Reuters Market Eye - Barclays downgrades GAIL to "underweight" from "overweight", after cutting its earnings per share forecast for fiscal years 2014 to 2016 by 26-31 percent.
Brokerage adds domestic gas output has fallen faster than expected due to a drop in output from the KG-D6 block, and expects a recovery to be 12-18 months away.
The fall in output from KG-D6 will also raise gas costs for GAIL, Barclays adds.
GAIL shares are down 3.11 percent, having lost 13.67 percent so far this year.
(Reporting by Himank.Sharma)