Danish banks are required to identify and register whether a customer is tax resident (that is, fully tax liable) in a country/countries other than Denmark. Please therefore inform us of the country or countries in which you are tax resident. We also need your tax identification number (TIN).You could also check „Where to find TINs?“ guide from European Commision
A person is generally tax resident in the country in which he or she lives or spends more than 183 days per 12-month period. In some countries, a person may be considered to be tax resident even though the person is stationed in another country – for example if the person maintains a home or has his or her family in the country. You may be liable to pay tax in the US, for example, because you were born there, have US citizenship or have a work permit there (known as a Green Card).