Market capitalisation is price multiplied by circulating supply, and the second term is not an observed fact. It is an estimate produced by applying a definition to on-chain balances.
Total supply and circulating supply differ
Total supply counts every token that exists. Circulating supply attempts to count only those genuinely available to trade.
The gap covers locked allocations, treasury holdings, tokens reserved for future emission and anything provably burned.
Deciding which of those belong in the second figure requires judgement, and the judgement is what data providers disagree about.
No rule forces a project to report either number a particular way, so the input is frequently supplied by the project itself and accepted with limited verification.
Treasury holdings are the main argument
A project treasury holding a large allocation can spend it at any time, so those tokens are not locked in any technical sense.
Excluding them treats a discretionary holding as unavailable, and including them treats tokens nobody intends to sell as float.
Providers split on this, which is why the same token can show materially different market capitalisations on two sites at the same instant.
Lock verification is inconsistent
Some lockups are enforced by a contract anyone can inspect, and others exist only as a commitment in a document.
Contractual locks are verifiable and can be relied on; promised locks depend on the project honouring them and can be reversed quietly.
Where providers accept stated lockups without on-chain enforcement, the reported figure rests on trust rather than on evidence.
Burned and lost tokens are treated differently
Tokens sent to an unspendable address are permanently removed, and most methodologies deduct them from supply.
Tokens lost through forgotten keys are equally unavailable and entirely invisible, so they remain counted indefinitely.
The distinction is practical rather than principled: one is provable and the other is not, so only the provable case is reflected.
For older assets the quantity presumed lost is large enough that reported supply overstates what could ever reach the market.
Fully diluted valuation answers a different question
Multiplying price by total eventual supply produces a figure that assumes every token exists today at the current price.
It is useful as a ceiling and misleading as a valuation, since tokens released over many years will meet a different market than today's.
The informative comparison is the ratio between the two figures, because a large gap indicates that most of the supply is still to arrive.