Where Does Costco Get Its Gas? Who Supplies Kirkland Signature Fuel

Costco sells a lot of gas under its own Kirkland Signature name, but it does not own a single oil well or refinery. So where does Costco get its gas, and who supplies it: Shell, Chevron, Esso, someone else? This post explains how gasoline gets from a refinery to a Costco pump, what Costco itself says about its suppliers, what has been reported about specific refiners, and where the gas at Canadian gas bars comes from.

Short answer: Costco does not have one supplier. It says it buys gasoline "from the same major refineries and distributors that supply all of the gas stations in an area," and that the gas it buys is typically unbranded. The supplier depends on the region and can change over time. What makes it Kirkland Signature is the detergent additive Costco blends in, not the refinery it came from.

Where does Costco get its gas?

From the local wholesale market, like most large fuel retailers. Costco's US gas pages do not discuss suppliers, but its Canadian customer service site answers the question directly: "We receive our gasoline from the same major refineries and distributors that supply all of the gas stations in an area. Costco does not purchase gasoline from a single supplier. Typically, the gasoline we purchase is unbranded" (Costco Canada customer service).

"Unbranded" is the key word. Refiners sell gasoline at fuel terminals in two ways: branded, for stations flying their flag, and unbranded, for independent retailers that sell under their own name. The Federal Trade Commission describes unbranded rack prices as the prices a distributor, "often, but not always a refiner," charges for gasoline that will be sold "under the name of an independent gasoline retailer" (FTC). Costco is, in effect, a very large independent.

Costco's annual report adds one more detail. In its fiscal 2025 10-K, Costco says it enters into "variable-priced contracts" for "some of the fuel for our gas stations, on an index basis" (Costco 10-K, fiscal 2025). In plain terms, at least part of its fuel is bought on contracts priced against a published market benchmark, not at fixed prices. The filing does not name any counterparties.

How gas gets from the refinery to a Costco pump

Nearly every gallon sold in North America follows the same four steps, whatever brand is on the canopy.

1. Refinery. Crude oil is refined into base gasoline (plus diesel, jet fuel and other products).
2. Pipeline. The US Energy Information Administration says "most gasoline moves from refineries through pipelines to large storage terminals near consuming areas" (EIA). The biggest example is the Colonial Pipeline, which EIA says connects to 29 refineries and 267 customer terminals and carries Gulf Coast gasoline to the East Coast (EIA).
3. Terminal. Gasoline from different refiners travels in batches that "are not physically separated in pipelines and some mixing, or commingling, of products occurs," according to EIA. Competing companies often load at the same terminal.
4. Truck to the station. Tanker trucks carry the fuel to each station. This is where brands usually add their own additive package.

The result, in EIA's words, is that "branded stations may not necessarily sell the gasoline their companies produce," and the real difference between brands is "the small amount of additives they might blend into gasoline before delivery." EIA also says the exact origin of the gasoline at a given station "cannot be determined."

Costco adds its additive at the station, not the terminal

Most brands inject their detergent at the terminal rack. Costco says it does it differently. Its auto program article explains that "Costco decided the best system would be to blend the additives at Costco gas stations during the fuel delivery," so it has "complete control over both the process and the quality aspects of the fuel" (Costco Auto Program).

So a Shell station and a Costco across the road may well have loaded base gasoline from the same terminal that morning. The Shell tanker leaves with Shell's additive in it. The Costco load gets Kirkland Signature detergent, which Costco says is five times the government minimum, as it goes into the tanks. For what that additive does and how the Top Tier licence works, see our post on whether Costco gas is Top Tier.

Who supplies Costco gas? What has been reported

Costco does not publish a supplier list, and we found no Costco filing or press release naming one. Here is everything we could find from a reputable source, clearly labelled.

That 2012 report is the only named supplier we found in mainstream news, and it covered one region at one moment. Supply deals change.

Beyond that, you will see names on forums: Husky or Esso in Alberta, Shell in Ontario, Tesoro (now Marathon) in the Bay Area. These are guesses by posters, sometimes based on a logo spotted on a nozzle or a truck. None is confirmed by Costco, and a logo on a nozzle or tanker does not tell you who refined the gasoline.

Costco's scale as a fuel buyer

Costco is one of the biggest gasoline sellers in North America, which gives it real buying power. According to its fiscal 2025 10-K:

• Costco operated 747 gas stations worldwide at the end of fiscal 2025 (August 31, 2025).
• Gasoline was "approximately 10% of total net sales," which were $269.9 billion.
• Gallons sold rose about 2% in the year, while the average price per gallon fell 8%.

When Middle East supply disruptions pushed prices up in spring 2026, CEO Ron Vachris told analysts that "our gas team performed exceptionally well" through record demand that "requires multiple daily gas deliveries to many locations" (Yahoo Finance, May 29, 2026). Why this scale translates into low pump prices is covered in why Costco gas is so cheap.

Where Costco gas comes from in the US, by region

Because Costco buys locally, the practical answer to "where does Costco get its gas" is "from whoever refines for your region." The US is split into five Petroleum Administration for Defense Districts (PADDs), and each has a very different supply picture.

Refinery counts and capacity are from the EIA Refinery Capacity Report (barrels per calendar day). Costco averages are from our database across 592 US stations, excluding Puerto Rico. The refiner names are examples of companies that operate refineries in each region, not confirmed Costco suppliers.

Two things stand out. The Gulf Coast holds about 54% of US refining capacity, which is a big reason the Gulf Coast region, including Texas, has the lowest Costco average in our data. The East Coast has little refining of its own and relies on pipelines from the Gulf, so stations in states like Georgia and Florida are often supplied by Gulf Coast refineries hundreds of miles away.

The West Coast is a special case

The West Coast is not connected to Gulf Coast refineries by major pipelines, and it keeps losing refineries. EIA reports that Phillips 66 closed its Los Angeles refinery in October 2025, and that Valero's Benicia refinery in the Bay Area stopped refining in early 2026 (EIA). Valero plans to keep importing gasoline into Northern California through the site (Argus Media, seen in search results). California also requires its own cleaner-burning blend, which only some refineries can make (EIA).

That means a growing share of the gas at a California Costco can be imported, including from Asia, then run through the same terminals. It also explains the price gap: Costco regular in California averaged $6.05 a gallon in our September 29, 2026 reading, against $4.64 nationally. Washington, which has its own refineries around Puget Sound, averaged $5.22.

Who supplies Costco gas in Canada?

The same system, with Canadian refiners. This is the market Costco's supplier statement was written for: Costco Canada says it buys from "the same major refineries and distributors that supply all of the gas stations in an area," typically unbranded, and "all Costco gasoline is fully guaranteed to meet or exceed Canadian General Standards Board (CGSB) requirements" (Costco Canada).

Canada has 17 operating refineries (two of them asphalt plants) with about 2 million barrels a day of capacity, according to the Canadian Association of Petroleum Producers (CAPP, April 2026). The main fuel refineries, and where the Canada Energy Regulator (CER) says each province's gasoline comes from:

Refinery lists are from CAPP and the CER provincial energy profiles for Alberta, British Columbia, Ontario and Quebec. As in the US table, these are the refiners in each market, not confirmed Costco suppliers. Sunoco's purchase of Parkland closed on October 31, 2025 (BNN Bloomberg, seen in search results).

Who supplies Costco gas in Alberta?

No one has published a confirmed answer. What is certain is that almost all gasoline sold in Alberta is refined in Alberta, at the Edmonton-area refineries run by Imperial, Suncor and Shell, and moved south to Calgary by pipeline, according to the CER. So a Costco gas bar in Edmonton or Calgary is selling Alberta-refined base gasoline, whichever company's rack it was bought from. Forum posts name Esso (Imperial) or Husky, but those are not confirmed. Short supply lines are one reason Alberta had the lowest Costco average in Canada in our data, at 160.7¢/L.

Is Costco gas in Canada Canadian or American?

Mostly Canadian-refined, with some American product in the mix depending on the province. (For why the price differs from the US, see Costco gas in Canada vs the US.) Canada is a net exporter of refined products, and in Alberta, Quebec and Ontario most gasoline is refined in-province or in a neighbouring province, per the CER.

Imports still matter at the margin. Canada imported 485,000 barrels a day of refined petroleum products in 2025, and 79.6% of that came from the US (CER). But that total includes a lot of condensate that Alberta imports to thin oil sands bitumen, not gasoline. The provinces where US gasoline is most likely to reach the pump are:

• British Columbia: barge and ship imports from Washington State refineries supplement Alberta product.
• Ontario: some refined product arrives from US Midwest refineries.
• Quebec and Atlantic Canada: tidewater access means imports from the US East Coast and Europe.

The crude oil behind Canadian gasoline is also mixed. CAPP says the US now supplies more than three-quarters of the crude oil Canadian refineries import, and that Irving's Saint John refinery is the only one still importing meaningful overseas oil. Because fuel is commingled at terminals, nobody can say where a specific litre was refined, but it meets the same Canadian standard either way.

Does it matter who supplies Costco's gas?

Much less than people think. Three things decide the quality of what goes into your tank, and none of them depends on the refinery's logo. (If you have heard Costco gas is watered down or burns faster, see is Costco gas bad for your car.)

1. The fuel spec. US gasoline must meet EPA rules and, in most states, the ASTM D4814 specification (ASTM, seen in search results). California has its own stricter CARB blend. In Canada, gasoline is made to the CGSB standard, CAN/CGSB-3.5 (Standards Council of Canada, seen in search results). Every refiner selling at a terminal has to meet the local spec.
2. The additive. This is where brands actually differ. Costco's Kirkland Signature detergent is Top Tier licensed in the US and Canada, and Costco says it is five times the EPA and CGSB minimum.
3. Station upkeep. Costco says its fuel is filtered so sediment and water stay out of your tank (Costco gasoline Q&A). Busy Costco stations also turn their tanks over fast; the CEO's comment about multiple daily deliveries gives a sense of how fast.

So the useful question is not "who makes Costco gas" but "is it Top Tier, and what octane does my car need." The first is answered in our Top Tier post, and the second in Costco gas grades explained. To see today's price at your warehouse, use the Costco gas price finder or browse US stations and Canadian gas bars.

Frequently asked questions

Who makes Costco gas?

No single company. Costco buys mostly unbranded gasoline from the refiners and distributors that supply each region, so the refiner can differ between cities and change over time. Costco then adds its own Kirkland Signature detergent package, which is what makes it Costco gas.

Does Costco own its own refinery?

No. Costco does not own refineries or produce gasoline. It buys finished fuel on the wholesale market, partly on index-priced contracts according to its annual report, and blends in its own additive at the station during delivery.

Is Costco gas the same as Shell or Chevron gas?

The base gasoline can be the same, because stations in an area often load from the same terminals where fuel from several refiners is commingled. The difference is the additive: Shell and Chevron inject their own detergent packages, and Costco uses its Kirkland Signature package. All three are Top Tier licensed.

Is Costco gas Shell gas?

Not as a rule. Costco says it does not buy from a single supplier and that its gasoline is typically unbranded. In some areas Shell may be one of the refiners or terminal operators Costco buys from, but that has not been confirmed by Costco for any region.

Is Costco gas in Canada imported from the US?

Mostly not. Most gasoline sold in Alberta, Ontario and Quebec is refined in Canada, according to the Canada Energy Regulator. British Columbia, Ontario and eastern Canada do import some gasoline, mainly from the US, so some US-refined product can reach Canadian gas bars in those provinces.

Why is Costco gas cheaper if it comes from the same refineries?

Because the price difference comes from the retailer, not the refinery. Costco buys in very large volumes, usually unbranded, and treats gas as a membership benefit with a thin margin rather than a profit centre.

Can I find out which refinery my Costco uses?

Generally no. Costco does not publish supplier details, and the US Energy Information Administration says the exact origin of gasoline at a station cannot be determined because products from different refiners are mixed in pipelines and terminals.

Sources

• Who are the gasoline distributors/vendors?, Costco Canada customer service — "same major refineries and distributors," no single supplier, typically unbranded, CGSB guarantee.
• Costco Wholesale Form 10-K, fiscal 2025, SEC — 747 gas stations, gas about 10% of net sales, 2% volume growth, 8% lower price per gallon, index-priced fuel contracts, gas drives warehouse traffic.
• Gasolines Are Not Created Equal, Costco Auto Program — additives blended at Costco stations during fuel delivery.
• Gasoline FAQs, Costco.com — fuel filtration, Top Tier certification.
• Where our gasoline comes from, U.S. EIA — refinery to pipeline to terminal to station, commingling, brands differ by additives, origin cannot be determined.
• For transportation fuels, the Gulf Coast produces, the East Coast consumes, U.S. EIA — Colonial Pipeline connections to 29 refineries and 267 terminals.
• Refinery Capacity Report, Table 1 (January 1, 2026), U.S. EIA — refinery counts and capacity by PADD.
• U.S. refining capacity decreased during 2025, U.S. EIA — Phillips 66 Los Angeles closure, Benicia stopped refining, 130 operable refineries.
• Refinery closures present risk for higher gasoline prices on the West Coast, U.S. EIA — West Coast imports, California's special blend.
• Valero ends fuel production at Benicia refinery, Argus Media (seen in search results) — Benicia fuel units shut in 2026.
• Retail Gasoline Pricing: What Do We Know?, FTC working paper (seen in search results) — branded vs unbranded rack prices.
• Supply shortages forcing LA stations to shut down gas pumps, CBS Los Angeles (October 4, 2012) — analyst quote that Chevron was supplying Costco in Los Angeles in 2012.
• Costco sells "record-breaking" amounts of gas as fuel costs soar, Yahoo Finance (May 29, 2026) — CEO comments on the gas team and multiple daily deliveries.
• Canadian Refining Industry, April 2026, CAPP — 17 refineries, about 2 million b/d, refinery list and capacities, US share of crude imports, Irving.
• Canada's refined petroleum product imports rose in 2025, Canada Energy Regulator — 485,000 b/d of imports, 79.6% from the US, provincial breakdown, Alberta condensate.
• CER provincial energy profiles for Alberta, British Columbia, Ontario and Quebec — refineries and where each province's gasoline comes from.
• The Refining Sector in Canada, Natural Resources Canada — Canada as a net exporter of products, BC imports from Washington State.
• Sunoco completes cash-and-stock deal to buy Parkland, BNN Bloomberg (seen in search results) — Parkland, owner of the Burnaby refinery, now part of Sunoco.
• ASTM D4814 and CAN/CGSB-3.5-2026, Standards Council of Canada (both seen in search results) — US and Canadian gasoline specifications.