Abstract: | This study examines differences in profit and sales performance between the different Wrigley/Rumelt categories of diversification strategy. Our sample comprised 305 large U. K. manufacturing companies over the period 1972–84. Although diversification strategy explained only a small proportion of inter-firm performance differences, once the influence of other firm and industry variables were taken into account, significant differences did emerge. Our findings conflict with those of earlier U.S. studies. In particular, we find that diversified firms outperformed specialized firms and there was no evidence that related diversification was more successful than unrelated. |