We examine the empirical implications of learning under ambiguity for the cross-section of stock returns. We introduce a theoretically-motivated ambiguity measure and find that ambiguity is priced in the cross-section of average stock returns. Ambiguity is not subsumed by state variables known to predict stock returns, nor by value, size, and momentum factors. In R-squared comparative tests, a model that takes ambiguity into account performs better than empirical implementations of the Bayesian learning model, the intertemporal CAPM, and the four-factor model of Fama and French (1993) and Carhart (1997).

We develop a model of the dynamic interaction between CEO overconfidence and dividend policy. The model shows that an overconfident CEO views external financing as costly and hence builds financial slack for future investment needs by lowering the current dividend payout. Consistent with the main prediction, we find that the level of dividend payout is about one-sixth lower in firms managed by CEOs who are more likely to be overconfident. We document that this reduction in dividends associated with CEO overconfidence is greater in firms with lower growth opportunities and lower cash flow. We also show that the magnitude of the positive market reaction to a dividend-increase announcement is higher for firms with greater uncertainty about CEO overconfidence.

The Credit Card Accountability and Disclosure Act (CARD Act) of 2009 restricted several risk management practices of credit card issuers. Using a quasi-experimental design with credit bureau data on consumer lending, we find evidence consistent with the hypothesis that the act's restrictions on risk management practices contributed to a large decline in bank card holding by higher risk, nonprime consumers but had little effect on prime consumers. Looking at consumer finance loans, historically a source of credit for higher risk consumers, we find greater reliance on such loans by nonprime consumers in states with high consumer finance rate ceilings following the CARD Act than by nonprime consumers in states with low rate ceilings or by prime consumers. That nonprime consumers in states with high consumer finance rate ceilings relied more heavily on consumer finance loans suggests that consumer finance loans were a substitute for subprime credit cards for risky consumers when rate ceilings permit such loans to be profitable. Consumer finance loans would not be available to many higher risk, nonprime consumers in low rate states because such loans would be unprofitable, and prime consumers would not need consumer finance loans because other less expensive types of credit would generally be available to them.

This paper surveys the growing literature on payments. We begin by presenting a simple model that illustrates the essential function of payments and how this may be implemented through various arrangements. We show how the basic models of payments have been used to address a variety of microeconomic and macroeconomic policy issues. We then discuss the links between payments economics and other fields, including monetary theory, corporate finance, and industrial organization. We conclude with an overview of the empirical literature and directions for future research.