Financial markets reveal information that firm managers can utilize when making equity value-enhancing investment decisions. However, for firms with risky debt, such investments are not necessarily socially efficient. Despite this friction, we show that learning from prices improves investment efficiency. This effect is asymmetric, however, as investors learn less about projects that decrease the riskiness of cash flows: efficiency is lower for diversifying investments than for focusing (risk-increasing) investments. This also implies that investors’ endogenous learning further attenuates risk shifting but amplifies debt overhang. Our model provides a novel channel through which learning from financial markets affects agency frictions between stakeholders.

We analyze a tractable rational expectations equilibrium model with margin constraints. We argue that constraints affect and are affected by informational efficiency, leading to a novel amplification mechanism. A decline in wealth tightens constraints and reduces investors’ incentive to acquire information, lowering price informativeness. Lower informativeness, in turn, increases the risk borne by financiers who fund trades, leading them to further tighten constraints faced by investors. This information spiral leads to (a) significant increases in risk premium and return volatility in crises, when investors wealth declines, (b) complementarities in information acquisition in crises, and (c) complementarities in margin requirements.

Stock prices aggregate investor information about investment opportunities and reflect managerial performance. These dual roles may be in tension: when prices are more informative about investment opportunities, they may be less effective at incentivizing managerial effort. This tradeoff has novel consequences. Lower information costs can lead to both more efficient investment but lower firm value. The principal may strictly prefer to delegate investment to a manager who has no informational advantage and makes ex-post inefficient choices. Investment in diversifying and (ex-ante) negative NPV projects mitigate agency problems. Finally, standard measures of price efficiency provide an incomplete picture of firm value.

No. In the presence of speculative opportunities, investors can learn about both asset fundamentals and the beliefs of other traders. We show that this learning exhibits complementarity: learning more along one dimension increases the value of learning about the other. As a result, regulatory changes may be counterproductive. First, increasing transparency (i.e., making fundamental information cheaper to acquire) can make prices less informative when investors respond by learning relatively more about others. Second, public disclosures discourage private learning about fundamentals, while encouraging information acquisition about others. Accordingly, disclosing more fundamental information can decrease overall informational efficiency by decreasing price informativeness. Received April 20, 2016; editorial decision September 30, 2017 by Editor Itay Goldstein.