Costco Limits Purchases of Kirkland Synthetic Motor Oil Amid Rising Energy Prices

Costco announced that members can buy no more than two packs of its Kirkland Signature 5W-30 full-synthetic motor oil every seven days, according to the retailer’s website and industry reports. Each pack contains two five-quart bottles, and the price for a ten-quart supply has risen to $58 from as low as $30 earlier in the year.

The restriction comes as the closure of the Strait of Hormuz has tightened global oil supplies, pushing up crude, gasoline and diesel prices for U.S. consumers. Data from a university energy-cost tracker estimates that the conflict has added over $100 billion in gasoline and diesel expenses nationwide, with the average household facing more than $750 in extra costs since February.

Gasoline prices averaged $4.31 per gallon, up from $4.14 during the Labor Day weekend, while diesel reached $6.23 per gallon, according to industry monitoring.

"The point is that Costco via Kirkland, has a high resolution view of all supply chains relevant to Costco," wrote a legal analyst, noting that the retailer’s decision may reflect broader upstream supply challenges.

Costco has not provided a specific explanation for the rationing. The move follows broader concerns about the impact of the Iran conflict on American households, with recent polling showing a majority of respondents view the war’s costs as unacceptable.