Mergers and acquisitions (hereafter: M&A) change the ownership of companies on an almost daily basis. The large amounts of money involved are usually justified by the pursuit of increased profitability, for example through new product development skills, improved sales channels or increased manufacturing capacity. At the same time, research shows that acquisitions often fail. One branch of acquisition research has highlighted the importance of experience: that firms that are able to learn from previous acquisitions should be more successful in selecting, pricing and integrating acquisition candidates. However, existing theory is still not developed regarding which organizational conditions in the firms that favor or inhibit the accumulation of such experience. The purpose of this proposed project is therefore to develop theories on how acquisition experience is built up in acquisition-intensive firms. Since experience and experience building are organizational and sometimes unconscious processes, the project is conducted as a qualitative, comparative study based on interviews and observations. Between eight and twelve acquisition-intensive Swedish companies will be studied in order to achieve sufficient depth and spread in the results. The project is expected to make clear contributions to existing research. The results are also expected to be highly relevant for the ability of acquisition-intensive firms to succeed in later acquisitions, and thus also provide insights useful for firms that make fewer acquisitions.