Last month, Tesla founder Elon Musk complained that lithium refiners were “minting money” and making “software-like margins”.

Close to the heart of global lithium processing sits Ganfeng Lithium, a highly profitable Chinese group that is pivotal to western automakers’ dreams of going electric, but also vulnerable to state influence as Beijing tightens its control over strategic sectors.

With customers including Tesla, BMW and Volkswagen, Ganfeng’s every move faces mounting scrutiny. In recent weeks, the group has drawn headlines for an insider trading probe launched by Beijing’s top securities regulator, its near-$1bn acquisition of lithium mines in Argentina and a subsidiary’s participation in a joint venture to explore for lithium in Xinjiang, the western region where China has been accused of human rights abuses.