how do I explain the insurable interest to the insurer

Insurable interest is the question of whether you actually suffer loss

Insurable interest means: you must demonstrate that you incur financial loss if the insured object is damaged, lost, or ceases to exist. The insurer does not ask this out of curiosity, but because insurance without demonstrable interest is not insurance — then it is a gamble, and that is not permitted. In practice, the insurer usually does not ask this with that term, but hides it in questions such as "what is the relationship between the policyholder and the object" or "on what basis do you hold this object".

The substantiation usually consists of proof of ownership, a rental or lease agreement, or an extract showing the legal form and business activities of the enterprise — you obtain the latter from the business register. If direct proof of ownership is lacking, for example with rented business assets or inventory belonging to third parties, the underlying agreement plus a brief explanation of why your enterprise bears the risk is usually sufficient. If you have neither, answer that the document is not available instead of providing an estimate; the insurer is asking here for evidence of title, not an estimate.

Where this comes from: evidence from the chain file, not from an assumption

Insurers usually ask this in combination with questions about the business structure, because the interest often relates to who has actual control or ownership. That touches on the question who are the ultimate beneficial owners of the company, and sometimes also the question at which banks the enterprise maintains accounts, if financing is part of the ownership relationship. The basic information about the enterprise itself — legal form, place of establishment, managers — comes from the extract under the Trade Register Act 2007, and this is usually the first document that also substantiates the insurable interest, because it demonstrates that the requesting party and the enterprise bearing the risk are the same.

Sources

• Trade Register Act 2007: wetten.overheid.nl/BWBR0021777