The paper focuses on the discussion of significata propositionum, the proper semantic correlates of sentences, as the alleged objects of mental act of arriving to a conclusion, as developed in Gregory of Rimini’s Prologue to his commentary to the Sentences. After a brief account of arriving to a conclusion presented by Gregory as some kind of mental act, I present his arguments for the thesis that neither the actual thing the conclusion is about, nor the actually formulated conclusion itself as some actuality in the mind, are direct objects of that mental act (I). Then I present Gregory's account of what kind of entities are the significata propositionum: that no kind of actuality (neither in thought, nor in extramental reality) can be ascribed to them, and so they have to considered as entities in some special sense (II). In (III) I show that: (1) this sense needs further elucidation; (2) it is possible to demonstrate the way this sense is connected with the actuality in mind and actuality of a thing the conclusion is about; and (3) the activity of arriving to a conclusion needs to be investigated. A possible line of investigation is demonstrated by showing why Gregory’s arguments in (I) are invalid.