We present a simple model in which rational but uninformed traders occasionally chase noise as if it were information, thereby amplifying sentiment shocks and moving prices away from fundamental values. In the model, noise traders can have an impact on market equilibrium disproportionate to their size in the market. The model offers a partial explanation for the surprisingly low market price of financial risk in the spring of 2007.

We study asset prices in an economy where some investors categorize risky assets into different styles and move funds among these styles depending on their relative performance. In our economy, assets in the same style comove too much, assets in different styles comove too little, and reclassifying an asset into a new style raises its correlation with that style. We also predict that style returns exhibit a rich pattern of own- and cross-autocorrelations and that while asset-level momentum and value strategies are profitable, their style-level counterparts are even more so. We use the model to shed light on several style-related empirical anomalies.

We present a simple model of an entrepreneur going public in an environment with poor legal protection of outside shareholders. The model incorporates elements of Becker's (J. Political Econ. 106 (1968) 172) “crime and punishment” framework into a corporate finance environment of Jensen and Meckling (J. Financial Econ. 3 (1976) 305). We examine the entrepreneur's decision and the market equilibrium. The model is consistent with a number of empirical regularities concerning the relation between investor protection and corporate finance. It also sheds light on the patterns of capital flows between rich and poor countries and on the politics of reform of investor protection.

The analysis of corporate governance begins with a central feature of modern capitalism – the separation of ownership and control in large corporations – first empirically documented by Berle and Means (1932). Such separation entails several agency problems reflecting conflicts between managers and shareholders, such as self-dealing by managers, low effort, consumption of perquisites, and excessive growth and diversification. Berle and Means saw self-dealing as the central agency problem and stressed the law as the fundamental mechanism of addressing it. Jensen and Meckling (1976) considered the consumption of perquisites and emphasized private mechanisms, such as financial incentives for managers, to counter wasteful perks. Jensen (1986) instead focused on excessive growth and diversification, which led him to count on leverage and takeovers. The combination of public corporate governance mechanisms, mostly the law, and market governance shaped both theory and practice.

We address the joint hypothesis problem in cross-sectional asset pricing by using measured analyst expectations of earnings growth. We construct a firm-level measure of Expectations Based Returns (EBRs) that uses analyst forecast errors and revisions and shuts down any cross-sectional differences in required returns. We obtain three results. First, variation in EBRs accounts for a large chunk of cross-sectional return spreads in value, investment, size, and momentum factors. Second, time variation in these spreads is predictable from that in EBRs, holding constant scaled price variables (as proxies for time varying required returns). Third, firm characteristics often seen as capturing risk premia predict disappointment of expectations and low EBRs. Overall, return spreads typically attributed to exotic risk factors are explained by predictable movements in non-rational expectations of firms’ earnings growth.

We introduce diagnostic expectations into a standard setting of price formation in which investors learn about the fundamental value of an asset and trade it. We study the interaction of diagnostic expectations with learning from prices and speculation (buying for resale). With diagnostic (but not with rational) expectations, these mechanisms lead to price paths exhibiting three phases: initial underreaction, then overshooting (the bubble), and finally a crash. With learning from prices, the model generates price extrapolation as a by-product of beliefs about fundamentals, lasting only as the bubble builds up. When investors speculate, even mild diagnostic distortions generate substantial bubbles.

We propose a theory of financial intermediaries operating in markets influenced by investor sentiment. In our model, banks make, securitize, distribute, and trade loans, or they hold cash. They also borrow money, using their security holdings as collateral. Banks maximize profits, and there are no conflicts of interest between bank shareholders and creditors. The theory predicts that bank credit and real investment will be volatile when market prices of loans are volatile, but it also points to the instability of banks, especially leveraged banks, participating in markets. Profit-maximizing behavior by banks creates systemic risk.

We present a model of mergers and acquisitions based on stock market misvaluations of the combining firms. The key ingredients of the model are the relative valuations of the merging firms and the market's perception of the synergies from the combination. The model explains who acquires whom, the choice of the medium of payment, the valuation consequences of mergers, and merger waves. The model is consistent with available empirical findings about characteristics and returns of merging firms, and yields new predictions as well.

We describe how managers can entrench themselves by making manager-specific investments that make it costly for shareholders to replace them. By making manager-specific investments, managers can reduce the probability of being replaced extract higher wages and larger perquisites from shareholders, and obtain more latitude in determining corporate strategy. Our model of entrenchment has empirical implications that are consistent with the evidence on managerial behavior.

We evaluate Eugene F. Fama's claim that stock prices do not exhibit price bubbles. Based on US industry returns (1926‒2014) and international sector returns (1985‒2014), we present four findings (1) Fama is correct in that a sharp price increase of an industry portfolio does not, on average, predict unusually low returns going forward; (2) such sharp price increases predict a substantially heightened probability of a crash but not of a further price boom; (3) attributes of the price run-up, including volatility, turnover, issuance, and the price path of the run-up, help forecast an eventual crash; and (4) these attributes also help forecast future returns. Results hold similarly in US and international samples.