A new independent report finds that The Metals Company’s (TMC) deep-sea mining projects would destroy economic value in more than eight out of ten realistic scenarios. Koinon Consulting produced the analysis by stress-testing TMC’s own financial projections.

The report found a median outcome of a $5 billion loss. It also estimated a 61% chance that investors would never recoup their investment.

Titled “Case Not Proven: The Economics of Deep-Sea Mining,” the report was commissioned by the Deep-Sea Conservation Coalition and other environmental groups. It argues that TMC’s business model relies on overly optimistic assumptions about metal prices, recovery rates and operating costs. The analysis concluded that the projects’ promise of economic prosperity did not withstand scrutiny when realistic risks were included.