This chapter argues for high argument merge (HiAM), whereby all arguments are merged above the complex predicate, associated with their theta-sources within the predicate by means of a composed theta-grid at the level of vP. The lowest referential thematic argument merges in specifier of PredP, which derives ergativity. PredP can be selected by one or two applicative heads, saturating an agent and an instrument role. Theta roles introduced within the predicate can be referential or non-referential. Referential roles must be saturated by a syntactic argument, but non-referential roles remain in vP and are satisfied through an operation of restrict, which explains noun incorporation, the distribution of null and overt arguments, and fluctuations in case-marking. All types of arguments in Niuean are discussed, including internal, external, applicative, middle, indirect, and sentential arguments. The chapter concludes with a discussion of argument sharing, and raising, arguing for an ECM analysis.