Addendum to Investment Agreement with YPF

Pampa Energía Announces an Addendum to the Investment Agreement between its Subsidiary Petrolera Pampa and YPF Related to the Rincón del Mangrullo Block

Buenos Aires, May 27, 2015. Pampa Energía S.A. (NYSE: PAM; Buenos Aires Stock Exchange: PAMP “Pampa” or the “Company”) informs that Petrolera Pampa and YPF S.A. (“YPF”) signed an addendum to the investment agreement dated November 6, 2013 (the “Agreement”), related to the exploitation of Rincón del Mangrullo block (the “Block”), in which both parties have agreed to amend certain terms and conditions of the Agreement, mainly to add certain investments to those already involved in the Block.

Thus, upon completion of certain conditions precedent and as of January 1, 2015, the main amendments to the Agreement are the following:

• i. The incorporation of other formations not included in the former Agreement, being excluded Vaca Muerta and Quintuco formations;
• ii. Petrolera Pampa shall be entitled to the production of all existing wells in the Block and must meet all investments in surface facilities -estimated in US$75 million for the 2015-2016 period- as well as expenses incurred in the Block’s operation, all based on its ownership stake;
• iii. Petrolera Pampa will invest US$22.5 million for wells drilling in the Mulichinco formation and/or additional surface investments for the 2016-2017 period. Moreover, jointly with YPF, Petrolera Pampa agreed to expand the 2015 drilling plan at the Mulichinco formation for about US$70 million.
• iv. Petrolera Pampa will invest in exploratory wells at the Lajas formation, which will involve an investment of US$34 million for the 2016-2017 period.

Since the entry into force of this addendum, it is estimated that Petrolera Pampa will add approximately 300,000 m3 per day to its average production in the Block, which will represent an increase of over 35% of its current average production. Therefore, the committed investment of Petrolera Pampa for the period 2014-2017 in the Block would exceed US$350 million.

For further information, contact:

Ricardo Torres – Co-Chief Executive Officer
Gustavo Mariani – Co-Chief Executive Officer
Mariano Batistella – Special Projects Manager and Investor Relations Officer
Lida Wang – Special Projects and Investor Relations Associate

3302 Ortiz de Ocampo, Building #4
(C1425DSR) Ciudad Autónoma de Buenos Aires, Argentina
Phone: +54 (11) 4809 9500
http://www.pampaenergia.com/ir
investor@pampaenergia.com