1 Many researchers have explored the topic with the intent of identifying the logic of the variation between CC and non-CC. In this paper we want to address a specific problem pointed out in the literature about CC in Spanish: its incidence is far less frequent in written texts. This can be interpreted as a problem in face of the diachronic evolution of the phenomenon, which showed higher frequency in medieval times. Therefore, the tendency for grammatical innovations (non-CC) to be more common in speech seems to be contradicted. I want to shed light on this problem by assigning the difference between registers to the dependence of the phenomenon to Information Structure. In order to do so, I demonstrate not only that register is a relevant variation factor in European Portuguese (EP), but also that it is connected to internal factors which are relevant to understand variation. The paper presents the results from a EP corpus made up of about 1,000 data from different registers and sources: we have collected sentences from interviews given to linguistic databases and newspapers through the Corpus do Portugues (Davies & Ferreira 2006), and from contemporary Portuguese novels, all listed in the Appendix. The sentences include a finite verb followed by an infinitive, once CC is obligatory in EP in verb sequences involving a gerund or a participle. Before moving along, it is necessary to differentiate between two constructions that show CC: and union. 2 While restructuring is usually linked to governing verbs of the modal, aspectual and movement classes which usually display semantic bleaching - see (1) - in union the governing verb is causative or perceptive. A verb of the latter type selects a complement with a non-coreferent subject. This embedded subject occurs in accusative or dative form, and climbs obligatorily, alongside other clitics - (2)b. Once there is no variation with respect to CC in clause union, we will only deal with restructuring data, similarly to previous studies about variation in CC.