Costco has imposed strict purchase limits on motor oil and raised prices sharply, signaling tightening supply in refined products.
Members can now buy only one transaction of Kirkland Signature full synthetic motor oil per membership period, with a maximum of two units every seven days for the two-pack of 5-quart bottles. The price jumped to $57.99 from a typical range near $30.
Mobil 1 motor oil sales on Costco's website are capped at five units of the 6-pack of 1-quart bottles, priced at $43.99.
Brent crude, the international oil benchmark, traded above $109 per barrel Monday morning—the highest level since May, after a 9 percent weekly gain. West Texas Intermediate futures also broke above $104 per barrel. Both benchmarks retreated slightly by close: Brent settled at $105.68, WTI at $101.39.
The rally stems from Saudi Arabia's closure of its critical East-West oil pipeline following drone attacks from Iraq last week. That supply squeeze is forcing refiners to prioritize diesel and gasoline production over base oil, a key component in synthetic motor oil. Tighter base oil supply directly drives motor oil prices higher.
U.S. gasoline and diesel prices have climbed in tandem. Gasoline hit record levels for Labor Day, while diesel crossed $6 per gallon for the first time.
Costco did not respond to requests for comment on the purchase limits and price increases.
