Ever since the East India and New East India Companies merged back in 1708, major companies have been joining forces to cut costs and increase market share. This year AT&T and Time Warner joined forces to the tune of $100 billion (£78.5bn), a move that risks putting AT&T into "terrifying" debt. But AT&T's former Chief Strategy Officer John Stankey (pictured), now CEO of WarnerMedia, will be hoping that with risk comes reward as the company seeks to reshape the media landscape. Read on as we reveal the 30 most costly corporate amalgamations of all time, adjusted for inflation.

In 2008, Belgian brewing firm InBev teamed up with Anheuser-Busch, the American firm most famous for producing Budweiser, to create the world's most prominent brewer. The deal cost $52 billion (£38.95bn).

The largest-ever international takeover by a Japanese company, Takeda Pharmaceutical has just snapped up larger Irish rival Shire, the maker of ADHD drug Adderall, for $62 billion (£46.45bn) in cash and stock.

In 1997, American telecoms behemoth Worldcom beat GTE and the UK's BT to link up with rival MCI Communications. At the time, the $42 billion (£31.45bn) deal, which capitalised on the powerful overlap between the two companies, was the largest corporate merger in US history.

Another record-breaking merger, Dell's acquisition of EMC Corporation in 2015 for $67 million (£50.19bn) was the biggest straight tech deal of all time, making Dell EMC the largest private integrated tech firm on the planet.

Now doing business as CenturyLink, American telecoms firm Qwest Communications paid $48 billion (£35.96bn) in 1999 to acquire 'Baby Bell' US WEST in what was considered a hostile takeover.

In March 2019, Disney finalised its merger with 20th Century Fox for a whopping $71.3 billion (£56.1bn). Before the deal, Disney already had a 26% market share of the 2018 box office. Its acquisition of 20th Century Fox, which had a 9.1% share in the same year, is only going to bolster Disney's domination of cinema, with the freshly-formed entertainment power commanding a record 35% of the industry.

Energy company mergers are never modest affairs. In 2015, the Netherlands' Royal Dutch Shell forked out a hefty $70 billion (£52.44bn) to unite with the UK's BG Group, making it the world's largest producer of liquefied natural gas (LNG).

In 2015, global pharmaceutical giant Actavis merged with rival Allergan in a $70.5 billion (£52.81bn) deal, assuming its name. Later that year, the all-new Allergan announced a record $160 billion (£119.86bn) merger with Pfizer, but abandoned the plan in 2016.

Two of America's biggest banks, J. P. Morgan Chase and Bank One Corporation, merged in 2004 to become the second largest banking institution in the US after Citigroup. The deal was worth a cool $59 billion (£44.21bn) at the time.

Pfizer made a shrewd move in 2009 merging with rival firm Wyeth, which was formally known as American Home Products. The merger, which created one of the world's largest biopharmaceutical companies, cost Pfizer $68 billion (£50.95bn).

In 1998, energy titan BP coughed up $53 billion (£39.71bn) to merge with Amoco, the American company that brought the world drive-through filling stations and gasoline tanker trucks, in what was up to that point the world's biggest industrial merger.

Telecoms company mergers were all the rage in the late 1990s. Big in local markets, Bell Atlantic shelled out $53.36 billion (£39.98b) in 1998 to integrate with long-distance and internet phone company GTE.

Charter Communications created one of America's largest cable TV companies when it merged with Time Warner Cable in 2015. The deal, which received final approval in 2016, was worth $78.7 billion (£58.97bn).

Before it absorbed Wyeth, Pfizer, which is no stranger to mega-mergers and acquisitions, paid $60 billion (£44.96bn) to amalgamate with Pharmacia Corporation, partly to secure full rights to the painkilling drug Celebrex.

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The first of two enormous Vodafone Group mergers in 1999, the British telecoms company joined forces with American wireless telephone service provider AirTouch Communications in a deal worth $60 billion (£44.96bn) at the time.

Telecoms firms SBC Communications and Ameritech Corporation had a hard time getting their $63 billion (£47.19bn) merger approved in 1999, but the regulators eventually permitted it with a number of conditions.

The most amicable mega-merger in history, Royal Dutch/Shell combined its Dutch and UK operations in 2004, dropping the slash to create Royal Dutch Shell, in a deal worth $75 billion (£56.18bn).

AT&T's merger with Time Warner has been a long time coming, following a fight with the Department of Justice to declare it legal. Finally, in 2018 the paid-TV provider was given the all-clear to buy up the media company which owns HBO and the Warner Bros film studio. But the $100 billion (£78.5bn) deal isn't without risk, as the purchase leaves AT&T with what one analyst described as a "terrifying" debt. Perhaps WarnerMedia's CEO John Stankey (pictured), who previously headed up strategy for AT&T, will weather the storm, as this isn't the first mega-merger for the company. It hooked up with the BellSouth Corporation for $73 billion (£54.70bn) in 2006.

Comcast Corporation merged with AT&T Broadband in 2001 to create one of the biggest cable and internet companies on the globe and a serious force to be reckoned with. All in all, the transaction cost $72 billion (£53.94bn).

A consortium that included Warren Buffett's Berkshire Hathaway and investment firm 3G Capital got together in 2015 to orchestrate the merger of American food giants Heinz and Kraft. The tax-free deal amounted to a staggering $100 billion (£74.91bn).

Big pharma got a whole lot bigger in 2000 when the UK's Glaxo Wellcome and SmithKline Beecham amalgamated. The merger created GlaxoSmithKline, which is currently the world's sixth largest pharmaceutical company.

Citicorp and Travelers Group merged in 1998, forming Citigroup, the biggest financial services company on the planet. The banking institutions ran into trouble with the regulators and had to sell off several key assets in order to get the green light.

A consortium made up of major financial institutions Royal Bank of Scotland (RBS), Fortis and Santander teamed up in 2007 to acquire Dutch bank ABN Amro for $98 billion (£73.41bn), outbidding the UK's Barclays. The company was broken up but resurfaced in 2010 when the Dutch government bought out Fortis' operations.

The $77.2 billion (£57.83bn) merger of energy titans Exxon and Mobil in 1998 created the world's largest corporate entity and reunited the two key pieces of John D. Rockefeller's Standard Oil, which was broken up in 1911 following a notable anti-trust case.

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Budweiser producer Anheuser-Busch InBev was already the biggest brewer in the world when it bagged London-listed competitor SAB Miller in 2015. The mammoth deal worked out at $130 billion (£97.39bn).

A merger of two gargantuan equals, American chemicals giants Dow Chemical and DuPont came together in 2015 in a deal worth $130 billion (£97.39bn), a shade higher than what Anheuser-Busch InBev paid for SAB Miller.

The second largest telecoms merger in history, Verizon Communications bought out Vodafone Group in 2013 to gain full ownership of Verizon Wireless and unite the two businesses. In total, the deal cost $130 billion (£97.39bn).

Pre-dating its mergers with Pharmacia Corporation and Wyeth by several years, Pfizer acquired rival Warner-Lambert in the biggest deal of its kind. The pharmaceutical giant parted with $111.80 billion (£83.75bn) in 1999 to clinch the deal.

The disastrous merger of AOL and Time Warner in 2000 has been described by Time Warner CEO Jeff Bewkes as “the biggest mistake in corporate history”. The $165 billion (£123.60bn) link-up failed to capitalise on the two firm's strengths and ended up wiping billions off their respective values.

Eclipsing all other deals, the most humongous merger of all time was UK telecoms firm Vodafone Group's hostile acquisition of the German mobile provider Mannesmann in 1999. The British company parted with a total of $202 billion (£151.31bn) to snag its continental rival.

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