We often think about information as having some kind of substantial content. Texts and their parts (sentences, words, letters…), pictures and musical scores are all substantial in some sense. However, some pieces of information seem to be less substantial, such as a space between two words, a portion of canvas left unpainted, a silence during the performance of a piece of music or a field in a form that is left unfilled. To analyze them, we build on slot mereology applied to informational entities, which introduces two entities: informational slots and informational fillers that may fill those slots. We identify three heterogeneous ways in which one may speak of "empty" information: first, a concretization of information that involves some absence, such as an empty pattern or a silent process; second, informational slots that can act as receptacles for fillers; third, empty informational fillers indicating that some information is voluntarily not provided. The introduction of such empty informational fillers makes it possible to satisfy an important axiom of company in slot mereology applied to informational entities.