bank asks if I manage money from others what should I say about this

Trust service or third-party funds account, not ordinary client work

No, ordinary trading — supplying, invoicing, getting paid — is not "managing assets for third parties". The bank is asking here about something specific: does the company hold money or assets on behalf of someone else, without this being its own business asset? Think of a foundation for third-party funds, a trust office, a notary or lawyer with a client account, or an asset manager holding positions for clients. If the company simply buys, sells and trades on its own name and at its own risk, the answer is no.

Doubt often arises in intermediate forms: a holding that passes on dividends to shareholders, a company that holds client deposits or warranties, or an enterprise that acts as a payment agent in a chain. This is usually not asset management in the sense the bank means, but it depends on whether the money is held in a separate account, whether there is separate administration for it, and whether the company receives a fee for it separate from its normal turnover. If the company has no separate structure for third-party funds, then "no" with a brief explanation is usually sufficient. This question is often linked to other questions about the client structure itself, such as who are the ultimate beneficial owners of the company and where the company's assets come from — the bank wants to see the complete picture of money flows, not just this one question.

Why the bank wants to know this precisely

This question comes from the customer due diligence that banks must conduct under the Law on the Prevention of Money Laundering and Financing of Terrorism. An institution that itself manages assets for third parties falls under a different risk profile than an ordinary trading company: there are then money flows that do not belong to the company itself, which raises additional control questions about whose money it is exactly and where it comes from. The bank checks this therefore not out of curiosity, but to determine what level of investigation fits the client profile.