bank asks about the industry of my end customers why is that relevant

Sector codes feed risk models, not just KYC

The bank usually asks about the sectors of your end customers for two purposes simultaneously: anti-money laundering risk and climate risk. For the first, the bank uses NACE or SBI-like classifications to see whether your sales market contains sectors that are considered higher risk — think of cash-intensive businesses, commodity trading or sectors with significant international throughput. For the second — increasingly the dominant reason at larger banks — the bank aggregates the sector exposure of its entire credit portfolio, because supervisory authorities and its own sustainability reporting ask for transition risk per sector. Your answer then counts as one line in an aggregated overview, not as an individual assessment of you or your customers.

The fact that the question concerns the end customer and not yourself is usually a sign that it is for the second reason: the bank wants to know how vulnerable the chain behind you is to, for example, CO2 pricing or sector-specific regulation. If you do not know this exactly — many suppliers do not have a breakdown of revenue by customer sector — an indication based on the largest customer groups is usually sufficient; the supply chain file keeps this separate from the question in what sector is the business itself active, which is a different question with a different answer.

Foundation: own sector code from the Business Register, customer sector is supplementary

Your own business's sector code is registered with the Chamber of Commerce on the basis of the Business Register Act 2007, and the bank can request that code directly without you needing to provide it. The question about the sector of your end customers has no comparable legal basis — banks formulate it themselves, usually as part of customer due diligence under the AML Act or their own sustainability reporting that aligns with the CSRD (Directive (EU) 2022/2464). There is no fixed formula that prescribes how detailed you must provide this; some banks accept a top 3 of sectors, others ask for a percentage distribution. If the portal does not allow for "unknown" or "varying", that is a shortcoming of the format, not an obligation to make up a figure that you do not have.