Abu Dhabi’s investment vehicle Mubadala is considering an initial public offering (IPO) of its fully-owned energy company Cepsa, instead of a private stake sale, according to a report.

The IPO of Spain-based Cepsa, owned by Mubadala’s Petroleum & Petrochemicals division, could happen as early as September, Reuters reported.

The Abu Dhabi wealth fund is reportedly having negotiations for the potential stock listing of Cepsa, and is also eyeing the Madrid Stock Exchange over the London bourse as Spanish investors would be more familiar with the company, the report said.

Cepsa was previously listed on the Madrid market until 2011, when Abu Dhabi’s erstwhile International Petroleum Investment Company (IPIC) bought all of the firm’s shares. It is now estimated to be valued around $11.6bn.

Mubadala in March said it was considering a public listing, or sale of all, or a stake in Cepsa. The company has exploration and production interests in Latin America, North Africa and Asia.

Cepsa was awarded a 20 per cent stake by Abu Dhabi National Oil Company (Adnoc) in the Sarb and Umm Lulu block of Abu Dhabi’s offshore oil concession in February, for $1.5bn.

Cepsa is also working with Adnoc to jointly develop a linear alkylbenzene plant in the Ruwais downstream complex.

Last year, Mubadala's CEO Khaldoon al-Mubarak said the holding company was eyeing new overseas investments, and might sell or reduce some of its existing stakes in companies; this would be part of Mubadala's plan to consolidate profitability from its portfolio.