Split noun phrase topicalization has been the subject of intense studies across languages in the syntactic literature of the last few decades. One of the key questions raised for these constructions is whether they involve syntactic movement or base-generation. This paper explores this phenomenon in two understudied Iranian languages, Gilaki (Northwestern Iranian, Caspien) and Persian. In particular, we explore splits in two contexts, possessive constructions and numeral constructions. We develop diagnostics for distinguishing the two derivational possibilities, movement or base-generation, for the cases under investigation. We show that while Gilaki uses both derivational possibilities, movement in possessor split and base-generation in numeral split, Persian only allows for the latter with very similar behavior. We argue that possessor split occurs when the whole possessum DP/DemP moves out of its base position in a small clause. Numeral split occurs when the NP is replaced by a null nominal element, which is associated with an overt or pragmatic antecedent. We end the paper with a discussion of why an operation, movement or base-generation, is available for one construction but not the other.