This study investigates the role of CEO narcissism in the cost stickiness behavior of companies listed on the Tehran Stock Exchange and examines whether past performance and firm-level uncertainty can moderate this relationship. CEO narcissism was measured using signature size indicators, and the extended Anderson–Banker model was applied to panel data from 147 companies over the period 2013 to 2022. The results indicate that CEO narcissism increases cost stickiness during periods of sales decline; however, this effect weakens in companies that have achieved high profitability over the past two years and does not significantly change under high firm-level uncertainty. A detailed analysis of cost structures further revealed that none of the individual components—selling, general and administrative expenses, cost of goods sold, and personnel expenses—exhibit distinctive stickiness on their own. These findings expand the cost behavior literature by incorporating personality dimensions in an emerging market context, support the theoretical framework of upper echelons in operational decision-making, and suggest that boards of directors can prevent the accumulation of inefficient resources by monitoring managerial traits alongside multi-period cost efficiency indicators.
Keywords: "CEO narcissism", "cost stickiness", "past performance", "corporate uncertainty"