Key Takeaways
- New research from ARK Invest and Glassnode finds that just three entities are enough to cross critical block-production thresholds on both Bitcoin and Ethereum, although that does not mean three companies directly control either network.
- Bitcoin still ranked as the most decentralized of Bitcoin, Ethereum and Solana overall, helped by low verification costs, geographic distribution and miners’ ability to switch pools quickly.
- Willy Woo argues Bitcoin may also be moving away from its familiar four-year market cycle as new supply falls toward negligible levels, leaving global liquidity and traditional debt cycles with greater influence.
Bitcoin and Ethereum are supported by thousands of miners, validators, nodes and users around the world. Yet a new attempt to measure decentralization has found a surprisingly narrow pressure point underneath both networks.
A joint ARK Invest and Glassnode study published Sept. 1 found that the minimum number of entities required to reach a critical block-production threshold is just three for Bitcoin and three for Ethereum.
Solana, by comparison, requires 19.
That finding sounds much worse than it is if read as “three companies control Bitcoin.” They do not. But it exposes the difference between the number of people participating in a blockchain and where their mining or staking power is actually coordinated.
Bitcoin’s 51% Threshold Can Be Reached by Three Mining Pools
For Bitcoin, the calculation centers on mining pools.
The report uses the 51% hash-rate threshold, above which coordinated miners could theoretically gain enough block-production power to reorganize transactions or censor particular transactions.
Its 2026 snapshot puts Foundry USA at 27.27% of the mining pool hash rate, AntPool at 17.06%, and F2Pool at 16.96%. Together, the three account for about 61.3%, comfortably above 51%.
But a mining pool is not the same as a mining company owning all the machines connected to it.
Individual miners direct their computing power to pools to smooth out revenue and can move that hash rate elsewhere. ARK and Glassnode estimate that exiting a 1% Bitcoin mining position can take roughly 30 seconds, making Bitcoin’s concentration considerably more fluid than the headline number suggests.
That mobility matters because pool concentration has already produced smaller real-world effects.
In March, Foundry briefly mined seven consecutive Bitcoin blocks, producing a rare two-block reorganization that replaced blocks previously produced by AntPool and ViaBTC. Bitcoin resolved the event normally by following the chain with the most accumulated proof of work, and the episode was not a 51% attack. But it showed how concentrated mining can increase the likelihood that a single pool produces several consecutive blocks.
Ethereum Also Reaches Its Critical Threshold With Three Entities
Ethereum has a different weak point because it uses proof-of-stake.
Here, the relevant line is 33% of staked ETH. An entity or coordinated group controlling more than one-third cannot simply steal everyone’s ETH, but it could interfere with Ethereum’s ability to reach finality.
ARK and Glassnode found that only three staking entities were needed to cross that threshold in their dataset.
Again, the number needs context.
Ethereum staking is frequently aggregated through services that represent many separate users and, in some cases, many separate node operators. Lido, for example, is a protocol rather than one server farm controlled by a single operator.
Lido’s own H1 2026 report shows just how quickly that landscape is changing. Its share of staked ETH fell from 23.93% at the beginning of the year to 21.18% by June 30, even as the amount staked through Lido rose to 9.13 million ETH. Institutional staking, meanwhile, expanded from 25.9% to 35.3% of the market during the period.
Coinbase separately reported an average of 4.76 million ETH staked to its validators during the second quarter, equal to 12.16% of total staked ETH.
The issue, therefore, is not necessarily ownership. It is how much coordination can accumulate at a small number of gateways.
Why Solana Needs 19 — But Bitcoin Still Ranks More Decentralized
The most counterintuitive result concerns Solana.
ARK and Glassnode estimate that 19 validator entities would need to coordinate to reach Solana’s comparable 33% threshold, substantially more than Ethereum’s 3.
That does not make Solana the most decentralized blockchain in the study.
The report deliberately measures more than validator distribution. It also looks at ownership, node accessibility, exit flexibility, blockchain reconstruction costs, and physical infrastructure.
Bitcoin ultimately ranked strongest overall. About 63% of its measured nodes operated through Tor, while another portion was residential or self-hosted. Ethereum had greater cloud exposure, with approximately 20% of nodes hosted by AWS, while Solana’s infrastructure was overwhelmingly concentrated in professional data centers.
Decentralization, in other words, produces different weak points depending on where it is measured.
Willy Woo Says Bitcoin’s Four-Year Cycle May Be Weakening Too
The structural debate comes as analyst Willy Woo argues that another defining characteristic of Bitcoin may also be changing: its four-year market cycle.
Woo said Bitcoin’s price history has long been shaped by the supply shock created by each halving. But annual new supply has now fallen to roughly 0.8%, and he expects it to decline toward 0.4% after the next halving.
With the supply shock easing, Woo argues that Bitcoin could begin moving closer to traditional finance’s six-to-eight-year short-term debt cycle, making global liquidity and macro conditions more important than the halving calendar.
“BTC has been locked into the gravity of a 4 year orbit,” Woo wrote, before arguing that its internal supply forces are becoming “de minimis.”
It remains a hypothesis, not evidence, that Bitcoin has entered a new six- to eight-year cycle. But it fits a broader change in how the network is being assessed.
Bitcoin is becoming large enough that simple labels increasingly explain less. A network can rank as the most decentralized major blockchain while still routing more than half its mining power through three pools. And Bitcoin can have a fixed supply of 21 million, while its price becomes increasingly dependent on the liquidity cycle outside Bitcoin itself.
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Dr. Guneet Kaur is a senior editor at CCN.com and a Science Fellow at Exponential Science. She is a fintech and blockchain expert with extensive experience in digital finance education, blockchain ecosystems, and cryptocurrency markets. She has worked with global media such as Cointelegraph, as well as education and blockchain platforms, to design and lead strategic content and learning initiatives. As an educator and assessor for top-tier executive programs, she bridges real-world fintech trends with academic insight.
Dr. Kaur is also a published researcher and peer reviewer across fintech and data science journals, including Financial Innovation Journal and International Journal of Big Data Intelligence and Applications. Her work spans data-driven analysis, Web3 innovation, and technical content development. With a strong foundation in both industry and academia, she translates complex financial technologies into practical applications, empowering learners, professionals, and institutions across the rapidly evolving digital finance landscape.
