List of largest mergers and acquisitions

The following tables list the largest mergers and acquisitions by decade of transaction. Transaction values are given in the US dollar value for the year of the merger, adjusted for inflation. As of February 2024^[update], the largest ever acquisition was the 1999 takeover of Mannesmann by Vodafone Airtouch plc at $183 billion ($334.7 billion adjusted for inflation). AT&T appears in these lists the most times with five entries, for a combined transaction value of $311.4 billion. Mergers and acquisitions are notated with the year the transaction was initiated, not necessarily completed. Mergers are shown as the market value of the combined entities.