Migrating storage accounts to new subscription

Hi all,

Does anyone have any insight into how long migrating a storage account to a new subscription might take? For example, if I'm migrating a storage account that contains multiple file shares totaling around 100 TB, is the data actually physically moving (if the storage account stays in the same region)? Am I in for a really long haul migration of that data vs a short duration where Azure just marking the same storage account as belonging to a new subscription?

Thanks!