This article discusses two relatively novel properties of possessive noun phrases in Arabic and explores their implications for existing analyses. First, in some dialects of Moroccan Arabic the genitive preposition shows agreement in number and gender with the possessum to its left in analytic (Free State) noun phrases. Preposition-possessum agreement appears to parallel verb-subject agreement and is to all intent and purposes an instance of predicate-subject agreement. Secondly, in many Arabic varieties inalienable noun phrases are incompatible with the analytic pattern and can only have the synthetic (Construct State) pattern. These two properties are difficult to accommodate under an analysis that assigns a uniform syntactic structure to both alienable and inalienable noun phrases, where the possessum is the head noun and the possessor is its specifier. Instead, they point to an analysis where the two types of noun phrases derive from radically different syntactic structures. While inalienable noun phrases derive from a structure where the inalienable possessum is the head noun and the possessor is its argument, alienable noun phrases derive from a structure along the lines outlined in Den Dikken (2006), where the possessum is the subject and the possessor a predicate complement, and the relationship between the two is necessarily mediated by a relational category that corresponds to the genitive preposition in the analytic pattern. A version of this analysis is adopted here that accounts for additional known properties of analytic and synthetic noun phrases, including their PF interface properties. The latter part builds on the analysis outlined in Ouhalla (2009b) and addresses questions left open there.