May 19 (Reuters) - Gran Tierra Energy Inc GTE.TO -
* Gran Tierra Energy Inc - on May 17, co, others entered into sixth amendment to credit agreement dated as of September 18, 2015 - sec filing
* Gran Tierra Energy Inc - sixth amendment is effective as of June 1, 2017 and, among other things, increases borrowing base from $250 million to $300 million
* Gran Tierra Energy-amendment excludes somecash collateralized letters of credit from definition of total debt, amends pricing for some letters of credit Source text: Further company coverage: GTE.TO