Using the NOx budget program (NBP) as a quasi-natural experiment, we study how air quality affects the productivity of patent inventors. Motivated by previous studies linking air quality to people's risk-taking tendencies and cognitive abilities, we find that after the implementation of the NBP, inventors located in NBP participating states produce more patents and the quality of their patents increases. These inventors engage more in exploratory innovation and less in exploitative innovation, and they shift their strategies toward risky, high-value innovation. Our findings suggest that risk-taking and cognitive ability are the channels through which improved air quality enhances inventor productivity.

We find that mutual funds whose managers are socially connected with firm auditors hold more shares of these firms and generate superior portfolio returns. Cross‐sectional results reveal that the relation between social connections and mutual fund stockholdings is more pronounced: when the social connections are stronger, when the auditor is in a better position or has stronger incentives to acquire private information, when the fund manager exercises more power, for small audit firms, for auditors in areas with poor investor protection, and for public firms with greater business opacity or private information. Other results are consistent with fund managers electing to schedule their corporate site visits to coincide with the fieldwork of their connected auditors, as would be expected if fund managers time their visits to meet with these auditors to facilitate information transfer. Additionally, we observe associations between fund trading prior to earnings surprises and audit opinions, and the presence of social connections between fund managers and firm auditors. Finally, we show that mutual funds and firms in which they invest tend to appoint connected auditors and pay them higher fees. Collectively, we document empirical patterns that would arise if socially connected auditors and mutual fund managers share information.