In this paper, we examine how brand managers can utilize the knowledge function to devise a brand strategy that reinforces a luxury brand’s reputation and counteracts the actions of counterfeiters. We explain why brand managers need to develop insights into how knowledge is utilized so that they can understand the behaviour of the “informed-poseur”. Attention focuses on how the knowledge function addresses the conflict between the “social” function and the “self-ego” function when consumers consider purchasing counterfeits. We extend existing knowledge by identifying two sub-groups: the “Informed poseur-realistic” and the “informed poseur-neo”, and distinguish between the two sub-groups by making links with their social context. This adds to our knowledge of how millennials think and make purchase related decisions, and how brand managers can develop brand portfolio strategies that highlight the uniqueness of the value proposition and communicate more effectively with the “informed-poseur” group. A small group interview and survey were used to collect data and the findings suggest that when an “informed-poseur” considers purchasing a counterfeit product, they corroborate their actions by utilizing the knowledge function, which takes them through various cognitive and evaluative processes.