The presence of traders with superior information leads to a positive bid-ask spread even when the specialist is risk-neutral and makes zero expected profits. The resulting transaction prices convey information, and the expectation of the average spread squared times volume is bounded by a number that is independent of insider activity. The serial correlation of transaction price differences is a function of the proportion of the spread due to adverse selection. A bid-ask spread implies a divergence between observed returns and realizable returns. Observed returns are approximately realizable returns plus what the uninformed anticipate losing to the insiders.

This paper measures the effects on stock proces of corporate investments in 5% or more of another company's equity securities. Such investments initiate a process that may end with a takeover, targeted repurchase, takeover by a third party, or sale of the shares. The total valuation effect of the investment for acquiring and target firms includes returns at disclosure of the investment position, the outcome announcement, and related intervening events. For example, the positive return for target firms at initial disclosure of the investment more than offsets the negative return at a targeted repurchase

This paper hypothesizes that the risk per unit of time and the required rate of return are higher than normal during an event period whose timing can be predicted. Consistent with this hypothesis this paper presents empirical evidence indicating that the unconditional mean rate of return, the variance of stock returns and their systematic risk are higher than ‘usual’ during dividend announcement periods. However, the documented increases in the systematic risk are not large enough to fully explain the ‘excess returns’. This finding is puzzling and hard to reconcile with existing theory

When the assumption of constant risk premiums is relaxed, financial valuation models may be tested, and risk measures estimated without specifying a market index or state variables. This is accomplished by examining the behavior of conditional expected returns. The approach is developed using a single risk premium asset pricing model as an example and then extended to models with multiple risk premiums. The methodology is illustrated using daily return data on the common stocks of the Dow Jones 30. The tests indicate that these returns are consistent with a single, time-varying risk premium.

Carl Icahn, Irwin Jacobs, Carl Lindner, David Murdock, Victor Posner, and the late Charles Bluhdorn are usually portrayed as corporate ‘raiders’. The evidence here, however, shows that between 1977 and 1982 when it was first announced that they had purchased stock in a given firm, stock prices on average increased significantly. The investors' activities in target firms for the two years following the initial stock purchase are likewise inconsistent with ‘raiding’. We discuss two hypotheses that are consistent with the evidence: first, these investors improve the management of target firms; second, they are systematically able to identify under-priced stocks.

This paper examines properties of daily stock returns and how the particular characteristics of these data affect event study methodologies. Daily data generally present few difficulties for event studies. Standard procedures are typically well-specified even when special daily data characteristics are ignored. However, recognition of autocorrelation in daily excess returns and changes in their variance conditional on an event can sometimes be advantageous. In addition, tests ignoring cross-sectional dependence can be well-specified and have higher power than tests which account for potential dependence

We investigate the firm size effect for the period 1958 to 1977 in the framework of a multi-factor pricing model. The risk-adjusted difference in returns between the top five percent and the bottom five percent of the NYSE firms is about one to two percent a year, a drop from about twelve percent per year before risk adjustment. The variable most responsible for the adjustment is the sensitivity of asset returns to the changing risk premium, measured by the return difference between low-grade bonds and long-term government bonds.

Optimal policies for selling a risky depreciable asset with proportional taxes and transaction costs are derived for a representative investor who maximizes the market value of his investment. Also calculated are the market value of his investment and the competitive price of the depreciable asset. Depending upon the values of various parameters, the investor realizes either capital gains and no losses, capital losses and no gains, or neither gains nor losses. Additional properties of the solution are derived numerically.

A ‘cross-sectional regression test’ (CSRT) of the CAPM is developed and its connection to the Hotelling T2 test of multivariate statistical analysis is explored. Algebraic relations between the CSRT, the likehood ratio test and the Langrange multiplier test are derived and a useful small-sample bound on the distribution function of the CSRT is obtained. An application of the CSRT suggests that the CRSP equally-weighted index is inefficient, but that the inefficiency is not explained by a firm size-effect from February to December.