The current thesis concerns the relationship that exists between the experience in acquisitions that a company accumulates and the probability of devestiture of the acquired companies. In order to analyse and validate our research hypotheses, we have constructed our study in five chapters : an analysis of the literature on the approach through resources, the field of organisational learning and divestiture; the presentation of our research methodology; a case study with qualitative interviews regarding the takeover of an english group, Blue Circle by the french cement manufacturer, Lafarge; quantitative study of disinvestments following 140 acquisitions made in the United States in 1994 and finally, a discussion on the results obtained. The results reveal, from a qualitative viewpoint, that an accumulation of experience and an evolution in its organisation and strategy have led the Lafarge groupto modify its integration process. The case studies also revealed the organisational impacts of the integration process and the way in which Lafarge managed its human resource difficulties. For a quantitative viewpoint, we analysed 140 acquisitions made in the United States in 1994 using a longitudinal design. We formulated twelve hypothesis, aiming to determine the relationship between the accumulation of experience (industry, country and total) and the probability of divestiture of the acquired companies. Using a panel logistic regression model, we validate four out twelve hypothesis. We demonstrated a quadratic relationship between post acquisitions experience and the probability of divestiture (U shaped); a quadratic relationship between pre and post industry acquisitions experience and the probability of divestiture (U shaped). Discussion supports the idea that only strong acquierers experience a low probability of divesting previous acquisitions and makes the difference between long term and short terme divestitures.
