ARK Invest and on-chain analytics firm Glassnode said in a joint research report that, based on block production concentration, Bitcoin and Ethereum would each need only three major entities working together to cross their respective critical consensus thresholds. Solana would require 19 validator entities.
The report, titled The Decentralization Spectrum: Design Tradeoffs in Digital Assets, uses the Nakamoto coefficient to measure how many independent entities would need to collude to control enough hash power or staking weight to disrupt network operations. For Bitcoin, the study uses a 51% network hash power threshold. For Ethereum and Solana, it uses a 33% staking-weight threshold, mainly reflecting the liveness risk of preventing the network from reaching finality.
Bitcoin and Ethereum were both assigned a Nakamoto coefficient of 3
Using a July 2026 data snapshot, the report said Foundry USA controlled 27.27% of Bitcoin mining pool hash power, while AntPool and F2Pool accounted for 17.06% and 16.96%, respectively. Combined, the three represented about 61.29%, above the 51% threshold. On that basis, Bitcoin’s Nakamoto coefficient was listed as 3.
For Ethereum, Lido accounted for 23.04% of staked ETH, while Binance and Kraken held 8.88% and 6.91%, respectively. Together, the three accounted for about 38.83%, above the 33% threshold, leaving Ethereum with a Nakamoto coefficient of 3 as well.
Solana would need 19 validator entities
The report said Solana’s largest validator, Figment, held only 3.78% of delegated stake. It would take the top 19 validators combined to cross the 33% threshold.
The report says this does not mean three institutions can fully take over either network
The study also warned against reading the result as proof that three institutions could fully seize control of Bitcoin or Ethereum.
For Bitcoin, the metric is based on mining pool hash power, and participating miners can redirect their hash power to other pools. Mining pools may influence block templates, transaction inclusion, and ordering, but that is not the same as owning the underlying mining machines or the Bitcoin held by miners.
On Ethereum, Lido is a liquid staking protocol operated by multiple node operators rather than a single validator. The report said that controlling more than one-third of staking weight can obstruct finality, but sustaining control over fork choice or finalizing preferred blocks independently would require a higher share of stake.
Thresholds are not directly comparable across chains
The report also said Bitcoin’s 51% threshold and the 33% threshold used for proof-of-stake networks are not the same. As a result, the authors said it is not valid to conclude from a simple “3 versus 19” comparison that Solana is, overall, more decentralized than Bitcoin or Ethereum.
Glassnode said the three chains show different trade-offs across different dimensions. Bitcoin scored better in independent verification, ownership distribution, and geographic resilience. Solana posted a higher Nakamoto coefficient in validator staking-weight dispersion, but it also showed greater dependence on node hardware and data centers.