Short interest has climbed this year in US Antimony Corporation, American Resources Corporation and MP Materials. MP Materials, backed by an early investment from Chamath Palihapitiya, saw shares more than triple last year after Washington took an equity stake and guaranteed minimum prices. US Antimony nearly tripled too, aided by a Pentagon supply contract and Ukraine-linked emergency funding. American Resources’ affiliate ReElement Technologies secured Defense Department funding, while USA Rare Earth landed $1.6bn in conditional commerce department backing. Shares on loan in US Antimony have nearly doubled this year to 42% of market capitalisation, S&P data shows, while American Resources’ short interest has more than doubled.