What this is
The RareEarth Index is a rules-based global equity benchmark of public companies whose primary business is rare earth element production: mining, processing and separation, magnet and alloy manufacturing, recycling, or advanced-stage exploration with a defined REE resource.
The index is rules-based. There are no discretionary inclusions or exclusions outside the methodology’s §10 dispute framework. Eligibility is set by six screens applied in order: activity, exclusion, listing, market-cap floor, liquidity floor, English reporting standard. The full rulebook is on the methodology page.
Why it exists
Rare earth elements are essential to permanent magnets used in electric vehicle drivetrains and wind turbine generators, and there are no commercially viable substitutes at scale. The energy transition depends on rare earth supply; the rare earth supply chain depends on a small number of public companies. There was no transparent, freely available, rules-based global equity benchmark for that universe. The RareEarth Index fills that gap.
Existing rare earth equity products tend to include companies whose rare earth activity is a minority of enterprise value, or whose primary listings are on exchanges that international investors cannot readily access. The RareEarth Index applies a strict pure-play activity screen and a defined enumerated list of eligible exchanges, then publishes the result — including the cases where the rules produce a smaller universe than would be marketable.
Voice
There is no marketing layer over the math. The index does not claim to be the best, the leading, or the most comprehensive of anything. It claims to apply the published methodology and report what that methodology produces. Where the rules produce a finding that looks small, or concentrated, or unbalanced, the finding is published as-is.
Companies considered and excluded are documented in the audit trail, with the specific reason for each exclusion. Borderline cases are recorded in the inaugural constituent note with the reasoning at the time of decision.
Clay Indices family
The RareEarth Index is part of the Clay Indices family, administered by George Clay. Clay Indices treats methodology as a product. Every index in the family publishes a complete, versioned methodology document; every methodology is rules-based; the boundary of what each index measures is part of the claim, not a footnote to it.
The RareEarth Index is a companion to the Climate50 Index. Climate50 tracks the demand-side companies of the energy transition — electric vehicles, renewable generation, grid infrastructure, energy storage. The RareEarth Index tracks the upstream supply side that makes those technologies possible.
Other published members of the family include the Total Market Index, the TrueCost Index, and the Greek Index Series (Lambda, Theta, Rho). The full family is at clayindices.com.
Attribution
The RareEarth Index is administered by George Clay. Methodology questions, exclusion challenges, and corrections are welcome via the contact page.