Is it permitted to be a silent partner in a business dealing in the same line of products as the company you are already employed?
Islam aims at establishing good relations. Muslims are commanded to avoid all things that lead to conflict and hatred. It is permissible to be a silent partner. This is called Mudarabah in which you contribute the capital and leave the management to other partners. There is a conflict of interest here as the Mudarabah deals with the same products of your employer unless he does not object.