Apparel Knitting Mills (NAICS 3151) — a U.S. industry-group primer

1. Overview

Apparel knitting mills are factories that turn yarn directly into finished garments — socks, sweaters, hosiery, T-shirts, underwear, and other knit clothing — usually knitting the fabric and shaping the product in one integrated operation. That sets them apart from the rest of the clothing industry, which mostly buys finished fabric and cuts and sews it. [5][7]

This page covers the 4-digit industry group 3151. In practice it is a pass-through: 3151 contains only one industry, so its story, economics, and investable names are identical to that single child. The short version is a nearly complete offshore migration — domestic U.S. output has shrunk for three decades, and the federal statistics now describe a small surviving remnant rather than the market Americans actually buy from. BLS puts the 2024 decline alone at −11.2% of output and −17.0% of hours worked, on top of a 6.7% average annual output decline across 1987–2024. The ways in for an investor are correspondingly narrow: one large public name (Gildan Activewear), one major private integrated competitor (Fruit of the Loom, inside Berkshire Hathaway), and a long tail of family-owned mills. For the full analysis, read the child primer, 31512. [4][8][11][15]

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

NAICS (the North American Industry Classification System) is a nested code that gets more specific as digits are added. The 4-digit industry group 3151 sits above the 5-digit industry beneath it. Here, 3151 contains exactly one child — 31512, Apparel Knitting Mills — so the two are, for practical purposes, the same thing. Every establishment counted in 3151 is a 31512 establishment; the rollup adds nothing the child does not already contain. [5]

(One level further down, 31512 in turn contains a single 6-digit national industry, 315120, itself the product of a 2022 NAICS revision that merged two older codes — 315110, Hosiery and Sock Mills, and 315190, Other Apparel Knitting Mills. So the whole branch 3151 → 31512 → 315120 collapses to one industry.) [5][6]

For everything specific — scope and exclusions, the investable names, how the economics work, trade policy, and the outlook — read the 31512 primer. The rest of this page gives this level's own ground-truth figures and a short orientation.

3. Size (this level's rollup figures)

Our ingested ground-truth federal statistics for NAICS 3151:

Because 3151 equals its single child, these are the same figures reported for 31512. Together they describe a universe of roughly 180–220 mostly small firms doing about $1.2 billion of domestic sales and about $651 million of value added — a modestly concentrated industry where a top-50 that holds 82.5% of receipts means a handful of mid-size mills do most of the domestic work. [1][2][3]

The head counts disagree, and both point the same way. County Business Patterns records ~7,656 workers in 2023; the BLS industry productivity series implies roughly 6,100 in 2024. The gap is vintage and method, not contradiction — BLS is a year later and measures a shrinking base, with hours worked down 17.0% in 2024 alone. Treat ~6,000–7,700 as the honest range and the trend line as the real signal. [1][4]

Undercount caveat — the opposite of the usual one. This is not a case of tiny operators slipping past the survey. It is the reverse: the ~$1.2 billion of domestic mill output is a small slice of what Americans actually spend on knit apparel, because the market is served overwhelmingly by imports and by U.S. brands producing offshore. Knit socks and hosiery imports alone ran about $2.63 billion in 2024 — more than double total domestic knitting-mill receipts — total U.S. apparel imports were $79.3 billion in 2023, and only an estimated ~2.5% of apparel bought in the U.S. is domestically produced. The industry's footprint as consumers experience it is far larger than these domestic figures; most of that value is simply offshore. [9][10][8]

4. Investable universe (where value concentrates)

Because this level equals its one child, the investable picture is the child's picture. There is no pure-play, U.S.-domestic apparel-knitting-mill public stock. Value concentrates at three points, only one of which you can buy:

• One scaled public name. The practical large-cap way in is Gildan Activewear (NYSE/TSX: GIL), a vertically integrated knitter of tees, fleece, underwear, and socks — FY2025 net sales of $3.62 billion, ~21.5% adjusted operating margin, market cap ~$9.4 billion — which in December 2025 acquired HanesBrands and roughly doubled its size, but knits mostly offshore (Central America/Caribbean, Bangladesh). [11][12][13]
• One major private integrated player, not separately investable. Fruit of the Loom is a wholly owned Berkshire Hathaway subsidiary that manufactures 89% of its products in its own global facilities, with North American cloth production primarily in Honduras — the same offshore-integrated model, wrapped inside a conglomerate. [15]
• A private domestic remnant. The genuinely U.S.-located mills are almost all private and family-owned — legwear/sock makers concentrated in North Carolina and Alabama (e.g., Renfro, ~$540M revenue) and performance/military niche makers (e.g., Darn Tough, ~$50M+ revenue). [16][17][25]

Full names, tickers, and scale are in the 31512 primer. [2]

5. How the money works

This is a capacity-utilization and input-cost business, like other commodity manufacturing — not a fee-income or same-store-sales business. Owners earn the spread between what a garment sells for and the cost to convert yarn into it. Yarn (cotton, polyester and nylon, wool, spandex) is the dominant cost, so margins move with commodity cycles, and large integrated players may hedge input prices 12–24 months forward; labor is the next-largest line, with Census data putting annual payroll at roughly 26% of sales before benefits and non-payroll costs. Keeping capital-intensive knitting machines full is what turns thin gross margins into profit, and vertical integration (spin–knit–finish–sew, the Gildan model) captures more of the margin. [8][14]

There are two ways to win — global commodity scale at rock-bottom cost, which in practice means offshore production given roughly $15–$20/hour U.S. labor against under $1/hour in Bangladesh, or protected/premium niches (military, medical compression, performance wool, quick-turn private label). Demand also arrives in a seasonal shape — Q2 T-shirts, fall/winter fleece, back-to-school and holiday hosiery. See 31512 for the full mechanics. [8][14][20]

6. Demand drivers

• Overall clothing spending, which tracks consumer income and confidence; basics like socks and underwear are staples, so demand is less cyclical than fashion. [7]
• Fashion and activity trends — the athleisure and performance-sock boom lifted premium knit categories. [7]
• Import competition and the dollar — now the single biggest swing factor for domestic mills. [8]
• Government procurement — the military must buy domestic, a guaranteed niche. [21]
• Fiber substitution — cotton competes with synthetics on price, performance, and durability, and the underlying fiber market is mature rather than growing: USDA put 2025 U.S. apparent retail cotton use at 8.3 billion raw-fiber-equivalent pounds, roughly flat. [24]

7. Regulation

Trade policy is the regulatory story, and 2025 was a turning point:

• De minimis repeal (2025). The long-standing rule letting parcels under $800 enter duty-free (Section 321 of the Tariff Act) was eliminated for Chinese-origin goods in May 2025 — the biggest policy tailwind for domestic mills in years. [19]
• "Yarn-forward" rules of origin. Under USMCA (the U.S.–Mexico–Canada Agreement) and CAFTA-DR (the Central America–Dominican Republic Free Trade Agreement), knit apparel gets duty-free access only if spinning, knitting, and assembly all happen inside the bloc — which is why so much U.S.-brand knitting sits in Central America. [20]
• Berry Amendment. The Department of Defense must buy U.S.-grown-and-produced clothing, yarn, and footwear, including socks — a price-insulated domestic niche. [21]
• Labor compliance. DOL enforces minimum wage, overtime, and recordkeeping for garment workers; a Southern California survey found FLSA violations in 80% of investigations, though that survey covered the wider garment-contractor sector rather than knitting mills specifically. [22]
• Environmental. Wet finishing carries wastewater and energy exposure; EPA textile-mill effluent guidelines regulate pollutants, and EPA is studying PFAS use in textile mills — a live source of future obligations. [23]
• Labeling/safety (FTC, CPSC) and forced-labor screening (the Uyghur Forced Labor Prevention Act, UFLPA) also apply.

8. Consolidation

The domestic data looks fragmented (HHI 273.8; CR4 24.3%), but the brands selling knit apparel into the U.S. are consolidating fast and mostly produce offshore. The defining event is Gildan's December 2025 acquisition of HanesBrands (~$2.2 billion equity / ~$4.4 billion enterprise value, ~$200 million targeted synergies), which created a dominant vertically integrated activewear-and-innerwear player. Domestically the pattern is ownership change rather than scale-building — Renfro was acquired by The Renco Group in 2021 — while the commodity-blanks segment keeps failing outright, with Delta Apparel bankrupt in 2024. The survivors' playbook is niche: military, medical compression, performance wool, quick-turn private label. [12][16][18][2]

9. Risks

• Structural import competition — the offshore cost gap is permanent barring policy intervention; commodity domestic knitting keeps shrinking. [8]
• Trade-policy whiplash — tariffs and the de minimis repeal help domestic mills but raise import costs, and policy can reverse. [19]
• Input-cost volatility — cotton and oil-linked synthetic prices swing margins directly. [7]
• Customer concentration — losing one mass-retailer program can sink a mill. [7]
• Demand cyclicality and destocking — retail inventory corrections hit order volumes even for staples. [7]
• Capital intensity and labor scarcity — automation demands ongoing capex, and skilled machine technicians, programmers, and linking operators are scarce and getting costlier. [8]
• Buyer consolidation — fewer, larger brand customers means less pricing power for independent knitters. [12]
• Environmental and compliance exposure — wet finishing faces EPA effluent rules and potential PFAS obligations; labor compliance is material wherever contract sewing sits in the chain. [22][23]

10. How to invest, and the outlook

Public route. The practical large-cap way in is Gildan (GIL) — a scaled, low-cost, vertically integrated basics manufacturer that returns cash via dividends and buybacks. Understand what you are buying: Gildan is a play on low-cost, offshore, vertically integrated commodity knitting and brand distribution, not on U.S. domestic mills. [11][12]

Private route. Because the domestic industry is almost all private, the real domestic plays are direct — buying or backing a family-owned mill (many face succession questions, a classic small-cap/private-equity roll-up opening), supplying protected niches (Berry-compliant military, medical compression, performance/outdoor), or direct-to-consumer sock/underwear brands (though most of those outsource the actual knitting). The diligence variables that matter are customer concentration, machine age and utilization, operator retention, yarn-price pass-through, and environmental obligations. [17][25]

Outlook (forward-looking judgment). The multi-decade decline of commodity U.S. knitting is unlikely to reverse — the BLS series shows no inflection, only a steepening — but 2025 delivered the strongest policy tailwind in a generation (de minimis repeal plus higher China tariffs). Industry insiders caution it will take "more than tariffs" to reshore volume, given thin domestic spinning, knitting, capex, and labor. The most durable value sits where it already is: global low-cost scale (Gildan) at one end and legally or functionally protected domestic niches (military, medical, performance) at the other, with the undifferentiated middle continuing to erode. For the full analysis, see the 31512 primer. [19][8][4][12]

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Sources

1. U.S. Census Bureau. County Business Patterns (CBP) 2023, NAICS 315120 — establishments, employment, payroll. 2023. https://www.census.gov/programs-surveys/cbp.html
2. U.S. Census Bureau. 2022 Economic Census — receipts, firms, and concentration ratios (CR4/CR8/CR20/CR50, HHI), NAICS 3151 / 31512 / 315120. 2022. https://www.census.gov/programs-surveys/economic-census.html
3. Federal Reserve. G.17 Industrial Production — value added by industry, apparel knitting mills ($651M, 2022). 2022. https://www.federalreserve.gov/releases/g17/SandDesc/table1.17.htm
4. U.S. Bureau of Labor Statistics. Productivity and Costs by Industry — apparel knitting output, hours, and productivity trends (2024; 1987–2024 series). April 2025. https://www.bls.gov/news.release/archives/prin_04242025.htm
5. NAICS Association / Livesight. 2022 NAICS updates — consolidation of 315110 (Hosiery and Sock Mills) and 315190 (Other Apparel Knitting Mills) into 315120 (Apparel Knitting Mills). 2022. https://www.naics.com/naics-code-description/?v=2022&code=315120
6. Federal Register. North American Industry Classification System (NAICS) Updates for 2022 — merger of 315110 and 315190 into 315120. 2021. https://thefederalregister.org/documents/2021-14249/north-american-industry-classification-system-naics-updates-for-2022-update-of-statistical-policy-directive-no-8-standar
7. IBISWorld. Apparel Knitting Mills in the US — Industry Analysis (market size ~$945m, ~161 businesses, −3.3% CAGR 2020–2025). 2025. https://www.ibisworld.com/united-states/industry/apparel-knitting-mills/2034/
8. Sheng Lu (FASH455, University of Delaware) / U.S. Fashion Industry Association. State of U.S. Textile and Apparel Manufacturing, Employment and Trade. April 2025. https://shenglufashion.com/2025/04/07/state-of-u-s-textile-and-apparel-manufacturing-employment-and-trade-updated-april-2025/
9. Observatory of Economic Complexity (OEC) / IndexBox. Knit Socks and Hosiery (HS 6115) trade — U.S. imports ~$2.63B in 2024; China ~$1.09B. 2024. https://oec.world/en/profile/hs/knit-socks-and-hosiery
10. U.S. International Trade Commission. Apparel Competitiveness — U.S. apparel imports $79.3B in 2023; China and Vietnam ~40%. 2024. https://www.usitc.gov/publications/332/pub5543_0.pdf
11. Finviz / Yahoo Finance / SEC (Form 6-K). Gildan Activewear FY2025 results — record revenue ~$3.6B, adj. operating margin ~21.5%. 2026. https://finance.yahoo.com/news/gildan-activewear-gil-achieves-record-072420754.html
12. Apparelist / BNN Bloomberg / SEC. Gildan Announces Completion of HanesBrands Acquisition (Dec 1, 2025) — ~$2.2B equity / ~$4.4B enterprise value, ~$200M synergies. 2025. https://www.apparelist.com/2025/12/02/gildan-announces-completion-of-hanesbrands-acquisition/
13. Macrotrends. Gildan Activewear (GIL) Market Cap — ~$9.4B (2026). 2026. https://www.macrotrends.net/stocks/charts/GIL/gildan-activewear/market-cap
14. Gildan Activewear. 2025 SEC-filed annual report (MD&A) — net sales breakdown, cost structure, commodity hedging, seasonality. 2026. https://www.sec.gov/Archives/edgar/data/1061894/000106189426000006/exhibit991-mdax2025.htm
15. Fruit of the Loom / Berkshire Hathaway. Fruit of the Loom company profile (89% self-manufactured); Berkshire Hathaway 2024 Form 10-K (Honduras cloth manufacturing). 2024–2025. https://www.fotlinc.com/our-company/
16. PR Newswire / ZoomInfo. Renfro Brands acquired by The Renco Group (2021); ~$540M revenue legwear maker. 2021. https://www.prnewswire.com/news-releases/worlds-most-renowned-sock-manufacturing-company-renfro-brands-acquired-by-the-renco-group-301308934.html
17. Merino Wool Gear / ZoomInfo. Darn Tough (Cabot Hosiery Mills) company profile — ~$50M+ revenue, 5M+ pairs/yr, Northfield, VT. 2025. https://merinowoolgear.com/darn-tough-company-profile/
18. Yahoo Finance / Bloomberg Law. Delta Apparel Files for Chapter 11 Bankruptcy (June 30, 2024); Salt Life sold for $28M. 2024. https://finance.yahoo.com/news/delta-apparel-files-bankruptcy-warns-203240207.html
19. Congressional Research Service (Congress.gov, R48380) / Fortune. Imports and the Section 321 (De Minimis) Exemption; elimination for Chinese-origin goods, May 2025. 2025. https://www.congress.gov/crs-product/R48380
20. U.S. Department of Commerce (trade.gov) / U.S. Trade Representative. CAFTA-DR and USMCA textile "yarn-forward" rules of origin. 2024. https://www.trade.gov/summary-cafta-fta-textiles
21. U.S. Department of Commerce (trade.gov) / U.S. Department of Defense. The Berry Amendment (10 U.S.C. §4862) — domestic sourcing of clothing, fiber, yarn, and footwear including socks. 2024. https://www.trade.gov/berry-amendment
22. U.S. Department of Labor. Garment industry compliance toolkit; Southern California garment survey (FLSA violations). 2023. https://www.dol.gov/newsroom/releases/whd/whd20230322-0
23. U.S. Environmental Protection Agency. Textile Mills Effluent Guidelines — pollutant regulations and PFAS study. 2024. https://www.epa.gov/eg/textile-mills-effluent-guidelines
24. U.S. Department of Agriculture. Cotton and Wool Outlook — U.S. apparent retail cotton use 8.3B lbs in 2025. March 2026. https://www.ers.usda.gov/sites/default/files/_laserfiche/outlooks/113948/CWS-26c.pdf
25. Encyclopedia of Alabama / Wikipedia. Fort Payne, Alabama — "Sock Capital of the World"; W. B. Davis Hosiery Mill. 2024. https://encyclopediaofalabama.org/article/fort-payne/