Costco Wholesale Corp announced that its Kirkland Signature motor oil will be subject to purchase limits in United States locations as of September 15, 2026, citing a worldwide shortage of a key ingredient needed to produce the oil.
The restriction applies only to U.S. stores, while outlets in Quebec continue to carry the product without limits. Costco says the measure is intended to stretch existing inventories until the supply of the scarce component improves.
Industry sources describe the shortage as affecting a chemical additive that enhances oil performance. Disruptions in the production of that additive have reduced the volume of motor oil that can be blended, prompting retailers to ration the product.
Costco has not disclosed the exact quantity each shopper may purchase, but the cap will be enforced at the point of sale. Customers seeking larger amounts will be advised to shop at locations where the limit does not apply or to consider alternative brands.
The decision follows similar rationing actions taken by other retailers in recent months as the component shortage persisted. Analysts note that the limited supply could affect vehicle maintenance costs for drivers who rely on the Kirkland brand, which is positioned as a cost‑effective alternative to name‑brand oils.
Costco indicated that it is monitoring the situation closely and will adjust the purchasing limits as soon as the supply chain stabilizes. The company’s statement emphasized its commitment to ensuring product availability for members across its network while managing the constraints imposed by the global shortage.