Does Diversification Destroy Value? Evidence From Industry Shocks

Does corporate diversification reduce shareholder value? Since firms endogenously choose to diversify, exogenous variation in diversification is necessary in order to draw inferences about the causal effect. We examine changes in the within-firm dispersion of industry investment, or diversity.' We find that exogenous changes in diversity, due to changes in industry investment, are negatively related to firm value. Thus diversification destroys value, consistent with the inefficient internal capital markets hypothesis. This finding is not caused by measurement error. We also find that exogenous changes in industry cash flow diversity are negative related to firm value.

The Diversification Discount: Cash Flows vs. Returns

Diversified firms have different values than comparable portfolios of single-segment firms. These value differences must be due to differences in either future cash flows or future returns. Expected security returns on diversified firms vary systematically with relative value. Discount firms have significantly higher subsequent returns than premium firms. Slightly more than half of the cross-sectional variation in excess values is due to variation in expected future cash flows, with the remainder due to variation in expected future returns and to covariation between cash flow and returns.

The Real Effects of Investor Sentiment

We study how stock market mispricing might influence individual firms' investment decisions. We find a positive relation between investment and a number of proxies for mispricing, controlling for investment opportunities and financial slack, suggesting that overpriced (underpriced) firms tend to overinvest (underinvest). Consistent with the predictions of our model, we find that investment is more sensitive to our mispricing proxies for firms with higher R&D intensity suggesting longer periods of information asymmetry and thus mispricing) or share turnover (suggesting that the firms' shareholders are short-term investors). We also find that firms with relatively high (low) investment subsequently have relatively low (high) stock returns, after controlling for investment opportunities and other characteristics linked to return predictability. These patterns are stronger for firms with higher R&D intensity or higher share turnover.

New Forecasts of the Equity Premium

If investors are myopic mean-variance optimizers, a stock's expected return is linearly related to its beta in the cross section. The slope of the relation is the cross-sectional price of risk, which should equal the expected equity premium. We use this simple observation to forecast the equity-premium time series with the cross-sectional price of risk. We also introduce novel statistical methods for testing stock-return predictability based on endogenous variables whose shocks are potentially correlated with return shocks. Our empirical tests show that the cross-sectional price of risk (1) is strongly correlated with the market's yield measures and (2) predicts equity-premium realizations especially in the first half of our 1927-2002 sample.

The Value Spread

We decompose the cross-sectional variance of firms' book-to-market ratios using both a long U.S. panel and a shorter international panel. In contrast to typical aggregate time-series results, transitory cross-sectional variation in expected 15-year stock returns causes only a relatively small fraction (20%) of the total cross-sectional variance. The remaining dispersion can be explained by expected 15-year profitability and persistence of valuation levels. Furthermore, this fraction appears stable across time and across types of stocks. We also show that the expected return on value-minus-growth strategies is atypically high at times when the value spread (the difference between the book-to-market ratio of a typical value stock and a typical growth stock) is wide.

Money Illusion in the Stock Market: The Modigliani-Cohn Hypothesis

Modigliani and Cohn [1979] hypothesize that the stock market suffers from money illusion, discounting real cash flows at nominal discount rates. While previous research has focused on the pricing of the aggregate stock market relative to Treasury bills, the money-illusion hypothesis also has implications for the pricing of risky stocks relative to safe stocks. Simultaneously examining the pricing of Treasury bills, safe stocks, and risky stocks allows us to distinguish money illusion from any change in the attitudes of investors towards risk. Our empirical resuts support the hypothesis that the stock market suffers from money illusion.

The Price is (Almost) Right

Most previous research tests market efficiency and asset pricing models using average abnormal trading profits on dynamic trading strategies, and typically rejects the joint hypothesis. In contrast, we measure the ability of a simple risk model and the efficient-market hypothesis to explain the level of stock prices. First, we find that cash-flow betas (measured by regressing firms' earnings on the market's earnings) explain the prices of value and growth stocks well, with a plausible premium. Second, we use a present-value model to decompose the cross-sectional variance of firms' price-to-book ratios into two components due to risk-adjusted fundamental value and mispricing. When we allow the discount rates to vary with cash-flow betas, the variance share of mispricing is negligible.

Growth or Glamour? Fundamentals and Systematic Risk in Stock Returns

The cash flows of growth stocks are particularly sensitive to temporary movements in aggregate stock prices (driven by movements in the equity risk premium), while the cash flows of value stocks are particularly sensitive to permanent movements in aggregate stock prices (driven by market-wide shocks to cash flows.) Thus the high betas of growth stocks with the market's discount-rate shocks, and of value stocks with the market's cash-flow shocks, are determined by the cash-flow fundamentals of growth and value companies. Growth stocks are not merely "glamour stocks" whose systematic risks are purely driven by investor sentiment. More generally, accounting measures of firm-level risk have predictive power for firms' betas with market-wide cash flows, and this predictive power arises from the behavior of firms' cash flows. The systematic risks of stocks with similar accounting characteristics are primarily driven by the systematic risks of their fundamentals.

Growth or Glamour? Fundamentals and Systematic Risk in Stock Returns

The cash flows of growth stocks are particularly sensitive to temporary movements in aggregate stock prices (driven by movements in the equity risk premium), while the cash flows of value stocks are particularly sensitive to permanent movements in aggregate stock prices (driven by market-wide shocks to cash flows. ) Thus the high betas of growth stocks with the market's discount-rate shocks, and of value stocks with the market's cash-flow shocks, are determined by the cash-flow fundamentals of growth and value companies. Growth stocks are not merely "glamour stocks" whose systematic risks are purely driven by investor sentiment. More generally, accounting measures of firm-level risk have predictive power for firms' betas with market-wide cash flows, and this predictive power arises from the behavior of firms' cash flows. The systematic risks of stocks with similar accounting characteristics are primarily driven by the systematic risks of their fundamentals.

Comomentum: inferring arbitrage activity from return correlations

We propose a novel measure of arbitrage activity to examine whether arbitrageurs can have a destabilizing effect in the stock market. We apply our insight to stock price momentum, a classic example of an unanchored strategy that exhibits positive feedback as arbitrageurs buy stocks when prices rise and sell when prices fall. We define our measure, which we dub comomentum, as the high-frequency abnormal return correlation among stocks on which a typical momentum strategy would speculate on. We show that during periods of low comomentum, momentum strategies are profitable and stabilizing, reflecting an underreaction phenomenon that arbitrageurs correct. In contrast, during periods of high comomentum, these strategies tend to crash and revert, reflecting prior overreaction resulting from the momentum crowd pushing prices away from fundamentals. Theory suggests that we should not find destabilizing arbitrage activity in anchored strategies. Indeed, we find that a corresponding measure for the value strategy, covalue, indicates that arbitrage activity in that strategy is always stabilizing and, in fact, positively correlated with the value spread, a natural anchor for the value-minus-growth trade. Additional tests at the firm, fund, and international level confirm that our approach to measuring arbitrage capital in the momentum strategy is sensible