Labor Unions and Similar Labor Organizations (NAICS 813930)

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

1. Overview

Labor unions are member-funded organizations that bargain collectively with employers over pay, benefits, and working conditions. They are not businesses in the ordinary sense: they have no shareholders, distribute no profit, and are organized as tax-exempt labor organizations under Internal Revenue Code (IRC) section 501(c)(5), which bars private inurement of net earnings [6]. The "owners" are the dues-paying members, who elect officers and govern the organization.

Why should an investor care about a sector with nothing obvious to buy? Because unions are a large, organized counterparty to a big slice of the U.S. economy. In 2025, 14.7 million U.S. workers (10.0% of wage-and-salary employees) were union members, and 16.5 million were represented by a union [1]. Where unions are strong — autos, airlines, freight, grocery, healthcare, education, entertainment, the building trades, and the public sector — they shape labor costs, strike risk, contract cycles, and pension obligations that flow straight into the income statements of investable employers. Union pension and benefit funds are also multi-hundred-billion-dollar institutional investors.

The right way to read this industry is two-sided:

• Public-market exposure is indirect. There is essentially no listed "union" to buy (Section 4). The angle is the employers unions bargain against, one union-rooted bank, and a set of diversified benefits, payroll, and insurance firms whose union work is a small slice of a much larger business.
• Private-market exposure is more direct — labor-owned insurers and investment managers, benefit-fund third-party administrators, actuarial consultants, and the Taft-Hartley pension and health trusts themselves.

For this sector the useful metrics are membership and density, dues retention, organizing win rate, contract renewals, strike-fund liquidity, and benefit-fund solvency — not same-store sales or capacity utilization.

2. What it is and how it's structured

Scope. NAICS (North American Industry Classification System) code 813930 covers establishments primarily engaged in promoting the interests of organized labor and union employees — local trade unions, national and international unions, labor federations, and employee/collective-bargaining associations [4].

What it excludes (adjacent codes to keep out of 813930):

• 813110 Religious Organizations.
• 813910 Business Associations — chambers of commerce and trade groups promoting members' business interests [4].
• 813920 Professional Organizations — bodies promoting a profession (e.g., bar or medical associations) [4].
• 813940 Political Organizations — parties, PACs (political action committees), campaign-fundraising groups [4].
• 813990 Other Similar Organizations.
• Apprenticeship training is generally classified separately under educational services [4].

Occupational and professional associations that also bargain (some nurse and teacher associations) blur these lines, but a body whose core purpose is collective bargaining sits in 813930.

How it's structured (the ownership/organizational mix). The movement is a federated, three-tier pyramid:

1. Local unions — the shop-floor unit that negotiates and administers the contract, processes grievances, and organizes. Most of the ~12,800 counted establishments (Section 3) are locals; many are small and partly volunteer-run.
2. National/international unions — e.g., the Teamsters or the United Steelworkers (USW) — which charter locals, supply legal/organizing/political/training resources, and hold strike funds.
3. Federations — chiefly the AFL-CIO (American Federation of Labor and Congress of Industrial Organizations), a federation of roughly 60 affiliated unions representing close to 15 million active and retired workers [7]. Federations coordinate policy and solidarity but do not own affiliated unions as corporate subsidiaries. The Service Employees International Union (SEIU) rejoined the AFL-CIO in 2025 after a two-decade absence [8].

Benefit funds are typically a separate legal layer — trusts jointly administered by union and employer trustees (Section 5), not part of the union corporate entity.

The largest individual unions:

Other major nationals include the USW, the International Brotherhood of Electrical Workers (IBEW), the United Auto Workers (UAW), the Laborers' International Union of North America (LIUNA), and the Communications Workers of America (CWA). Note the concentration in public-sector and services unions — a reversal from the mid-20th-century private-industrial base. None of these are equity investments.

3. How big it is

Two very different measures matter, and they don't agree — which is the key thing for an investor to understand.

As a movement (members and money).

• 14.7 million members and a 10.0% membership rate in 2025, up roughly 400,000 members on the year [1]. That is far below the 17.7 million members and 20.1% membership rate of 1983, the first year of comparable data [1].
• Public sector 32.9% unionized vs. private sector 5.9% — the private rate is the lowest on record, and public-sector density is more than five times higher [1].
• One analysis of Department of Labor (DOL) filings put aggregate union net assets at roughly $32.7 billion in 2022, up from $14.4 billion in 2010, with three unions each holding over $1 billion by 2025 [9].

As a set of business establishments (our federal figures, and the undercount). The U.S. Census Bureau's County Business Patterns (CBP) program counts unions only as employers — i.e., the paid staff they put on payroll. For NAICS 813930 in 2023 that was [2]:

The undercount caveat is central here. These CBP figures are employer-establishment statistics, not industry revenue, and our stats file provides no total dues, membership, assets, or investment income for the code — so we do not state those. Two structural gaps matter:

• The ~137,000 payroll employees are the organizers, negotiators, and administrative staff unions hire — not the 14.7 million members they represent, whose dues fund the organizations and whose wages and benefits they bargain over.
• CBP excludes most establishments reporting government employees, along with nonemployer businesses and businesses without an Employer Identification Number; it also notes small multi-unit establishments may be missed and does not estimate total undercoverage [3]. Because the public sector is the most heavily unionized part of the movement (32.9%), a large share of union activity sits outside CBP coverage by construction.

So treat the establishment count as a benchmark for paid union-office employment, while the economically meaningful footprint — dues revenue, tens of billions in assets, and the far larger payrolls unions negotiate at outside employers — sits mostly outside those figures.

4. The investable universe

This is the section where a stock-picker will be disappointed, and that honesty is the point: there is no listed pure-play whose primary business is a labor union. Unions are non-profit member organizations with no equity. Public exposure is therefore proxy exposure, in three buckets.

Public companies

Treat AON, AJG, WTW, ADP, and PAYX honestly: union and Taft-Hartley work is a small, often undisclosed slice of each firm's revenue, so they are diffuse proxies, not bets on the labor movement.

Private and member-owned organizations

• ULLICO (Union Labor Life Insurance Co.) — labor-owned insurer and investment manager serving unions, members, signatory contractors, and multiemployer benefit funds; not publicly traded [30].
• Segal — independent, employee-owned benefits, actuarial, retirement, and investment consultant with a long labor-market history [31].
• Harbour Benefit Holdings / Zenith American Solutions — private third-party administrator (TPA) of Taft-Hartley and multiemployer benefit funds; a BPOC portfolio company pursuing add-on acquisitions [32].
• BeneSys — private specialist in Taft-Hartley trust-fund administration and IT [33].
• AFL-CIO Housing Investment Trust — a fixed-income vehicle open to labor-affiliated and public pension investors, not retail.
• Taft-Hartley multiemployer pension and benefit plans — jointly union-employer-trusteed funds; collectively a very large pool of institutional capital and a force in proxy voting and private markets — not securities you buy.

Bottom line: treat this industry as a cost and event driver for employer equities and a steward of institutional capital. AMAL is the rare listed security whose franchise is serving the labor movement rather than opposing it.

5. How the money works

Because there are no profits or share prices, the economics run closer to a subscription membership business than to a manufacturer.

Revenue. The engine is dues, typically 1–2% of a member's gross earnings (in the building trades, often a set number of hours' pay per month) [11]. Revenue therefore scales with two things: how many members you have (density) and how much they earn. Secondary revenue: initiation fees, special assessments, investment income on reserves and strike funds, property income, and remittances from local affiliates. Money also flows up the pyramid as a per-capita tax — the fee a local pays its national, and a national pays a federation, per member [10].

The economics in one line: revenue ≈ members × dues rate. The union analog of "same-store sales" is membership density and retention in the units it already holds; the analog of "new store openings" is the organizing win rate at new employers.

Costs. Staff salaries and representation (grievances, arbitration, contract enforcement), organizing campaigns, strike benefits paid to members during a walkout, training and member benefits, political and legislative spending, and per-capita to the parent body.

"Profit" and financial health. The surplus shows up as growth in net assets, which capitalizes the strike fund — the war chest that determines how long members can be supported through a work stoppage, and therefore the credibility of a strike threat. Financial health is disclosed publicly: covered unions file an annual Form LM-2 with the DOL's Office of Labor-Management Standards (OLMS), itemizing dues and interest receipts, assets, liabilities, benefits, officer/employee pay, and representational, political, and lobbying activity [10]. A DOL final rule effective July 1, 2026 modernizes LM-2 and adds a "Long Form" for unions with $40 million or more in annual receipts (roughly 99 organizations); first filings under the revised system are not expected until after June 30, 2027 [10].

The benefit-fund layer. Separate from union operating cash flow, a Taft-Hartley multiemployer plan is created through collective-bargaining agreements involving multiple employers and one or more unions; its assets are run by a joint trustee board under fiduciary duties set by the Employee Retirement Income Security Act (ERISA) [34]. For the TPAs and consultants that serve these funds, the economics are recurring fees per participant or per fund, contract retention, claims/eligibility accuracy, technology and cybersecurity cost, and client concentration.

6. What drives demand

"Demand" here means demand for union representation — the pipeline of members and bargaining units.

• Employment in union-heavy sectors. Density is concentrated in utilities (17.8%), transportation and warehousing (13.6%), and educational services (13.4%), and in protective-service and education occupations [12]. Growth or contraction in those payrolls moves the member base.
• The public sector. With roughly one in three government workers unionized versus one in seventeen private workers [1], public-sector employment, budgets, and state bargaining laws are the single biggest structural driver.
• Worker sentiment and cost of living. Approval of unions sits at 68% of U.S. adults — near a six-decade high — but splits sharply by politics (about 90% of Democrats vs. 41% of Republicans) [19]. High approval has coincided with a surge in interest without yet reversing the density decline.
• Organizing wins at new employers. High-profile drives at Starbucks (11,000+ workers across 500+ stores certified by late 2024), Amazon, Trader Joe's, and REI expanded the frontier into services and tech-adjacent retail [20].
• Bargaining leverage and headline wins. The UAW's 2023 strike at the Detroit Three won raises of at least 25% over roughly four-and-a-half years [21]; the simultaneous 2023 Hollywood strikes by the Writers Guild of America (WGA) and SAG-AFTRA (Screen Actors Guild–American Federation of Television and Radio Artists) ran 148 and 118 days over streaming residuals and AI (artificial intelligence) protections [22]. Visible wins feed organizing demand.
• Workplace disruption. The Bureau of Labor Statistics (BLS) recorded 30 major work stoppages involving 306,800 workers in 2025, with education and health services accounting for 64.0% of workers idled [23] — a signal of both bargaining intensity and where union leverage concentrates.

7. Regulation

Labor law is the industry's operating environment, and it splits by sector:

• National Labor Relations Act (NLRA / Wagner Act, 1935) — the charter of private-sector collective bargaining; created the National Labor Relations Board (NLRB) to run union elections and police unfair labor practices [13]. It does not cover public-sector employees, agricultural or domestic workers, independent contractors, supervisors, or workers under the Railway Labor Act [15].
• Labor Management Relations Act (Taft-Hartley, 1947) — rebalanced toward employers: banned closed shops and secondary boycotts, added an 80-day "cooling-off" period for strikes threatening national health or safety, let employers campaign against unions, and authorized states to pass "right-to-work" laws barring compulsory dues [14]. About half the states — 26 as of 2024 (down from 27 after Michigan repealed its law) — have such laws, where a worker can get the bargained contract without joining or paying dues [15].
• Labor-Management Reporting and Disclosure Act (LMRDA / Landrum-Griffin, 1959) — union-member rights, officer-election standards, and financial transparency; the basis for the LM-2 filings OLMS oversees. OLMS does not have jurisdiction over unions that represent only state, county, or municipal employees [16].
• Railway Labor Act — a separate regime for rail and airlines, administered by the National Mediation Board, with its own strike procedures.
• Public sector — governed by state law (and, for federal workers, the Federal Labor Relations Authority), not the NLRA.
• Tax. IRC 501(c)(5) exempts qualifying labor organizations; germane lobbying is permitted, but political-campaign intervention carries separate tax treatment [6].
• Benefit plans. ERISA governs most union pension and health plans; the Pension Benefit Guaranty Corporation (PBGC) runs the federal guarantee and the special financial-assistance program for troubled multiemployer plans [34].

The most important recent shift: Janus v. AFSCME (2018). A 5–4 Supreme Court ruling held that requiring government workers to pay "agency fees" to a union they don't join violates the First Amendment — effectively imposing right-to-work on the entire public sector [17]. It invalidated agency-fee rules in more than 20 states and pressured the dues base of the very public-sector unions that dominate the movement [17]. Because dues collection often runs through employer payroll "checkoff," what unions may charge and collect is directly a revenue question.

Politically sensitive. NLRB composition swings with the administration; a 2025 change in control is widely expected to slow the organizing surge and unwind pro-union case law from the prior board [18].

8. Competitive dynamics and consolidation

Unions compete — for members, bargaining units, jurisdiction, and political influence — even as they cooperate.

• Consolidation via merger. Long-run membership decline has pushed unions to merge to preserve scale, staff, and strike funds; today's mega-unions (SEIU, UFCW, USW, UNITE HERE) are products of decades of combinations. Concentration is high: a handful of unions hold most members and most assets, with roughly two-thirds of union net assets sitting at the local level [9].
• Inter-union competition and "raiding." Unions vie to represent the same workers; AFL-CIO affiliation rules constrain raiding among members, which is part of the federation's value.
• Federation politics. The 2005 split that created the rival Change to Win coalition (later the Strategic Organizing Center) fractured the movement; SEIU's 2025 return to the AFL-CIO marks a partial reconsolidation [8].
• Barriers to entry are institutional, not price-based — member trust, organizing capability, legal expertise, bargaining history, employer relationships, and control of established benefit-fund networks. National unions also take over troubled locals through trusteeship.
• Consolidation in the service layer. Among Taft-Hartley administrators, private buyers roll up TPAs — BPOC's Zenith/Harbour pursuing add-ons, BeneSys combining with another administrator — while funds outsource pension, health, claims, investment, and communications functions [32][33].
• The structural squeeze. The backdrop is a shrinking private-sector base and a public sector that, post-Janus, must continually re-sign members it once collected from automatically.

9. Risks

• Secular density decline. Private-sector membership at 5.9% is the lowest on record [1]; without a break in the trend, the dues base keeps eroding relative to the workforce.
• Legal and political headwinds. A less union-friendly NLRB, state right-to-work expansion, the ongoing drag from Janus, and even constitutional challenges to the NLRB's structure raised by large employers [15][17][18].
• Strike and operating risk. Stoppages can raise member engagement but reduce dues, disrupt employers, and can erode public support [23].
• Automation and AI. Technology can shrink unionized job classes (autos, logistics, media) — the explicit concern behind the 2023 Hollywood strikes [22].
• Governance and fraud risk. Unions manage member money and must control officers, investments, related parties, and disbursements; scandals (the UAW's federal case last decade being the prominent example) damage member trust and invite tighter oversight [10][16].
• Benefit-fund exposure. Union-linked multiemployer (Taft-Hartley) plans faced insolvency until the American Rescue Plan Act (ARPA) of 2021 created a Special Financial Assistance program — an estimated ~$94 billion federal backstop [34]; underfunding, health-cost inflation, contribution delinquencies, and employer withdrawals remain standing risks for members, trustees, and vendors.
• Proxy mismatch (for the investable names). Public companies may have only a small, undisclosed portion of revenue tied to unions; private service providers may offer limited disclosure, concentrated customer bases, and difficult exits.
• For employer investors: the mirror-image risk is strike disruption, wage inflation, and contract cycles — the UAW and Teamsters have signaled aggressive 2028 bargaining rounds.

10. How to invest and the outlook

Public routes.

• The closest direct security is Amalgamated Financial (AMAL) — a bank whose franchise is serving unions, their members, and progressive institutions; underwrite it as a bank (net interest margin, deposits, credit) with a labor-aligned client base [24].
• Diversified proxies: benefits, retirement, and payroll firms with Taft-Hartley or union-employer exposure (AON, AJG, WTW, ADP, PAYX) — but size the actual union slice, which is usually small [25][26][27][28][29].
• Indirect and more liquid: position around unionized employers, treating labor as a cost and event variable — contract-expiration calendars, strike headlines, and settlement terms are tradable catalysts in autos, logistics, grocery, airlines, and media.

Private routes.

• Union-side capital lives in Taft-Hartley multiemployer pension and benefit funds, ULLICO, and the AFL-CIO Housing Investment Trust — vehicles for labor-affiliated and institutional investors, meaningful limited partners and lenders in real estate and infrastructure [30].
• The service layer is investable through private buyers of benefit-fund administrators and consultants — Segal, Zenith American/Harbour, BeneSys — where diligence should center on recurring per-participant fees, contract retention, fiduciary and cybersecurity controls, claims accuracy, and customer concentration [31][32][33].

Outlook (forward-looking). The tension is unusually stark. On one side, public approval near a 60-year high, a doubling of NLRB election petitions since 2021, and a string of high-profile wins suggest genuine organizing momentum [18][19]. On the other, record-low private density, a hostile federal regulatory turn expected in 2025 and beyond, and the continuing bite of Janus argue for further structural decline [1][17][18]. The most likely path is a two-speed sector: energetic, headline-grabbing organizing at the margin (services, tech-adjacent retail, entertainment) layered on a slowly shrinking aggregate footprint, with public-sector unions and established benefit funds providing stability and the clearest investable cash flows likely to stay in diversified adjacent service providers rather than in unions themselves. Near-term watch items: NLRB composition, state right-to-work and public-bargaining legislation, the 2028 auto and freight contract cycles, PBGC multiemployer-plan developments, major work stoppages, and how AI reshapes the unionized job classes it touches.

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Sources

1. U.S. Bureau of Labor Statistics, "Union Members Summary — 2025," 2026. https://www.bls.gov/news.release/union2.nr0.htm
2. U.S. Census Bureau, County Business Patterns 2023, NAICS 813930 (establishments, employment, payroll); figures per the supplied ground-truth file. https://www.census.gov/programs-surveys/cbp.html
3. U.S. Census Bureau, "County Business Patterns: About and Methodology," 2026 (coverage exclusions). https://www.census.gov/programs-surveys/cbp/technical-documentation/methodology.html
4. U.S. Census Bureau / NAICS, "813930 Labor Unions and Similar Labor Organizations" definition and related 8139 codes, 2022. https://www.census.gov/naics/?details=813930&input=813930&year=2022
5. U.S. Small Business Administration, Table of Small Business Size Standards, 2023 (NAICS 813930). https://www.sba.gov/document/support-table-size-standards
6. Internal Revenue Service, "Labor and Agricultural Organizations" (IRC 501(c)(5)), 2026. https://www.irs.gov/charities-non-profits/other-non-profits/labor-and-agricultural-organizations
7. AFL-CIO, "Our Affiliated Unions," 2026. https://aflcio.org/about-us/our-unions-and-allies/our-affiliated-unions
8. WorldAtlas, "The Largest Labor Unions in the US," 2024; LegalClarity, "Largest Unions in the US: Members, Dues and Rights," 2024. https://www.worldatlas.com/society/the-largest-labor-unions-in-the-us-56536.html · https://legalclarity.org/largest-unions-in-the-us-members-dues-and-rights/
9. Radish Research, "New 2023 Data on Union Membership and Finances" (analysis of DOL OLMS LM-2 filings), 2024. https://radishresearch.substack.com/p/new-2023-data-on-union-membership
10. U.S. DOL OLMS, "Final Rule Modernizing Labor Organization Annual Reports" (Form LM-2 / Long Form), 2026; Institute for the American Worker summary, 2026. https://www.dol.gov/agencies/olms/notice-lm-2-longform-rule · https://i4aw.org/regulation-watch/2026-updated-labor-organization-annual-financial-reports-dol-final-rulemaking/
11. Emergency Workplace Organizing Committee, "Union dues explained," 2024. https://workerorganizing.org/union-dues-explained-16597/
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15. U.S. National Labor Relations Board, "Are You Covered?" and "Union Dues" (right-to-work), 2026. https://www.nlrb.gov/about-nlrb/rights-we-protect/the-law/employees/are-you-covered · https://www.nlrb.gov/about-nlrb/rights-we-protect/the-law/employees/union-dues
16. U.S. Department of Labor, "Labor-Management Reporting and Disclosure Act" (LMRDA), 2023. https://www.dol.gov/agencies/olms/compliance-assistance/fact-sheet/lmrda
17. LegalClarity, "Janus v. AFSCME: A Supreme Court Breakdown," 2024; Manhattan Institute, "The Legal Aftermath of Janus v. AFSCME." https://legalclarity.org/what-is-janus-v-afscme-a-supreme-court-breakdown/
18. The National Law Review, "Not Your Grandparents' Unions: NLRB Sees Large Rise in Organizing Petitions," 2024. https://natlawreview.com/article/not-your-grandparents-unions-nlrb-sees-large-rise-organizing-petitions
19. Gallup, "Labor Union Approval Relatively Steady at 68%," 2025. https://news.gallup.com/poll/694472/labor-union-approval-relatively-steady.aspx
20. NPR, "Amazon, Starbucks worker unions are in limbo, even as UAW and others triumph," 2023. https://www.npr.org/2023/12/26/1219882722/union-amazon-starbucks-contract-worker-rights-uaw-nlrb
21. The Washington Post, "UAW workers ratify new contracts with Big Three automakers," 2023. https://www.washingtonpost.com/business/2023/11/20/uaw-contract-ford-general-motors-stellantis/
22. Wikipedia, "2023 SAG-AFTRA strike," 2023. https://en.wikipedia.org/wiki/2023_SAG-AFTRA_strike
23. U.S. Bureau of Labor Statistics, "30 Major Work Stoppages Began in 2025 and Idled 306,800 Workers," 2026. https://www.bls.gov/opub/ted/2026/30-major-work-stoppages-began-in-2025-and-idled-306800-workers.htm
24. Amalgamated Financial Corp., Form 10-K FY2025, 2026; Wikipedia, "Amalgamated Bank." https://www.sec.gov/Archives/edgar/data/1823608/000182360826000048/amal-20251231.htm · https://en.wikipedia.org/wiki/Amalgamated_Bank
25. Aon plc, "Taft-Hartley Investment Strategy," 2026. https://www.aon.com/en/capabilities/investments/taft-hartley-investment-strategy
26. Arthur J. Gallagher & Co., "Taft-Hartley and Retirement Solutions," 2026. https://www.ajg.com/
27. Willis Towers Watson plc, Form 10-K FY2025, 2026. https://www.sec.gov/Archives/edgar/data/1140536/000119312526069307/wtw-20251231.htm
28. Automatic Data Processing, Inc., Form 10-K FY2025, 2025. https://www.sec.gov/Archives/edgar/data/8670/000000867025000037/adp-20250630.htm
29. Paychex, Inc., Form 10-K FY2025, 2025. https://www.sec.gov/Archives/edgar/data/723531/000095017025095300/payx-20250531.htm
30. Ullico, "Providing Financial Security for Unions and Their Members," 2026. https://www.ullico.com/
31. Segal, "Multiemployer Plan Services," 2026. https://www.segalco.com/consulting-industries/multiemployer-plans/
32. BPOC, "Zenith American Solutions," 2026. https://www.bpoc.com/portfolio/zenith-american-solutions
33. BeneSys, "Taft-Hartley Trust Fund Administration," 2026. https://www.benesys.com/
34. U.S. Pension Benefit Guaranty Corporation, "American Rescue Plan Act of 2021" (Special Financial Assistance program) and ERISA multiemployer guarantee. https://www.pbgc.gov/american-rescue-plan-act-of-2021