PNW Sub Oct Reg Basis Falls 5cts as Supply Concerns Ease

MIAMI, FL (DTN) – Pacific Northwest sub octane regular gasoline basis weakened Monday (6/15), falling by 5cts on softer supply conditions and with the absence of recent refinery flaring events.

An offer was heard in the market at an 18cts premium to July NYMEX RBOB futures, bringing the Pacific Northwest sub octane basis to a last indication of a 17.5cts premium, down 5cts from the prior session. The product was last seen trading at this level on October 17, 2025, according to DTN data.

No significant refinery flaring events or unplanned unit outages have been reported recently at major U.S. West Coast refining facilities, reducing concerns over potential supply disruptions that have supported gasoline basis values in recent months.

The lower basis reflects improving market sentiment around regional gasoline supply availability. With no fresh operational issues reported at West Coast refineries, traders appeared less concerned about near-term supply risks, pressuring Pacific Northwest gasoline differentials lower.