John D. Rockefeller dominated the oil industry more completely than any single person or company in history. At its peak, his Standard Oil controlled 91% of U.S. oil production and 85% of final sales, a level of market power that has never been replicated. But the story of oil industry dominance stretches well beyond Rockefeller, from a small group of Western corporations that carved up the global market in the mid-20th century to the state-owned giants that control the vast majority of the world’s oil reserves today.
Rockefeller and Standard Oil
Standard Oil didn’t start with drilling. Rockefeller recognized early that the real money was in refining and transporting crude oil, not pulling it out of the ground. He built his first refinery in Cleveland in 1863 and spent the next two decades buying out competitors, negotiating secret railroad rebates, and vertically integrating every step of the supply chain. By the 1880s, Standard Oil had consolidated over 90% of the U.S. oil refining industry.
The company operated through a legal structure called a “trust,” which allowed Rockefeller to coordinate dozens of nominally independent companies under a single management. This gave Standard Oil enormous pricing power. It could undercut competitors in one region while subsidizing losses with profits from another, a strategy that made it nearly impossible for smaller firms to survive. By 1904, the company controlled 91% of production and 85% of final sales in the United States, making it one of the most powerful monopolies the world had ever seen.
That dominance eventually drew the attention of federal regulators. In 1911, the U.S. Supreme Court ruled that Standard Oil violated the Sherman Antitrust Act and ordered the trust dissolved into 34 separate companies. Several of those successor companies went on to become some of the largest oil firms in the world, including what would eventually become ExxonMobil, Chevron, and others that shaped the industry for the next century.
The Seven Sisters
After Standard Oil’s breakup, a handful of its successor companies joined forces with other major producers to form a loose cartel that controlled most of the world’s oil supply from the 1940s through the early 1970s. These seven firms became known as the “Seven Sisters”: Standard Oil of New Jersey (later Exxon), Standard Oil of New York (later Mobil), Standard Oil of California (later Chevron), Texaco, Gulf Oil, Anglo-Persian (later British Petroleum), and Royal Dutch/Shell.
These companies dominated exploration, production, refining, and distribution across the Middle East, Latin America, and Southeast Asia. They negotiated concession agreements with oil-producing countries that gave the companies control over extraction in exchange for royalty payments, arrangements that heavily favored the corporations. The 1928 Red Line Agreement, for example, divided up access to former Ottoman Empire territories among several of these companies, effectively carving the Middle East into corporate zones of influence.
The Seven Sisters didn’t hold a formal monopoly the way Standard Oil had, but their coordination and scale gave them enormous leverage over pricing and supply. For roughly three decades, they set the terms for global oil markets.
The Rise of State-Owned Oil Companies
The Seven Sisters’ grip began to slip in the 1970s when oil-producing nations started nationalizing their petroleum reserves. Countries like Saudi Arabia, Iran, Venezuela, and Iraq took control of the oil fields that Western companies had operated for decades, creating national oil companies (NOCs) to manage production directly. This was one of the most dramatic power shifts in the history of global energy.
The numbers tell the story clearly. In the 1970s, national oil companies controlled less than 10% of the world’s oil and gas reserves. Today, they control more than 90%. That reversal has fundamentally changed who holds power in the industry. The top 10 NOCs have an average reserve life of 78 years, compared to just 13 years for the top 10 international oil companies, according to the U.S. Energy Information Administration. That gap means state-owned firms are sitting on enough oil to produce for decades, while private companies face a constant scramble to find and secure new reserves.
NOCs have also closed the technology and financing gaps that once kept them dependent on Western expertise. Since 2005, the largest national oil companies have grown their research budgets at twice the rate of the biggest private firms. They raise billions in global capital markets, often at more favorable interest rates than their private competitors. The result is that private international oil companies increasingly find themselves pushed toward the most difficult, expensive projects: Arctic drilling, deepwater fields, and unconventional formations where their technical expertise still offers an edge.
Who Dominates Today
Saudi Aramco is the single most dominant oil company on the planet. In its 2024 fiscal year, Saudi Arabia’s state-owned giant produced more than three times the daily output of its closest competitor. Its net income for the year was $106.2 billion, roughly triple what ExxonMobil earned ($33.7 billion) and more than six times Shell’s profit ($16.1 billion).
The top 10 oil companies by net income in 2024 reflect how thoroughly the industry’s center of gravity has shifted:
- Aramco (Saudi Arabia): $106.2 billion
- ExxonMobil (USA): $33.7 billion
- PetroChina (China): $23.1 billion
- CNOOC (China): $19.4 billion
- TotalEnergies (France): $18.3 billion
- Chevron (USA): $17.7 billion
- Shell (UK): $16.1 billion
- Gazprom (Russia): $14.8 billion
- Petronas (Malaysia): $12.5 billion
- ConocoPhillips (USA): $9.2 billion
State-owned or state-affiliated companies make up half this list. The old Western supermajors, descendants of the Seven Sisters, remain enormously profitable, but they no longer set the terms for global oil markets the way they once did. Since 2006, oil production by the five largest private companies (known as the supermajors) has actually decreased by about 2%, even as global demand has grown.
What Comes Next for Oil Power
The International Energy Agency projects that global oil demand will peak by 2030, leveling off near 106 million barrels per day. Demand in advanced economies is already in a long-term decline, expected to drop from about 46 million barrels per day in 2023 to less than 43 million by the end of the decade. Growth in clean energy, the shift in China’s economy, and the fading of post-pandemic demand rebounds are all pulling in the same direction.
This doesn’t mean oil companies will suddenly lose relevance, but it does change the competitive dynamics. National oil companies with vast, low-cost reserves (Aramco being the prime example) are best positioned to remain profitable even in a lower-demand world. Private companies face a harder calculation: they need to keep finding expensive new reserves while the long-term trajectory of their core product points downward. The companies that dominated each era of oil, from Rockefeller’s refineries to the Seven Sisters’ global concessions to today’s state-owned giants, have always been the ones that controlled the cheapest barrels. That logic still holds.