Is it typically necessary for a company to use an investment bank to conduct a merger? Mergers are fairly common in the U.S. There are a variety of reasons why mergers occur between two companies. One reason is because of a synergy. Under a synergy, the goal is to increase the value of combined company. There can be synergies from such areas as increased market power, operating economies, and differential efficiency. Another reason for a merger is for tax reasons. Additionally, other mergers occur for diversification reasons or for an officers own incentives.