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Gas stations sell so-called “Top Tier Gas” for a major premium. But in California, there is no substantial difference, argue state Sens. Jerry McNerney and Henry Stern.

Motorists around the nation and the world have been paying higher prices for gasoline because President Donald Trump’s war in Iran sparked a global oil supply shortage.

Yet California still gets a lot of criticism for high gas prices. There are a few reasons why we pay more at the pump than motorists in other states, most notably our nation-leading standards for limiting air pollution. 

And those standards have been effective. Since 2000, the state has slashed harmful emissions by 65%, contributing to significantly improved air quality in the Los Angeles basin, the Central Valley and other regions of the state.

And those standards have been effective. Since 2000, the state has slashed harmful emissions by 65%, contributing to significantly improved air quality in the Los Angeles basin, the Central Valley and other regions of the state.

But it turns out that there is also a nefarious reason why the average price of gas is higher in the Golden State. Major gasoline brands, such as Chevron, Shell, Mobil and 76, are causing California’s gas prices to be higher than they should be because their retailers charge significantly more per gallon here — up to about 70 cents more — than unbranded gasoline of the same quality that discount retailers such as Costco and Walmart sell in the state. 

Under California law, all base-level gasoline sold in the state has been considered effectively identical — including by Gov. Gavin Newsom — because it must meet the same clean-air standards. Some major brands and unbranded gas stations sell so-called “Top Tier Gas,” but according to the California Energy Commission’s Division of Petroleum Market Oversight, there is no substantial difference in California between Top Tier Gas and regular gas.

So why are the big-name brands charging so much more in California for a very similar product? It’s all about profits and margins.

We know this because in recent years, California enacted gas-price transparency laws that required oil companies to open their books. In early June, state regulators revealed some of what they’ve discovered to the Senate Energy, Utilities and Communications Committee.

Their findings were eye-opening. Since 2013, Chevron has consistently charged the highest gas prices in the state and reaped the biggest profit margins. Last year, for example, Chevron charged 73 cents per gallon, on average, more than Costco and Walmart, and 54 cents more than other unbranded gas. And Chevron’s margins were about seven to 11 percentage points higher.

Shell has consistently been a close second to Chevron for high prices and fat margins, followed by the other large oil company brands, according to data collected and analyzed by the California Department of Tax and Fee Administration (CDTFA).

And the gap in prices between the major brands and unbranded sellers is even wider when there’s less competition. Take Humboldt County.

Humboldt County has the highest average gas prices in Northern California. As of late May, the average price of gas in the county ranged between $6.35 and $6.50 per gallon — more than $2 above the national average and about 70 cents more than the California average. The county also has very little competition. Nearly half of the gas stations there are Chevron or Shell.

There’s also evidence that big oil companies are imposing a California specific surcharge. The gap between what major brands charge in California compared to their unbranded competitors is 25 cents per gallon higher than the gap in other states, according to data compiled by the state Division of Petroleum Market Oversight.

Over the past several months, everyone has been paying more at the pump because of the Iran War. Nationally, the average gas price as of early June had soared about $1.37 a gallon since the war started. In California, it went up by the same amount.

The skyrocketing prices have been a boon for big oil companies. Shell alone hauled in $7 billion in profits in just the first three months of 2026.

Even with the recent Iran War ceasefire, gas prices are expected to remain high this summer. One simple thing California drivers can do to save money is buy unbranded gasoline and steer clear of Big Oil.

State Sens. Jerry McNerney, D-Pleasanton, and Henry Stern, D-Los Angeles, are members of the Senate Energy, Utilities and Communications Committee.