What are the largest mergers and acquisitions in history?

Mergers and acquisitions involve transferring or consolidating corporate ownership through takeovers, mergers, or direct asset purchases. Historical transaction rankings measure values in US dollars adjusted for inflation, with the largest ever recorded being the 2026 acquisition of xAI by SpaceX at $250 billion. Regulatory frameworks such as antitrust laws and advance-notice requirements heavily govern these massive corporate combinations.

What we know

• As of February 2026, the largest ever acquisition in history was the takeover of xAI by SpaceX at a value of $250 billion. [2]
• AT&T appears the most times in the historical lists of largest mergers and acquisitions with six entries totaling $334.4 billion. [2]
• Transaction values in historical M&A rankings are given in US dollars for the transaction year and adjusted for inflation. [2]
• In legal terms, a merger consolidates two entities into a single legal entity, while an acquisition occurs when one entity takes ownership of another's share capital, equity, or assets. [5]

Where to go next

• a case in pointHow do pharmaceutical companies merge?
• how it workedWhat laws regulate corporate takeovers?
• what caused itWhy do companies pursue mergers and acquisitions?
• the bigger pictureWhat happens during a hostile takeover?
• whenHow are transactions organized chronologically?
• an unexpected connectionHow does antitrust law prevent monopolies?Even the largest multi-billion-dollar corporate mergers must pass strict government reviews to ensure they do not substantially lessen market competition.

Sources

• [1]list of largest mergers and acquisitions (Wikidata Q25036828) · CC0 1.0
• [2]List of largest mergers and acquisitions · CC BY-SA 4.0
• [3]List of largest pharmaceutical mergers and acquisitions · CC BY-SA 4.0
• [4]Lists of corporate mergers and acquisitions · CC BY-SA 4.0
• [5]Mergers and acquisitions · CC BY-SA 4.0

Your path

1. What was the last imperial forum built in ancient Rome?
2. /What is a warrant under general law?
3. /What role do marine microorganisms play in biogeochemical cycles?
4. /How are Fort Boyard and The Crystal Maze connected?
5. /What is the role of Atlantis in Plato's Timaeus and Critias?
6. /What was Southwick House's role in planning the Normandy landings?
7. /How does carbon dioxide enhanced oil recovery work?
8. /What are the largest mergers and acquisitions in history?