I test whether social influence affects individual investors’ trading and stock returns. In each of the 20 most active stocks in Finland over 9 years, the number of owners in a municipality multiplied by the number of investors who do not own a stock, a measure of the rate of transmission of diseases and rumors through social contact, predicts individual investor trading. I control for known determinants of trade, including daily news, and show that competing explanations for the relation are unlikely. Socially motivated trades predict stock returns, and the effects are not reversed, suggesting that individuals share useful information. Individuals’ susceptibility to social influence has declined during the period, but the opportunities for social influence have increased.

This study examines the effect of locally informed investors on market efficiency and stock prices using large power outages, which are exogenous events that constrain trading. Turnover in stocks headquartered in an outage area with 0.5% of U.S. electrical customers drops by 3–7% on the first full day of the outage, and bid–ask spreads narrow by 2.5%. Firm-specific price volatility is 2.3% lower on blackout dates. This effect is larger for smaller, lesser-known stocks and in higher income areas. Consistent with a valuation discount and higher expected returns for stocks with more informed traders, firms with a one-standard-deviation higher local trading propensity have market-to-book values that are 5% lower, Tobin's Q that is 6% lower, annualized four-factor alphas that are 1.2% higher, and average spreads that are 6.5% higher. Together, the evidence suggests that informed investors contribute disproportionately to both liquidity and price discovery, and that these contributions are reflected in valuations and expected returns.

A large literature finds evidence that pricing kernels nonparametrically estimated from option prices and historical returns are not monotonically decreasing in market index returns. We argue that existing estimation methods are inconsistent and propose a new nonparametric estimator of the pricing kernel that reflects the information available to investors who set asset prices. In simulations, the estimator outperforms existing techniques. Our empirical estimates using S&P 500 index option data from 1996 to 2014 and FTSE 100 index option data from 2002 to 2014 suggest that the “pricing kernel puzzle” is due to flaws in existing estimators rather than a behavioral or economic phenomenon.

We investigate the motivations and effects of financial firms’ hiring of former US financial regulatory employees. The number of top executives with regulatory experience per firm has increased 24% over 2001–15, and hiring is associated with positive average announcement returns and a salary premium. In the quarter after hire, market and balance sheet measures of firm risk decrease significantly and measures of risk management activity increase, especially for hires from prudential regulators, who directly monitor financial firm risk. The absence of this result for unregulated firms and for exogenous shocks to regulatory experience suggests that firms hire ex-employees of their regulators when they perceive a need to reduce risk, consistent with a schooling hypothesis. We find little direct evidence of quid pro quo behavior in regulatory event frequency and fines.

The number of U.S. publicly traded firms has halved in 20 years. How will this shift in ownership structure affect the economy’s externalities? Using comprehensive data on greenhouse gas emissions from 2007 to 2016, we find that independent private firms are less likely to pollute and incur EPA penalties than are public firms, and we find no differences between private sponsor-backed firms and public firms, controlling for industry, time, location, and a host of firm characteristics. Within public firms, we find a negative association between emissions and mutual fund ownership and board size, suggesting that increased oversight may decrease externalities.

A large literature finds evidence that pricing kernels nonparametrically estimated from option prices and historical returns are not monotonically decreasing in market index returns. We argue that existing estimation methods are inconsistent and propose a new nonparametric estimator of the pricing kernel that reflects the information available to investors who set asset prices. In simulations, the estimator outperforms existing techniques. Our empirical estimates using S&P 500 index option data from 1996 to 2014 and FTSE 100 index option data from 2002 to 2014 suggest that the “pricing kernel puzzle” is due to flaws in existing estimators rather than a behavioral or economic phenomenon. Received August 2, 2015; editorial decision April 15, 2017 by Editor Andrew Karolyi.

We find that patient traders profit from the predictable, flow-induced trades of mutual funds. In anticipation of a 1%-of-volume change in mutual fund flows into a stock next quarter, the institutions in the same 13F category as hedge funds trade 0.29–0.45% of volume in the current quarter. A third of the trading is associated with the subset of 504 identified hedge funds. The effect is stronger when quarterly mutual fund portfolio disclosure is required and among hedge funds with more patient capital. A one standard deviation higher measure of anticipatory trading by a hedge fund is associated with a 0.9% higher annualized four-factor alpha. A one standard deviation higher measure of anticipation of a mutual fund's trades by institutions is associated with a 0.07–0.15% lower annualized four-factor alpha. The effect is stronger for more constrained mutual funds.

This is the first paper to examine the microstructure of how mispricing is created and resolved. We study dual-class shares with equal cash flow rights and show that a simple trading strategy exploiting gaps between their prices appears to create abnormal profits after transactions costs. Trade and quote data show that investors shift their trading patterns to take advantage of gaps. Contrary to common perception, long–short arbitrage plays a minor part in eliminating gaps, and one-sided trades correct most of them. We also show that the more liquid share class is usually responsible for the price discrepancies.