Max supply

Max supply is the largest number of coins or tokens that can ever exist for an asset under its rules. It is a ceiling, not a count of what exists today. Bitcoin's 21 million cap is the best-known example, and it holds because nodes reject any block that would issue more.

On a native blockchain, the cap lives in the consensus rules, and new coins are issued on a schedule until it is reached. Changing it would mean changing those rules, but nodes can refuse the new rules, so an attempt would most likely split the network into two chains. For a token on Solana, BNB Chain, Base, or Ethereum, the cap is usually a number in the smart contract. Some assets have no cap at all, so supply can keep growing through inflation or an unlimited mint function.

Supply matters because it determines how much dilution is possible. Keep in mind that a token does not necessarily represent ownership of a project. It is a unit with whatever rights the project defines, which may be none. Max supply also feeds fully diluted valuation, which multiplies the price by the max supply. A big gap between market cap and that figure means much of the supply is not circulating yet, but it does not prove all of it will reach the market.

Check whether the cap is actually enforced. On a block explorer, look for a mint function and see whether it is bounded by a hard-coded cap that the owner cannot change or bypass. A bounded mint is fine, while an unlimited one, or a cap the owner can edit, makes the stated max supply meaningless. Minting everything at launch is not a cap by itself either, because it only holds if further minting is impossible, such as when the mint authority has been revoked. Also confirm that max supply, total supply, and circulating supply are not mixed up on aggregator sites.

Don't read a big number as cheap or a small one as scarce. A token with a trillion units at a tiny price is not automatically cheaper than one with a million units. Market cap tells you size.