Mergers and Acquisitions (M&A) is the important business strategies for the growth and development of the companies. M&A has been racked up over the years, both in volume and value. There are different types of M&A deals and each deal is unique in nature. So, the motives
behind each deal differ one from the other. Thus, a single theory is not enough to explain the motives for mergers, acquisitions or takeovers. The literature suggests various theories of mergers that explain different motives for which an M&A deal can take place. The motives can subsequently lead to increase, decrease or status quo in value. This paper discusses the theoretical foundations of M&A by making a detailed analysis of prior studies for each and every type of theories of M&A and its impact on the performance of companies in the post-M&A period. The research method to carry out the study is that the study is made by revisiting reviewing and synthesizing the academic literature on diverse theories of M&A and have reassessed various past studies to know various motives for which companies go for the M&A strategy. The analysis of various studies is made to get a direction to look into empirical evidence of pre and post M&A performance in Indian M&A cases to know whether managers are going for value enhancing mergers or motivated by hubris taking practical examples from the real corporate world. The review results show that different companies have different motives to go for M&A. Very few cases of M&A were found on hubris motive. Companies mainly go for M&A to have synergy gain through the combined firm. The practical implication of this study is that managers can know M&A as a financial and investment decision is worthy or not to achieve their M&A goals and then reassess and redefine their strategic alternatives to achieve growth.