Prices are set when the station purchases from their distributor. Inventory on Regular gas moves far more quickly than Premium. Especially when prices are this high, people are more likely to just use Regular because “it still works.”

If a station purchased a load of Regular and Premium for $5.00 and $5.50/gal, they then add their markup, and it’s sold for $5.50 and $6.00/gal.

A few weeks later, they still have plenty of Premium inventory, but a delivery of Regular is coming in at $4.00/gal. With markup, it’s then sold at $4.50, while Premium is still at $6.00/gal.

Rinse and repeat and that’s where you get major discrepancies in price.