Oceanic languages typically display possessor-indexing suffixes that distinguish the usual four Oceanic person categories, along with at least singular and plural. However, a group of languages of central Choiseul (Solomon Islands), including Ririo, Babatana, and Sisiqa, display only three possessor-indexing suffixes. Two reflect Proto-Oceanic forms and index 1sg and 2sg possessors. The third, an innovated form, indexes all other person number categories (that is, 3sg and all nonsingular categories). This paper investigates the formal and structural characteristics of this innovated non-1/2sg suffix. It examines the phenomenon in each of the three languages, including allomorphy of the suffix, and the manner in which person and number categories are expressed in the presence of the innovated suffix. In terms of the former, it finds each language displays different allomorphy patterns, with both -e and -a occurring, along with -i when following a high vowel. Various other factors are at play in one or more languages, including vowel harmony and presuffix vowel loss. In terms of the coding of non-1/2sg person and number categories, the paper finds that the innovated suffix licenses a possessor NP that may contain a lexical noun or dependent pronoun. However, in the absence of an overt possessor NP, the suffix prompts a default 3sg reading.