bank asks who is authorized to sign on behalf of the company how do I answer that

Extract from the Commercial Register is the evidence, not the e-mail confirmation

The bank usually does not ask this as an open question, but as part of customer due diligence or account opening, and the evidence for this is the extract from the Commercial Register. It shows who is a director and whether that person may sign independently or only jointly with another ("jointly authorized"). That is the answer the bank wants: not your assessment, but what is registered.

In practice, someone fills in this field incorrectly by paraphrasing the statutory text instead of reproducing the registration. If the articles of association state that a director is independently authorized, but the extract states "jointly authorized" because, for example, a temporary restriction has been registered, then the registration counts for the bank. If you are unsure whether the extract is current, request a recent copy from the Commercial Register — an extract more than a few months old is often no longer accepted by banks. This topic also relates to the question under which registration number the company is registered, as the bank extract must reference the same number. If there are multiple locations, also check which location the bank is referring to; this aligns with the question in which countries the enterprise has establishments, if it concerns a group with foreign entities.

Where this derives from: Business Register Act 2007

The obligation to register directors and their signing authority is derived from the Commercial Register Act 2007, which specifies which company data are maintained, including the directors and their signing authority. The extract is the official representation of that registration and therefore serves as evidence, not the articles of association themselves and not an internal declaration. If you do not have a recent extract at hand, there is no other source that the bank will accept in its place; the question remains open until the extract has been requested.