We argue that team information acquisition mediates the effect of the relationship of team locus-of-control composition and leadership structure on team financial performance in a decision-making context. Hypotheses were tested on 44 teams participating in an elaborate and lengthy international management simulation. As predicted, teams with high average internal locus-of-control scores performed better without leaders and with low locus-of-control heterogeneity. The opposite was found for teams with high average external locus-of-control scores. Contrary to expectations, teams with high locus-of-control heterogeneity did not benefit more from having leaders than teams with low heterogeneity. Information acquisition mediated relationships between locus-of-control composition and performance.