We investigate the extent to which a country's degree of genetic variation contributes to the observed variation in financial market activity across countries. We postulate that genetic variation can affect financial markets through its impact on aggregate investment behavior, innovation in the financial sector, and productivity. Our country-level, cross-sectional analysis reveals a significant hump-shaped relation between a country's predicted genetic variation and the size of its financial markets. This result is consistent with the conjecture that at relatively intermediate degrees of genetic variation, the associated intermediate levels of trust and risk-taking within the country result in the largest investment flows into public financial markets. Our results are robust to different measres of financial market size, several regression specifications, and the inclusion of a broad range of controls such as legal origin, institutional characteristics, culture, natural endowment, and trade openness. Our main findings appear to be restricted specifically to equity markets (vs. debt markets) where there is relatively more uncertainty and, thus, trust and risk-taking are relatively more important. Additional analysis suggests that better overall country-level governance can moderate the role that genetic variation plays in shaping equity market size.

We study the stock market reactions to the Tax Cuts and Jobs Act (TCJA), the most significant structural U.S. tax reform in over 30 years. In line with the stated intent of TCJA proponents, we find that the Act benefited highly taxed firms. However, the Act hindered firms with international operations as well as firms with high interest expense and tax losses. Counter to claims that the TCJA would quickly spur economic growth, we find that financially constrained and high growth opportunity firms did not benefit. Rather, market participants anticipate that most of the TCJA's benefits will be passed on to shareholders via higher corporate payouts. We confirm these market expectations by documenting that firms did increase payouts via repurchases after the TCJA, but did not increase their corporate investments.