List of largest mergers and acquisitions
Updated: 5/20/2026, 7:05:04 PM Wikipedia source
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 ($250 billion adjusted for inflation). AT&T appears in these lists the most times with six entries, for a combined transaction value of $334 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.
Tables
· Free market enterprises › 1870s
1
1
Rank
1
Year
1874
Purchaser
Honeybrook Coal Company
Purchased
Wilkesbarre Coal and Iron Company
Transaction value
(in billions USD)
0
Inflation adjusted
(in billions USD)
0
2
2
Rank
2
Year
1879
Purchaser
Pacific Coast Oil Company
Purchased
Star Oil
Transaction value
(in billions USD)
0
Inflation adjusted
(in billions USD)
0
| Rank | Year | Purchaser | Purchased | Transaction value (in billions USD) | Inflation adjusted (in billions USD) |
| 1 | 1874 | Honeybrook Coal Company | Wilkesbarre Coal and Iron Company | 0 | 0 |
| 2 | 1879 | Pacific Coast Oil Company | Star Oil | 0 | 0 |
· Free market enterprises › 1880s
1
1
Rank
1
Year
1884
Purchaser
New York Gas Light Company
Purchased
Manhattan Gas Light Company
Metropolitan Gas Light Company
Municipal Gas Light Company
Knickerbocker Gas Light Company
Harlem Gas Light Company
Transaction value
(in billions USD)
0
Inflation adjusted
(in billions USD)
1
2
2
Rank
2
Year
1883
Purchaser
Buffalo, Pittsburgh and Western Railroad
Purchased
Buffalo, New York and Philadelphia Railway
Olean and Salamanca Railroad
Oil City and Chicago Railroad Company
Transaction value
(in billions USD)
0
Inflation adjusted
(in billions USD)
0
| Rank | Year | Purchaser | Purchased | Transaction value (in billions USD) | Inflation adjusted (in billions USD) |
| 1 | 1884 | New York Gas Light Company | Manhattan Gas Light Company Metropolitan Gas Light Company Municipal Gas Light Company Knickerbocker Gas Light Company Harlem Gas Light Company | 0 | 1 |
| 2 | 1883 | Buffalo, Pittsburgh and Western Railroad | Buffalo, New York and Philadelphia Railway Olean and Salamanca Railroad Oil City and Chicago Railroad Company | 0 | 0 |
· Free market enterprises › 1890s
1
1
Rank
1
Year
1899
Purchaser
American Spirits Manufacturing Company
Purchased
Kentucky Distilleries and Warehouse Company
Spirits Distributing Company
Transaction value
(in billions USD)
0
Inflation adjusted
(in billions USD)
4
2
2
Rank
2
Year
1899
Purchaser
Pullman Palace Car Company
Purchased
Wagner Palace Car Company
Transaction value
(in billions USD)
0
Inflation adjusted
(in billions USD)
2
| Rank | Year | Purchaser | Purchased | Transaction value (in billions USD) | Inflation adjusted (in billions USD) |
| 1 | 1899 | American Spirits Manufacturing Company | Kentucky Distilleries and Warehouse Company Spirits Distributing Company | 0 | 4 |
| 2 | 1899 | Pullman Palace Car Company | Wagner Palace Car Company | 0 | 2 |
· Free market enterprises › 1900s
1
1
Rank
1
Year
1901
Purchaser
Carnegie Steel Company
Purchased
Federal Steel Company
National Steel Company
Transaction value
(in billions USD)
0
Inflation adjusted
(in billions USD)
19
2
2
Rank
2
Year
1907
Purchaser
New York, New Haven and Hartford Railroad Company
Purchased
Boston and Maine Corporation
Transaction value
(in billions USD)
0
Inflation adjusted
(in billions USD)
10
3
3
Rank
3
Year
1909
Purchaser
Interborough Rapid Transit Company
Purchased
Metropolitan Street Railway
Transaction value
(in billions USD)
0
Inflation adjusted
(in billions USD)
8
| Rank | Year | Purchaser | Purchased | Transaction value (in billions USD) | Inflation adjusted (in billions USD) |
| 1 | 1901 | Carnegie Steel Company | Federal Steel Company National Steel Company | 0 | 19 |
| 2 | 1907 | New York, New Haven and Hartford Railroad Company | Boston and Maine Corporation | 0 | 10 |
| 3 | 1909 | Interborough Rapid Transit Company | Metropolitan Street Railway | 0 | 8 |
· Free market enterprises › 1910s
1
1
Rank
1
Year
1915
Purchaser
Midvale Steel Company
Purchased
Remington Arms Company
Worth Brothers Company
Transaction value
(in billions USD)
0
Inflation adjusted
(in billions USD)
3
2
2
Rank
2
Year
1915
Purchaser
United Dry Goods
Purchased
Associated Merchants Company
Transaction value
(in billions USD)
0
Inflation adjusted
(in billions USD)
1
3
3
Rank
3
Year
1918
Purchaser
General Motors
Purchased
United Motors Company
Transaction value
(in billions USD)
0
Inflation adjusted
(in billions USD)
0
| Rank | Year | Purchaser | Purchased | Transaction value (in billions USD) | Inflation adjusted (in billions USD) |
| 1 | 1915 | Midvale Steel Company | Remington Arms Company Worth Brothers Company | 0 | 3 |
| 2 | 1915 | United Dry Goods | Associated Merchants Company | 0 | 1 |
| 3 | 1918 | General Motors | United Motors Company | 0 | 0 |
References
- Joint Venture
- Dual Structure Consolidation
- Bailout
- Tax Inversion
- US Inflation Calculatorhttps://web.archive.org/web/20131028120632/http://www.usinflationcalculator.com/
- The New York Timeshttps://www.nytimes.com/1874/02/06/archives/consolidation-of-coal-companies-the-wilkesbarre-coal-and-iron-and.html?searchResultPosition=2
- The Corporate Planet: Ecology and Politics in the Age of Globalizationhttps://books.google.com/books?id=2CHLmPx2PJ0C&pg=PA61
- The New York Timeshttps://www.nytimes.com/1884/11/11/archives/reducing-the-price-of-gas-election-of-officers-of-the-consolidated.html?searchResultPosition=4
- The New York Timeshttps://www.nytimes.com/1883/02/15/archives/railroads-consolidated-organization-of-the-buffalo-newyork-and.html?searchResultPosition=1
- The New York Timeshttps://www.nytimes.com/1899/06/22/archives/immense-liquor-trust-distilling-company-of-america-capital.html
- The New York Timeshttps://www.nytimes.com/1899/10/21/archives/wagner-company-to-sell-out-pullman-directors-vote-to-buy-the-rival.html?searchResultPosition=1
- The New York Timeshttps://www.nytimes.com/1899/10/27/archives/vanderbilts-get-control.html?searchResultPosition=2
- "History of United States Steel Corporation – FundingUniverse"http://www.fundinguniverse.com/company-histories/united-states-steel-corporation-history/
- The New York Timeshttps://timesmachine.nytimes.com/timesmachine/1907/06/10/106755201.html
- The New York Timeshttps://www.nytimes.com/1905/12/27/archives/traction-merger-terms-made-public-222000000-holding-company-for-all.html
- The New York Timeshttps://timesmachine.nytimes.com/timesmachine/1905/12/27/100496412.html
- The New York Timeshttps://www.nytimes.com/1915/10/07/archives/midvale-steel-co-heads-big-merger-absorbs-worth-brothers-and.html
- The New York Timeshttps://timesmachine.nytimes.com/timesmachine/1915/10/07/105041761.html
- The New York Timeshttps://www.nytimes.com/1915/12/04/archives/plan-a-50000000-dry-goods-merger-new-company-proposed-to-take-over.html
- "The turning wheel; the story of General Motors through twenty-five years, 1908–1933"https://archive.org/stream/turningwheelstor00pounrich#page/174/mode/2up