Deep Sea, Coastal, and Great Lakes Water Transportation (U.S.) — NAICS 4831

A short rollup primer for a general investing audience — relevant to both public-market and private investors. This is an industry group that contains exactly one child industry, so it is effectively identical to that child; this page gives the level's own federal figures and points you to the full 48311 primer for detail. NAICS = North American Industry Classification System, the U.S. government's standard code for grouping businesses by activity. Federal figures are reported facts with citations; forward-looking statements are worded as judgments.

1. Overview

NAICS 4831 is the federal industry group covering the businesses that run large ships on oceans and the Great Lakes — the seagoing (and lake-going) end of water transportation, as distinct from river-and-canal barge traffic, which sits in a separate group (NAICS 4832). In plain terms, it is the deep-water and Great Lakes fleet that moves both cargo and people, on both international and domestic routes.[4]

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

In the NAICS hierarchy, the four-digit industry group 4831 contains a single five-digit industry: 48311 (Deep Sea, Coastal, and Great Lakes Water Transportation). Because there is only one child, 4831 and 48311 are the same population of businesses — the group is a pass-through wrapper, and every federal figure at this level equals the figure at 48311.

The real internal structure lives one level further down, inside 48311, which splits into four national industries along two distinctions — freight versus passenger and international versus domestic:

Those four are genuinely different businesses — different owners, economics, regulators, and ways in for an investor. All of that detail lives in the 48311 primer; read it for the full picture. This page stays at the rollup level.

3. How big it is (this level's rollup figures)

These are the U.S. Census Bureau / Small Business Administration (SBA) ground-truth figures for NAICS 4831, and — because the group equals its one child — they are identical to 48311. Receipts and concentration are from the 2022 Economic Census; employment, establishments and payroll are from 2023 County Business Patterns (CBP).

(CR4 = share of receipts held by the four largest firms; HHI = a standard concentration index; SBA = U.S. Small Business Administration.) Average U.S. payroll runs roughly $117,000 per employee[1] — these are unionized, licensed merchant mariners and skilled shore staff, not low-wage labor.

The undercount caveat — read this before trusting $43.95 billion. This figure captures only the U.S. employer establishments classified here, and it understates the real economic weight of the sector in four compounding ways: (1) the foreign lines that move most U.S. container trade (Maersk, MSC, CMA CGM, Hapag-Lloyd, COSCO) book their revenue abroad;[10] (2) U.S.-listed tanker, bulk, gas and cruise owners run their ships through foreign-flag subsidiaries — Carnival Corporation alone booked $26.6 billion in fiscal 2025, more than half the entire U.S. rollup, yet only its U.S. footprint lands here;[12] (3) governments are excluded entirely, so the public ferry authorities that carry roughly 105.8 million passengers a year are invisible to business statistics;[14] and (4) CBP omits nonemployer firms and the self-employed. So $43.95 billion is best read as the U.S. corporate-and-operating footprint of a sector whose true weight — global freight flows, global cruise revenue, public ferry ridership — is many times larger. The federal file reports no fleet size, freight or fare rates, fuel cost, or volumes.

4. Investable universe — where value concentrates

Because the level equals 48311, the map is the same: public-market value concentrates in ocean cruise (483112), the largest child by revenue and the deepest listed pool in the sector — Carnival (NYSE: CCL/CUK), Royal Caribbean (NYSE: RCL), Norwegian Cruise Line Holdings (NYSE: NCLH), Viking (NYSE: VIK) and Lindblad (Nasdaq: LIND).[12][13] Everywhere else, listed access is thin, partial or absent: international freight (483111) is a set of foreign-flagged tanker and bulk cyclicals plus foreign-listed liners; domestic Jones Act freight (483113) has essentially one large listed name, Matson (NYSE: MATX), with the marquee operators (Crowley, Saltchuk/TOTE, Pasha, Interlake) private; and domestic passenger (483114) has no U.S.-listed pure-play because its biggest carriers are governments. The through-line: value clusters where the customer is discretionary and global (cruise) or where the asset is scarce and protected (Jones Act tonnage). See the 48311 primer for the full ticker-by-ticker breakdown.

5. How the money works

All of these are capital-intensive businesses that own or finance long-lived, expensive vessels and earn a spread over the cost of running them — but the earnings engine differs by child. International freight lives on charter rates and vessel asset-trading, measured in Time Charter Equivalent (TCE, daily earnings net of voyage costs). Ocean cruise earns a net yield per berth-day (revenue per available bed) over cost per berth-day, on a debt-financed fleet, with pre-paid deposits as float. Domestic freight earns utilization × rate on scarce, protected hulls whose U.S.-build requirement is both a cost burden and a moat. Domestic ferries chase cost recovery, not profit — the key gauge is the farebox recovery ratio (share of operating cost covered by fares). Across all four, the discipline is to reconcile headline EBITDA (earnings before interest, taxes, depreciation and amortization) back to cash flow after maintenance capital spending and drydock, and to judge names on through-cycle cash flow. Full detail is in the 48311 primer.

6. Demand drivers

The children rarely peak together. Global trade and ton-miles (cargo × distance) drive international freight — longer routes soak up capacity. Discretionary travel and demographics drive ocean cruise — a record 37.2 million passengers sailed globally in 2025, with supply capped by shipyard throughput.[15] Non-contiguous economies (Hawaii, Alaska, Guam, Puerto Rico import nearly everything by sea) and commodity cycles drive domestic freight. Essential ridership plus a tourism upcycle drive domestic passenger. The shared driver and shared risk is the fleet supply side: in every child, a demand boom met by a wave of newbuilds still crushes returns.

7. Regulation

One of the most heavily regulated corners of the economy. Cabotage law defines the domestic children: the Jones Act (Merchant Marine Act of 1920) reserves domestic cargo for U.S.-built, -flagged, -owned and -crewed ships, and the Passenger Vessel Services Act of 1886 (PVSA) does the same for domestic passengers.[6][7] International liner freight answers to the Federal Maritime Commission (FMC); cruise leans on the Section 883 tax exemption for foreign-operated ships. Binding the whole level, the International Maritime Organization (IMO) sets global safety and pollution standards, and its tightening carbon rules (a 2050 net-zero target) are the defining forward cost driver, alongside U.S. Coast Guard (USCG) certification and Maritime Administration (MARAD) support programs. Decarbonization is the one theme that hits all four children at once, forcing expensive fleet renewal that larger operators are better placed to fund.[5][14]

8. Consolidation

The level's blended concentration figures — HHI 1,081.5, CR4 56.4%[2] — sit in the "moderately concentrated" range under the 2023 federal merger guidelines, but they are a misleading average across four unlike markets: ocean cruise is a completed global oligopoly (child CR4 ~98%), international freight is a container-liner oligopoly beside a fragmented tanker/bulk sector, domestic freight is unconcentrated nationally but tight lane-by-lane, and domestic passenger is a concentrated revenue head over a long tail of small local operators.[10][12] Because there is only one child at this level, that averaging happens entirely inside 48311 — see its primer for the child-by-child split.

9. Risks

The headline risks are cyclicality and overcapacity (freight rates and cruise yields fall hard when newbuilds outrun demand; ferries are the steady exception); balance-sheet leverage (vessels are debt-financed sector-wide); fuel and decarbonization capex; policy risk (the Jones Act, PVSA and Section 883 tax exemption each underpin a child's economics, and erosion of any would reprice that business — two-edged for incumbents); geopolitics and chokepoints (Red Sea / Panama Canal disruptions); government-budget and grant dependence (domestic passenger); fleet aging, shipyard scarcity and crew shortages; and undercount and private-market opacity — much of the real activity is foreign-flagged, privately held or governmental, so disclosure is thin and valuation harder than in most industries.

10. How to invest & outlook

There is no single "shipping" trade here — match the route to the child (all four are detailed in the 48311 primer): ocean cruise (483112) for the deepest public access, international freight (483111) for cyclical tanker/bulk/liner trades, domestic freight (483113) for the Matson franchise plus private tonnage, and domestic passenger (483114) via only diluted slivers, private ferry/small-cruise ownership, municipal bonds, or the shipyards building the renewal wave. Cross-cutting discipline: compare names on normalized, through-cycle cash flow (enterprise value to normalized EBITDA, free-cash-flow yield, net asset value, fleet age, orderbook growth) — dividend yields and price multiples are unreliable when freight rates or cruise yields are unusually high or low.

Outlook (forward-looking judgment). The children are not aligned: ocean cruise enters 2026 with the strongest setup (record demand, disciplined shipyard-capped supply), tempered by leverage and Section 883 tax risk; coastal freight splits between tight coastal tankers and soft Great Lakes bulk; international freight stays cyclical, currently reroute-supported and watching proposed U.S.-flag revival legislation (the SHIPS for America Act);[13] domestic passenger faces real demand throttled by shipyard capacity, mariner shortages and strained public budgets.

Bottom line. NAICS 4831 is a single-child pass-through of 48311 — strategically indispensable as the physical backbone of U.S. trade, tourism and island life, but really four different investments wearing one code. For the full analysis — child economics, tickers, concentration by segment, and the case-by-case investment map — read the 48311 primer. Pick the child before you pick the trade.

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Sources

1. U.S. Census Bureau. County Business Patterns (NAICS 4831 / 48311 and children), 2023 — establishments, employment, payroll (and nonemployer/coverage caveat). https://www.census.gov/programs-surveys/cbp.html
2. U.S. Census Bureau. 2022 Economic Census — Concentration of Largest Firms (NAICS 4831 / 48311) — receipts, firm count, CR4/CR8/CR20/CR50, HHI. https://data.census.gov/table/ECNSIZE2022.EC2200SIZECONCEN
3. U.S. Small Business Administration. Table of Small Business Size Standards (NAICS 4831 series), 2023. https://www.sba.gov/document/support-table-size-standards
4. U.S. Census Bureau / NAICS. NAICS 4831 / 48311 Deep Sea, Coastal, and Great Lakes Water Transportation — definition and child boundaries, 2022. https://www.census.gov/naics/?details=4831&year=2022
5. UN Trade and Development (UNCTAD). Review of Maritime Transport 2024/2025 — seaborne share of trade, ton-miles, fuel transition, IMO carbon strategy. https://unctad.org/publication/review-maritime-transport-2025
6. U.S. Customs and Border Protection. The Jones Act & The Passenger Vessel Services Act (PVSA; 46 U.S.C. §55103). https://www.help.cbp.gov/s/article/Article-1004?language=en_US
7. Congressional Research Service. Shipping Under the Jones Act: Legislative and Regulatory Background, R45725. https://www.congress.gov/crs-product/R45725
8. Container News / InvestSnips. Shipping alliances and MSC control over 80% of container market, 2025; publicly traded tanker & dry-bulk companies and flags of registry. https://container-news.com/shipping-alliances-msc-global-market-share-2025/
9. Carnival Corporation & plc / Royal Caribbean Group / Norwegian Cruise Line Holdings / MSC Group. FY2025 results and 10-Ks; cruise-line ownership guide (Carnival FY2025 revenue $26.6B; concentration; foreign incorporation; Section 883; shipyard cap). https://www.prnewswire.com/news-releases/carnival-corporation--plc-achieves-record-full-year-adjusted-net-income-and-investment-grade-leverage-metrics-reinstates-dividend-302646558.html
10. Company investor filings — International Seaways, Scorpio Tankers, Frontline, Star Bulk, Genco, Dorian LPG, Global Ship Lease, Kirby, Algoma Central, Viking, Lindblad, Matson. https://www.sec.gov/cgi-bin/browse-edgar
11. U.S. Bureau of Transportation Statistics. National Census of Ferry Operators (≈105.8M ferry passengers); CLIA/American Cruise Lines/Great Lakes cruise sources. https://www.bts.gov/ncfo
12. Cruise Lines International Association (CLIA). State of the Cruise Industry Report 2026 (37.2M passengers; economic impact; demographics). https://cruising.org/resources/state-cruise-industry-report-2026
13. U.S. Congress. SHIPS for America Act of 2025 (S.1541); Strategic Commercial Fleet. https://www.congress.gov/bill/119th-congress/senate-bill/1541/text
14. International Maritime Organization. EEXI, CII and 2023 Greenhouse Gas Strategy; SOLAS/MARPOL. https://www.imo.org/en/mediacentre/hottopics/pages/eexi-cii-faq.aspx
15. U.S. DOT Maritime Administration (MARAD). U.S.-Flag Fleet Dashboard; Maritime Security Program; Title XI. https://www.maritime.dot.gov/data-reports/us-flag-fleet-dashboard