how do I describe the group structure to the bank

Group structure: parent, subsidiaries and control mapped

With this question, the bank wants to know how the company is legally structured: is there a parent company, are there subsidiaries, and who has control where. This is different from the legal name of the company or the registration number — those questions are about the entity itself, this is about the entities around it. The bank usually asks this as part of customer due diligence: they need to know who the ultimate beneficial owner (UBO) is and whether there is involvement with other parties that is relevant for risk assessment.

The supporting document that usually goes with this is an extract from the Commercial Register showing the shareholding structure or group relationship, possibly supplemented with an organization chart. If the company has no group structure — if it is an independent entity without a parent or subsidiaries — then that in itself is also a valid answer: "not applicable" is not a loophole, as long as it is correct. Doubt mainly exists with intermediate holdings or with a structure that has just been changed; in that case, the extract from the Commercial Register is the source that counts, not an internal memo that has not yet been updated.

Where this follows from the Commercial Register

The Commercial Register Act 2007 determines which data of a company are recorded, including the establishment of the company and the relationships within a group such as parent and subsidiary companies. This makes the Commercial Register the appropriate source for this question: it is a public register, so the bank can also verify the answer itself. This is immediately the reason why a divergent or outdated internal document has little value here — in case of doubt, what is in the register applies at the time of submission.