Closing of CIESA’s debt acquisition

Pampa Energía announces the closing of the acquisition of CIESA’s debt

Buenos Aires, January 28, 2011. Pampa Energía S.A. (NYSE: PAM; Buenos Aires Stock Exchange: PAMP) (“Pampa” or the “Company”), announcement today, in relation to its announcement of January 19, 2011, that, through its subsidiary Pampa Inversiones S.A., it has acquired from AEI 100% of the outstanding bonds issued on April 22, 1997 (the “Bonds”) by Compañía de Inversiones de Energía S. A. (“CIESA”), the controlling company of Transportadora de Gas del Sur (“TGS”), and other credits against CIESA (the “CIESA Debt”), together with the rights over certain current lawsuits related to the Bonds and certain CIESA’s debt restructuring agreements.

Pampa Energía is the largest integrated electricity company in Argentina that, through its subsidiaries, participates in the generation, transmission and distribution of electricity.

For further information, contact:

Ricardo Torres – Chief Executive Officer
Mariano Batistella – Strategic Planning and Investor Relations
3302 Ortiz de Ocampo, Building #4
(C1425DSR) Ciudad Autónoma de Buenos Aires, Argentina
Phone: 5411 4809 9500
http://www.pampaenergia.com/ir
investor@pampaenergia.com