| 35. | Subsequent events |
| - | On April 13, 2018, Ecopetrol redeemed all of its outstanding 4.250% notes due September 18, 2018 in an aggregate principal amount of US$350 million. The notes were issued in September 2013. |
| - | On March 14, 2018, Ecopetrol formed the subsidiary Ecopetrol Energía SAS E.S.P., domiciled in Colombia, whose corporate purpose is the commercialization of electric energy for the Ecopetrol Business Group. Ecopetrol has a direct participation of 99% in the capitalization of the new subsidiary, and indirect participation in the remaining 1% interest through Andean Chemicals Ltd. |
| - | On March 2, 2018, a seepage of water and traces of crude oil occurred near the Lisama 158 well, located in the village of La Fortuna, in the Middle Magdalena Valley of Colombia. Ecopetrol activated its contingency plan to contain the spill. It is estimated that 550 barrels of crude, mixed with mud and rainwater, seeped into the streams of La Lisama and Caño Muerto. As of March 30, 2018, the Lisama 158 well was sealed and stopped flowing. Ecopetrol has ordered an investigation to determine the cause of the seepage. As of the date of this annual report, the National Environmental Licenses Agency (ANLA) has opened an investigation into the incident and the Prosecutor’s Office and other control entities may also open investigations. Besides the notice of seven constitutional actions for protection of fundamental rights. Ecopetrol is not aware of any other third party claims in connection with this incident, it cannot offer any assurance as to whether or not there will be third party actions in the future. |
| - | As part of the investigations carried out by various control entities of the modernization and expansion project of Reficar the following developments in the investigations and proceedings have occurred: |