Fetching primary parquet sources and computing exhibits.
supply side · HS6 concentration
Which products are concentrated, and which countries have market power
When a single country or a small set of countries produces most of the world's supply of a particular good, a tariff, sanction, or natural disaster there becomes everyone's shock. This page measures supply-side concentration across the full HS6 catalog in 2024, identifies the products where one country commands a majority share, and tracks whether global trade is becoming more concentrated over thirty years.
HS6 products measured4,637
products with >50% single-country share (2024)20+
world avg top-1 share 202434.2%
change since 1995+5.0 pp
The 20 most supply-concentrated products
For each HS6 line, we compute the Herfindahl-Hirschman index over exporter shares of world exports, on the 0-10,000 scale. HHI = 10,000 means a single country supplies everything; HHI near 0 means the product is produced everywhere. The US DOJ/FTC (2023) Horizontal Merger Guidelinesflag HHI > 2,500 as 'highly concentrated' and HHI > 1,500 as 'moderately concentrated'. Beck, Georgiadis & Gräb (2021), in their IMF Working Paper on critical inputs, argue that concentrated supply combined with low substitutability is the right operational definition of 'critical dependence'. The list below is restricted to products with more than US$500M of world trade in 2024 to suppress artefacts from ultra-thin markets.
Figure 1
Top 20 HS6 products by supply-side HHI, 2024
The most concentrated product in 2024 is HS 711039 (Metals: rhodium, semi-manufactured) with HHI = 8825; the top exporter is South Africa at 94% of world exports. Concentrated lines cluster in specialised chemicals, narrow textile categories, and mineral processing.
Method: HHI over exporter shares of world trade per HS6, 2024. Beck, Georgiadis & Gräb (2021) 'Rising Geoeconomic Fragmentation and Critical Inputs,' IMF Working Paper. CEPII BACI 202501 (retrieved 2026-04-28).
Products where one country is the market
Chowdhry & Felbermayr (2023) define strategic dependenceas a product-country pair where the importer sources a dominant share from a single supplier and no easy substitute exists. The supply-side counterpart is simpler: HS6 lines where one country controls more than half of world exports. We restrict to products with non-trivial world value (> US$500M) and rank by total trade value to emphasise where the stake is largest.
Figure 2
Top HS6 with a single country commanding >50% of world exports, 2024
On the import side: which countries are most single-source dependent
Goldberg & Pavcnik (2007), surveying the effects of trade liberalisation in developing countries, emphasise that import-side concentration reshapes domestic labour markets and prices through the intensity of foreign competition. The geodep database of Arjona, Connell & Pisu at the OECD (2023, ECO/WKP 1775 'An analysis of trade interdependencies') computes, for every importer × HS6 × year, the share of imports coming from the dominant supplier. The figure below reports the share of each country's HS6 import basket that is sourced from a single foreign supplier as defined by the OECD methodology (a high-C1 threshold, not a literal 100%), restricted to economies importing at least 4,000 distinct HS6 lines.
Figure 3
Single-source dependence: share of imported HS6 lines with one supplier, 2022
Critical minerals: export-market concentration of rare earths, lithium, and cobalt
The IEA (2022) Critical Minerals Review and the USGS Mineral Commodity Summariesconsistently flag rare earths, lithium, and cobalt as the choke points of the energy transition. The BACI HS6 lines below map onto those products, but with an important distinction: these are export-market shares, not mining- or processing-production shares. For mined cobalt the USGS reports DRC at ~74% in 2023; for mined lithium (spodumene), Australia at roughly 46%. Those production shares will not equal the BACI shares below because producers may refine or consume domestically, ore may cross borders en route to refiners (e.g. DRC → China for cobalt), and spodumene, carbonate and hydroxide sit under different HS codes. Read this chart as 'where world buyers source from', not 'where this mineral is produced'.
Figure 4
Top-3 exporter shares for selected critical-mineral HS6 lines, 2024
Is world trade becoming more concentrated?
Gaulier & Steingress (2020), tracking global value-chain unbundling through BACI, document that the median product became more, not less, concentrated after 2001 as China took over entire HS6 categories. Below, the world-average top-1 exporter share across every HS6 line traces that arc: a slow rise from 29% in 1995 to 34% in 2024. The drop in 2020 reflects a Covid-year reshuffling rather than a trend break, by 2024 the series has resumed its upward path.
Figure 5a
World average top-1 exporter share per HS6, 1995-2024
Across ~4,637 HS6 lines, the unweightedaverage top exporter's share of world trade rose by +5.0 pp between 1995 and 2024. This counts every HS6 line equally, so it is sensitive to niche products where one country dominates a thin market; a value-weighted version (weighting each HS6 by its share of world trade) would down-weight such niches. The unweighted trend documented here is the construct used by Gaulier & Steingress (2020); read it as a count-based concentration signal, not as a value-share of world trade.
Method: for each year × HS6, compute the largest exporter's share of world exports; take the UNWEIGHTED mean across HS6. A value-weighted version would be a different series. After Gaulier & Steingress (2020) 'Trade in Value Added and the Decoupling Narrative,' CEPII Working Paper. Source: CEPII BACI 202501 (retrieved 2026-04-28).Figure 5b
World average supply-side HHI per HS6, same period
Method: world-average Herfindahl over exporter shares per HS6, on the 0-10,000 scale. Hirschman (1945); Herfindahl (1950).
Where in the chain is the concentration? Upstreamness by BEC stage
Antràs & Chor (2013, Econometrica81:6) formalised upstreamness as the weighted mean steps-to-final-demand implied by the Leontief inverse; Antràs, Chor, Fally & Hillberry (2012, AER P&P) built the cross-country series. A coarser but globally comparable cut is the UN BEC classification (primary, semi-finished, parts, capital, consumption). We plot world trade composition by stage, 2000-2024. The intermediate stages (primary + semi-finished + parts) correspond to Antràs-Chor Ui> 2 and are the layers where concentration propagates most (Baqaee & Farhi 2019, Econometrica 87:4). Baldwin (2013, WTO/Fung) coined this the 'second unbundling': tasks, not goods, are what crosses borders.
Figure 6
World trade composition by BEC production stage, 2000-2023
CR4 and CR8 on the 20 most-concentrated HS6 lines
HHI captures second-moment concentration; concentration ratios CRN are the top-N exporter cumulative share (Bain 1951, QJE; Saving 1970, IER; Miller-Pauly-Sobel 2000, International Economic Review 41:3). For supply-chain risk, CR4 is the share that a four-country blockade would take out and CR8 the share a G7+friends-only exclusion would still leave exposed. The DOJ/FTC (2023) Horizontal Merger Guidelines use HHI; Miller-Pauly-Sobel (2000) argue CRNtracks disruption pass-through more linearly because concentration ratio is invariant to small-tail reshuffling.
Figure 7
Top-20 concentrated HS6 lines: CR4 and CR8 exporter share, 2024
The Baldwin unbundling index: trade-in-intermediates share, 2000-2023
The Herfindahl, CRN, and single-source measures above are all snapshots. Baldwin's (2013, in Elms & Low eds., Global Value Chains in a Changing World, WTO/FGI) 'second unbundling' thesis is the time-series backbone behind why those snapshots look the way they do: once ICT and air cargo made it cheap to coordinate multi-country production, the share of world trade that is intermediate (primary + semi-finished + parts & components) rose relative to the share that is final (capital + consumption goods). We operationalise the Baldwin index as the UN-BEC intermediate-stage trade divided by total world trade, annually from 2000 to 2023. A rise means the world produces more jointly; a fall means re-shoring or regionalisation is winning. Pair this with the CR4/HHI data above: if the unbundling index is rising but CR4 on intermediate HS6 lines is also rising, the world is simultaneously more interconnected andmore concentrated, which is the specific fragility pattern Baqaee & Farhi (2019, Econometrica 87:4) show propagates shocks super-linearly.
Figure 8
Baldwin unbundling index: intermediates (primary + semi + parts) as share of world trade, 2000-2023
The intermediate share moved from 58.9% in 2000 to 61.5% in 2023, a net change of +2.6 pp. The peak was 64.5% in 2022. Read the series against three break points in the literature: 2001 WTO accession of China (Autor-Dorn-Hanson 2013 AER103:6), the 2008 global financial crisis (which compressed trade sharply but not permanently), and the 2018 US-China tariff war plus Covid (which is where Baldwin & Freeman 2022 argue the second unbundling plateaued). Slow-down, not reversal, is the right reading of the post-2018 data.
Source: UN COMTRADE WITS BEC stage classifications, world aggregate totals from global_trade_by_stage.parquet, 2000-2023. Method: share = (primary + semi-finished + parts & components) / total world trade by year. Literature: Baldwin (2013) "Global Supply Chains: Why They Emerged, Why They Matter, and Where They Are Going" in Elms & Low (eds.) Global Value Chains in a Changing World (WTO/Fung Global Institute); Baldwin & Freeman (2022) "Risks and global supply chains: What we know and what we need to know" Annu Rev Econ 14; Baqaee & Farhi (2019) Econometrica 87:4; Autor, Dorn & Hanson (2013) AER 103:6.
The cleanest descriptive proxy for the post-2018 'Great Reallocation' (Alfaro & Chor 2023, NBER 31661) is foreign direct investment into Mexico, the closest low-cost production base to the US market and the only USMCA partner with meaningful industrial capacity. US Census FT-900 reports that Mexico overtook China as the largest source of US goods imports in 2023 for the first time since 2002. The World Bank WDI series BX.KLT.DINV.CD.WD tracks net FDI inflows in current USD; we plot Mexico 2015-2024 below and compare the 2024reading against the 2015-2021 pre-IRA average. Freund, Mulabdic & Ruta (2022, World Bank Economic Policy) document that nearshoring reallocations follow FDI before they show up in customs data, so this chart leads Figures 1-8 by roughly two years.
Figure 9
Mexico FDI net inflows, current USD, 2015-2024
Mexico received $45.5B in net FDI inflows in 2024, +31% against the 2015-2021 pre-IRA average of $34.8B. The step-up after 2022 coincides with IRA enactment and with the Mexican auto and electronics manufacturing build-out documented in Bown (2023, PIIE WP 23-1). FDI is a leading indicator of trade: Freund, Mulabdic & Ruta (2022) show typical lags of two to three years between a location-decision FDI shock and measurable export reallocation in customs data.
Source: World Bank World Development Indicators, indicator BX.KLT.DINV.CD.WD (Foreign direct investment, net inflows, BoP, current USD), iso3 MEX, 2015-2024. Literature: Alfaro & Chor (2023) NBER 31661 'Global Supply Chains: The Looming Great Reallocation'; Freund, Mulabdic & Ruta (2022) 'Is 3D Printing a Threat to Global Trade?' Journal of International Economics 138; Bown (2023) PIIE WP 23-1; US Census FT-900 monthly goods-trade release.
Bown's semiconductor tracker: world trade in the HS6 lines CHIPS + IRA target
Bown (2023, PIIE Working Paper 23-1) and Bown & Clausing (2023) argue that the semiconductor incentives in the CHIPS and Science Act ($52.7B, P.L. 117-167, enacted 9 Aug 2022) and the battery/clean-energy rules in the Inflation Reduction Act ($369B CBO score, P.L. 117-169, enacted 16 Aug 2022) are most precisely read off six HS6 lines: integrated circuit processors and controllers (HS 854231), memory ICs (854232), amplifier ICs (854233), other ICs (854239), doped semiconductor wafers (HS 381800), and semiconductor fabrication machinery (HS 848620). The last line, ASML / Applied Materials / Tokyo Electron / Lam Research lithography and deposition tools, is the canonical leading indicator of fab capacity build-out, because the tools ship 6 to 18 months before the wafers they produce appear in customs data. Total world trade in these six lines at 2024 stands at $970.4B, a -13% move from the 2022 enactment baseline of $1.12T.
Figure 10
Bown semiconductor tracker: world exports in 6 CHIPS + IRA HS6 lines, 2015-2024
Where the critical-input exposure sits: sectoral cut by importer
Figure 3 measured single-source dependence as a count over the entire HS6 import basket. The OECD geodep panel (Arjona, Connell & Pisu 2023, ECO/WKP 1775) goes further: each critically-dependent HS6 line is tagged to one of seven WTO-style strategic sectors (agri-food, chemicals, pharmaceuticals, steel, defence, transport, electronics) plus an 'other' bucket. This decomposition is what the European Commission's 2023 Economic Security Strategy (JOIN(2023) 20 final, 20 June 2023) and the US Department of Commerce's 100-day supply-chain review (E.O. 14017, 24 February 2021) both use to score 'strategic dependence': not the raw count of dependencies but the count weighted by how strategic the underlying sector is. The bars below report, for the 15 importers with the highest total critical-product count in 2022, how that count splits across the seven strategic sectors.
Figure 11
Critical-product exposure by importer × strategic sector, 2022
Policy read: IRA, CHIPS, CRMA, dual circulation
The four panels of Figures 2, 4, 6 and 7 together describe the fragility pattern that the post-2022 industrial-policy wave is pushing against. The US Inflation Reduction Act(H.R. 5376, 16 Aug 2022) and CHIPS Act (P.L. 117-167) use local-content rules and foreign-entity-of-concern exclusions to pull battery, semiconductor and clean-energy supply chains away from the concentrated-and-distant corner of Figure 7. The EU Critical Raw Materials Act (Regulation (EU) 2024/1252, 11 April 2024) sets a 65% ceiling per third-country origin per strategic raw material, which is a direct response to Figure 4's single-country export shares. China's dual-circulation strategy (14th Five-Year Plan, 2021) plus the 2023 MOFCOM export controls on gallium, germanium and graphite run in the opposite direction: convert Figure 4's concentration into leverage. The lesson is symmetric: the same HS6 lines are strategic from both ends.
References
Antràs, P., & Chor, D. (2013). 'Organizing the Global Value Chain.' Econometrica 81(6): 2127-2204.
Antràs, P., Chor, D., Fally, T., & Hillberry, R. (2012). 'Measuring the Upstreamness of Production and Trade Flows.' American Economic Review Papers & Proceedings 102(3): 412-416.
Arjona, R., Connell, W., & Pisu, M. (2023). 'An analysis of international trade interdependencies.' OECD ECO/WKP 1775.
Baldwin, R. (2013). 'Global Supply Chains: Why They Emerged, Why They Matter, and Where They Are Going.' In Elms & Low (eds.), Global Value Chains in a Changing World. WTO / Fung Global Institute.
Baqaee, D., & Farhi, E. (2019). 'The Macroeconomic Impact of Microeconomic Shocks: Beyond Hulten's Theorem.' Econometrica 87(4): 1155-1203.
Beck, R., Georgiadis, G., & Gräb, J. (2021). 'Rising Geoeconomic Fragmentation and Critical Inputs.' IMF Working Paper.
Chowdhry, S., & Felbermayr, G. (2023). 'Trade in Times of Uncertainty.' Kiel Working Paper.
Gaulier, G., & Steingress, W. (2020). 'Trade in Value Added and the Decoupling Narrative.' CEPII Working Paper.
Goldberg, P. K., & Pavcnik, N. (2007). 'Distributional Effects of Globalization in Developing Countries.' Journal of Economic Literature 45(1): 39-82.
Johnson, R. C., & Noguera, G. (2012). 'Accounting for Intermediates: Production Sharing and Trade in Value Added.' Journal of International Economics 86(2): 224-236.
Miller, M. H., Pauly, M. V., & Sobel, J. (2000). 'Disruption of Supply Networks.' International Economic Review 41(3).
11 of the top 20 lines with majority single-country supply are held by China. The largest by trade value is HS 847193 (Data processing machinery: storage units, whether or not presented wit) with China at 70% of US$171.6B in world exports.
Method: Chowdhry & Felbermayr (2023) 'Trade in Times of Uncertainty,' Kiel Working Paper. Single-exporter share > 0.5 on CEPII BACI HS6 exports.
SWZ sources 87% of its 4,281 imported HS6 lines from a single foreign supplier; the next two most dependent importers are LSO (83%) and BWA (60%). Small open economies and landlocked states dominate the top of the ranking; even large industrial importers have double-digit single-source shares.
The concentration is stark: cobalt ores (HS 260500), DRC at 70%; lithium carbonate (HS 283691), Chile at 75%; lithium hydroxide/oxide (HS 282520), China at 76%; rare-earth compounds (HS 284690), Myanmar at 34%. Across the six HS6 lines plotted, the smallest top-exporter share is 34%.
Source: CEPII BACI HS6 exports 2024; product codes follow USGS Mineral Commodity Summaries 2024. Method note after IEA (2022). CAVEAT: these are EXPORT-market shares, not mining-production shares. USGS MCS 2024 reports DRC at ~74% of mined cobalt and Australia at ~46% of mined lithium (spodumene), but those mining shares do not equal BACI export shares because (i) producers may refine or consume domestically rather than export ore, (ii) ore shipped for refining crosses jurisdictions (e.g. DRC → China), and (iii) spodumene, carbonate and hydroxide map to different HS lines.
The upstream bucket (primary + semi-finished + parts & components) is the majority of world trade every year since 2000, and concentration in Figures 1 and 2 mostly sits in this bucket (specialty chemicals, ores, intermediate components). A shock to a concentrated HS6 line in this band passes through many more subsequent steps than a shock to a final consumption good, which is the super-linear propagation result in Baqaee-Farhi (2019).
Across the 20 most concentrated lines in Figure 1, the average CR4 is 93% and the average CR8 is 96%. A CR4 above 80% means four countries set world pricing for the product; above 90% they effectively set world quantity too. These are the lines where a single export control or a coordinated G7 friendshoring measure would move world prices within weeks.
Method: cumulative share of top-4 and top-8 exporters of each HS6, world exports 2024. Literature: Bain (1951) QJE 65:3; Saving (1970) IER 11:1; Miller-Pauly-Sobel (2000) Int Econ Review 41:3; US DOJ/FTC (2023) Horizontal Merger Guidelines. Source: CEPII BACI 202501 (retrieved 2026-04-28).
The dominant line by value is IC processors and controllers (HS 854231), the single largest line at around two-fifths of the six-line basket, tracking Taiwan's TSMC and Korea's Samsung output. Memory ICs (854232) track the Samsung / SK Hynix / Micron cycle (the 2023 trough is visible). The fab-machinery line (848620) is the leading indicator: a sustained step-up there foreshadows wafer output 12-18 months later. Bown (2023, PIIE WP 23-1) frames the CHIPS + IRA test as whether US and allied shares within these six lines grow visibly faster than the global basket, the partner-resolved cut required for that answer is not in this workbench (BACI is country-product, not bilateral-product), but the aggregate trajectory here is the base case the partner-resolved series would modify.
Source: CEPII BACI 202501 (retrieved 2026-04-28), HS22 revision (country_year_product_ext) for semiconductor HS6 lines 854231 (IC processors/controllers), 854232 (memories), 854233 (amplifiers), 854239 (other ICs), 381800 (semiconductor wafers, doped), 848620 (semiconductor fab machinery). Policy context: CHIPS and Science Act (H.R. 4346, P.L. 117-167, 9 Aug 2022, $52.7B appropriation per Division A Title XCIX); IRA (H.R. 5376, P.L. 117-169, 16 Aug 2022, $369B CBO score). Literature: Bown (2023) PIIE WP 23-1; Bown & Clausing (2023) on post-IRA global-subsidy races. Values in current USD (BACI stores thousands USD; multiplied by 1,000 for display).
KOR records the largest critical-product count at 476 HS6 lines, of which 148 (31%) sit in the six WTO-style strategic sectors (chemicals, pharmaceuticals, electronics, steel, defence, transport) rather than the catch-all 'other' bucket. Across the top 15 the chemicals and pharmaceutical buckets dominate the strategic count, followed by electronics; the agri-food and defence buckets are thin everywhere because the underlying tariff sub-books are themselves narrow. The European Commission's Economic Security Strategy (JOIN(2023) 20 final) and the US 100-day supply chain review (E.O. 14017) both treat the chemicals + pharma + electronics triad as the highest-priority dependence cluster, which is what these bars show.
Source: OECD geodep_country_summary (Arjona, Connell & Pisu 2023, ECO/WKP 1775), year 2022, restricted to importers with >= 4,000 HS6 lines. Sector tags follow the OECD geodep crit_* fields, which mirror the WTO sectoral dependency taxonomy used in EU JOIN(2023) 20 final (Economic Security Strategy, 20 June 2023) and US E.O. 14017 (24 February 2021). Counts are number of HS6 lines flagged as critical (high import dependence + low substitutability) per sector.