Cobalt is the most concentrated of the 90 commodities, with an index of 4,988 out of 10,000: DR Congo (Democratic Republic of the Congo) makes 74% of world output and DR Congo (Democratic Republic of the Congo) supplies 65% of exports. Sesame seed is the least concentrated, at 494.
The index is a Herfindahl-Hirschman index: each supplier's percentage share is squared and the results are added up, so one supplier scores 10,000 and ten equal suppliers score 1,000. It is calculated separately for production and for exports by value, and the ranking uses the average of the two (production alone where there is no trade line). Concentration matters because a supply shock in one place is felt worldwide when that place is a large share of supply.
Price volatility is the annualised standard deviation of monthly price changes over the last ten years. Among the 41 commodities with a current benchmark price, the more concentrated half has a median annualised volatility of 23%, against 19% for the less concentrated half. That is a comparison of two groups of different commodities (metals against crops, for one), not evidence that concentration causes swings.
Supply concentration index, with price volatility and stocks
Production: FAOSTAT, USGS, Energy Institute, FAO FishStat, latest year, top 25 producers. Exports: CEPII BACI, value in US dollars for the primary HS line, top 15 exporters; countries outside those lists are small, so indexes are very slightly understated. Price volatility: World Bank Pink Sheet primary series, last 120 months. Stocks-to-use: USDA PSD, latest marketing year (partly an estimate), available for eight crops. Uranium, orange juice and cardamom are left out because their production series is a proxy.
Source snapshot and downloads
Recreated from Commodity Origins' published derived reports under CC BY 4.0. Report figures retain the publisher's definitions, coverage and reporting years. Selection of underlying commodity rows in our commodity explorer is separate and may have different coverage. Source notes above identify the upstream data; no publisher endorsement is implied.