Abu Dhabi’s Mubadala Investment Company has completed its sale of a significant stake in Spanish player Compania Espanola de Petroleos (Cepsa) to private equity giant Carlyle Group.

Carlyle now has a 37% stake in Cepsa following closure of a deal that was first revealed in April.

At that time, the precise size of the stake to be acquired by Carlyle was not revealed, although it was known to be between 30% and 40%.

No acquisition price was revealed on Tuesday, but the deal, when announced in April, was based on an enterprise value for Cepsa of $12 billion.

Mubadala will, however, remain the majority shareholder of Cepsa on 63%.

The board will be comprised of five Mubadala-nominated directors, three Carlyle-nominated directors, one independent director, and the chief executive – a position that is also changing.

Current chief executive Pedro Miro is retiring to be replaced by long-time Total executive Philippe Boisseau.

Musabbeh al-Kaabi, chief executive of petroleum & petrochemicals at Mubadala and Cepsa chairman, said: “I want to thank Pedro Miro, especially, for his long and dedicated service to Cepsa.

“He has played a vital role in developing Cepsa in recent years to become one of Spain’s leading companies and a business that is looking strong for the future.

“I also want to welcome our incoming chief executive Philippe Boisseau, who will be leading the company’s next phase of growth.

“Philippe is well known to Mubadala from his time in the Middle East with one of our long-term partners and we are pleased to have him on board.”

Marcel van Poecke, head of offshoot Carlyle International Energy Partners (CIEP) and vice-chairman of Cepsa, added: “Cepsa is an attractive, well-positioned international integrated energy player led by Pedro and his strong leadership team.”

Cepsa has operations in more than 20 countries and holds stakes in the Umm Lulu and SARB fields off the coast of Abu Dhabi, as well as oil production in Algeria and also operates in Central and South America, as well as South-East Asia.

It also has a retail business which includes service stations across the Iberian Peninsula, while it also owns and operates two refineries in Spain.

Carlyle has a vast stable of oil and gas assets, including UK North Sea player Neptune Energy, US giant Chesapeake Energy, US midstream giant Kinder Morgan and Gabon-focused Assala Energy, which took the assets of Shell in Gabon.

In recent weeks it has added to the stable, as CIEP is bankrolling a start-up called Boru Energy, headed by former Tullow Oil chairman and chief executive Aiden Heavey and two other ex-Tullow executives.

The company will chase producing assets in Sub-Saharan Africa, and is primarily after a non-operated position, teaming up with national oil companies, international oil companies and independents.

The aim is to build up a portfolio of assets "with significant commercialisation potential" in numerous countries on the continent.

CIEP will provide funding for any acquisitions, with parent Carlyle Group saying that Boru will target acquisitions of up to $1 billion.