Why it matters
The registry operator decides what an extension costs at wholesale and what rules apply to it. Verisign runs .com and .net, for example. Registrars cannot ignore these rules, so a registry price change flows straight to every owner of that extension. Registries can also lock, suspend or delete names under their own policies. For buyers and sellers, the registry is the final record of who holds a name. A common mistake is treating the registrar as the owner of the data. The registrar only sends your changes to the registry.
Source: icann.org
Read nextHow Domain Transfers Work: Auth Codes, Transfer Locks, and Push vs Transfer