An address is not a person or wallet
One person may control thousands of addresses, while a custodian's address may aggregate coins belonging to thousands of customers. Change outputs, multisig and an exchange's internal ledger further disrupt simple counts. A rich-address list measures the distribution of outputs, not human wealth directly.
Analysts use heuristics, public labels and proprietary records to cluster addresses into entities. Makarov and Schoar used such methods and found high concentration among large individual holders. Their result is important evidence for a particular period and method, not a live registry of every owner.
Concentration is real; the exact share is uncertain
Early participants could acquire many BTC when competition was low, and later market prices created large wealth differences. Lost keys, unknown beneficial owners behind custodians and transfers among one's own addresses alter both assignments and denominators. Credible studies can therefore report different percentages.
Concentration raises a distributional concern and a large sale may move markets. A large balance does not grant authority to sign another person's coins, create a valid invalid block or rewrite issuance alone. Bitcoin is not proof of stake, where coin quantity directly weights a consensus vote.
A miner, pool, manufacturer and node hold different power
Individual miners commonly direct work to a pool that assigns jobs and distributes revenue. Pool-share charts therefore show concentration in block-production coordination, not necessarily ownership of all machines. A miner can switch pools, although switching has friction and a pool can influence transaction selection or ordering in the short run.
Cambridge's report also found a highly concentrated ASIC manufacturing market. That is a supply-chain risk distinct from pools. Developers propose and maintain software, but nodes choose releases; exchanges influence liquidity and ticker naming, but cannot alone make every full node accept an invalid rule.
- coins confer market wealth
- hashrate influences the ordering of valid blocks
- a node decides which rules it accepts
- developers and services influence coordination
Open access is not equal distribution
Bitcoin lets anyone create an address or verify rules without a central account allocation. It does not guarantee equal incomes, equal entry dates or equal access to cheap energy and hardware. An open protocol and unequal outcomes can coexist.
A sound assessment therefore tracks several measures: beneficial owners, exchange liquidity, pools, physical operators, hardware manufacturers, client software and geography. No single Nakamoto coefficient or Gini index captures every channel of power.