What do you mean by no turnover? an active stock trading company would still quality as a passive NFFE, no?Active or passive is just a question of definition.
Page 10 of https://www.credit-suisse.com/media/production/pb/docs/uk/fatca-entity-classification-guide.pdf will give you the answer.
I think a family office or personal investment company earns mainly financial income (no turnover) which is qualified as passive income. Hence, the entity is a passive NFFE.