After dropping 10% and 9.8%, respectively, in July and August, shares of The Metals Company (TMC 4.00%) reversed the downward trend and buoyed notably higher in September.
With investor enthusiasm for domestic critical mineral companies soaring, shares of The Metals Company rose 18.8% in September, according to data provided by S&P Global Market Intelligence.

Image source: Getty Images.
Investors are reading tea leaves -- and clicking the buy button in response
While The Metals Company stock rose significantly last month, investors won't find anything that links the stock's rise with a company announcement. Instead the rise is attributable to a healthy dose of conjecture that The Metals Company will have something auspicious to share in the near future.
What forms this conjecture? For one, Reuters reported in late September that India had signed an agreement with the International Seabed Authority (ISA), an international organization the U.S. established to oversee activities on the seafloor. According to Reuters, the 15-year agreement India signed with ISA provides it with exclusive rights to exploration of polymetallic sulphides in the Indian Ocean -- similar to the polymetallic nodules The Metals Company hopes to mine in the Clipperton Clarion Zone in the Pacific Ocean.
Investors may be speculating that ISA is becoming more amenable to companies mining the seafloor, and that the agency may be closer to releasing the final rules for deep sea mining that have precluded The Metals Company from commencing operations.
Secondly, investors bid The Metals Company stock higher last month after learning of the apparent interest the Trump administration has in lithium stock Lithium Americas. With rumors swirling that the U.S. government is discussing an equity investment in the lithium company, investors are imagining that The Metals Company may be next to partner with the Trump administration as MP Materials did some months ago -- which led to skyrocketing interest in MP Materials stock.
The potential deal is particularly noteworthy for investors because like Lithium Americas, The Metals Company is a Canadian company; therefore, investors who imagined that Canada-based companies wouldn't attract interest from the Trump administration are having to reconsider their positions.
Is it too late to buy The Metals Company stock after its rise in September?
Up more than 560% as of this writing, The Metals Company stock has been on an absolute tear in 2025. While speculation is rampant that the company will soon receive some green lights to proceed with commencing operations, it's important to recognize that there are still a variety of risks, including whether the actual mining of the seabed can be a profitable endeavor.
At this point, only investors with significant tolerances for risk should consider positions in this metal stock.