While prior research has focused on the impact of external factors in network structure formation, the influence of internal factors in shaping these networks remains relatively less explored. This paper aims to extend scholarly understanding by examining the role of executives' personality characteristics and demographic traits in firms’ alliance structural holes creation. Specifically, we investigate the role of CEO narcissism on structural hole spanning and further examine how CEO gender moderates this relationship. Using an exogenous instrument to account for CEO selection effects, our hypotheses regarding the effects of CEO narcissism, CEO gender, and their interactions in the context of structural holes spanned in the alliance networks of 663 CEOs in S&P 1500 firms from 1998 to 2017 corroborate our arguments. Our findings indicate that firms led by narcissistic CEOs tend to develop alliance networks with plentiful structural holes. Moreover, we find that the positive relationship between CEO narcissism and structural holes spanning is attenuated if a firm has a female CEO.
