Kraken holds a bank account with Fidor Bank AG in Germany that is used to process most of the exchange's EUR transactions.
Fidor Bank enables Fidor DE (not Fidor UK!) bank account holders to send transactions to other Fidor account holders within minutes, via the functionality Freunden Geld senden (send money to friends). Kraken also benefits from this option as all Fidor customers with Kraken accounts can send deposits and withdrawals to and from their Fidor bank account to their Kraken accounts very quickly.
Near-instant transactions from a bank account to a Digital Asset Exchange like Kraken come with an additional compliance risk. As a result every first-time transaction from and to a Fidor Bank account requires additional checks from a compliance specialist at Fidor Bank AG. This means that the first transaction will not be processed within minutes, but will appear on the funding page with the status “On Hold”. It will be automatically released after the transaction has been reviewed and approved.