The first wave mergers commenced from 1897 to 1904. During this phase merger occurred between companies, which enjoyed monopoly over their lines of production like railroads, electricity etc. the first wave mergers that occurred during the aforesaid time period were mostly horizontal mergers that took place between heavy manufacturing industries.
Majority of the mergers that were conceived during the 1st phase ended in failure since they could not achieve the desired efficiency. The failure was fuelled by the slowdown of the economy in 1903 followed by the stock market crash of 1904. The legal framework was not supportive either. The Supreme Court passed the mandate that the anticompetitive mergers could be halted using the Sherman Act.
The second wave mergers that took place from 1916 to 1929 focused on the mergers between oligopolies, rather than monopolies as in the previous phase. The economic boom that followed the post world war I gave rise to these mergers. Technological developments like the development of railroads and transportation by motor vehicles provided the necessary infrastructure for such mergers or acquisitions to take place. The government policy encouraged firms to work in unison. This policy was implemented in the 1920s.
The 2nd wave mergers ended with the stock market crash in 1929 and the great depression. The tax relief that was provided inspired mergers in the 1940s.
The mergers that took place during this period (1965-69) were mainly conglomerate mergers. Mergers were inspired by high stock prices, interest rates and strict enforcement of antitrust laws. The bidder firms in the 3rd wave merger were smaller than the Target Firm. Mergers were financed from equities; the investment banks no longer played an important role.
The 3rd wave merger ended with the plan of the Attorney General to split conglomerates in 1968. It was also due to the poor performance of the conglomerates.Some mergers in the 1970s have set precedence. The most prominent ones were the INCO-ESB merger; United Technologies and OTIS Elevator Merger are the merger between Colt Industries and Garlock Industries.
The 4th wave merger that started from 1981 and ended by 1989 was characterized by acquisition targets that wren much larger in size as compared to the 3rd wave mergers. Mergers took place between the oil and gas industries, pharmaceutical industries, banking and airline industries. Foreign takeovers became common with most of them being hostile takeovers. The 4th Wave mergers ended with anti takeover laws, Financial Institutions Reform and the Gulf War.