Evaluating the Strategic Effectiveness of Celebrity Endorsements: A Cross-Industry Analysis of Revenue Impact and Reverse Endorsement Spillover

Celebrity marketing has become a widely used strategy across industries, yet its financial impacts remain unexplored in cross-industry quantitative analysis. This paper examines the extent to which celebrity endorsements generate measurable revenue growth and boost sales performance across industries, and how firm-level financial deterioration affects endorsement value. A hybrid methodology is employed, combining quantitative before-and-after comparison of financial data post celebrity anchor events with qualitative case study analysis. Nike and L’Oréal are associated with positive revenue impact from celebrity endorsement. Pepsi strengthened the defensive endorsement hypothesis, where celebrity endorsement acts as a defensive mechanism for revenue in mature industries. Budweiser displayed revenue growth yet compressed margins, reflecting market volatility in the sin goods industry. BYJU’s engagement with Shah Rukh Khan confirmed the reverse endorsement spillover effect, where poor firm-level financial management negatively impacted the celebrity’s reputation. Two novel theoretical contributions are introduced: the defensive endorsement hypothesis and the reverse endorsement spillover effect, both analysed through qualitative and quantitative methods. A cross-industry comparative framework is presented as a replicable methodology for marketing research. Firms show stronger endorsement returns when identifying congruency and market maturity, while celebrities must account for asymmetric risks in endorsement agreements.