bank asks where the money from the first deposit comes from, what should I answer

Origin of start-up capital is part of customer due diligence

This is a standard question for a new business account and not an incident. The bank asks this as part of the mandatory customer due diligence under the Anti-Money Laundering and Countering the Financing of Terrorism Act (Wwft). When opening an account, the bank must, among other things, verify that the money coming in has a logical and explicable origin. For a newly established enterprise, there is usually no turnover history to fall back on, so the bank immediately asks about the source of the first deposit: the owner's personal savings, a loan, an investment, or a transfer from another enterprise.

The answer you provide must be consistent with what you can actually substantiate. If it is the entrepreneur's own money, a bank statement from the source account is usually sufficient. If the money comes from an investor or shareholder, the bank often wants to know who that is — that touches on the question who are the ultimate beneficial owners of the company. For a loan, a loan agreement helps. If you do not have a document at hand, fill in what you do know for certain and leave the rest for the entrepreneur to complete; making an educated guess without a source will raise more questions in a later audit than an honest "to be provided". This question about the first deposit is separate from the broader question about the source of the company's assets, which usually comes back later in the process and concerns the enterprise as a whole, not a single transaction.

Where this follows from: the client due diligence under the Wwft

The obligation to investigate the origin of funds derives from the Anti-Money Laundering and Countering the Financing of Terrorism Act, which obliges banks to conduct customer due diligence before and during the establishment of a business relationship. The Commercial Register Act 2007 plays no role here: it regulates which data about the enterprise itself are recorded, not the origin of money flows.