Mining Pool Centralization is the concentration of pooled mining or decision-making authority among a small number of pools. An assessment must specify whether it measures attributed blocks, connected hashrate, template construction, payouts or actual operational control.
Bitcoin Developer Guide describes a Mining Pool as combining individual miners’ work and distributing rewards. A pool’s share therefore does not establish that its operator owns the same share of ASICs. Separately identify who selects transactions, who holds payout funds and who can redirect device work. [Bitcoin Developer Guide — Pool mining] [Stratum V2 — Job Declaration Protocol]
The mempool project attributes pools using coinbase_tags and payout_addresses. These are recognition rules for coinbase tags and addresses, not an ownership register of all connected machines. Keep an unknown block unknown; automatically assigning it to the largest pool would invent information the data do not establish. [mempool — Mining pool attribution]
Illustration: of 100 blocks, 40 belong to pool A, 20 to B, 20 to other known pools and 20 are unknown. A+B represent 60% of all blocks but 75% of identified blocks alone. This is not the current network. Report the full period and unknown cases; random discoveries in a short window are not an exact inventory of physical hashrate. [Bitcoin Developer Guide — Pool mining] [mempool — Mining pool attribution]
The mempool README warns that inconsistent renaming can create two entries for the same pool. Updating pools-v2.json can also trigger reassignment of previously unknown or affected blocks. Preserve the mapping version and grouping rules when comparing periods; a chart change may be a data correction rather than miners moving. [mempool — Mining pool attribution]
The Stratum V2 Mining Protocol can operate without Job Declaration and let the pool distribute work unilaterally. A deployed Job Declaration setup with JDC, JDS and a Template Provider enables miner-side transaction selection. A Stratum V2 label alone therefore does not demonstrate decentralized template construction. [Stratum V2 — Mining Protocol] [Stratum V2 — Job Declaration Protocol]
Job Declaration distinguishes Coinbase-only, where the pool does not know the transaction set, from Full-Template, where JDS can obtain transaction data. On rejection or non-response, it requires JDC to switch to another Pool+JDS, or solo. This needs a working alternative; it proves neither instant migration of all miners nor separation of payout operators by itself. [Stratum V2 — Job Declaration Protocol]
Section 11 of the Bitcoin whitepaper explains that even producing an alternative chain faster cannot arbitrarily create coins or spend others’ outputs without authorization. Concentration can raise concerns over coordinated reordering or exclusion of transactions; a sum of chart shares alone proves neither collusion among pools nor nodes accepting invalid blocks. [Bitcoin whitepaper — Calculations]
Cambridge’s 2025 report overview cites 49 mining firms covering 48% of hashrate at collection time. It also acknowledges potential overstatement of the US share due to stronger participation by US firms. These are sampled operational data, not today’s complete network map. A pool’s headquarters or coinbase tag does not locate all connected devices. [Cambridge — Digital Mining Industry Report 2025 overview]
For the clearest picture, read this entry together with Mining Pool, Hashrate, Job Negotiation, Proof of Work. The reverse links also lead from Selfish mining, Jihan Wu.