Inhaltsangabe:Abstract: The ultimate management challenge is said to be the management of a conglomerate. Diversified companies, especially conglomerates, are complex organisations that in the larger cases resemble full-blown economies, rather than firms. They develop internal capital markets with billion dollar budgets, enormous internal labour markets, and often a decent amount of bureaucracy. The International Telephone and Telegraph Corporation (ITT) owned more than 150 businesses in the 1960s, ranging from electronics to insurance companies, with operations across the globe. The architect of ITT, Harold Greneen, once acquired 20 unrelated business in a single month and was strongly convinced that sound management principles could be applied to any type of business. He believed that information was key to good management. During his reign earnings increased a 100 consecutive quarters and seemed to support this management belief. In the late 1960s, earnings did not increase any longer and the stock price lost significantly in value. By the early 1980s the company was already heavily involved in deconglomeration and had divested more than a 100 businesses. ITT was not the only diversified company in the 1980s that was on the search for focus. The conglomerate strategy went out of fashion with investors, due to poor performance associated with this strategy. The result was a conglomerate discount of an average 15 percent on the stock market that persists until today. Despite this investor aversion, some companies continued the conglomerate path and managed to be highly successful at the same time. General Electric has a broad product portfolio, which contains electronics and insurance businesses, too, and is currently the most valuable company in the world in terms of market capitalisation. Warren Buffet¿s Berkshire Hathaway, Citigroup or Virgin are diversified as well and have created substantial value for their owners. These and other successful diversifiers have mastered managing the diversified company. Diversification has been studied in strategic management, finance, economics, organisations theory and other subjects. Each of these subjects views the duties of corporate management of a diversified company slightly different. Combining the views yields an integrated approach for managing a diversified company. First is the management of the corporate portfolio that includes a selection of businesses that are desired and a continuous [...]