May 17 (Reuters) - Ecopetrol Sa
* Ecopetrol announces non-filing of its annual report on form 20-f for year ended December 31, 2016
* Does not anticipate any changes from results reported in its 2016 earnings release published on march 6, 2017
* Audit committee of board retained u.s.-based outside law firm to commence third-party investigation
* Ecopetrol says the company and Reficar have cooperated closely and extensively with control entities in furthering their investigations
* ICC proceeding is currently in its preliminary stage and is scheduled for a hearing in October 2018.
* No current executives of Ecopetrol, Reficar or members of board are included in prosecutor's office press release Source text for Eikon: Further company coverage: