Celebrity vs influencer endorsements: exploring the effects of credibility and parasocial relationships on consumer-based brand equity

Purpose Brands increasingly rely on both celebrities and social media influencers to build brand equity in digitally mediated environments. Despite their widespread managerial use, it remains unclear why these two types of opinion leaders shape consumer-based brand equity (CBBE) through different psychological mechanisms. This study addresses this issue by examining whether credibility and parasocial relationships (PSRs) operate as distinct pathways through which celebrities and influencers contribute to brand equity on social media. Clarifying these mechanisms is essential for advancing endorsement theory and for guiding more effective endorsement strategy decisions. Design/methodology/approach The study employs a quantitative, cross-sectional design based on survey data from 310 active social media users in Lithuania. To capture both contributory and indispensable mechanisms, the analysis integrates partial least squares-structural equation modeling with Necessary Condition Analysis (NCA), allowing for a comparison of sufficiency-based effects and non-compensatory conditions across celebrity and influencer endorsement contexts. Findings The results reveal structurally different endorsement mechanisms. For influencers, credibility strengthens PSRs, which in turn positively drive CBBE. In contrast, for celebrities, PSRs do not significantly translate into brand equity. Instead, credibility emerges as a critical prerequisite for celebrities to generate brand equity, even though it does not exert a direct net effect. NCA further shows that PSRs are required, albeit weakly, for influencer-driven brand equity, whereas credibility constitutes a necessary condition in celebrity endorsements. Practical implications The findings demonstrate that celebrities and influencers should not be treated as interchangeable endorsement sources. Influencer strategies should prioritize long-term collaborations that foster relational closeness and emotional attachment, whereas celebrity endorsements require careful credibility screening and strategic fit with brand values. These insights enable managers to align endorsement choices with specific brand equity objectives and to evaluate endorsement effectiveness using mechanism-consistent performance metrics. Originality/value This study advances endorsement research by incrementally extending and refining existing theory to explain why celebrities and influencers influence brand equity through fundamentally different causal pathways. By combining structural equation modeling with NCA, it introduces an asymmetric perspective that moves beyond traditional net-effect explanations and clarifies theoretical boundary conditions in social media endorsement research.