The mean return for stocks is positive only for days immediately before and during the first half of calendar months, and indistinguishable from zero for days during the last half of the month. This ‘monthly effect’ is independent of other known calendar anomalies such as the January effect documented by others and appears to be caused by a shift in the mean of the distribution of returns from days in the first half of the month relative to days in the last half.

This paper evaluates the power of multivariate tests of the Capital Asset Pricing Model. The results indicate that when employing an unspecified alternative hypothesis, the ability of the tests to distinguish between the CAPM and other pricing models is poor. An upper bound is derived for the distance the alternative distribution of the test statistic can be from the null distribution when the deviations from the CAPM are due to missing factors. This upper bound explains the low power of the tests.

We measure the differential effects on shareholder wealth and tendering behavior of any-or-all, two-tier and partial tender offers and find no evidence that shareholders are disadvantaged by front-end-loaded corporate takeovers. Shareholders fare as well when the terms of an offer for control are negotiated with target-firm management as when they are not. Most cash tender offers executed between 1981 and 1984 were negotiated, and almost all two-tier offers were negotiated.

Antitakeover amendments (shark repellents) restrict the transfer of corporate control. On average, the public announcement of antitakeover amendments by 600 firms in the period 1979–1985 has an insignificant effect on the value of announcing firms' shares. However, different types of amendments have varying effects. Non-fair-price amendments have an average significant negative effect of 2.95% on share prices, while fair-price amendments have an insignificant effect. The more harmful amendments have larger insider holdings and lower institutional holdings, suggesting a partial explanation of why shareholders approve these amendments.

Abnormal returns earned by target firms at the time of initial acquisition announcements are related to form of payment, degree of resistance, and type of offer. Results indicate that interdependence among these characteristics is important. Previous research suggests that tender-offer targets earn higher abnormal returns than merger targets. After controlling for payment method and degree of resistance, however, the difference in abnormal returns between tender offers and mergers is insignificant. Resisted offers are associated with insignificantly higher returns than unresisted offers. Abnormal returns associated with cash offers are significantly higher than those associated with stock offers.

We examine companies that franchise some units and centrally operate (‘own’) others. The agency problems confronting these two organizational forms are analyzed. Testable hypotheses are developed. The empirical results support the notion that owning versus franchising reflects a trade-off among agency-related problems. The cost of monitoring store managers appears to be especially important in the own/franchise decision. The level of repeat business and initial investment requirements per unit also appear to be important.