Index methodology

All three Tantalum Strategy indexes are calculated from publicly sourced inputs and published weekly. Constituent baskets and weights are proprietary.

Tantalum AI Materials Index (TAI)

A weighted basket of materials disproportionately scaling with AI infrastructure buildout. Inputs include rare-earth ETF proxies, copper futures, uranium, lithium, power-proxy gas, and reference prices for materials without transparent spot markets (gallium, helium).

The index is recalculated weekly from Friday closing values. Base date: January 1, 2026, base value 100.

Sovereignty 50 Index (SOV50)

Materials with greater than 50% single-country supply concentration. The basket spans rare earths (China-dominant), niobium (Brazil-dominant), gallium and germanium (China-dominant), cobalt (DRC-dominant), and graphite, tungsten, and antimony where one country accounts for the majority of global supply.

Weighted by a combination of supply concentration and downstream criticality to AI infrastructure and defense supply chains. Recalculated weekly.

Southern Basket Index (SOUTH)

Brazil + Lithium Triangle + DRC resource exposure. Equity weighted exposure to major Latin American and African resource producers. Brazilian iron ore, niobium, lithium; Chilean copper; Argentine lithium; DRC copper.

Data sources

Input prices are sourced from publicly available endpoints: COMEX and NYMEX futures via Stooq.com (delayed market close), ETF proxies (REMX for rare earths, LIT for lithium, URA for uranium) for materials without transparent spot markets, USGS quarterly reference prices for gallium and helium, and EIA / Henry Hub for the power proxy.

We do not use paid commodity-price feeds at this time. All inputs are reproducible from public data.

Update cadence

Indexes are recalculated weekly, on Friday after US market close, and published Monday morning UTC. Daily ticker values on the home page reflect the most recent close from the same public sources.

Why weights aren't public

Constituent baskets and exact weights are proprietary to Tantalum Strategy. The methodology — how we choose constituents, what data sources we use, the calculation cadence — is fully open. The weights themselves are the editorial judgment of the desk and are revised over time as the AI-materials thesis evolves.

Institutional clients can license the full index methodology, constituents, weights, and historical data under separate agreement. Talk to the desk →