Mining Pool Concentration HHI
Herfindahl-Hirschman Index applied to top 10 mining pools hash share - concentration of hash power. CBECI Cambridge methodology, range [0, 10000] where 10000 = monopoly. Distinct from `supply-concentration-hhi` which measures BTC supply distribution.
What is it?
This metric applies the Herfindahl-Hirschman Index to the 10 top 10 mining pools (foundryusa, antpool, f2pool, viabtc, binancepool, marapool, poolin, bwpool, braiinspool, spiderpool). Formula : HHI = Σ (share_i)² × 10,000, with 30d rolling smoothing for stability. Theoretical range [0, 10,000] : 0 = perfect distribution, 10,000 = pure monopoly. DOJ Antitrust conventions transposed to crypto industry : < 1,500 = unconcentrated, > 2,500 = concentrated.
How to read
Y axis : HHI value ∈ [0, 10,000]. High reading = dominant pool or few dominant pools (concentration). Low reading = pools more evenly distributed (decentralization). Crossing of 2,500 threshold = switch to « concentrated » zone by DOJ convention. Crossing of 1,500 threshold = exit from « unconcentrated » zone. The value is 30d smoothed to neutralize daily noise.
Key zones
Zone < 1,500 : unconcentrated pool market (historically rare, pre-China ban 2021 maximum fragmentation). Zone 1,500-2,500 : moderately concentrated (normal regime). Zone 2,500-5,000 : structurally concentrated (post-2022 regime with Foundry + AntPool dominance). Zone > 5,000 : strong centralization (rare). Zone > 10,000 impossible (pure monopoly). BTC HHI has historically stayed between 1,500 and 3,000.
What to observe
Watch long-term trend changes : an HHI gradually climbing toward 3,000 = continued consolidation (fewer pools dominate). A declining HHI = fragmentation, mining democratization. Compare with `top-3-pools-share` : HHI captures GLOBAL top 10 concentration, top-3-pools-share captures EXTREME concentration (3 leaders). Both typically converge.
Historical context
Pre-China ban (before 2021-06-21) : HHI typically around 1,500-2,000 (Chinese + Western fragmentation). Post-China ban : massive exodus → HHI temporarily jumped (loss of F2Pool / Poolin / BTC.com Chinese share + FoundryUSA emergence). 2022-2023 stabilization around 2,200-2,800 (Foundry + AntPool dominate). 2024-04-19 halving : HHI structurally +10% (consolidation of pools with capital). Bitcoin HHI remains lower than other mining industries (vs gold mining HHI > 5,000).
Expert notes
Cambridge CBECI standard institutional HHI methodology. Trinity computes on top 10 pools (coverage ~85-95% of hash power). For absolute HHI (including solo miners + small pools), would require exhaustive attribution - Trinity uses top 10 attributable + others bucket non-weighted in HHI (others does not increase concentration but does not formally reduce it either). In practice, the gap vs exhaustive HHI is marginal for Bitcoin (solo miners contribute <5% of hash power).
Common mistakes to avoid
DIFFERENTIATION WARNING : do not confuse `mining-pool-concentration-hhi` with `supply-concentration-hhi`. The FORMER measures MINING POWER centralization (hash power distributed among pools) ; the LATTER measures BTC STOCK centralization (supply distributed among addresses). Distinct dimensions. A high mining HHI = theoretical 51% attack risk. A high supply HHI = market manipulation risk (whales). Both are independent and must not be aggregated nor confused in cycle analysis.
Programmatic access
REST API
curl -sS \
'https://api.trinityinsights.io/api/v1/onchain/mining-pool-concentration-hhi/history?days=90' \
-H 'X-API-Key: $TRINITY_API_KEY'MCP server
{
"tool": "get_chart_value",
"metric_id": "mining-pool-concentration-hhi",
"timeframe": "1y"
}Required tier: performance. See the pricing grid for the tier list and the MCP documentation for multi-client configuration.
Related metrics
Institutional disclaimer
Trinity Insights is an educational and analytical tool. The metric above does not constitute investment advice. Trinity Insights is not a Crypto-Asset Service Provider (CASP) registered under MiCA Regulation (EU) 2023/1114. See the full disclaimer.