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. , 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:
RankYearPurchaserPurchasedTransaction value(in billions USD) Inflation adjusted(in billions USD)11874 Honeybrook Coal Company Wilkesbarre Coal and Iron Company0.0121879 Pacific Coast Oil Company Star Oil0.001
1880s Top 2 M&A deals worldwide by value from 1880 to 1889:
RankYearPurchaserPurchasedTransaction value(in billions USD) Inflation adjusted(in billions USD)11884 New York Gas Light Company Manhattan Gas Light Company Metropolitan Gas Light Company Municipal Gas Light Company Knickerbocker Gas Light Company Harlem Gas Light Company0.04521883 Buffalo, Pittsburgh and Western Railroad Buffalo, New York and Philadelphia Railway Olean and Salamanca Railroad Oil City and Chicago Railroad Company0.02085
1890s Top 2 M&A deals worldwide by value from 1890 to 1899:
RankYearPurchaserPurchasedTransaction value(in billions USD) Inflation adjusted(in billions USD)11899 American Spirits Manufacturing Company Kentucky Distilleries and Warehouse Company Spirits Distributing Company0.12521899 Pullman Palace Car Company Wagner Palace Car Company0.074
1900s Top 3 M&A deals worldwide by value from 1900 to 1909:
RankYearPurchaserPurchasedTransaction value(in billions USD) Inflation adjusted(in billions USD)11901 Carnegie Steel Company Federal Steel Company National Steel Company0.49221907 New York, New Haven and Hartford Railroad Company Boston and Maine Corporation0.31031909 Interborough Rapid Transit Company Metropolitan Street Railway0.222
1910s Top 3 M&A deals worldwide by value from 1910 to 1919:
RankYearPurchaserPurchasedTransaction value(in billions USD) Inflation adjusted(in billions USD)11915 Midvale Steel Company Remington Arms Company Worth Brothers Company0.10021915 United Dry Goods Associated Merchants Company0.05031918 General Motors United Motors Company0.045
1920s Top 5 M&A deals worldwide by value from 1920 to 1929:
RankYearPurchaserPurchasedTransaction value(in billions USD) Inflation adjusted(in billions USD)11928 Consolidated Gas Company of New York Brooklyn Edison Company1.021929 Niagara and Eastern Power Corporation MohawkHudson Power Corporation Northeastern Power Corporation0.66531928 United Light and Power Company American Light and Traction0.52241928 Hodenpyl & Hardy Stevens & Wood0.50051928 Middle West Utilities National Electric Power National Public Service New England Public Service Inland Power and Light0.400
1930s Top 5 M&A deals worldwide by value from 1930 to 1939:
RankYearPurchaserPurchasedTransaction value(in billions USD) Inflation adjusted(in billions USD)11930 Pacific Gas and Electric Company Great Western Power Company San Joaquin Light and Power Corporation Midland Counties Public Service Corporation0.65021932 Sinclair Consolidated Oil Corporation Prairie Oil and Gas Prairie Pipe Line Company0.54231934 Republic Steel Corrigan-McKinney Steel Corporation0.32341931 Bethlehem Steel Pittsburgh Steel Company0.08051932 Studebaker Corporation White Motor Company0.026
1940s Top 5 M&A deals worldwide by value from 1940 to 1949:
RankYearPurchaserPurchasedTransaction value(in billions USD) Inflation adjusted(in billions USD)11945 Consolidated Edison Brooklyn Edison Company New York and Queens Light and Power Company1.221948 Central New York Power Corporation New York Power and Light Corporation Buffalo Niagara Electric Corporation0.50031945 Pittsburgh Coal Company Consolidation Coal Company0.16041948 Long Island Lighting Company Queens Borough Gas and Electric Company Nassau & Suffolk Lighting Company0.14051941 Celanese Corporation Celluoid Corporation0.096
1950s Top 10 M&A deals worldwide by value from 1950 to 1959:
RankYearPurchaserPurchasedTransaction value(in billions USD) Inflation adjusted(in billions USD)11959 General Telephone Sylvania Electric Products1.821957 Armco National Supply Company0.76831957 American Can Company Marathon Corporation0.71741955 Monsanto Lion Oil0.55051956 Continental Can Company Robert Gair Company0.54961954 Olin Industries Mathieson Chemical0.50071955 Sunray Oil Corporation Mid-Continent Petroleum Corporation0.48681955 Sperry Corporation Remington Rand0.46691953 Gulf Oil Warren Petroleum Corporation0.420101954 Hudson Motor Car Company Nash-Kelvinator0.355
1960s Top 10 M&A deals worldwide by value from 1960 to 1969:
RankYearPurchaserPurchasedTransaction value(in billions USD) Inflation adjusted(in billions USD)11969 Atlantic Richfield Sinclair Oil Corporation3.721965 Union Oil Pure Oil1.531968 Hunt-Wesson Canada Dry McCall Corporation1.041969 Xerox Corporation Scientific Data Systems0.92551967 Rockwell-Standard North American Aviation 0.92261968 Sun Oil Sunray DX Oil Company0.76371965 Continental Oil Company Consolidation Coal 0.62081961 American-Marietta Corporation Glenn L. Martin Company 0.60091968 Control Data Corporation Commercial Credit Company 0.582101967 Studebaker Corporation Worthington Corporation 0.550
1970s Top 15 M&A deals worldwide by value from 1970 to 1979: RankYearPurchaserPurchasedTransaction value(in billions USD) Inflation adjusted(in billions USD)11979 Shell Oil Company Belridge Oil Company3.6521976 General Electric Utah International2.1731979 RCA CIT Financial1.341979 Exxon Reliance Electric1.251978 United Technologies Carrier Corporation1.061979 Mobil General Crude Oil0.76571976 Atlantic Richfield Anaconda Copper0.76081978 R. J. Reynolds Industries Del Monte Corporation0.62091978 Johns Manville Olinkraft Inc0.585101977 Kennecott Copper Carborundum Corporation0.567111978 Philip Morris Seven-Up Bottling Co0.520121978 Beatrice Foods Tropicana Products0.488131977 Unilever National Starch and Chemical0.485141974 Burmah Oil Signal Oil & Gas0.480151979 American Brands Franklin Life Insurance0.465
1980s Top 30 M&A deals worldwide by value from 1980 to 1989:
RankYearPurchaserPurchasedTransaction value(in billions USD) Inflation adjusted(in billions USD)11989 Kohlberg Kravis Roberts RJR Nabisco31.021989 Mitsui Bank Taiyo Kobe Bank22.831989 Time Inc. Warner Communications15.241984 Standard Oil of California Gulf Oil13.251988 Philip Morris Kraft Foods13.161989 Bristol Myers Squibb12.071984 Texaco Getty Oil10.181989 Beecham Group SmithKline Beckman7.991987 BP Standard Oil of Ohio7.8101981 E. I. du Pont de Nemours and Company Conoco7.3111988 Campeau Corporation Federated Department Stores6.6121985 General Electric RCA6.3131982 United States Steel Corp. Marathon Oil6.0141985 Kohlberg Kravis Roberts Beatrice Companies6.0151985 Philip Morris Companies General Foods5.8161987 Dome Mines Placer Development Campbell Red Lake Mines5.8171984 Mobil Superior Oil Company5.7181988 Grand Metropolitan Pillsbury Company5.7191989 Dow Chemical Company Marion Laboratories5.7201984 Royal Dutch/Shell Group Shell Oil Company5.5211989 Hanson plc Consolidated Gold Fields5.5221985 General Motors Hughes Aircraft Company5.2231988 British American Tobacco ( Batus Inc.) Farmers Insurance Group5.2241987 John Philp Thompson Sr. Southland Corporation5.1251988 Thomas F. Frist Jr. Richard Rainwater HCA Healthcare5.1261988 Eastman Kodak Sterling Drug5.1271981 Elf Aquitaine Texasgulf Inc.5.0281985 R.J. Reynolds Industries Nabisco Brands4.9291986 Burroughs Corporation Sperry Corporation4.8301989 Sony Columbia Pictures4.8
1990s Top M&A deals worldwide by value ($20 billion or larger) from 1990 to 1999:
RankYearPurchaserPurchasedTransaction value(in billions USD)Inflation adjusted(in billions USD)11999 Vodafone Airtouch plc Mannesmann183.021999 Pfizer Warner-Lambert90.031998 Exxon Mobil77.241998 Citicorp Travelers Group70.051999 Bell Atlantic (Wireless Unit) Vodafone Airtouch plc (US Wireless Unit)70.061998 Zeneca Astra AB67.071998 NationsBank Bank America62.081999 SBC Communications Ameritech Corporation62.091999 Vodafone Group AirTouch Communications56.0101999 TotalFina Elf Aquitaine54.3111998 Bell Atlantic GTE53.36121996 Bell Atlantic NYNEX52.0131998 BP Amoco49.0141999 AT&T Tele-Communications Inc.48.0151999 The Sumitomo Bank The Sakura Bank45.5161999 Qwest Communications US West44.0171998 Hoechst AG Rhône-Poulenc43.0181999 Royal Bank of Scotland Group National Westminster Bank plc42.5191999 Fuji Bank Dai-Ichi Kangyo Bank Industrial Bank of Japan40.1201997 Zurich Insurance Group British American Tobacco (Financial Division) 38.0211998 Daimler-Benz Chrysler38.0221997 Worldcom MCI Communications37.0231999 Mannesmann Orange UK36.0241999 Viacom CBS Corporation35.6251998 Wells Fargo Norwest Corporation34.0261999 Olivetti Telecom Italia (55% Stake)34.0271995 Mitsubishi Bank The Bank of Tokyo33.8281998 Banc One First Chicago Bank29.8291996 Ciba-Geigy Sandoz27.0301999 BP-Amoco Atlantic Richfield Company26.8311999 Monsanto Pharmacia & Upjohn26.5321999 Lucent Ascend Communications25.2331997 Union Bank of Switzerland Swiss Bank Corporation25.0341999 Clear Channel Broadcasting AMFM Broadcasting Licenses, LLC23.8351998 Berkshire Hathaway Gen Re22.0361999 Banque Nationale de Paris Paribas20.0
2000s Top M&A deals worldwide by value ($20 billion or larger) from 2000 to 2009: