In the light of the findings of extensive fieldwork on existential constructions, we provide an account of the micro-variation in finite (number) agreement in Italo-Romance and Sardinian. Starting from the assumption that this type of agreement is a subjecthood diagnostic, we claim that the said micro-variation is the result of the interaction of a structural constraint promoting agreement, which is sensitive to the markedness of the potential controller as a subject, and a principle of structural economy (Samek-Lodovici 2002). An important role in our analysis is played by existential pivots with inde-cliticisation, which fail to control agreement in a number of dialects. We capture this tendency in terms of the combined effect of the markedness of these pivots as subjects (Beaver et al. 2005, Bentley 2010, in press, Mikkelsen 2002) and their split focus structure.