Ecopetrol : Publishes the Offering Regarding the Fourth Auction of the Equity Divestment Plan for its Shares in Interconexión Eléctrica S.A. E.S.P (ISA)

MATERIAL INFORMATION

Ecopetrol S.A. (BVC: ECOPETROL; NYSE: EC) ("Ecopetrol" or the "Company") hereby announces that on December 10, 2016, as established in the Offering Notice of Second Stage, the Company published the offering notice regarding the fourth auction for the second stage of Ecopetrol's equity divestment plan for its shares in Interconexión Eléctrica S.A.

E.S.P (ISA) in a newspaper widely circulated in Colombia.

The fourth auction is part of the second stage of the equity divestment plan and the purpose is to offer publicly, in Colombia and/or abroad, the shares that were not acquired during the first, second and third auctions.

The public offering will be conducted prior to the beginning of common stock trading in the Colombian Stock Exchange on December 14, 2016, in accordance with the provisions set forth in the Divestment Regulation and the applicable addenda.

The documentation concerning the offer (available only in Spanish) can be found on the website of Ecopetrol www.ecopetrol.com.co with the following link:

http://www.ecopetrol.com.co/wps/portal/es/ecopetrol-web/relacion-inversionistas/para-el- accionista/Enajenacion-adjudicacion-acciones-ISA/

Ecopetrol's equity divestment plan, including the second stage, was approved by the National Government of Colombia through Decree 1800 of September 09, 2015.

This announcement is not an offer of securities for sale in the United States. Securities may not be offered or sold in the United States absent registration under the U.S. Securities Act of 1933, or an exemption from registration. No public offering of securities has been or will be made in the United States and, accordingly, the securities will not be registered under the U.S. Securities Act of 1933. This announcement is being issued pursuant to Rule 135e of the U.S. Securities Act of 1933.

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This release contains statements that may be considered forward looking statements within the meaning of Section 27A of the U.S. Securities Act of 1933 and Section 21E of the U.S. Securities Exchange Act of 1934. All forward-looking statements, whether made in this release or in future filings or press releases or orally, address

MATERIAL INFORMATION

matters that involve risks and uncertainties, including in respect of the Company's prospects for growth and its ongoing access to capital to fund the Company's business plan, among others. Consequently, changes in the following factors, among others, could cause actual results to differ materially from those included in the forward- looking statements: market prices of oil & gas, our exploration and production activities, market conditions, applicable regulations, the exchange rate, the Company's competitiveness and the performance of Colombia's economy and industry, to mention a few. We do not intend, and do not assume any obligation to update these forward-looking statements.

María Catalina Escobar Phone: (+571) 234 5190

E-mail: investors@ecopetrol.com.co

Jorge Mauricio Tellez Phone: + 571-234-4329

e-mail: mauricio.tellez@ecopetrol.com.co