The research in the Mergers and Acquisitions (M&A) field has been prolific in recent years. This is unsurprising, as M&A have been increasingly relevant in the scope of corporate growth and restructuring, as proved by the magnitude of the latest M&A global wave. Nevertheless, despite the large contribution from literature, some relevant issues remain to be explained by economic and finance research. Although much is known about the pattern of the M&A activity, the fact that M&A tend to occur in waves continues to puzzle researchers worldwide. This paper examines the M&A wave's phenomenon and discusses the need for a theoretical framework that may shed light on the determinants of its complex occurrence. Accordingly, this paper studies the evolution of M&A over time, focusing on its pattern of activity, and also covering different methodologies used in M&A activity research. This paper also considers the M&A abandonment issue. A substantial number of announced M&A deals is never completed, often resulting in significant loss of resources for economic agents. Like the waves issue, the topic of the abandonment in M&A activity raises questions that are yet to be addressed, thereby offering interesting prospects for further research, as both theory and evidence are missing in literature.

This paper examines the Mergers & Acquisitions (M&As) waves phenomena and discusses the need for a theoretical framework allowing a comprehensive understanding of its occurrence. Accordingly, this paper studies the evolution of M&A over time, focusing on its pattern of activity. Finally, it also examines some of the methodologies used in M&A activity research.

The paper is structured as follows. First, the major M&A waves which occurred in the United States of America (US) are examined. The historical pattern of M&A is widely documented in existing data and literature, allowing an extensive review of past M&A waves.

Second, this paper discusses the reasons underlying the non-existence of a comprehensive theoretical framework explaining why M&A tend to occur in waves, a major issue in finance research. This discussion is made possible through an extensive literature review analysis, benefiting from the existence of widespread research focused on M&A waves and on M&A activity drivers and it aims to contribute to a better understanding of the M&A waves issue.

Business Strategy Journal, Electronic Media, Mergers and Acquisitions, Corporate Restructuring, Entrepreneurial Environments, Manufacturing Industries, Investment Banks, Economic Environment, Globalization, Global Economy, Business Cycles, Financial Markets, Ccapital Markets, Technological Innovations.