This article discusses three variable coding properties of Spanish objects: flagging ( a -marking vs. ø-marking), indexing (clitic doubling vs. no doubling), and clitic case form (accusative lo vs. dative le ). These properties are essential for the formal identification of grammatical relations. They are triggered by similar parameters that partly overlap and partly show distinct distributions, yet they also challenge the boundaries between direct objects [DO] and indirect objects [IO] and raise the question whether the typological alignment of Spanish (di)transitive clauses is indirective or secundative. The study draws on quantitative and qualitative corpus data on formal, semantic, and discourse properties of core participants in Spanish clauses, relating these properties to the distribution of variable coding. It is concluded that a -marking, clitic doubling, and leísmo are less frequently employed than unmarked objects, no doubling, and accusative case for clitics, that Spanish DO and IO must be taken as extreme points of a more general Object syntactic function, and that, in general, all variable object coding follows an indirective alignment type. Consequently, animate and topical objects are considered as formally and functionally marked atypical objects both in monotransitive and ditransitive clauses.