the balance sheet decide the outcome far more than the sector label.

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Sources

1. U.S. Census Bureau, County Business Patterns, 2023 (NAICS 336390: establishments, employment, annual payroll). https://www.census.gov/programs-surveys/cbp.html
2. U.S. Census Bureau, 2022 Economic Census — Industry Statistics and Concentration (NAICS 336390: receipts, firms, CR4/CR8/CR20/CR50, HHI). https://www.census.gov/programs-surveys/economic-census.html
3. U.S. Small Business Administration, Table of Small Business Size Standards, 2023 (NAICS 336390: 1,000 employees). https://www.sba.gov/document/support-table-size-standards
4. NAICS Association, "NAICS Code 336390 — Other Motor Vehicle Parts Manufacturing" (industry definition, product examples, cross-references), 2024. https://www.naics.com/naics-code-description/?code=336390
5. U.S. Census Bureau, 2022 NAICS Manual and detailed 336390 definition. https://www.census.gov/naics/reference_files_tools/2022_NAICS_Manual.pdf
6. Autoliv, Inc., 2025 Form 10-K (sales $10.815 billion; 10.1% operating margin; ~44% airbag and ~45% seatbelt global share; direct materials ~54% of sales; customer concentration; contract duration; product-liability disclosure). https://www.sec.gov/Archives/edgar/data/1034670/000119312526058162/alv-20251231.htm
7. Modine Manufacturing Co., FY2025 results — record net sales of $2.6 billion (Form 8-K, 2025); market capitalization via StockAnalysis. https://www.sec.gov/Archives/edgar/data/67347/000155837025008029/tmb-20250520xex99d1.htm
8. Gentex Corporation, 2025 Form 10-K (sales $2.534 billion; ~34% gross margin; ~19% operating margin; 79% auto-dimming mirror share; tariff impact ~110 bps). https://www.sec.gov/Archives/edgar/data/355811/000035581126000010/gntx-20251231.htm
9. Dorman Products, Inc., 2025 Form 10-K (sales $2.130 billion; 42.1% gross margin; 14.1% operating margin; 77% of purchases from outside U.S., 38% from China). https://www.sec.gov/Archives/edgar/data/868780/000086878026000014/dorm-20251231.htm
10. Standard Motor Products, Inc., "Fourth Quarter and 2024 Year-End Results" (net sales $1.46 billion) and "SMP Completes Acquisition of Nissens Automotive" (~$390 million), 2024–2025. https://www.smpcorp.com/newsroom/financial/smp-releases-fourth-quarter-and-2024-year-end-results/
11. Superior Industries International, Inc., FY2024 Form 10-K (revenue $1.267 billion; 8.7% gross margin; ~92% OE aluminum wheels; customer concentration; pass-through timing) and "Superior Industries International Receives NYSE Delisting Notice" (Businesswire, June 2025). https://www.sec.gov/Archives/edgar/data/95552/000095017025034599/sup-20241231.htm
12. Tenneco Inc. / Apollo Global Management, acquisition completion announcement (November 2022; 2021 revenue ~$18 billion; 71,000 employees; 260+ sites). https://www.sec.gov/Archives/edgar/data/1024725/000119312522287303/d190359dex991.htm
13. Flex-N-Gate, corporate profile (27,000+ employees; 78 facilities). https://flex-n-gate.com/our-group/
14. FORVIA, 2025 Annual Results (sales €26.2 billion; 5.6% operating margin). https://www.forvia.com/en/press/2025-annual-results
15. U.S. Department of Justice, "First Brands Executives Charged With Multibillion-Dollar Fraud" (2026), and Transport Topics, "Auto Parts Maker First Brands Files for Bankruptcy" (Chapter 11, September 2025; >$10 billion liabilities; tariffs cost $219 million). https://www.justice.gov/usao-sdny/pr/first-brands-executives-charged-multibillion-dollar-fraud
16. S&P Global Mobility, "U.S. Vehicle Age Rises Again to 12.8 Years in 2025" (289 million vehicles in operation; >16 million registrations in 2024), May 21, 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
17. Mordor Intelligence and The Business Research Company, automotive airbags-and-seatbelts market reports (market ~$52.5 billion in 2024; key players Autoliv, Joyson Safety Systems, ZF), 2024–2025. https://www.mordorintelligence.com/industry-reports/automotive-airbags-and-seatbelts-market
18. Grand View Research / Mordor Intelligence, U.S. auto-parts and aftermarket market sizing (OEM channel ~68% of parts value; total U.S. auto-parts output far larger than any single NAICS sub-code), 2025. https://www.grandviewresearch.com/industry-analysis/aftermarket-automotive-parts-market
19. PMR and Recohub, catalytic-converter precious-metal content and pricing analyses (platinum, palladium, rhodium content; rhodium >$11,000/oz in 2026; aftermarket units carry ~10% of OEM PGM content), 2025–2026. https://pmrcc.com/en/news-blog/catalytic-converter-101/catalytic-converter-value/
20. GlobeNewswire, "Automotive Wheels Aftermarket … Maxion Wheels, Accuride Corp, and Ronal Group Lead" and "Alloy Wheels Aftermarket … Superior Industries Int'l," September 2025. https://www.globenewswire.com/news-release/2025/09/19/3153329/0/en/
21. Federal Reserve Bank of St. Louis (FRED), U.S. Motor Vehicle Assemblies (seasonally adjusted annual rate, 2024–2025). https://fred.stlouisfed.org/graph/?g=1PwAf
22. MarketsandMarkets and GMInsights, automotive exhaust-system market analyses (structural decline of ICE exhaust/catalytic converters, ~–3% to –8% CAGR; growth in EV thermal management), 2025; BCG, "2026 Global Automotive Supplier Study." https://www.marketsandmarkets.com/Market-Reports/automotive-exhaust-system-market-87800437.html
23. Alliance for Automotive Innovation, "Get Connected — Electric Vehicle Sales Dashboard" (U.S. EV share 9.4% in 2025, down from 9.8% in 2024), January 2026. https://www.autosinnovate.org/posts/papers-reports/stay-connected1-30-2026
24. National Highway Traffic Safety Administration (NHTSA), manufacturer guidance and defect-reporting requirements. https://www.nhtsa.gov/vehicle-manufacturers
25. Congressional Research Service, "Addressing Catalytic Converter Theft" (IF11870) and EPA Clean Air Act anti-tampering enforcement (fines up to $50,000/vehicle, 2025); CARB aftermarket-converter certification. https://www.congress.gov/crs_external_products/IF/PDF/IF11870/IF11870.2.pdf
26. U.S. Environmental Protection Agency, Final Rule: Rescission of Greenhouse Gas Endangerment (February 2026; traditional air-pollutant rules unaffected). https://www.epa.gov/regulations-emissions-vehicles-and-engines/final-rule-rescission-greenhouse-gas-endangerment
27. Congressional Research Service, "Section 232 Automotive Tariffs: Issues for Congress" (2025), and Federal Register, "Adjusting Imports of Automobiles and Automobile Parts" (25% parts tariff effective May 3, 2025; USMCA treatment). https://www.congress.gov/crs-product/IN12545
28. Office of the United States Trade Representative, USMCA automotive rules summary (75% regional value content for vehicles; 65% complementary parts; 70% principal parts). https://ustr.gov/sites/default/files/files/Press/Releases/USTR%20USMCA%20Autos%20White%20Paper.pdf
29. Motor & Equipment Manufacturers Association (MEMA), tariff survey (March 2025; >80% of suppliers exposed to steel or aluminum derivative tariffs). https://www.mema.org/news/mema-statement-ongoing-impact-steel-and-aluminum-tariffs
30. MarketsandMarkets, "Automotive Exhaust System Market — Leading Players" (Forvia, Tenneco, Eberspächer, Friedrich Boysen), 2025. https://www.marketsandmarkets.com/ResearchInsight/automotive-exhaust-system-market.asp