Several authors propose that performative speech acts are self-guaranteeing due to their self-referential nature (Searle 1989;Jary 2007). The present paper offers an analysis of self-referentiality in terms of truth conditional semantics, making use of Davidsonian events. I propose that hereby can denote the ongoing act of information transfer (more mundanely, the utterance) which thereby enters the meaning of the sentence. The analysis will be extended to cover self-referential sentences without the adverb hereby. While self-referentiality can be integrated in ordinary truth conditional semantic analysis without being a mystery, the resulting account shows that self-referentiality in this sense is a necessary but not a sufficient condition for performative utterances. I propose that the second ingredient of performative utterances consists in an act of the speaker defining her utterance to be an act of the respective kind. The final theory can successfully predict the performativity, or lack thereof, of a wide range of performative sentences, and leads to an explicated interface between compositional sentence meaning and speech act.