Knowledge that Transforms

This paper introduces a new approach to constructing optimal mean-variance portfolios. The approach relies on a novel unconstrained regression representation of the mean-variance optimization problem combined with high-dimensional sparse-regression methods. Our estimated portfolio, under a mild sparsity assumption, controls for risk and attains the maximum expected return as both the numbers of assets and observations grow. The superior properties of our approach are demonstrated through comprehensive simulation and empirical analysis. Notably, using our strategy, we find that investing in individual stocks, in addition to the Fama-French three-factor portfolios, leads to substantially improved performance. Received October 6, 2014; editorial decision July 13, 2018 by Editor Andrew Karolyi.

We consider the case of changing competition that comes from stronger antitrust enforcement around the world to show that, as the equilibrium switches from collusion to oligopolistic competition, firms step up investment and increase equity issuance. As a result, debt ratios fall. These results imply the importance of financial flexibility in surviving competitive threats. Our identification relies on a difference-in-differences estimation based on the staggered passage of leniency programs in 63 countries around the world from 1990 to 2012. Received December 12, 2016; editorial decision July 10, 2018 by Editor Andrew Karolyi.

What moves stock prices? Prior literature concludes that the revelation of private information through trading, and not public news, is the primary driver. We revisit the question by using textual analysis to identify fundamental information in news. We find that this information accounts for 49.6% of overnight idiosyncratic volatility (vs. 12.4% during trading hours), with a considerable fraction due to days with multiple news types. We use our measure of public information arrival to reinvestigate two important contributions in the literature related to individual R^2s of stock returns on aggregate factors.Received February 24, 2016; editorial decision May 19, 2018 by Editor Andrew Karolyi.

We develop a tractable equilibrium asset pricing model with cumulative prospect theory (CPT) preferences. Using GMM on a sample of U.S. equity index option returns, we show that by introducing a single common probability weighting parameter for both tails of the return distribution, the CPT model can simultaneously generate the otherwise puzzlingly low returns on both out-of-the-money put and out-of-the-money call options as well as the high observed variance premium. In a dynamic setting, probability weighting and time-varying equity return volatility combine to match the observed time-series pattern of the variance premium. Received May 30, 2017; editorial decision August 10, 2018 by Editor Andrew Karolyi.

Blockchain technology provides decentralized consensus and potentially enlarges the contracting space through smart contracts. Meanwhile, generating decentralized consensus entails distributing information that necessarily alters the informational environment. We analyze how decentralization relates to consensus quality and how the quintessential features of blockchain remold the landscape of competition. Smart contracts can mitigate informational asymmetry and improve welfare and consumer surplus through enhanced entry and competition, yet distributing information during consensus generation may encourage greater collusion. In general, blockchains sustain market equilibria with a wider range of economic outcomes. We further discuss the implications for antitrust policies targeted at blockchain applications.Received May 31, 2017; editorial decision May 29, 2018 by Editor Itay Goldstein.

Analysts strategically allocate more effort to portfolio firms that are relatively more important to their careers. Thus, the other firms the analysts cover indirectly affect a firm’s information environment. Controlling for analyst and firm characteristics, we find that an analyst makes more accurate, frequent, and informative earnings forecasts and recommendations for firms ranked higher within her portfolio based on proxies for importance to institutions. A firm’s relative rank widely varies across analysts, but its information environment improves when a larger proportion of analysts consider it to be relatively important. Analysts experience more favorable career outcomes when strategically allocating their efforts. Received August 23, 2017; editorial decision June 27, 2018 by Editor Lauren Cohen.

[Firms that buy assets in fire sales earn excess returns that are 2 percentage points higher than in regular acquisitions. The mechanism behind this result is the sellers’ reduced bargaining power. We find no difference in real effects or in the combined returns for buyers and sellers between fire sales and regular acquisitions, suggesting that the quality of the match is similar in both types of transactions. The externalities of fire sales for other stakeholders are limited. These results indicate that the welfare losses associated with fire sales are smaller than previously thought.]

We propose a protocol for identifying genuine risk factors. A genuine risk factor must be related to the covariance matrix of returns, must be priced in the cross-section of returns, and should yield a reward-to-risk ratio that is reasonable enough to be consistent with risk pricing. A market factor, a profitability factor, and traded versions of macroeconomic factors pass our protocol, but many characteristic-based factors do not. Several of the underlying characteristics, however, do command premiums in the cross-section. Received July 20, 2017; editorial decision June 9, 2018 by Editor Andrew Karolyi.

This paper examines how external governance pressure affects the type of debt that firms issue. Consistent with a governance mechanism substitution effect, we find that an exogenous increase (decrease) in governance pressure from the product (takeover) market has a significant negative (positive) impact on the use of bank (public debt) financing over public debt (bank loan) issuance. Tests using changes in the strictness of loan covenants provide corroborative evidence. These findings are consistent with the notion that firms endogenously substitute governance mechanisms and that demand for creditor governance depends on the relative strength of alternative external governance mechanisms. Received May 18, 2016; editorial decision November 11, 2017 by Editor David Denis.

We develop and estimate a dynamic model of risk-shifting over the business cycle. First, equity holders with Epstein-Zin preferences increase their taking of idiosyncratic risk substantially more than the standard model in repeated games, because they perceive the arrival probability of bad states to be higher than the actual probability and prefer an early resolution of macroeconomic uncertainty. Second, sudden switches to bad states and large shocks in the bad states induce the countercyclical and “synchronized” idiosyncratic risk. Third, combined with the high market risk premium in the bad states, clustered risk-taking generates a countercyclical idiosyncratic volatility discount on equity returns.Received July 1, 2017; editorial decision January 22, 2018 by Editor Stijn Van Nieuwerburgh.