Critical materials

How does the critical materials supply chain work, from mining to processing?

The critical materials supply chain runs in two distinct stages, and the strategic value sits more in the second than the first. The first stage is mining: pulling rare earth ore, beryllium-bearing rock, iron ore, and other raw inputs out of the ground. The second stage is processing and refining, where that raw material is separated, purified, and converted into the oxides, alloys, magnets, and specialty inputs that manufacturers actually use. Western companies have historically mined plenty; the bottleneck is processing capacity.

MP Materials is the clearest illustration in the critical materials theme: it runs the only fully integrated rare earth mining-to-processing operation in the Western Hemisphere at Mountain Pass, California, and is extending downstream into magnet manufacturing in Texas. Materion sits almost entirely on the processing side, converting beryllium into specialty alloys that few Western suppliers can qualify to make. Nucor and Linde occupy the refining and conversion end too, turning scrap and feedstock into domestic steel and into industrial and specialty gases that customers cannot easily substitute.

Why are critical materials strategically important, and what is the China concentration problem?

Critical materials are strategically important because a handful of them are irreplaceable inputs to defense systems, semiconductors, electric vehicles, and the electrical grid, while their supply is concentrated in a single country. China dominates global processing of rare earths and several other strategic materials, and it has shown willingness to use that position as a policy lever through export controls. That concentration is the core reason the critical materials theme exists as an investment idea rather than a generic materials sector bet.

The response is reshoring: US and allied industrial policy is funding Western alternatives across the critical materials supply chain. MP Materials anchors the rare earth and magnet end of that effort, Materion supplies defense-grade specialty alloys that procurement rules increasingly want sourced domestically, and Nucor represents a structurally lower-carbon domestic steel base. The critical materials theme groups public companies positioned to benefit if Western capacity continues to be built out rather than left dependent on Chinese processing.

What drives critical materials prices and how do these companies make money?

Critical materials companies make money in different ways depending on where they sit in the chain. Miners and integrated processors like MP Materials earn on the spread between extraction and processing cost and the price of the refined product, which means their economics are directly exposed to commodity prices for rare earth oxides and magnets. Specialty processors like Materion earn more stable margins on hard-to-qualify alloys, where the value is the engineering and the customer relationship rather than the underlying metal price. Linde sells industrial and specialty gases on long contracts, which produces steadier cash flow that is less tied to any single material price.

Critical materials prices are driven by the interaction of concentrated supply and policy-sensitive demand. Chinese export decisions can move rare earth and specialty material prices sharply, while demand is shaped by EV magnet volumes, defense procurement, semiconductor manufacturing, and grid buildout. Because so much of the critical materials thesis rests on policy support and multi-year capacity ramps, prices and equity values in the theme can be volatile even when the long-run structural drivers hold.

What gets a stock into the Critical materials theme?

Production, processing, or licensing of materials with limited Western supply, including rare earths, beryllium, specialty alloys, and other strategic materials.

Critical materials stocks

Every public name that fits the Critical materials thesis, with the rationale for inclusion. Click any ticker for the full stock guide. The basket above starts equal-weighted; you set your own target weights inside Walnut.

How to invest in Critical materials

There are a few ways to get exposure to the critical materials theme. The most direct is owning individual miners and processors, which lets you target specific points in the supply chain: MP Materials for integrated rare earths and magnets, Materion for defense-grade specialty alloys, Nucor for domestic steel, and Linde for industrial and specialty gases. A second route is ETF proxies. From the funds tied to this space, REMX (VanEck Rare Earth and Strategic Metals) is the closest pure-play, though it is dominated by international producers rather than US-domestic names; LIT covers lithium and battery technology, and URNM covers uranium. The tradeoff with these ETFs is real: they give you breadth and one-ticker simplicity, but they carry heavy commodity-price sensitivity and none of them cleanly captures the Western reshoring angle that defines the critical materials theme, because the investable universe is too narrow for a tightly US-domestic index.

The third route is building a critical materials basket in Walnut. You describe the idea to Walnut's AI assistant, for example a US-domestic critical materials and rare earths supply chain, and it proposes a set of constituents and starting weights, typically a 3-5 stock structure across miners, processors, and a steadier anchor. You review the proposed critical materials basket, adjust the weights to match your own view, and fund it through your connected broker. Walnut shows you every order before anything happens and you approve each one; Walnut never trades for you and is not an investment adviser. Once funded, the critical materials basket tracks as a single performance line you can follow over time and compare against proxies like REMX.

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