do I have to report all branches of my company to the bank

All locations registered in the Commercial Register belong in the list

Yes, in most cases the bank asks for all locations registered with the Chamber of Commerce, including branch locations and subsidiaries abroad if they fall under the same legal entity. The bank usually asks this question as part of customer due diligence: they want to know where the company is actually active, not just where the head office is located. A location that exists only on paper but has never been operationally active is sometimes listed separately in practice — but that is a nuance you discuss with the bank yourself, not something that follows from the Commercial Register itself.

Where it often becomes problematic is the question of whether foreign subsidiaries also count. A subsidiary with its own legal personality is not a "location" of the Dutch company in the sense of the Commercial Register Act, but banks often ask about this separately, for example under a question about group structure. That is therefore different information than the location list itself. This question is closely related to in which countries the enterprise has establishments and with the establishment address of the company — if these two are already correctly and completely recorded in the chain file, this question is usually quickly answered.

Where this follows from: the Trade Register Act 2007

The obligation to register locations follows from the Commercial Register Act 2007: every company must register its head office and any branch locations, with address and activities per location. A bank conducting customer due diligence asks in practice for an extract or for the data corresponding to that extract — which is why the answer to this question is essentially a copy of what is already in the Commercial Register, and not a separate assessment that the bank makes.