Incorporated companies are separate legal entities. The registration liability of an incorporated company will be determined on its own. It is required to register for GST if its turnover for the past 12 months is more than S$1 million or is expected to be more than S$1 million in the next 12 months.To determine the registration liability for sole-proprietorship business, a sole-proprietor (who can be an individual or a corporate entity) will need to combine the turnover from all his trade, provision or vocation and all his sole-proprietorship businesses. If the combined turnover is more than S$1 million or is expected to be more than S$1 million or is expected to be more than S$1 million, he will be liable to register. The registration will be in the name of the sole-proprietor.
Singapore Company Registration Knowledge Base