Bitcoin mining is globally distributed, yet three pools coordinate the majority of block production, raising questions about who truly controls the network. While Foundry USA, AntPool, and F2Pool account for approximately 61.46% of observed mining activity over the past year, this concentration at the pool layer does not automatically mean these operators own 61% of Bitcoin's mining equipment.

What's the Difference Between Pool Operators and Hardware Owners?

Understanding Bitcoin mining concentration requires separating two distinct layers: the physical mining layer and the pool coordination layer. The physical layer consists of companies and independent operators that own or operate ASIC machines, mining facilities, and electrical infrastructure. The pool coordination layer includes mining pools that aggregate computing power from participating miners and coordinate block production.

This distinction is crucial because a mining company can operate its own machines while directing some or all of its computing power to an external pool. Conversely, a large pool can coordinate computing power supplied by many miners without owning the underlying hardware. A pool producing 20% of observed Bitcoin blocks should not automatically be interpreted as a single company owning 20% of the network's mining equipment.

How Concentrated Is Bitcoin Mining Really?

Recent data from Hashrate Index reveals the scale of pool concentration. Foundry USA leads with approximately 24.82% of observed pool hashrate over a one-year period, followed by AntPool at 20.33% and F2Pool at 16.31%. Together, these three pools represent approximately 61.46% of the one-year distribution. The concentration extends further down the ranking, with SpiderPool accounting for approximately 8.75% and MARA Pool representing about 5.20% over the same period.

The one-year measurement window provides a more stable view of mining-pool concentration than short-term snapshots. Short-term pool shares can move significantly as blocks are discovered and miners redirect computing power. This stability matters because it reveals a fundamental reality: a majority of observed Bitcoin mining-pool hashrate is coordinated through just three pools.

• Foundry USA: Approximately 24.82% of observed pool hashrate, the largest single pool operator
• AntPool: Approximately 20.33% of observed pool hashrate, the second-largest pool coordinator
• F2Pool: Approximately 16.31% of observed pool hashrate, the third-largest pool in the network
• SpiderPool: Approximately 8.75% of observed pool hashrate, representing the next tier of pool operators
• MARA Pool: Approximately 5.20% of observed pool hashrate, rounding out the top five pool coordinators

Why Pool Concentration Still Matters for Bitcoin's Decentralization

Even though pool concentration does not directly equal hardware ownership, it remains relevant to Bitcoin's decentralization debate. Pool operators play an important role in constructing candidate blocks and coordinating the work miners perform. If a large share of network hashrate relies on a small number of coordinators, the distribution of that coordination becomes a critical part of understanding Bitcoin's actual decentralization.

Pool operators can influence block construction and transaction selection, which means the distribution of decision-making power is as important as the distribution of physical mining machines. This is why understanding Bitcoin's mining decentralization requires looking at both who owns the hashrate and who coordinates it.

How Are Miners Addressing Pool Concentration?

Major industry participants are taking steps to reduce dependence on centralized pool operators. Foundry USA, AntPool, F2Pool, MARA Foundation, and SpiderPool all joined the Stratum V2 Working Group in 2026, an initiative developing an open mining protocol designed to improve efficiency, privacy, security, and miner autonomy. This collaborative effort suggests that pool operators themselves recognize the importance of addressing concentration concerns.

New mining protocols such as Stratum V2 are designed to give individual miners greater autonomy, potentially reducing some of the dependence on pool operators in block construction. By enabling miners to maintain more control over their own work, these protocols could reshape the relationship between individual miners and the pools that coordinate their hashrate.

Steps to Evaluate Mining Concentration Accurately

• Distinguish Pool Share from Hardware Ownership: Recognize that a pool's market share does not equal the pool operator's ownership of mining equipment; pools coordinate hashrate from independent miners who may own their own machines
• Use Long-Term Data Windows: Rely on one-year or multi-year pool distribution data rather than daily or weekly snapshots, which can fluctuate significantly as blocks are discovered and miners redirect computing power
• Assess Decision-Making Power: Evaluate not just who owns mining hardware but who coordinates block construction and transaction selection, as this distribution of coordination power affects Bitcoin's actual decentralization
• Monitor Protocol Developments: Track initiatives like Stratum V2 that aim to reduce miner dependence on pool operators and increase individual miner autonomy over block construction
• Track Hardware Ownership Separately: Seek data on which companies and operators actually own or operate ASIC machines and mining facilities, as this reveals the true physical distribution of mining power

The mining pool landscape continues to evolve as the industry matures. While concentration at the pool layer remains significant, the distinction between pool operators and hardware owners means the story of Bitcoin mining control is more nuanced than headline market-share figures suggest. As new protocols emerge and miners gain greater autonomy, the relationship between centralization and decentralization in Bitcoin mining will likely continue to shift.