Deep Sea Mining Companies: Who Is Listed and Who Is Not

Deep sea mining companies at a glance

Only a handful of the firms linked to seabed mining have a ticker. As of 26 October 2026, the listed names are The Metals Company (Nasdaq: TMC), Odyssey Marine Exploration (Nasdaq: OMEX, which is merging into American Ocean Minerals), The Metals Royalty Company (Nasdaq: TMCR) and the small-cap Deep Sea Minerals Corp. (CSE: SEAS). The other 17 or so holders of United Nations exploration contracts are governments, state-backed bodies, private firms or units of a larger company, such as Belgium’s DEME Group (Euronext Brussels: DEME). The International Seabed Authority (ISA) lists 19 polymetallic nodule contracts in total.

This page sorts the names into three groups: companies you can trade, companies you can only reach through a parent, and bodies with no shares at all. Every status carries a date, because a deal can close, a permit can arrive or a contract can lapse within weeks. It is a fact sheet, not advice: no price targets and no buy or sell views.

How we chose, and what counts as a deep sea mining company

The term covers three deposit types: polymetallic nodules (potato-sized rocks on the abyssal plain that carry nickel, copper, cobalt and manganese), cobalt-rich crusts on seamounts, and seafloor massive sulphides near hot vents. Nodules are what nearly every company below is chasing. The ISA, the UN body that grants exploration rights in international waters, publishes who holds them.

The ranking metric here is simple and checkable: which names hold an ISA nodule contract or a US application, and which of those you can trade. A company is listed if it appears on the ISA register, in an SEC or exchange filing, or in a company release we opened for this update. A name is left out if we found no filing that ties it to seabed minerals. Seabed explorers keep appearing, so treat the table as a dated snapshot and re-check the sources at the end of the page.

The Metals Company (TMC): the listed nodule developer

TMC began life as DeepGreen Metals and listed on Nasdaq in 2021 through a merger with a special-purpose acquisition company. Its subsidiaries Nauru Ocean Resources Inc. (NORI) and Tonga Offshore Mining Limited (TOML) hold ISA exploration contracts signed on 22 July 2011 and 11 January 2012 in the Clarion-Clipperton Zone, the nodule belt between Hawaii and Mexico. TMC has also run a pilot test: in 2022 its partner Allseas lifted about 3,000 tonnes of nodules up a 4.3 km riser at a sustained 86.4 tonnes an hour (Offshore Engineer, November 2022).

The US permit path through NOAA

Because the United States is not a party to the UN Convention on the Law of the Sea, TMC USA applies to the National Oceanic and Atmospheric Administration (NOAA) under the Deep Seabed Hard Mineral Resources Act of 1980. NOAA describes the TMC USA consolidated application as the first-ever commercial recovery application of its kind. On 19 August 2026 NOAA said the application met the information requirements, opened a 60-day comment period that closed on 19 October 2026 and set a public hearing for 13 October 2026. Both dates have passed, and we found no certification decision as of 26 October 2026. If NOAA certifies it, an environmental impact statement follows. That is a step toward a decision, not a granted permit.

TMC’s own project page splits the work into two areas (TMC USA projects, accessed October 2026). USA-A covers 65,160 km² and an estimated 619 million tonnes of nodules; the company’s August 2025 pre-feasibility study declared a reserve of 51 million tonnes for part of it. USA-B is an exploration licence application over 121,830 km² and an estimated 1.02 billion tonnes. NOAA certified USA-B in May 2026, and on 17 August 2026 it published a notice of intent to prepare an environmental impact statement for it (TMC release filed with the SEC, 17 August 2026). The release notes that the Act sets no statutory deadline for NOAA.

When TMC filed in April 2025 it quoted resources of 1,635 million wet tonnes across its two exploration areas, holding about 15.5 million tonnes of nickel, 12.8 million tonnes of copper, 2.0 million tonnes of cobalt and 345 million tonnes of manganese (TMC release filed with the SEC, 29 April 2025). The areas have since been redrawn (199,895 km² then, 187,017 km² now), and the two current figures, 619 plus 1,020 million tonnes, add up to about the same total. These are company resource estimates, not reserves.

The ISA path and the dispute

TMC runs both tracks at once, and the ISA objects. In July 2025 the ISA opened an inquiry into whether NORI and TOML still comply with their contracts. In May 2026 the two firms took the ISA to the Seabed Disputes Chamber of the International Tribunal for the Law of the Sea. The Chamber’s orders of 18 July 2026 let the inquiry continue but required the ISA to follow due process (Mongabay, 29 July 2026). The ISA Council nonetheless extended the NORI contract by five years in July 2026, with a statement that the approval does not prejudice the inquiry (Ocean Vision Legal, July 2026).

Results and share price

TMC reported a second-quarter 2026 loss of $0.14 per share on 13 August 2026. Its chief executive said he expected the US permit well ahead of offshore vessel commissioning, which the company places at the end of 2027 (Motley Fool, 3 September 2026). The same page’s quote box showed an intraday range of $2.39 to $2.48, a market capitalisation of about $1.07 billion on listed shares and a 52-week range of $2.39 to $10.05, while its text put the shares at about $2.65 (page dated 25 October 2026). Prices move daily; check a live quote. Shares are volatile, the company is pre-revenue, and nothing here is a view on whether they will rise or fall.

Odyssey Marine Exploration and American Ocean Minerals

Odyssey Marine Exploration (Nasdaq: OMEX) signed a merger agreement with American Ocean Minerals Corporation (AOM) on 8 April 2026. The Northern Miner describes it as an all-stock reverse takeover creating a company worth roughly $1 billion, with more than $150 million of private placement financing (The Northern Miner, April 2026). A reverse takeover means the private company’s holders end up owning most of the listed shell.

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Who would own the combined company after closing

Expected share of American Ocean Minerals Corporation, %, if all exchange shares are issued

The proxy prospectus filed with the SEC sets the dates and terms: a virtual Odyssey shareholder meeting on 2 December 2026, a record date of 16 October 2026, and closing promptly afterwards if conditions are met. Each AOM share converts into 4.5017 Odyssey shares, after a planned 25-for-1 reverse split. The combined company would be renamed American Ocean Minerals Corporation and trade as Nasdaq: AOMC. Either party may extend the 8 December 2026 outside date by 30 days. Expected ownership after closing is shown below, assuming all exchange shares are issued (Odyssey Marine Exploration prospectus, October 2026).

Part of the value rests on Cook Islands exploration licence areas held by CIC Limited and OML, whose holders would receive 14.5% of the combined company. Their worth depends on regulatory milestones under the Cook Islands regime, so the stock carries both a merger risk and a licensing risk until the deal closes.

Royalty and small-cap names

The Metals Royalty Company (Nasdaq: TMCR) began trading on 8 April 2026. It holds a 2.00% gross overriding royalty on NORI, which would pay a share of revenue if NORI ever sells nodules, and it bought a 1.0% royalty on iron ore pellets from Nashwauk, Minnesota, for $132.5 million on 1 June 2026. At 30 June 2026 it had $11.8 million of cash and $44.6 million drawn on a term loan, and it reported no royalty revenue from NORI (Metals Royalty Company management discussion, 10 August 2026). It is a way to hold exposure to TMC’s NORI area without owning TMC, but the royalty pays nothing until nodules are sold.

Deep Sea Minerals Corp. (CSE: SEAS; OTCQB: DSEAF) is an exploration-stage seabed company that is still pursuing licences. On 6 July 2026 it signed a memorandum of understanding with Impossible Metals, a US marine technology company, to evaluate its robotic collector in prospective licence areas “if and as” licences are awarded (company release, 6 July 2026). An MOU is a framework, not a contract.

In Norway, the government agreed in December 2025 to rule out deep sea licences in Arctic waters until at least the end of 2029 (Marine Technology News, 4 December 2025).

Nautilus Minerals: the cautionary predecessor

Nautilus Minerals tried to mine copper and gold from sulphides in the Bismarck Sea off Papua New Guinea (project Solwara 1), not nodules. It filed for creditor protection in Canada in February 2019, and creditors were allowed to liquidate it in August 2019, leaving Papua New Guinea with a large debt (MINING.COM, 26 November 2019). Investors now ask how a seabed project is funded through first commercial output, not only through a pilot.

The contractors you cannot buy directly

Most holders of seabed rights have no stock. The ISA register lists 19 polymetallic nodule contracts: 17 in the Clarion-Clipperton Zone, one in the western Pacific and one in a separate ocean basin. China is the sponsor or home state of three of them, and UK Seabed Resources holds two. The table gives each contractor, its sponsoring state and the dates shown on the ISA page when we opened it on 26 October 2026. Eight contracts (including DORD, ending 19 June 2026) show end dates between March and July 2026. The ISA page lists those as the latest end dates and shows no further extension for them, except NORI, whose five-year extension the Council granted in July 2026. Check the ISA page for later decisions.

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ISA nodule contracts signed, cumulative

Number of contracts in force on the ISA register by year signed

Source: ISA, polymetallic nodule contractors, opened 26 October 2026.

DORD and Japan

Deep Ocean Resources Development Co., Ltd. (DORD) is a Japanese company that holds Japan’s nodule contract in the Clarion-Clipperton Zone, signed on 20 June 2001. It has no ticker. In March 2026 it signed a memorandum with GSR for a joint demonstration test aimed at possible co-development of nodule resources inside DORD’s licence area, with GSR supplying technical and operational expertise (DEME, 30 March 2026). The announcement gives no schedule.

GSR and DEME Group

Global Sea Mineral Resources NV (GSR) is the deep-sea exploration division of DEME Group NV, which trades on Euronext Brussels under the ticker DEME (DEME, GSR page). GSR has no share price of its own: buying DEME buys the whole dredging and offshore-energy business. In 2021 GSR tested its Patania II prototype collector in 4,500 m of water in the Clarion-Clipperton Zone with 29 European institutes monitoring the trial (Baird Maritime, May 2021). DEME said then that GSR would apply for a mining contract only if the science shows the seabed can be a responsible source of metals.

How big is the marine mining market, really

Estimates for the same market differ by a factor of five. Fortune Business Insights puts the 2025 market at $4.6 billion, rising to $6.18 billion in 2026 and $65.56 billion by 2034, a 34.34% annual growth rate (Fortune Business Insights, page dated 5 October 2026). Marketintelo gives $2.8 billion for 2025 and $6.3 billion for 2034, and The Insight Partners gives $945.6 million for 2025 and $4.13 billion for 2034.

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Marine mining market in 2025 by publisher

US$ billion; each publisher defines the market differently

The gap comes from scope. Fortune counts nodules, sulphides, crusts and an “others” group that includes rare earth elements and industrial minerals. Other publishers define the term more narrowly or more broadly. Before quoting a top-line number, read the scope section of the report. No operator has yet sold nodules commercially, so any figure for today’s market is a modelled estimate, not revenue.

The rules that decide whether any of it ships

Two unfinished rulebooks apply. The first is the ISA Mining Code. Exploration rules exist, but the exploitation regulations that would let a contractor sell nodules are still draft. At its July 2026 session the Council worked from a Revision 3 text dated 19 June 2026, and its Legal and Technical Commission listed 46 standards and guidelines still in development. Observers note that the ISA has worked on the code since 2014 and has repeatedly missed deadlines (Mongabay, 29 July 2026).

The second is the US route through NOAA described above. The ISA claims sole authority over seabed mining in international waters, while NOAA argues the ISA’s powers may not apply because the United States is not a party to the Convention (Motley Fool, 25 October 2026). By the July 2026 ISA session, 46 states supported a moratorium or precautionary pause on seabed mining (Ocean Vision Legal; Mongabay says 45). A company that wins a US permit could still face challenge from the ISA regime, and a company that follows the ISA code has no commercial rulebook to follow yet.

What is a nodule deposit worth? A calculator

Enter a nodule tonnage and metal contents to see the gross in-situ value of nickel, copper and cobalt. The defaults are a round 100 million wet tonnes and contents scaled from the April 2025 TMC estimate above (15.5 million tonnes of nickel in 1,635 million wet tonnes is about 0.95%). Swap in the figures from any company filing. The result excludes manganese, mining and processing costs, losses and any ISA or NOAA payments, so the realised value would be well below it.

Land-based supply is the competition

Seabed metals have to compete with mines on land. The US Geological Survey estimates world cobalt mine output at 310,000 tonnes in 2025 (estimate), of which the Democratic Republic of the Congo produced 230,000 tonnes, and world cobalt reserves at 12 million tonnes (USGS Mineral Commodity Summaries 2026, cobalt). For nickel it estimates 3.9 million tonnes of mine output in 2025, with Indonesia at 2.6 million tonnes, and says seafloor manganese crusts and nodules sit within a group of deposit types that together hold about 10% of world nickel resources (USGS Mineral Commodity Summaries 2026, nickel).

By that yardstick, TMC’s estimated 2.0 million tonnes of in-ground cobalt equals roughly six and a half years of world mine output, but it is a resource figure, not a reserve, and extracting it depends on the permits above. Land projects are screened long before drilling, and satellite mapping of a licence area is one of the ways that screening is done.

▶ A short look at Farmonaut Mining Pro, which turns a licence boundary into a geological and economic picture for land projects. · 4:56

How to check any seabed mining company yourself

1. Find the contractor on the ISA register and read the contract dates and sponsoring state.
2. Search the Federal Register and NOAA’s deep seabed minerals page for the company name; note whether the status is application, certification, environmental review or permit.
3. Read the latest quarterly filing on SEC EDGAR, SEDAR+ or the exchange, and look for cash, quarterly spending and the funding plan.
4. Separate a resource estimate from a reserve, and an agreement in principle from a signed contract.
5. Confirm the share class and ticker. Several names above are subsidiaries, joint ventures or private firms with no shares.

Our guides to polymetallic nodules and American deep sea mining companies cover the geology and the US names in more depth, and deep sea mining for rare earths looks at the other prize. Our rundown of mining-tech innovations covers the ROV and sensor hardware.

What satellites can and cannot see offshore

Farmonaut is not a seabed contractor and no optical satellite sees a nodule field 4,000 m down. Sunlight does not reach that depth, so satellites see the surface layer, ships and coastal sites. Where satellite data does help the sector is on land: mapping licence areas for nickel, cobalt and copper, and screening onshore targets for alteration zones and structure before drilling. Farmonaut offers this kind of screening for onshore mineral exploration targets.

▶ Remote sensing for mining explained in three minutes: what satellite instruments measure from a distance. · 2:01

Frequently asked questions

Which deep sea mining companies are publicly traded?

As of 26 October 2026: The Metals Company (Nasdaq: TMC), Odyssey Marine Exploration (Nasdaq: OMEX, becoming AOMC if the merger closes), The Metals Royalty Company (Nasdaq: TMCR) and Deep Sea Minerals Corp. (CSE: SEAS). DEME Group (Euronext Brussels: DEME) owns GSR but is mostly a dredging firm.

What are the biggest deep sea mining companies?

It depends on the metric. By ISA nodule contracts, China’s entities hold three of 19 and UK Seabed Resources holds two. By US application area, TMC USA’s two applications cover 187,017 km² (TMC, October 2026). By market value among listed names, TMC was about $1.07 billion in the Motley Fool quote box of 25 October 2026.

Is there a deep sea mining stock that is not TMC?

Yes, but the choices are narrow (this list is dated 26 October 2026): Odyssey (OMEX), the royalty vehicle TMCR and the small-cap SEAS. Each has a different risk, from merger completion to licence awards.

Who owns Deep Ocean Resources Development Co., Ltd.?

DORD is a Japanese company with no stock-exchange ticker. The ISA register and DEME’s March 2026 announcement name it as Japan’s nodule contractor but do not list its shareholders, so check its corporate disclosures for ownership.

Are there American deep sea mining companies?

TMC USA, a subsidiary of TMC, applies to NOAA, and Odyssey and American Ocean Minerals are merging under the AOMC name. Impossible Metals is described as a US-based marine technology company in its partner’s July 2026 release.

Is deep sea mining legal yet?

Exploration is. Commercial exploitation is not authorised under either rulebook. The ISA’s exploitation regulations were still in draft after its July 2026 session, and NOAA had not yet decided on TMC USA’s applications.

What minerals do seabed companies target?

Mainly nickel, copper, cobalt and manganese from nodules, plus copper, gold, silver and zinc from seafloor sulphides, the target of the failed Nautilus Minerals project.

What happened to Nautilus Minerals?

It filed for creditor protection in Canada in February 2019 and creditors were allowed to liquidate it in August 2019, as MINING.COM reported.

How big is the marine mining market?

Estimates range from $0.95 billion to $4.6 billion for 2025, depending on the publisher and what it counts. Read the scope section before comparing numbers.

Where can I check the current list of contractors?

The ISA’s polymetallic nodules page lists every contractor, contract date and sponsoring state. For US applications, use NOAA’s deep seabed minerals page and the Federal Register.

Companies, mergers and permits change quickly. Re-check the ISA register, NOAA’s pages and each company’s filings before relying on this snapshot.