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 2026, the largest ever acquisition was the 2026 takeover of xAI by SpaceX at $250 billion ($ billion adjusted for inflation). AT&T appears in these lists the most times with six entries, for a combined transaction value of $334.4 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.
Free market enterprises
1870s
Top 2 M&A deals worldwide by value from 1870 to 1879:
1880s
Top 2 M&A deals worldwide by value from 1880 to 1889:
1890s
Top 2 M&A deals worldwide by value from 1890 to 1899:
1900s
Top 3 M&A deals worldwide by value from 1900 to 1909:
1910s
Top 3 M&A deals worldwide by value from 1910 to 1919:
1920s
Top 5 M&A deals worldwide by value from 1920 to 1929:
State-owned enterprises
Top M&A deals worldwide by value ($20 billion or larger) between state-owned enterprises:
Largest ever deals which have failed to complete
This lists catalogues M&A deals ($20 billion or larger in transaction value) which were confirmed, but for a number of reasons, failed to complete.
See also
References
- US Inflation Calculator US Inflation Calculator, retrieved 2017-10-31^
- CONSOLIDATION OF COAL COMPANIES. The New York Times, 6 February 1874^
- Joshua Karliner. The Corporate Planet: Ecology and Politics in the Age of Globalization