United States Antimony Corporation (UAMY)

United States Antimony Corporation is a small but strategically important metals company. It owns and operates the only two antimony smelters in North America. For decades, the company was a backwater commodity producer, barely noticed by investors and struggling with margins as China supplied most of the world’s antimony at lower cost. That isolation ended abruptly in late 2024, when China banned the export of critical minerals to the United States. Suddenly, USAC’s sleepy operations became essential to American industry and defence. The company now operates under long-term contracts with the U.S. Department of Defence, secured supply for domestic manufacturers, and a dramatically different competitive position.

The business: Antimony, from scarcity to criticality

Antimony is a metal used in batteries, flame retardants, semiconductors, and military ordnance. It is not a household name, but it is essential to dozens of industrial processes. The world produces roughly 150,000 tonnes of antimony annually, with China accounting for more than 90 per cent of global output. For decades, that dominance meant antimony was cheap. Western companies paid minimal premiums and outsourced production to China or relied on Chinese imports. Antimony was simply not a geopolitical concern.

USAC has produced antimony products since 1969, operating in a low-margin, commodity business. The company ran a smelter in Thompson Falls, Montana, and mined antimony ore from properties in Montana, processing it into antimony metal and compounds for industrial buyers. Competing against China’s state-subsidised production was a losing game. USAC survived by maintaining a small U.S. presence and serving customers who preferred domestic sourcing for reasons of reliability, security of supply, or regulatory compliance. Margins were thin, operations were modest, and the company was effectively trapped in a low-return equilibrium.

The shock: China’s export ban and strategic reversal

In December 2024, China announced restrictions on the export of critical minerals, including antimony, to the United States and allied countries. The stated rationale was national security; the effect was immediate. U.S. manufacturers dependent on antimony imports faced the prospect of supply disruption. The U.S. Department of Defence, which relies on antimony for ammunition and ordnance, faced the same problem. Suddenly, USAC’s existence became strategically important.

Within weeks, the Defence Logistics Agency (DLA), the Pentagon’s supply agency, awarded USAC an Indefinite Delivery / Indefinite Quantity (IDIQ) contract worth up to $245 million to produce antimony metal ingots for the U.S. strategic stockpile. This was a sole-source contract, meaning no competitive bidding—USAC was the only domestic source capable of meeting the specification. The contract transformed USAC from a low-margin commodity player into a government contractor with a long-term, high-value revenue stream.

Mining restart and capacity expansion

The DLA contract created immediate pressure to increase production. USAC’s smelter in Thompson Falls could process ore, but ore supply had dwindled. In 1983, the company had ceased mining at Stibnite Hill in Montana due to poor economics. In 2025, that calculus flipped. USAC began reacquiring mining rights and land near Thompson Falls and restarted underground mining operations at Stibnite Hill. The company also acquired mines near its smelter and began expanding throughput.

In parallel, USAC restarted a smelter facility in Madero, Mexico (in Coahuila state) in April 2025, giving the company a second processing centre. The Mexican facility uses similar metallurgical processes and allows USAC to process additional ore feedstock. Combined, the two smelters give USAC capacity to serve both the DLA contract and commercial markets.

The dual revenue streams: Government and commercial

The DLA contract is the dominant revenue driver, but it is not the only one. USAC also sells antimony products to industrial customers in batteries, electronics, flame-retardant formulations, and other end uses. These commercial sales operate at lower prices than the DLA contract but with lower regulatory burden. USAC must balance production between the government contract (higher price, higher priority) and commercial sales (lower price, flexible volume).

The company also operates the Bear River Zeolite division in Idaho, which mines and processes zeolite—a microporous mineral used in water filtration, animal feed, soil amendment, and industrial applications. Zeolite is a lower-value, lower-margin business, but it provides diversification and uses some of USAC’s existing mining and processing infrastructure. It does not compete for the company’s strategic focus.

Competition and the duration of USAC’s advantage

USAC’s competitive position is now anchored to two facts: it is the only domestic antimony smelter in North America, and the U.S. government has committed to long-term purchasing. That is a formidable duopoly, but it is also brittle. If China lifts its export ban, competition and Chinese pricing return. If the U.S. government’s policy on critical minerals shifts, the contract could be renegotiated or allowed to lapse.

USAC also faces the possibility that competitors will invest to build new smelting capacity in the United States. The high price of the DLA contract and the strategic importance of domestic antimony make the market attractive. A large, well-capitalised competitor could build a new smelter, though the capital investment and permitting timeline are substantial. For now, USAC’s exclusive access to the DLA contract and its monopoly on existing U.S. smelting capacity give it room to operate without imminent competitive threat.

Risks: Geopolitics and policy dependency

USAC’s transformation is real, but it is also policy-dependent. The company’s strategic value rests on three assumptions: that China maintains export restrictions, that the U.S. government continues to prioritise domestic antimony supply, and that no new competitors enter the market. A shift in any of these could upend USAC’s business.

China may lift restrictions if negotiations succeed or if the geopolitical climate shifts. The U.S. government may reduce the contract or change its sourcing strategy. Environmental and permitting challenges could slow USAC’s mining expansion. The company’s profitability depends on these external factors, not purely on operational excellence.

There is also the question of scale. USAC is producing antimony to replace Chinese imports, but antimony is a relatively small market. The global market is measured in thousands of dollars per tonne, not the billions of dollars associated with major commodities. Even a successful, well-run USAC is a small, specialised company by the standards of major mining companies.

Reading USAC

USAC’s 10-K (SEC CIK 0000101538) details the DLA contract terms, mining operations, production volumes, and segment revenue. Watch the antimony production volumes from both the Montana and Mexico smelters; higher throughput indicates growing capacity. Monitor the mining operations at Stibnite Hill and surrounding properties; permitting and environmental approvals determine the pace of ore supply.

Track the company’s capital expenditures; expansion of smelting and mining capacity requires ongoing investment. Look at the contract’s pricing mechanisms; if the DLA contract is fixed-price, cost inflation will erode margins. Quarterly earnings calls reveal management’s thinking on mining expansion, smelter utilisation, and the company’s ability to service both the government and commercial markets. The dividend and capital allocation are less relevant here than the underlying production trajectory and the durability of the DLA contract.