Platts proposes to publish a regional USGC octane cost assessment

Platts, part of S&P Global Commodity Insights, proposes to launch a new daily assessment to reflect the value of one octane index point for US Gulf Coast conventional gasoline effective Dec. 1, 2025.

The octane value assessment would be published in US cents/gal per octane index point and derived from the differential between USGC Premium CBOB pipeline (AANYX78) and USGC regular CBOB pipeline (AANYX77), divided by 7.7 octane points.

The US Gulf Coast Value per one octane (83.7-91.4 AKI) represents the value of one octane point, considering a linear octane relationship for the pre-ethanol blending range of 83.7 AKI-91.4 AKI.

For reference, Platts understands that the pre-ethanol octane range of 83.7-91.4 AKI is the equivalent of the post-ethanol blend octane range of 87-93 AKI. In the US, AKI, or anti-knock index, is the typically referred unit for octane rating and is the average of Research Octane Number (RON) and the Motor Octane Number (MON) ratings.

These assessments would be used to value and adjust gasoline and gasoline blendstock prices where differing octane ratings apply, similar to existing RVP adjustments, in the absence of observed market activity.

Platts also seeks wider feedback on whether separate octane values should be published for adjustments outside of that range.

Please provide comments or feedback on this proposal by Nov. 15, 2025, to americas_products@spglobal.com and pricegroup@spglobal.com.

For written comments, please provide a clear indication if comments are not intended for publication by Platts for public viewing. Platts will consider all comments received and will make comments not marked as confidential available upon request.