Drawing on Catalan, we show how the aspectual classification of intransitive prepositional verbs is, partially, a predictor of their argument structure properties. Prepositional verbs qualifying as Stage-Level form a heterogeneous class, comprising both unergative and unaccusative verbs. By contrast, those prepositional verbs that qualify as Individual-Level predicates are homogenous as regards argument structure: their prepositional complement is robustly obligatory and their subject is not an external argument, suggesting that they involve a predicative configuration whose predicate is the prepositional complement. This result supports the more general Property Verbalization Constraint hypothesis (Acedo-Matellán 2019), which states that Individual-Level property predicates cannot be encoded as unergative verbs.