Intergroup changes occur often between subgroups who are asymmetric in status (e.g., size, power, prestige), with important consequences for social identification, especially among the members of lower-status groups. Mergers offer an example of such changes, when subgroups (merger partners) merge into a common, superordinate group (post-merger group). Lower-status subgroups frequently perceive they are less represented in the post-merger group, therefore committing less to the changes a merger implies. Five studies offered an intergroup relations’ perspective on mergers (N’s= 479, 150, 266, 113 and 229 respectively), examining how functional indispensability (instrumental contribution of the ingroup) positively influences perceptions of representativeness in the post-merger group (relative ingroup prototypicality), which, in turn, affect post-merger identification and, finally, change commitment. Additionally, the role of cognitive information processing (heuristic vs systematic) on prototypicality was explored. Results suggest that functional indispensability impacts relative ingroup prototypicality (Studies 1-5), and this may be moderated by information processing (Study 2). Moreover, prototypicality and identification with the superordinate post-merged group mediated the effect of functional indispensability on change commitment (Studies 1-3). These findings provide important theoretical insights into prototypicality perceptions held by lower-status merger-partners and minority groups in general, by identifying functional indispensability as a source of prototypicality other than relative status. In addition, by proposing a functional approach to the relations between social groups, these findings suggest better practices for managing structural changes, such as combining sources of strategic/functional and identity fit when announcing an intergroup change.