This research examines competing theories based on the strategic choice and organizational ecology perspectives by investigating strategic change in the banking industry preceding and following interest rate and product deregulation of financial institutions in the early 1980's. Adaptation theory suggests that the largest, oldest, and most powerful organizations have superior capacities for adapting to environmental circumstances and that organizational variability reflects changes in the strategy and structure of a firm in response to environmental changes. The organizational ecology perspective hypothesizes that a firm's ability to change is inversely related to organizational age and size and that organizations become inert as they grow and age. The propositions and hypotheses in this research examine the relationship between organizational age and size on both absolute and relative inertia. The association between strategic change on firm survival is also explored. Findings demonstrate partial support for both theories. An explanation for the mixed findings is offered which suggests that both adaptation and organizational ecology theories explain continuous change, while the deregulation period under study represented a period of discontinuous change. A third model of strategic change, proposed by Meyers, Brooks, and Goes (1990) is offered as a better explanation of strategic change among U.S. banks during the decade following deregulation. / Ph. D.