This book conducts an extensive study of the corporate diversification effect on a value of a multisegment company. In the beggining the author covers the prior literature on the subject and investigates theoretical benefits and costs of the diversification. Later, he formulates a hypothesis regarding the effect of diversification on firm value. In order to test the hypothesis he values all the segments of the conglomerates in the sample using DCF and Multiples methods and then adds them up to get the value of the firms. Finally, the author compares the obtained firms' values to their market values in order to examine whether the multisegment companies are traded at a premium or discount.