Tesla has been weighing a takeover of battery-metals miner Sigma Lithium, people with knowledge of the matter said, amid rampant demand for the metal used in electric vehicle batteries.

The EV maker run by Elon Musk has been speaking with potential advisers about a bid, said the people, who asked not to be identified discussing confidential information. Sigma Lithium is one of multiple mining options Tesla is exploring as it mulls its own refining, one of the people said.

Sigma Lithium’s biggest shareholder has been exploring a potential sale of the company and gauging interest from miners and carmakers, the people said. Its biggest investor, holding 46%, is A10 Investimentos, a Brazilian private equity fund that Sigma co-CEO Ana Cabral-Gardner helped establish. Co-CEO Calvyn Gardner, also owns part of the miner.

Deliberations are in the early stages and may not lead to a transaction, according to the people. Potential suitors may hesitate to bid after shares tripled in the last 12 months and on high price expectations by the owners, the people said. Sigma’s owners could also wait to develop the company’s main project further before seeking an exit, according to the people.

Representatives for Tesla did not respond to requests for comment. Sigma Lithium’s Cabral-Gardner declined to comment on “rumors".

The company is developing a large lithium rock deposit in Brazil known as Grota do Cirilo. The company said in December that it’s considering nearly tripling lithium production at the project in 2024 after survey revealed mineral reserves 63% higher than previously thought.

Sigma Lithium’s Toronto-listed shares have soared along with surging lithium prices, giving the company a market value of C$4.1-billion ($3-billion). Demand for the silvery white metal, which is key to making EV batteries, is greatly outstripping supply amid the push to electrify transportation in a shift away from fossil fuels.

Sigma Lithium may also attract interest from large miners as well as customers of the metal. Rio Tinto Group, the world’s second biggest mining company, is actively looking for lithium acquisitions, but isn’t currently interested in Sigma Lithium because of the high asking price, one of the people said.

The company has already signed supply deals with LG Energy Solution and Japanese trading house Mitsui & Co.