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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.

National industryNAICS 332613

U.S. Spring Manufacturing: Investor Primer — NAICS 332613

1. Overview

Spring manufacturing is a small but essential U.S. component industry. Springs are inexpensive relative to the machines, vehicles and devices in which they operate, yet fatigue or load failure can stop production or trigger recalls. Demand spans transportation, bedding, industrial equipment, aerospace, defense, medical devices and electronics.

Public investors generally enter through diversified U.S. or foreign-listed manufacturers. Private investors can acquire independent regional producers, join platform add-ons or back family-owned succession deals. The investment appeal is recurring component demand, customer qualification and consolidation potential; the main drawbacks are cyclicality, steel exposure and fixed-cost operating leverage.

2. What it is and how it is structured

North American Industry Classification System (NAICS) code 332613 covers establishments manufacturing springs from purchased wire, strip or rod. It includes light- and heavy-gauge products: compression, extension and torsion springs; flat, leaf, disc and ring springs; automotive suspension springs and torsion bars; precision instrument and valve springs; and mattress, furniture and upholstery spring units.[1]

Important exclusions are:

  • Watch and clock springs: NAICS 334519.
  • Plants that first produce wire, strip or rod and then fabricate springs: primary metals, NAICS subsector 331.
  • Fabricated wire products other than springs: NAICS 332618.
  • Motor-vehicle steering and suspension components other than springs: NAICS 336330.
  • Finished mattresses: NAICS 337910.[1]

These boundaries matter. NAICS classifies individual establishments by primary activity, not entire companies. Vertically integrated wire mills, bedding plants and automotive-parts factories can therefore manufacture springs while appearing outside 332613. Industry statistics omit some large integrated spring operations and are not a census of every spring sold in America.

Manufacturers translate a required load, travel, fatigue life, dimensional envelope and operating environment into material grade, wire or strip dimensions, coil geometry and finishing specifications. Light-gauge springs are generally CNC-coiled or formed cold; heavier suspension, rail and industrial springs may be heated and wound or bent. Production can involve stress relieving or quench-and-temper heat treatment, end grinding, presetting or "scragging," shot peening, coating or plating, dimensional inspection, load testing and fatigue validation. Shot peening is particularly consequential in safety-critical products because it introduces compressive surface stress and improves fatigue life; SAE describes it as an essential automotive-spring manufacturing step.[2]

Ownership is predominantly private. County Business Patterns (CBP) legal-form data show at least 297 of 341 employer establishments in corporate form, compared with 34 partnerships and 9 sole proprietorships; legal form does not reveal whether a corporation is listed, sponsor-owned or family-owned.[3]

3. How big it is

Federal measure Latest figure
Employer establishments 341 in 2023 [3]
Employment 15,671 in 2023 [3]
Annual payroll $955.9 million in 2023 [3]
First-quarter payroll $236.0 million in 2023 [3]
Employer revenue estimate $4.713 billion in 2023 [4]
Small Business Administration size standard 600 employees [5]

The revenue estimate comes from the Annual Integrated Economic Survey (AIES), while establishment, employment and payroll figures come from CBP. The programs have different measurement frames and should not be combined mechanically. The AIES separately reports 15,382 employees and $928.3 million of annual payroll, with coefficients of variation of 2.4% and 1.9% respectively.[4]

An SBA analysis using a special 2012 Economic Census tabulation reported a 31.5% four-firm receipts share, a simple average firm size of 45.1 employees and a weighted average firm size of 398.6 employees.[6] That supports a structure with many small firms alongside a limited number of substantially larger platforms, but it should not be presented as current concentration.

No federal margin, return-on-capital or firm-count value is stated because the supplied ground-truth extract did not contain a usable figure. No suppressed value has been inferred.

CBP covers establishments with paid employees, so it omits nonemployers. That omission is probably modest here because factory production normally requires employees. The more important undercount is spring output assigned to another NAICS because it occurs inside a vertically integrated or diversified plant.

The Bureau of Labor Statistics producer-price index for Spring Manufacturing rose from 113.9 in December 2019 to 237.18 in May 2026, an increase of approximately 108%.[7] This measures domestic producers' realized price changes, including product mix, and should not be interpreted as shipment-volume or market-size growth.

4. Investable universe

There is no clean U.S.-listed pure play.

Public company Listing Relevant exposure Limitation
Rosebank Industries London: ROSE Owns MW Components, whose U.S. operations include spring, fastener and precision-component businesses. MW operated 24 U.S. facilities, employed more than 1,750 people, served over 14,000 customers and housed more than 24 brands at the time of acquisition. Rosebank acquired MW in May 2026 for approximately $950 million, or approximately 10 times 2025 EBITDA.[8][9] MW is broader than springs, and Rosebank owns other industrial businesses.
Leggett & Platt New York Stock Exchange: LEG U.S. Spring makes bedding innersprings; the company is integrated from steel scrap through rod and drawn wire, with a U.S. rod mill of approximately 500,000 tons of annual capacity.[10] Exposure is bedding-heavy and mixed with foam, adjustable beds and finished products.
Beijer Alma Nasdaq Stockholm: BEIA-B Its spring platform owns Plymouth Spring, John Evans' Sons and Tollman Spring in the United States. The Lesjöfors group reported SEK 4.996 billion of 2025 revenue and SEK 883 million of adjusted EBITA, approximately 17.7%.[11][12] Diversified Swedish group; U.S. spring revenue is not separately disclosed, and the margin is global, not U.S.-specific.
NHK Spring Tokyo: 5991 U.S. subsidiaries manufacture automotive coil, disc, valve and precision springs. The global Automotive Suspension Springs segment reported ¥169.1 billion of sales and ¥464 million of operating profit for the year ended March 2025, approximately 0.3%.[13][14][15] Global and automotive-heavy; weak Thai demand and Mexican launch costs depressed margins.
Advanex Tokyo: 5998 Precision-spring manufacturer with North American subsidiaries.[16] Smaller foreign listing with currency and liquidity considerations.

Major private operators and owners include:

  • One Equity Partners' Associated Spring, a large engineered-spring and precision-component platform acquired from Barnes in 2024.[17]
  • Mubea, an owner-operated family company with substantial automotive spring operations.[18]
  • Peterson Spring, which describes itself as North America's largest privately held spring manufacturer.[19]
  • Newcomb Spring, a family-run custom spring and metal-forming group with multiple North American plants.[20]
  • Hendrickson, owned by private Boler, a major medium- and heavy-duty suspension supplier producing parabolic and multi-leaf springs, stabilizers and complete suspension systems; Hendrickson explicitly states it does not disclose financial information.[21][22]

5. How the money works

Most sales are either custom, build-to-print parts for original equipment manufacturers (OEMs) or stocked catalog products sold to engineers, distributors and maintenance customers.

Revenue depends on volume, material content, tolerances, certification, secondary processing and engineering support. Production typically combines computer numerical control (CNC) coiling or forming with heat treatment, grinding, shot peening, plating or coating, and load or fatigue testing.

Steel wire, strip and rod are the core purchased inputs. Alloy content, cleanliness, surface quality and heat-treatment response matter as much as commodity tonnage for high-fatigue products. Leggett & Platt describes steel as its principal raw material and says steel-market volatility can produce large year-to-year swings in pricing and margins; it normally passes material changes through to customers, but timing matters, and falling prices can also compress margins while higher-cost inventory is consumed.[10]

Economic quality varies sharply:

  • High-volume automotive and bedding programs reward automation and utilization but bring customer bargaining power, annual cost reductions and program concentration.
  • Aerospace, medical and precision-industrial parts usually offer more engineering content and switching costs, but require stronger traceability and quality systems.
  • Catalog springs can produce attractive pricing and inventory economics, provided stock turns remain healthy.

Key operating metrics are capacity utilization, steel-surcharge recovery lag, scrap and rework, labor hours per part, on-time delivery, defect rates, backlog, customer concentration, inventory turns and maintenance capital spending.

The Federal Reserve does not publish spring-only utilization. Broader fabricated-metal-products utilization was 76.9% in June 2026, below its 78.5% average for 1972–2025; this is context, not a 332613 measure.[23] Leggett's broader Bedding Products segment reported a 6.3% earnings-before-interest-and-taxes (EBIT) margin on $1.558 billion of 2025 trade sales, but that segment includes many products beyond springs and is not an industry benchmark.[10]

There is no reliable, publicly available NAICS 332613 industry operating- or EBITDA-margin figure. Public-company comparisons demonstrate wide dispersion: Leggett's mixed bedding segment at 6.3% EBIT, NHK's global suspension springs at approximately 0.3%, and Lesjöfors's global operations at approximately 17.7% adjusted EBITA.[10][12][15] Mix, utilization and execution dominate any generic "spring industry margin."

6. Demand drivers

  • Automotive: Vehicle production, platform awards and replacement demand support suspension, seating, transmission and engine springs. Electrification is mixed: suspension and seating content remains, and heavier batteries can intensify suspension and lightweighting requirements, while internal-combustion valve and traditional transmission content can decline. NHK's strategy explicitly separates suspension opportunities from motor-core and other non-spring electrification products, while Leggett cites uncertainty around delayed EV programs and changing powertrain-transition expectations.[10][15]
  • Bedding and furniture: Mattress replacement, housing turnover and consumer spending drive innerspring demand. Leggett identifies housing turnover and consumer confidence as its most significant demand variables and reported continued softness in U.S. and European bedding markets during 2025.[10]
  • Industrial equipment: Factory output, automation, construction machinery and maintenance spending support custom and replacement parts.
  • Aerospace, defense and medical: Long qualification cycles and traceability can create durable programs and higher switching costs.
  • Electronics: Precision springs and contacts benefit from miniaturization but face rapid product changes.

Demand is cyclical overall, but diversification across end markets can soften any single downturn.

7. Regulation

The Occupational Safety and Health Administration (OSHA) requires guarding of forming machines, presses, grinders and other hazardous equipment under Title 29 of the Code of Federal Regulations (CFR), section 1910.212. Lockout/tagout requirements under section 1910.147 cover hazardous energy during maintenance.[24][25] An OSHA spring-plant citation specifically identified ineffective guarding on wire and CNC spring-coiling machines, illustrating enforcement activity in this industry.[26]

Plating, coating and cleaning can trigger Environmental Protection Agency (EPA) wastewater rules under 40 CFR Part 433 and National Emission Standards for Hazardous Air Pollutants (NESHAP), as well as hazardous-waste and local air-permit obligations. Facilities performing plating, phosphating, chromating, chemical etching or related finishing can fall under federal metal-finishing wastewater rules; oily direct discharges can fall under Metal Products and Machinery effluent guidelines.[27][28]

Customer standards are often as important as government licenses. Automotive plants commonly require International Automotive Task Force (IATF) 16949 certification; aerospace and medical work may require the AS9100 aerospace standard or International Organization for Standardization (ISO) 13485 certification. Defense suppliers may also face International Traffic in Arms Regulations (ITAR) and Defense Federal Acquisition Regulation Supplement requirements.[14][17]

Trade policy affects both raw-material costs and import competition. As of April 2026, listed steel-spring tariff lines 7320.10 through 7320.90 were included in the 50% full-value Section 232 metals tariff annex, subject to applicable exceptions. Leggett reported that Section 232 steel tariffs expanded its rod and wire metal margins but had not produced noticeable improvement in innerspring demand.[10][29]

8. Competitive dynamics and consolidation

Commodity springs compete on delivered cost, availability and scale. Engineered springs compete on fatigue life, materials knowledge, tolerances, certifications, design support and delivery reliability.

Qualification, tooling and failure risk create switching costs, especially in automotive, aerospace and medical markets. Customers may nevertheless dual-source critical parts to reduce disruption risk.

Consolidators seek purchasing leverage, broader catalogs, cross-selling, geographic redundancy and better equipment utilization. Rosebank's acquisition of MW Components, Beijer Alma's U.S. spring acquisitions and One Equity Partners' Associated Spring platform demonstrate active strategic and sponsor interest.[8][11][17] MW's scale was assembled in part through nine add-on acquisitions under American Securities, which credited proprietary rapid-quoting software, e-commerce investment and acquisitions with building the platform.[8] The counter-risk is integration failure: spring manufacturing often relies on experienced engineers, toolmakers and undocumented process knowledge.

Lightweighting is producing higher-strength steels, more sophisticated peening and selective substitution by composites. Hendrickson markets composite springs for lower weight and better vehicle packaging, demonstrating a real substitution threat to steel leaf and coil products, though composites bring their own qualification and cost barriers.[30]

9. Risks

  • Steel, stainless steel and specialty-alloy inflation without timely price recovery.
  • Volume downturns that expose fixed labor and equipment costs.
  • Customer concentration, automotive cost-downs and lost platform awards.
  • Fatigue or load failures leading to recalls, warranty expense or liability.
  • Aging equipment and inadequate maintenance capital expenditure.
  • Skilled-operator, engineer and toolmaker shortages.
  • Environmental liabilities from plating, solvents, oils and heat treatment.
  • Tariff changes, retaliation and cross-border supply disruption.
  • Electric-vehicle adoption reducing some engine and transmission applications.
  • Acquisition overpayment or loss of local customer relationships after integration.
  • Substitution by composites for vehicle leaf or coil springs, foam-heavy mattress designs, imported finished assemblies, and customer redesigns that eliminate discrete components.

10. How to invest and outlook

Public investors should treat the listed companies as indirect exposures. Compare spring-related segment mix, end-market cycle, material pass-through, capital intensity and foreign-currency risk rather than relying on headline group revenue.

Private investors should normalize earnings before interest, taxes, depreciation and amortization (EBITDA) across the cycle and verify customer concentration, surcharge formulas, certification status, defect history, equipment condition, maintenance spending and working-capital needs. MW's approximately 10-times-EBITDA 2026 transaction provides a market precedent, but the multiple applies to a diversified precision-components platform, not a stand-alone spring shop.[9] The best acquisition candidates are usually diversified custom manufacturers with scarce certifications, transferable engineering knowledge and unused capacity that can be filled without major new investment.

Forward-looking judgment: The industry appears more durable than fast-growing. Aerospace, defense, medical, reshoring and nearby qualified supply support engineered producers, while weak bedding or industrial demand and volatile steel costs can pressure commodity operations. Consolidation should continue, but disciplined entry price and plant-level diligence will matter more than broad market growth. No dedicated exchange-traded fund (ETF) offers precise exposure.

Sources

  1. U.S. Census Bureau, "332613: Spring Manufacturing—Industry Profile and Cross-References," 2022, https://data.census.gov/profile/332613_-_Spring_manufacturing?codeset=naics~332613
  2. SAE International, "Leaf Springs Durability Analysis and Weight Reduction through Double Peening," 2012, https://saemobilus.sae.org/papers/leaf-springs-durability-analysis-weight-reduction-double-peening-2012-36-0128
  3. U.S. Census Bureau, "County Business Patterns: 2023," 2025, https://www.census.gov/data/datasets/2023/econ/cbp/2023-cbp.html
  4. U.S. Census Bureau, "AIES00BASIC: All Sectors Summary Statistics," 2026, https://data.census.gov/table/AIESBASICTIMESERIES.AIES00BASIC?codeset=naics~332613&g=010XX00US
  5. U.S. Small Business Administration, "Table of Small Business Size Standards," 2023, https://www.sba.gov/document/support-table-size-standards
  6. U.S. Small Business Administration, "Proposed Rule: Small Business Size Standards," 2022, https://public-inspection.federalregister.gov/2022-08091.pdf
  7. Federal Reserve Bank of St. Louis, "Producer Price Index: Spring Manufacturing," 2026, https://fred.stlouisfed.org/series/PCU332613332613
  8. American Securities, "American Securities Completes Sale of MW Components to Rosebank Industries," 2026, https://www.american-securities.com/news/press-release/american-securities-completes-sale-of-mw-components-to-rosebank-industries/
  9. Rosebank Industries, "Completion of ASP MWI Holdings Inc Acquisition," 2026, https://www.investegate.co.uk/announcement/rns/rosebank-industries-plc--rose/completion-of-asp-mwi-holdings-inc-acquisition-/9590603
  10. Leggett & Platt, "Form 10-K for 2025," 2026, https://leggett.com/leggett-form-10k-2025.htm
  11. Beijer Alma, "Acquisitions," 2026, https://beijeralma.se/en/about-beijer-alma/acquisitions/
  12. Beijer Alma, "Q4 2025 Report," 2026, https://beijercomponents.com/wp-content/uploads/2026/02/ba-2025-q4-en.pdf
  13. NHK Spring, "Company Overview," 2025, https://www.nhkspg.co.jp/en/company/outline
  14. NHK Spring, "North America, Central and South America," 2026, https://www.nhkspg.co.jp/en/company/global/foreign/america
  15. NHK Spring, "Annual Securities Report," 2025, https://www.nhkspg.co.jp/en/news/20250827
  16. Advanex, "Company Outline," 2026, https://www.advanex.co.jp/en/company/about/
  17. One Equity Partners, "One Equity Partners Completes Acquisition of Associated Spring," 2024, https://www.oneequity.com/news/one-equity-partners-completes-acquisition-of-associated-spring/
  18. Mubea, "Company and Global Organization," 2026, https://www.mubea.com/en/company
  19. Peterson Spring, "About Us," 2026, https://www.pspring.com/about-us/
  20. Newcomb Spring, "About Us," 2026, https://newcombspring.com/about/
  21. Hendrickson, "Company Executives," 2026, https://www.hendrickson-intl.com/company/company-executives
  22. Hendrickson, "FAQs," 2026, https://www.hendrickson-intl.com/work-for-us/faqs
  23. Federal Reserve Board, "Industrial Production and Capacity Utilization, Table 2 Supplement," 2026, https://www.federalreserve.gov/releases/g17/current/table2_sup.htm
  24. Occupational Safety and Health Administration, "29 CFR 1910.212—General Requirements for All Machines," current, https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.212
  25. Occupational Safety and Health Administration, "29 CFR 1910.147—Control of Hazardous Energy," current, https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.147
  26. Occupational Safety and Health Administration, "MCM Industries Co Inc Citation," 2024, https://www.osha.gov/sites/default/files/citations/MCMIndustriesCoInc_104722_104823.pdf
  27. U.S. Environmental Protection Agency, "Metal Finishing Effluent Guidelines," 2026, https://www.epa.gov/eg/metal-finishing-effluent-guidelines
  28. U.S. Environmental Protection Agency, "Metals Sector Regulations," 2026, https://www.epa.gov/regulatory-information-sector/metals-sector-primary-naics-331-and-fabricated-naics-332
  29. White House, "Strengthening Actions Taken to Adjust Imports of Aluminum, Steel, and Copper Into the United States," 2026, https://www.whitehouse.gov/presidential-actions/2026/04/strengthening-actions-taken-to-adjust-imports-of-aluminum-steel-and-copper-into-the-united-states/
  30. Hendrickson, "Composites," 2026, https://micro.hendrickson-intl.com/composites/about.html