Kernrechtsfrage
Whether the US request had become moot because of United States Tax Court decisions and ne bis in idem
Extrahierter Entscheid
The request was not moot; a further US proceeding based on new evidence remained possible, so ne bis in idem did not bar assistance.
Extrahierte Begründung
The US authority confirmed that the matter was not definitively closed and could be reopened if further concealed income appeared. Ne bis in idem does not exclude revision or a later procedure based on new evidence.