This paper summarizes nine case studies, by nine authors, on the efficiency effects of bank mergers. The mergers selected for study were ones that seemed relatively likely to yield efficiency gains. That is, they involved relatively large banks generally with substantial market overlap, and most occurred during the early 1990s when efficiency was getting a lot of attention in banking. All nine of the mergers resulted in significant cost cutting in line with premerger projections. Four of the nine mergers were clearly successful in improving cost efficiency but five were not. It is not possible to isolate specific factors from these mergers that are most likely to yield efficiency gains, but the most frequent and serious problem was unexpected difficulty in integrating data processing systems and operations.

U NFORTUNATELY, economic theory and existing empirical evidence provide little insight into the effects of diversification on industry performance. This is partially due to the fact that most previous empirical studies of diversification have been concerned with tabulating the extent of,1 or motives for,2 diversification. In order for the antiitrust authorities to develop a rational policy toward conglomerate mergers, it will be necessary to determine the competitive consequences of diversification. This study attempts to provide some empirical evidence on the effects of diversification by examining the relationship between industry price-cost margins and diversification.3 Specifically, the study examines the general proposition that diversification is an element of industry structure and the more narrow hypothesis that diversification raises barriers to entry into an industry. The study is based on a sample of 241 four-digit manufacturing industries from the 1963 Census of Manufactures. The primary testing technique is multivariate regression analysis. Results of the analysis provide tentative support for the proposition 'that diversification has a systematic influence on price-cost margins which may be attributable to certain barriers to entry.

The strategic groups hypothesis is tested using cluster analysis in -16 selected banking markets and based on portfolio composition in 1978, 1981, and 1984. The results indicate that approximately six strategic groups exist in banking and are stable over time. Strategy choices are similar across markets. Implications of the results are (1) intraindustry profit differences may be due to strategic groups rather than efficiency differences, (2) markets may generally be defined too broadly, (3) investigations for collusion need to focus on homogeneous groups in an industry rather than the whole industry, and (4) there is no simple strategy choice for banks between retail and wholesale banking.

Findings do not indicate poorly-managed firms are more likely to be acquired than well-managed firms. The analysis uses a sample of 1, 046Texas banks that existed in 1970, out of which 201 were acqui red during the period 1970-82. A multinomial logit procedure is used to estimate the relationship between the likelihood of acquisition and the characteristics of the target firm and its market. Additional results suggest that firms with la rge market shares, low capital/asset ratios, and operations in urban areas are r elatively likely to be acquired but not firms with low profits or low growth. Copyright 1987 by MIT Press.