Few industries have had such far-reaching, global impacts as the energy industry in the past half-century.

Since the Arab oil embargo of 1973, questions have persisted about the security and affordability of energy. And as global consumption grew, questions have been raised about the environmental sustainability of energy processes.

The build-out of these energy systems has taken the industry across the world, from the sands of the Middle East to the icy depths of the North Sea to the shrub-dotted fields of West Texas.

These systems have played key roles in fueling the growth of modern civilization. They’ve also fueled a robust market for massive deals—mergers and acquisitions that have defined the era’s energy landscape and most important players.

A look back at the largest 50 energy deals from the past 50 years offers a glimpse of how the industry’s biggest companies were formed, but more recent deals give us a glimpse into the industry’s future:  Exxon Mobil’s blockbuster $65 billion acquisition of Pioneer Natural Resources in 2023 positions the Permian Basin as one of the supermajor’s main pillars of future production. It was also the fourth-largest energy deal the market has seen in the past 50 years, according to data from S&P Global.

Here’s a look at the largest 50 energy deals in the past half-century—with perspective on some of the biggest-of-the-big transactions:

1. Exxon Corp. Merges with Mobil Corp. ($84.39 billion)

Exxon Corp. and Mobil Corp. merged in 1999 to form the world’s largest oil company. The mega-merger, inked as the industry weathered through a period of low oil prices, was aimed at improving earnings and saving costs as the U.S. companies navigated a more competitive—and global—energy landscape. The influence of Exxon Mobil, the nation’s largest energy company with a market cap of around $446 billion, is known the world over more than two decades later.


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2. Royal Dutch Shell Acquires BG Group ($81.11 billion)

The combination of Royal Dutch Shell  and BG Group united the U.K.’s first- and third-largest natural gas producers when the deal closed in 2016. The deal gave Shell an industry-leading position in the global liquefied natural gas market, as well as a large deepwater position offshore Brazil.

3. Energy Transfer Equity Merges with Energy Transfer Partners ($68.88 billion)

Energy Transfer Equity and Energy Transfer Partners completed their merger in October 2018, rolling up one of the nation’s largest infrastructure players into a single partnership. The deal helped streamline a complex organizational structure and created a company with an investment grade bond rating. And it was yet another nail in the coffin of the MLP structure of old, which had waned in influence for years.

4. Exxon Mobil Acquires Pioneer Natural Resources ($65.75 billion)

The king of all shale deals. Exxon Mobil’s acquisition of Permian Basin juggernaut Pioneer Natural Resources will reshape the future of the American oil patch. The merger adds Pioneer’s more than 850,000 net acres in the Midland Basin with Exxon’s 570,000 net acres in the Delaware and Midland. Combined, the companies have an estimated 16 billion boe resource in the Permian—volumes Exxon plans to extract from the rock for years to come.


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5. Occidental Petroleum Acquires Anadarko Petroleum ($57.81 billion)

Occidental’s massive acquisition of Anadarko Petroleum in 2019 was met with skepticism by many. Some analysts and investors knocked Occidental CEO Vicki Hollub and her team for chasing Anadarko with “a great degree of hubris and management ego.” Others cheered Chevron, which had also bid to acquire Anadarko, for not overpaying. Four years later, Hollub quieted her doubters, shepherding Occidental to a $58.8 billion market capitalization and closing in on paying off the acquisition in half a decade.

50 biggest deals
(Source: S&P Global Market Intelligence)
50 biggest deals 2
(Source: S&P Global Market Intelligence)