More than 20 financial institutions worldwide have publicly vowed not to finance deep-sea mining — an activity scientists say could cause irreversible harm to ocean ecosystems. However, a DW investigation has found that some have invested at least $684 million (€581 million) in companies linked to the industry.
Hundreds of millions of dollars are flowing into companies racing to extract nickel, cobalt, and copper for batteries and other industrial uses from deposits buried thousands of meters below the ocean surface — an environment where scientific knowledge remains limited. Less than 0.001% of the seafloor has been explored.
Among the investors are some of the world's largest financial institutions — including Deutsche Bank, UBS, Credit Suisse, Credit Agricole and BNP Paribas — according to DW's analysis of company filings compiled by Greenpeace Germany's investigation unit.
The investments come as the United States pushes to advance deep-sea mining as a future source of critical minerals. At the same time, some 40 countries have already announced a moratorium on the practise, arguing the environmental risks for these critical ecosystems need to be properly assessed.
The deep sea is "home to incredible life that is fragile, yet essential to the planet," Diva Amon, a marine biologist and scientific advisor at the University of California, told DW. "We don't yet understand what we're planning to destroy, and once it's gone, we can't bring it back."
'It's greenwashing' — when pledges and investments diverge
When contacted by DW, Deutsche Bank and Credit Agricole said their commitments apply to financing specific projects, not to investments in companies. Critics argue this distinction allows banks to avoid directly funding individual seabed-mining operations while continuing to invest in companies preparing to mine — akin to refusing to finance an oil drilling site for climate reasons but still buying shares in the drilling company.
The other banks did not respond to DW's questions.
"It's greenwashing," said Mauricio Vargas, a former investment strategist turned financial expert at Greenpeace. "Banks want to avoid negative PR related to environmental controversies."
Vargas added that banks often rely on technicalities and small-print exceptions, counting on the public not fully understanding the implications of their investment policies.
Andrew Whitmore of the Deep-Sea Mining Campaign said the gap between banks' public commitments and their investments often reflects internal incentives.
"Their policies are carefully worded," he said, adding any commitments are often made in good faith, "but there are pressures within banks to invest in areas deemed as potentially profitable, and/or mis-sold as profitable." Accordingly, commitments are not always applied uniformly across large institutions.
But some banks, such as one of Norway's largest financial groups Storebrand, have managed it. DW found the group recently divested millions of dollars from companies linked to deep-sea mining.
A Storebrand spokesperson told DW the decision followed the precautionary principle, which prioritizes avoiding harm in the face of scientific uncertainty.
"Storebrand will not invest in companies involved in deep-sea mining until we have more scientific knowledge on the impacts of these activities," they said.
When green commitments contradict short-term incentives
Goldman Sachs, on the other hand, has no public policy opposing deep-sea mining. Still, the Wall Street giant markets itself as a leader in environmental, social and governance (ESG) investing.
DW found it holds €187 million in stakes across companies enabling deep-sea mining. The company did not respond to requests for comment.
"Goldman Sachs is one of the biggest wealth managers in the world, and what it does matters," said Tariq Fancy, former chief investment officer for sustainable investing at BlackRock, which manages around $10 trillion in assets.
"It's much cheaper to paint yourself green than to actually be green," Fancy added. With time frames for high returns "the shortest they've been in decades," he said many CEOs operate on five-year timelines, making it rational to "squeeze every last penny and then use philanthropy as reputation laundering."
While ESG can "make differences at the edges," Fancy said, "the real change has to come from political reform and stronger regulation."
Taxpayer money flowing to private deep-sea mining companies
DW also analyzed investment data compiled by Washington-based nonprofit, the Anti-Corruption Data Collective (ACDC). The analysis found that taxpayer money from countries that officially support a precautionary pause on seabed mining was invested in companies linked to the industry.
Retirement savings are also on the hook. The Triton IV private-equity fund draws money from public pension funds across Europe and Canada, even as the governments behind them publicly oppose deep-sea mining. The fund managed subsea firms DeepOcean and Adepth Minerals until spring 2025 before selling the group to a new Triton-managed investment entity.
Triton disputed the characterization, saying that DeepOcean is not a seabed-mining company, and that its investment in Adepth Minerals is limited, regulated and not central to its strategy.
For Whitmore, accountability is the most effective way to push for change — especially for pension funds. "They invest on behalf of the public for the future," he said, adding that they must therefore take the potential environmental risks of deep-sea mining seriously.
"It is important for pension funds to join the growing number of financiers and insurers who are excluding deep-sea mining," he continued. So far, no pension funds have made such a pledge.
Some governments are drawing firmer lines though. Norway, a country with several companies positioning themselves to mine the deep sea, has agreed not to issue mining licenses in its national waters until at least 2029. At the same time, 40 countries now support moratoriums or precautionary pauses on mining in international waters amid uncertainty about how it could affect marine life.
Most deep-sea species haven't yet been discovered
"The deep sea is one of the most biodiverse places on the planet," said marine biologist Diva Amon, who has led deep-sea research expeditions around the world. Far below the surface of the Pacific, Amon has seen sharks glowing in perpetual darkness and corals that are thousands of years old. But many deep-ocean species remain largely unknown to humans.
"About 90% of deep-sea species still lack formal names," Amon said, adding that removing polymetallic nodules — potato-sized rocks containing many of the critical metals targeted by mining companies — could cause irreversible damage on million-year timescales.
Peter Thomson, UN Special Envoy for the Ocean, called for a 10-year moratorium on deep-sea mining to allow science to catch up and protect the "common heritage of humankind." The UN's finance initiative has also said there is "no foreseeable way" financing the practice can align with the sustainable use of the ocean.
Early evidence from trial operations has reinforced those warnings. A recent study funded by leading deep-sea mining firm The Metals Company (TMC) found test mining in the Pacific reduced seafloor abundance and biodiversity by more than a third.
But scientists say the risks extend beyond biodiversity loss. Some deep-sea microbes are already used in medicine, including enzymes for SARS-CoV-2 PCR tests and compounds now being studied in cancer trials. Mining could eliminate similar organisms before they are even identified.
"There is still so much the science doesn't know when it comes to the deep sea," Amon said. "If more people knew about its wonders, we wouldn't even be talking about mining it."
The reporting for this investigation was supported by a grant from theInvestigative Journalism for Europe (IJ4EU) fund.
