If you hire someone else to do your job, e.g. a babysitter, you can face the risk of losing money when she tells people around about how rich you are, and what you have in your house.
(D) For a company to provide a product or service for itself as efficiently as an independent supplier can provide it, the managers involved need to be as expert in the area of that product or service as the people in charge of that product or service at an independent supplier are.
If the information becomes known to the company’s competitors and gives them a business advantage, the company’s profitability may be harmed rather than helped by outsourcing. This possibility weakens the argument.