Washington, Sept. 24 -- The United States is preparing to move from lender to shareholder in the country's most consequential lithium project, with senior officials weighing the purchase of an equity stake of up to 10 percent in Lithium Americas as they renegotiate a $2.26 billion federal loan that underwrites processing facilities at Thacker Pass in Nevada. The proposed shift would mark a new phase of Washington's industrial policy, one that tests whether direct ownership can steady a project facing weak prices, financing friction and hard questions about long term offtake.

The loan at the heart of the talks sits inside the Department of Energy's Loan Programs Office. The agency's project page confirms the structure and the scope, inclu...