A prevalent feature in rating markets is the possibility for the client to hide the outcome of the rating process, after learning that outcome. This paper identifies the optimal contracting arrangement and the circumstances under which simple ownership contracts over ratings implement this optimal solution. We place ourselves in a setting where the decision to obtain a rating is endogenous and where the cost of such a piece of information is a strategic variable (a price) chosen by a rating agency. We then show that clients hiding their ratings can only be an equilibrium outcome if they are su±ciently uncertain of their quality at the time of hiring a certification intermediary and if the decision to get a rating is not observable. For some...