Supply policy refers to the set of rules and mechanisms within a blockchain system that govern the issuance, distribution, and total supply of its native assets in the form of tokens. It illustrates how new units are created, the rate at which they enter circulation, who receives those units, and any adjustments that influence the token's overall availability and scarcity. Supply policy is a critical feature of permissionless blockchain systems, influencing network security, economic incentives, and the overall sustainability and stability of the system.