Regulatory Perimeter
The boundary that decides which activities require a license and which fall outside a regulator's authority altogether.
Financial rules attach to activities and to the people performing them rather than to technologies: holding customer assets, matching orders, issuing an instrument, making a market, and giving advice are each regulated functions. Publishing software that others run, with no custody and no intermediation, may sit outside the perimeter, while operating a front end, running a market-making desk, or holding upgrade keys usually does not. Perimeter questions are where most decentralized finance policy debate actually happens, because the answer determines whether a rule reaches an arrangement at all. The perimeter also differs by jurisdiction and shifts over time as legislatures extend definitions, which is why the same protocol can be in scope in one country and out of it next door.
En pratique
MiCA excludes services provided in a fully decentralized manner without any intermediary, which makes the practical question who, if anyone, is performing the regulated function.
Le malentendu courant
That a project sits outside the perimeter because it describes itself as decentralized, when regulators look at who actually performs the regulated function, including front-end operators and holders of privileged keys.