We model and test the relations between the team management of mutual funds, managers’ ability, performance, and holdings. Our model predicts that team-managed funds perform better and behave more conservatively than single-manager funds. However, the effect of team management is masked in equilibrium because high-ability managers rationally self-select into single-manager funds. Consistent with the model’s prediction, we find that team-managed funds perform better and deviate less from their benchmark allocations than single-manager funds with the same characteristics. These differences are marked after we control for the endogenous self-selection of managers.

We apply machine learning methods to granular environmental variables and test if there is a strong positive relation between environmental sustainability and future stock returns. A long-short portfolio that longs stocks with high forecasted returns and sells stocks with low forecasted returns earns large abnormal returns, and it performs better when climate concerns in the media are more intense. Further diagnosis shows that various dimensions of environmental sustainability help return predictions. High forecasted returns are associated primarily with strong environmental operational performance. The return prediction based on a customized transformer model is similar.