We provide the first tests to distinguish whether individual investors equally balance their overall portfolios (naïve portfolio diversification--NPD) or engage in naïve buying diversification (NBD)--equally balancing values in same-day purchases of multiple assets. We find NBD in purchases of...

A decision maker constructs a convex set of nonnegative martingales to use as likelihood ratios that represent parametric alternatives to a baseline model and also non-parametric models statistically close to both the baseline model and the parametric alternatives. Max-min expected utility over...

We propose a unified theory of asset price determination encompassing both "conventional" and "alternative" asset classes (private equity, real estate, etc.). The model features disruption of old by young firms and skewness in the distribution of innovative rents among the young innovators. The...

We analyze a large number of industry- and company-level filings of global institutional investors to provide the first comprehensive estimate of foreign investors' U.S. dollar (USD) security holdings and currency hedging practices. We document four stylized facts. First, driven by increasing...

We study the role of risk preferences and frictions in portfolio choice using variation in 401(k) default options. Patterns of active choice in response to different default funds imply that, absent participation frictions, 94% of investors prefer holding stocks, with an equity share of...

We build a model of the law of small numbers (LSN)--the incorrect belief that even small samples represent the properties of the underlying population--to study its implications for trading behavior and asset prices. In our model, a belief in the LSN induces investors to expect short-term price...

Over the past two decades, respondents to the Shiller Investor Confidence Surveys assess the probability of a catastrophic stock market crash to be much higher that the historical frequency of such events. We decompose these crash probabilities into fundamental and subjective components and use...

We document that value-to-price, the ratio of Residual-Income-Model-based valuation to market price, subsumes the power of book-to-market ratio and many other value or quality measures in predicting stock returns. Long-short value-to-price portfolios hedge against momentum, revitalize the...

We study sources and implications of undiversified portfolios in a production-based asset pricing model with financial frictions. Households take concentrated positions in a single firm exposed to idiosyncratic shocks because managerial effort requires equity stakes, and because investors gain...

We analyze the financial performance of a hypothetical portfolio of 120 mRNA vaccine candidates in the preclinical stage targeting 11 emerging infectious diseases. We calibrate the simulation parameters with input from domain experts in mRNA technology and an extensive literature review. We find...