Natural Gas
October 13, 2026
Platts clarifies several US natural gas index methodologies
Platts, part of S&P Global Energy, is clarifying the written methodologies for several US natural gas indexes following a review of the Methodology and Specifications Guide US and Canada Natural Gas. These revisions are aimed at improving the precision and readability of the definitions but do not change published prices, the trades included in each index, or how reported trades are mapped to the relevant locations.
Columbia Gulf, mainline (daily and monthly market)
The revised definition specifies the geographic boundaries of the Columbia Gulf, mainline methodology.
| Existing definition | Revised definition |
| Deliveries into Columbia Gulf Transmission anywhere along its mainline system zone in Louisiana and Mississippi. The mainline system extends northeast from Rayne, LA to Leach, KY. | Deliveries into Columbia Gulf Transmission anywhere along its mainline system zone in Louisiana and Mississippi. Deliveries north of Corinth, MS and south of Rayne, LA are excluded. |
Associated symbols: IGBBH00 (daily), IGBBH03 (monthly)
MountainWest (daily market only)
The revised definition is more concise and clarifies that trades on the 20-inch line connecting the North and South systems are included.
| Existing definition | Revised definition |
| Deliveries into MountainWest Pipeline on its North system, which runs from northwestern Colorado through southern Wyoming to Salt Lake City, and on its South system, which runs from western Colorado to Payson, Utah, east of the Fidlar compressor station. A 20-inch line running parallel to the Utah-Colorado border connects the two systems. This point was discontinued in the monthly market effective May 1, 2014. It continues to be published in the daily market. | Deliveries into the MountainWest Pipeline, including into the North and the South systems, and the line connecting them. |
Associated symbol: IGBCN00
CIG, Rocky Mountains (daily and monthly market)
The revised definition more clearly identifies the portion of the CIG system included in the methodology.
| Existing definition | Revised definition |
| Deliveries into Colorado Interstate Gas' 20 inch, 22-inch and 24-inch mainlines in Wyoming and Colorado. Also included are deliveries into the Parachute to Natural Buttes segment in Uintah County, Utah, and deliveries into CIG's 16-inch lateral running from the Rawlins station in Carbon County, WY to the Elk Basin station in Park County, WY. Not included are deliveries into CIG's system at points south of Cheyenne, WY. | Deliveries into Colorado Interstate Gas north of Cheyenne, Wyoming, including deliveries into the Uintah lateral, which extends south from Wamsutter, Wyoming, into northwestern Colorado and Utah. Deliveries into the CIG system south of Cheyenne are excluded. |
Associated symbols: IGBCK00 (daily), IGBCK03 (monthly)
NGPL, Midcontinent (daily and monthly market)
The revised definition updates the compressor-station references and more precisely identifies the included portion of the Natural Gas Pipeline Co. of America system included in the methodology.
| Existing definition | Revised definition |
| Deliveries into Natural Gas Pipeline Co. of America starting at compressor station 155 in Wise County, TX, west to the Amarillo mainline at station 112 in Moore County in the Texas Panhandle, and then north to the Trailblazer Pipeline interconnection in Gage County, NE. Included are deliveries into NGPL at all Oklahoma points west of station 801, as well as those in North Texas north and east of station 170 and in Kansas south of station 103. | Deliveries into Natural Gas Pipeline Co. of America from compressor station 801 in Carter County, OK, west to the Amarillo mainline at station 111 in Hutchinson County in the Texas Panhandle, and then north to the Trailblazer Pipeline interconnection in Gage County, NE. The location also includes deliveries into NGPL on the M&M line that runs from station 156 in Kiowa County, OK, to station 103 in Ford, County, KS. |
Associated symbols: IGBBZ00 (daily), IGBBZ03 (monthly)
Florida city-gates (daily market only)
The revised definition confirms that deliveries to end-use facilities are included in the Florida city-gates methodology.
| Existing definition | Revised definition |
| Deliveries from Florida Gas Transmission into all city-gates in the Florida market area, which begins in Santa Rosa County just west of station 12 in the extreme western Florida Panhandle and extends into southern Florida. Also included in the development of Florida city-gates daily index are basis deals done within the defined Florida city-gates methodology at a differential to Florida Gas, Zone 3 final daily index. | Deliveries from Florida Gas Transmission into all city-gates and end-use facilities in the Florida market area, which begins in Santa Rosa County west of station 12 in the far western Florida Panhandle and extends into southern Florida. The Florida city-gates daily index also includes basis deals transacted within the defined Florida city-gates methodology at a differential to the final daily index for Florida Gas, Zone 3 final daily index. |
Associated symbol: IGBED00 (daily)
Alternate currency locations
The definitions for the following locations clarify that the prices are reported in US dollars per MMBtu:
· Niagara
· Dawn, Ontario
· Emerson Viking GL
· Northwest Canadian border (Sumas)
Please send any questions or comments on the above clarifications to AmericasGasPricing@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.