The phrase "substantial investment" appears throughout the guidance without a defined figure attached, leaving applicants unsure whether a lean freelance operation clears the bar at all. What the IND actually checks, at application and again at renewal, is more specific than the wording suggests.
In practice it means a minimum of €4,500 sitting in your Dutch business bank account, and it has to stay there — the IND checks this isn't a one-time deposit withdrawn the week after approval, but capital that remains invested in the business for the life of the permit. Beyond that number, the law doesn't spell out a formal minimum for "substantial business activity"; there's no revenue threshold written into the treaty itself. What the IND actually wants to see, especially at renewal, is that the €4,500 (or more, if your business plan calls for it) is genuinely at risk in a functioning business, with annual accounts and a balance sheet showing the company has been doing something rather than sitting dormant with money parked in an account. A one-page plan describing what you'll actually do and how the capital gets used is standard practice even though it's not exhaustively defined by regulation. Full-time commitment isn't required, so a lean freelance operation clears the bar as easily as something more ambitious, as long as the money and the activity are both real and traceable.