We empirically examine the effects of index investing using predictions derived from a Grossman-Stiglitz framework. An exogenous increase in index investing leads to lower information production as measured by Google searches, EDGAR views, and analyst reports, yet price informativeness remains unchanged. These findings are consistent with an equilibrium in which investors choose to gather private information whenever it is profitable. As index investing increases, there are fewer privately-informed active investors (so overall information production drops), but the mix of investors adjusts until the returns to active investing are unchanged. As a result, passive investing does not undermine price efficiency.

Using a novel empirical approach and newly available administrative data on U.S. tax filings, we estimate the corporate elasticity of taxable income, decompose the elasticity into economic responses versus other tax‐motivated “accounting” transactions, and determine how responsiveness varies depending on accounting method, firm size, and interest rate. In response to a 10% increase in the expected marginal tax rate, private U.S. firms decrease taxable income by 9.1%, which indicates a discernibly more elastic response than prevailing estimates. This response reflects a decrease in taxable income of 3.0% arising from real economic responses to a firm's scale of operations and 6.1% arising from accounting transactions via (for example) revenue and expense timing. Responsiveness to the corporate tax rate is more elastic if a firm uses cash (9.9%) rather than accrual accounting (7.4%), if the firm is small (9.9%) rather than large (8.6%), and if the firm discounts future cash flows at a lower rate.