I solve (with an approximation) a Grossman-Stiglitz economy under general preferences, thus allowing for wealth effects. Because information generates increasing returns, decreasing absolute risk aversion, in conjunction with the availability of costly information, is sufficient to explain why wealthier households invest a larger fraction of their wealth in risky assets. One no longer needs to resort to decreasing relative risk aversion, an empirically questionable assumption. Furthermore, I show how to distinguish empirically between these two explanations. Finally, I find that the availability of costly information exacerbates wealth inequalities.

By reaching a broad population of investors, mass media can alleviate informational frictions and affect security pricing even if it does not supply genuine news. We investigate this hypothesis by studying the cross-sectional relation between media coverage and expected stock returns. We find that stocks with no media coverage earn higher returns than stocks with high media coverage even after controlling for well-known risk factors. These results are more pronounced among small stocks and stocks with high individual ownership, low analyst following, and high idiosyncratic volatility. Our findings suggest that the breadth of information dissemination affects stock returns.

I investigate whether changes in stock market participation costs can explain the long-term increase in the number of U.S. stockholders. I separate these costs into two components: an information cost (the cost of collecting market information), and an entry cost (all other costs, including commissions and fees), and disentangle their general equilibrium implications in a noisy rational expectations economy. While a falling information cost cannot explain the observed increase in stock market participation, a falling entry cost can account for this plus several other features of the U.S. economy, including the falling equity premium, rising return variances, and the boom in passive relative to active investing.

A competitive stock market is embedded into a neoclassical growth economy to analyze the interplay between the acquisition of information about firms, its partial revelation through stock prices, capital allocation, and income. The stock market allows investors to share their costly private signals in a cost-effective incentive-compatible way. It contributes to economic growth by raising total factor productivity (TFP). A calibration indicates the effect on TFP to be large but that on income to be modest. Several predictions on the evolution of real and financial variables are derived. Finally, the growth impact of two common forms of investor irrationality, overconfidence and inattention, are analyzed.

[Traditional portfolio balance theory derives a downward sloping currency demand function from limited international asset substitutability. Historically, this theory enjoyed little empirical support. We provide direct evidence by examining the exchange rate effect of a major redefinition of the MSCI Global Equity Index in 2001 and 2002. The index redefinition implied large changes in the representation of different countries in the MSCI Global Equity Index and therefore produced strong exogenous equity flows by index funds. Our event study reveals that countries with a relatively increasing equity representation experienced a relative currency appreciation upon announcement of the index change. Moreover, stock markets that are upweighted (downweighted) feature a higher (lower) permanent comovement of their currency with the basket of other MSCI currencies.]

I solve (with an approximation) a Grossman-Stiglitz economy under general preferences, thus allowing for wealth effects. Because information generates increasing returns, decreasing absolute risk aversion, in conjunction with the availability of costly information, is sufficient to explain why wealthier households invest a larger fraction of their wealth in risky assets. One no longer needs to resort to decreasing relative risk aversion, an empirically questionable assumption. Furthermore, I show how to distinguish empirically between these two explanations. Finally, I find that the availability of costly information exacerbates wealth inequalities.

This paper demonstrates, theoretically and empirically, that firms’ research and development (R&D) efforts and investors’ analyses of their prospects are mutually reinforcing. Entrepreneurs attempt more research when financiers are better informed about projects’ profitability because they expect financiers to provide more funding to successful projects. Conversely, financiers collect more information about projects when entrepreneurs undertake more R&D because the opportunity cost of missing out on successful projects is then higher. Two natural experiments confirm that this interaction occurs and suggest that it contributes to about one third of the total effect of a policy designed to stimulate R&D. Overall, the analysis suggests that policies aimed at promoting R&D – such as research subsidies or tax breaks – have a multiplier effect owing to the induced improvement in capital efficiency. As a result, those policies can be rendered more effective by coupling them with other policies designed to increase capital efficiency. The feedback effect that we document also helps explaining why innovative ecosystems such as that in the Silicon Valley are challenging to set up.

The media are increasingly recognized as key players in financial markets. I investigate their causal impact on trading and price formation by examining national newspaper strikes in several countries. Trading volume falls 12% on strike days. The dispersion of stock returns and their intraday volatility are reduced by 7%, while aggregate returns are unaffected. Moreover, analysis of return predictability indicates that newspapers propagate news from the previous day. These findings demonstrate that the media contribute to the efficiency of the stock market by improving the dissemination of information among investors and its incorporation into stock prices.