Americans and so-called accidental Americans — people holding US citizenship through a parent, sometimes without ever having lived there — occasionally find a Dutch application refused or an existing account closed. The reason sits in international reporting rules rather than anything personal, and knowing which rules apply changes what is worth asking a bank up front.
FATCA is the short answer. It requires foreign banks to report US-person account holders to the IRS or face penalties themselves, which makes routine compliance a cost and a legal exposure some banks decide isn't worth carrying for a small slice of customers — including "accidental Americans" who've never set foot in the US but hold citizenship through birth or a parent. In practice, bunq reportedly excludes US persons from opening accounts at all. ABN AMRO and ING have generally continued accepting US citizens, but ask for extra paperwork — a US tax ID or proof of formally relinquished citizenship. Dutch courts have previously ruled that banks can't unilaterally close existing accounts solely because someone is a US person, which offers some protection once you're already a customer. None of this is fixed forever, though — it's tightened before and could again — so if you're a US citizen, it's worth calling ahead and asking directly rather than assuming a policy still holds.