AEI Energy has acquired an option to buy an indirect 5.53% stake in Argentine natural gas pipeline company Transportadora de Gas del Sur (TGS), or TGS, for $3 million.

AEI bought the option to buy 100% of Enron Pipeline Company Argentina, which holds a 10% stake in TGS's controlling company, Compania de Inversiones de Energia S.A., or Ciesa, TGS said in a statement filed with the Buenos Aires Stock Exchange late Friday.

AEI was born out of investment funds managed by U.K.-based Ashmore Investment Management Ltd.

Ciesa controls just over 55.3% of TGS's common stock. Brazil's Petroleo Brasileiro SA (PBR), through its local unit Petrobras Energia SA (PBE.BA) and another subsidiary, owns 50% of Ciesa, while a fiduciary trust owns 40% and the former subsidiary of the now defunct Enron Corp. owns 10%.

-By Taos Turner, Dow Jones Newswires; 5411-4103-6728; taos.turner@dowjones.com