This study contributes to the academics by integrating the upper echelon theory and competitive dynamics perspective to explore the relationships between CEO transformational leadership, CEO transactional leadership, TMT trust climate, and competitive aggressiveness. The mediating roles of TMT trust climate under the competitive dynamics and the moderating roles of environmental dynamism are investigated as well. The research findings based on a sample of 188 firms from Vietnam show that both two CEO leadership styles directly and TMT trust climate have direct and interaction effects on competitive aggressiveness. Furthermore, TMT trust climate is found to mediate the relationship between CEO transformational leadership and competitive aggressiveness under dynamic environment.

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