PurposeTop executive hubris is associated with positive/negative outcome. Little is known about the antecedent of hubris in top management team (TMT) and how they can be weakened to capitalize on TMT size and market complexity. This paper aims to address these issues.Design/methodology/approachThis study draws on the social information processing theory. Subsequently, it proposes and tests an inverted U-shaped relationship between task-related faultlines and top executive hubris. Top management team size and complexity can weaken the relationship between them. Panel data were collected longitudinally from 2011 to 2016 on China's listed firm on growth enterprises board.FindingsHierarchical regression analyses indicate that medium task-related faultlines experience stronger than weak and strong faultlines. TMT size and market complexity can weaken the inverted U-shaped relationship between them.Originality/valueThis study provides pioneering evidence for an inverted U-shaped relationship between task-related faultlines and top executive hubris. These findings inform practice by suggesting a tipping point of team faultlines.