Each player has an Account Bank, which can be used to transfer items between characters on that account. The account bank cannot be accessed when characters are locked into a Campaign.
The account bank exists at the account level – meaning that all of a player's characters share one account bank. The Embargo Vault, by contrast, is Campaign specific, meaning that each Campaign will have a different Embargo area. At the end of the Campaign, depending on how well players (and their team) did, some number of item(s) will be moved from the Embargo into their Account Bank. The rest of the items will be lost.