Natural Gas Producers

Anadarko Petroleum Corporation
Apache Corporation
Bill Barrett Corp.
Cabot Oil and Gas Corporation
Chesapeake Energy
Cimarex Energy
Devon Energy Corporation
El Paso Corporation
EnCana
Energen
EOG Resources, Inc.
EQT
Laredo Petroleum
Linn Energy
Newfield Exploration Company
Noble Energy, Inc.
PetroHawk Energy Corporation
Pioneer Natural Resources
Plains Exploration and Production Company
Questar
Quicksilver
Range Resources Corporation
SandRidge Energy, Inc.
Seneca Resources Corporation
SM Energy
Talisman
Ultra Petroleum Corp
Willams Companies
XTO Energy