August 31, 2015

Gastar Exploration Inc. (NYSE MKT: GST) (“Gastar”) today announced that it has completed its second scheduled borrowing base redetermination of its revolving credit facility for 2015 and, as a result, the borrowing base has been reaffirmed by the lending participants at $200.0 million. Currently, Gastar has drawn $65.0 million under its revolving credit facility, resulting in $135.0 million of unused borrowing