Kevin Lewis

October 15, 2018

Good Disclosure, Bad Disclosure
Itay Goldstein & Liyan Yang
Journal of Financial Economics, forthcoming


We study real-efficiency implications of disclosing public information in a model with multiple dimensions of uncertainty where market prices convey information to a real decision maker. Paradoxically, when disclosure concerns a variable that the real decision maker cares to learn about, disclosure negatively affects price informativeness, and in markets that are effective in aggregating private information, this negative price-informativeness effect can dominate so that better disclosure negatively impacts real efficiency. When disclosure concerns a variable that the real decision maker already knows much about, disclosure always improves price informativeness and real efficiency. Our analysis has important empirical and policy implications for different contexts such as disclosure of stress test information and regulation of credit ratings.

Short and Distort
Joshua Mitts
Columbia University Working Paper, September 2018


Pseudonymous attacks on public companies are followed by stock price declines and sharp reversals. I find these patterns are likely driven by manipulative stock options trading by pseudonymous authors. Among 1,720 pseudonymous attacks on mid- and large-cap firms from 2010-2017, I identify over $20.1 billion of mispricing. Reputation theory suggests these reversals persist because pseudonymity allows manipulators to switch identities without accountability. Using stylometric analysis, I show that pseudonymous authors exploit the perception that they are trustworthy, only to switch identities after losing credibility with the market.

How Effective Are Trading Pauses?
Nikolaus Hautsch & Akos Horvath
Journal of Financial Economics, forthcoming


Exploiting Nasdaq order book data and difference-in-differences methodology, we identify the distinct effects of trading pause mechanisms introduced on US stock exchanges after May 2010. We show that the mere existence of such a regulation makes market participants behave differently in anticipation of a pause. Pauses enhance price discovery during the break but have adverse effects on price stability and liquidity after the pause. We find that pauses ultimately do not “cool off” markets but cause extra volatility. This implies a regulatory trade-off between the protective role of trading pauses and their adverse effects on market quality.

Belief Disagreement and Portfolio Choice
Maarten Meeuwis et al.
NBER Working Paper, September 2018


Using a proprietary dataset of the portfolio holdings of millions of anonymized households with trillions in wealth, we test the central tenet of rational-expectations theories of asset pricing and portfolio choice – that agents believe in a common model and update their beliefs identically in response to public signals – against alternative theories in which agents hold different models of the world and update beliefs heterogeneously. We identify households that ex ante are likely to believe in different models of the world using political party affiliation (probabilistically inferred from zip code), and our public signal is the unexpected outcome of the US election of November 2016. Relative to Democrats, Republican investors actively increase the share of equity and market beta of their portfolios following the election. Inconsistent with the effect being driven by differences in hedging needs with common beliefs, the results are robust to controls for age, wealth, income, state, and even county-employer fixed effects.

Industry Familiarity and Trading: Evidence from the Personal Portfolios of Industry Insiders
Itzhak Ben-David, Justin Birru & Andrea Rossi
Journal of Financial Economics, forthcoming


We study whether industry familiarity is an advantage in stock trading by exploring the trading patterns of industry insiders in their own personal portfolios. To do so, we identify accounts of industry insiders in a large data set provided by a retail discount broker. We find that insiders trade firms from their own industry more frequently. Furthermore, they earn abnormal returns exclusively when trading own-industry stocks, especially obscure stocks (small, low analyst coverage, high volatility). In a battery of tests, we find no evidence of the use of private information. The results are most consistent with the interpretation that industry familiarity is an advantage in stock trading.

Time Will Tell: Information in the Timing of Scheduled Earnings News
Travis Johnson & Eric So
Journal of Financial and Quantitative Analysis, forthcoming


Using novel earnings calendar data, we show that firms’ advanced scheduling of earnings announcement dates foreshadows their earnings news. Firms that schedule later-than-expected announcement dates subsequently announce worse news than those scheduling earlier-than-expected announcement dates. Despite scheduling disclosures being observable weeks ahead of earnings announcements, we show that equity markets fail to reflect the information in these disclosures until the announcement itself. By also showing that option markets respond efficiently to volatility-timing information embedded in the same scheduling disclosures, we provide novel evidence that markets fail to react to information about future earnings despite investors immediately trading on the underlying signal.

The Twitter Myth Revisited: Intraday Investor Sentiment, Twitter Activity and Individual-Level Stock Return Volatility
Simon Behrendt & Alexander Schmidt
Journal of Banking & Finance, November 2018, Pages 355-367


Taking an intraday perspective, we study the dynamics of individual-level stock return volatility, measured by absolute 5-minute returns, and Twitter sentiment and activity. After accounting for the intraday periodicity in absolute returns, we discover some statistically significant co-movements of intraday volatility and information from stock-related Tweets for all constituents of the Dow Jones Industrial Average. However, economically, the effects are of negligible magnitude and out-of-sample forecast performance is not improved when including Twitter sentiment and activity as exogenous variables. From a practical point of view, we find that high-frequency Twitter information is not particularly useful for highly active investors with access to such data for intraday volatility assessment and forecasting when considering individual-level stocks.

Analyst Career Concerns, Effort Allocation, and Firms’ Information Environment
Jarrad Harford et al.
Review of Financial Studies, forthcoming


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.

Know Thy Neighbor: Industry Clusters, Information Spillovers, and Market Efficiency
Joseph Engelberg, Arzu Ozoguz & Sean Wang
Journal of Financial and Quantitative Analysis, October 2018, Pages 1937-1961


Firms in industry clusters have market prices that are more efficient than firms outside clusters. To establish causality, we analyze exogenous firm relocations and find that firms that relocate into industry clusters have higher levels of industry information in their prices. We argue that geographical proximity allows for information spillovers, reducing marginal cost to information producers. Our evidence supports this view: Analysts are more likely to cover stocks inside industry clusters, and when institutional investors have a large position in one stock in the industry cluster, they are more likely to hold other stocks in the same industry cluster.

Mark Twain’s Cat : Investment Experience, Categorical Thinking, and Stock Selection
Xing Huang
Journal of Financial Economics, forthcoming


This paper examines the effect of prior investment experience in specific industries on subsequent investment decisions. Using households’ trading records from a large discount broker between 1991 and 1996, I find that prior success in a given industry increases the likelihood of subsequent purchases in the same industry. The effect is stronger for more recent experiences and for less sophisticated or diversified investors, and it is not wealth enhancing. The results suggest investors categorize industries at a highly resolved level, finer than the Fama-French ten-industry classification. Similar effects are also apparent for size- and value-based categories but at smaller magnitudes.

Financial Sector Stress and Risk Sharing: Evidence from the Weather Derivatives Market
Daniel Weagley
Review of Financial Studies, forthcoming


I examine the effect of financial sector stress on risk sharing in a novel setting: the CME’s weather derivatives market. The structure of the market allows me to disentangle price movements due to financial sector stress from price movements due to fundamentals. Contracts, which are typically priced near their actuarially fair value, experience significant price declines during periods of financial sector stress. Contracts with greater margin requirements and total risk are the most affected. The results provide causal evidence of the effect of financial sector stress on the pricing of exchange-traded financial contracts and risk sharing in the economy.

Public hedge funds
Lin Sun & Melvyn Teo
Journal of Financial Economics, forthcoming


Hedge funds managed by listed firms significantly under-perform funds managed by unlisted firms. The under-performance is more severe for funds with low manager deltas, poor governance, and no manager co-investment, or those managed by firms whose prices are sensitive to earnings news. Notwithstanding the under-performance, listed asset management firms raise more capital, by growing existing funds and launching new funds post listing, and harvest greater fee revenues than do comparable unlisted firms. The results are consistent with the view that, for asset management firms, going public weakens the alignment between ownership, control, and investment capital, thereby engendering conflicts of interest.


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