The “Additional Basic Sum” is seen as an additonal security during your stay in Germany which you might need to deposit into your blocked account. Usually, you do not need to deposit an Additional Basic Sum. In case you need to do so, your local authority which is handling your visa application will inform you about this. If no such request has been made, please do not enter an Additional Basic Sum. Please be aware that this amount is blocked during your stay in Germany but will be refunded in full at the end of your stay.