The United States is home to some of the world’s largest oil and gas companies, ranging from global integrated producers to specialized exploration companies and enormous petroleum refiners.

But defining the biggest oil company depends on the measure used. Production, refining capacity, market value, reserves, profits, and revenue can produce very different rankings.

For this list, companies are ranked by 2025 consolidated revenue or the closest comparable operating revenue measure reported in their annual financial statements. The 2025 fiscal year is the latest complete annual reporting period available as of November 2026.

On that basis, ExxonMobil is by far the largest U.S. oil company, followed by Chevron. Large refiners such as Marathon Petroleum, Phillips 66, and Valero Energy also rank highly because of the enormous value of petroleum products that moves through their operations.

With $323.9 billion in sales and other operating revenue in 2025, ExxonMobil stands comfortably at the top of the ranking. Revenue declined from $339.2 billion in 2024, while total revenue and other income, which also includes equity-affiliate and other income, amounted to $332.2 billion.

ExxonMobil is an integrated energy company, meaning its operations extend across oil and natural gas production, refining, fuels, chemicals, and specialty products. That breadth distinguishes it from companies focused primarily on either producing hydrocarbons or refining them.

Its upstream business reached 4.736 million oil-equivalent barrels per day of net production in 2025, the company’s highest annual level in more than 40 years. ExxonMobil also processed an average of approximately 3.98 million barrels per day through its global refining system.

Those figures illustrate why ExxonMobil is in a different scale category from most U.S. energy companies. It combines one of the world’s largest upstream portfolios with major downstream and chemical businesses.

Chevron generated $184.4 billion in sales and other operating revenue in 2025, down from $193.4 billion a year earlier. Including income from equity affiliates and other income, total revenues and other income reached $189.0 billion.

Like ExxonMobil, Chevron operates across multiple parts of the energy industry. Its upstream operations produce crude oil and natural gas around the world, while its downstream businesses refine, market, and transport petroleum products.

The acquisition of Hess significantly expanded Chevron’s production portfolio during 2025. Worldwide net oil-equivalent production reached a record 3.7 million barrels per day, up 12 percent from 2024. Chevron said the Hess assets contributed about 261,000 barrels of oil equivalent per day to its 2025 average.

The acquisition also increased Chevron’s exposure to Guyana, one of the most important new offshore oil-producing regions to emerge in recent years.

Marathon Petroleum reported $132.7 billion in sales and other operating revenue in 2025, compared with $138.9 billion in 2024. The company attributed much of the decline to lower average refined-product selling prices, partially offset by higher sales volumes.

Unlike ExxonMobil and Chevron, Marathon Petroleum is primarily a downstream company. Refining and marketing accounted for $124.3 billion of its segment revenue before intersegment adjustments in 2025.

The company operates 13 refineries with roughly 3 million barrels per calendar day of crude oil refining capacity, making it the largest refining system in the United States.

Its average net refinery throughput reached approximately 2.99 million barrels per day in 2025, while crude oil refining capacity was reported at 2.963 million barrels per calendar day.

Marathon Petroleum also controls a major interest in MPLX, which owns pipelines, terminals, processing facilities, and other midstream infrastructure.

Phillips 66 recorded $132.4 billion in sales and other operating revenue in 2025, narrowly placing it behind Marathon Petroleum. The figure fell from $143.2 billion in 2024.

The company operates across refining, midstream infrastructure, chemicals, marketing, and specialty products. This diversified structure makes Phillips 66 broader than a traditional stand-alone refiner.

One accounting distinction is particularly important. Phillips 66 reported $136.6 billion in total revenues and other income in 2025, higher than the $132.4 billion used in this ranking. The larger figure included equity earnings, other income, and nearly $3.0 billion in net gains on asset dispositions.

Using sales and other operating revenue therefore provides a cleaner comparison with the operating revenue measures used for several other companies on the list.

Valero Energy generated $122.7 billion in revenue in 2025, compared with $129.9 billion in 2024.

Refining remains overwhelmingly the company’s largest business. Valero reported $116.2 billion in external refining revenue during 2025, accounting for nearly 95 percent of consolidated revenue. Its other businesses include renewable diesel and ethanol.

Valero has one of the largest independent refining businesses in the world. Its refining network processes crude oil and other feedstocks into gasoline, diesel, jet fuel, petrochemicals, and other petroleum products.

The company’s current refining portfolio consists of 14 petroleum refineries with about 3 million barrels per day of throughput capacity.

Valero illustrates an important feature of revenue-based oil-company rankings. A refiner can generate more than $100 billion in annual sales without producing crude oil on anything close to the scale of an upstream producer.

ConocoPhillips reported $58.9 billion in sales and other operating revenue in 2025, up from $54.7 billion in 2024. It was the only company among the top six to record year-over-year revenue growth on this measure.

ConocoPhillips differs substantially from the five companies above it. It is primarily an exploration and production company rather than a major refiner. Its revenue comes mainly from the sale of crude oil, natural gas, natural gas liquids, LNG, and related commodities.

Crude oil generated $39.1 billion of sales and other operating revenue in 2025, making it by far the company’s largest revenue category.

Total production averaged 2.375 million barrels of oil equivalent per day, 20 percent higher than in 2024. Much of the reported increase reflected the acquisition of Marathon Oil, which ConocoPhillips completed in late 2024. After adjusting for acquisitions and dispositions, the company reported underlying production growth of 2.5 percent.

PBF Energy generated $29.3 billion in revenue in 2025, down from $33.1 billion the previous year.

The company is an independent petroleum refiner with operations in California, Delaware, Louisiana, New Jersey, and Ohio. Its business is considerably smaller than the refining systems operated by Marathon Petroleum, Phillips 66, and Valero, but the high value and volume of refined petroleum products still place PBF among the largest U.S. oil companies by revenue.

Its refining segment produced approximately 838,500 barrels per day of refined products on average in 2025, while crude oil and feedstock throughput averaged about 832,900 barrels per day.

PBF’s position ahead of several much larger upstream producers by revenue reinforces the effect that refining activity has on this particular ranking.

HF Sinclair reported $26.9 billion in sales and other revenues for 2025, compared with $28.6 billion in 2024.

The Dallas-based company operates petroleum refineries across several western and central U.S. states and also has businesses in renewable diesel, lubricants, specialty products, transportation, storage, and fuel marketing.

HF Sinclair’s refineries processed an average of approximately 652,000 barrels per day in 2025, with average crude charge of about 604,000 barrels per day.

The company is also undergoing a broader portfolio shift. In July 2026, HF Sinclair announced plans to pursue a separation of its Lubricants and Specialties business into an independent publicly traded company and to retire certain Canadian base-oil refining assets.

That planned restructuring means the composition of HF Sinclair’s business could become less directly comparable with its 2025 structure over time.

EOG Resources reported $22.6 billion in operating revenues and other in 2025, down from $23.7 billion in 2024.

EOG is fundamentally different from the refiners that occupy several higher positions in the ranking. Its core business is finding and producing oil and natural gas, with major operations across U.S. shale and tight-oil regions.

Revenue directly from sales of crude oil, condensate, natural gas liquids, and natural gas totaled $17.7 billion in 2025. The broader $22.6 billion figure used for the ranking also includes gathering, processing and marketing revenue, derivatives, asset dispositions, and other items as defined by EOG.

Production expanded considerably during the year. EOG averaged 1.232 million barrels of oil equivalent per day in 2025, up from 1.062 million in 2024. Crude oil and condensate production alone averaged roughly 522,000 barrels per day.

The combination of rising production and declining total revenue also demonstrates how commodity prices can outweigh volume growth in upstream financial results.

Occidental Petroleum rounds out the ranking with $21.6 billion in net sales for 2025, compared with $22.0 billion in 2024. Total revenues and other income, which includes interest, dividends, asset-sale gains, and other items, reached $22.1 billion.

Occidental is primarily an oil and gas producer with extensive U.S. operations, particularly in the Permian Basin, along with international assets and midstream activities.

The company reported worldwide fourth-quarter 2025 production of 1.481 million barrels of oil equivalent per day. At the end of 2025, Occidental reported approximately 4.6 billion barrels of oil equivalent in proved oil and gas reserves under the reserve table presented with its year-end results.

One major change occurred immediately after the reporting period. Occidental completed the sale of OxyChem on January 2, 2026 and said proceeds helped reduce its debt.

Because the chemicals business was still part of Occidental during 2025, the revenue figure used in this ranking reflects a corporate structure that has since changed.

A striking feature of the ranking is the position of refining companies.

Marathon Petroleum, Phillips 66, and Valero each generated more than $120 billion in 2025 revenue, putting them well ahead of large oil producers such as ConocoPhillips, EOG Resources, and Occidental.

That does not mean the refiners necessarily produce more oil or own more petroleum resources.

Refiners purchase enormous quantities of crude oil and other feedstocks, process them, and sell gasoline, diesel, jet fuel, petrochemicals, and other products. Much of the value of the crude therefore passes through their income statements as both revenue and cost.

Upstream companies operate differently. Their revenue is more directly tied to the volume of hydrocarbons they produce and the prices they receive.

This is why revenue rankings should be interpreted as a measure of business scale and sales activity, rather than a direct measure of oil production, reserves, profitability, or corporate value.

The largest gap in the ranking appears near the top.

ExxonMobil generated roughly $324 billion in operating sales in 2025, about $140 billion more than Chevron and more than double the revenue of Marathon Petroleum.

Chevron, in turn, remains substantially larger by revenue than almost every other U.S.-headquartered oil producer.

The companies below them illustrate the diversity of the American petroleum industry. Marathon Petroleum, Phillips 66, Valero, PBF Energy, and HF Sinclair derive much of their scale from refining. ConocoPhillips, EOG Resources, and Occidental are much more heavily concentrated on producing oil and natural gas.

Together, the ranking shows why there is no single measure of the largest oil company. Revenue rewards high-volume refining and integrated operations, while production, reserves, profits, and market capitalization can tell a very different story.