The chief executive of Bahrain's $9 billion sovereign wealth fund, Mumtalakat, told Reuters he has resigned to set up a new investment firm in the kingdom.

"I'm leaving Mumtalakat after four years of helping set up an institution of the best international standards and corporate governance," Talal Al Zain, 52, said in a phone interview from Manama on Monday.

"I'm staying in Bahrain and will always be part of the system here."

Al Zain, who took the helm at Mumtalakat in 2008 after an 18-year stint at alternative asset manager Investcorp, will remain chairman of Bahrain's national carrier Gulf Air, which Mumtalakat owns.

Mumtalakat, which holds Bahrain's non-oil related companies, is among the smallest sovereign wealth funds in the Gulf Arab region which is also home to the Abu Dhabi Investment Authority (ADIA). The Sovereign Wealth Fund Institute estimates ADIA's value at $627 billion and ranks it among the largest in the world.

Set up in 2006 to help diversify Bahrain's economy away from hydrocarbons, Mumtalakat has stakes in over 35 commercial entities, including Bahrain Telecommunications Co, Gulf International Bank, and Aluminium Bahrain , one of the largest aluminium smelters in the world.

In December, Mumtalakat said it narrowed its 2010 operating loss to 48.9 million dinars ($129.71 million) from a loss of 123.4 million citing strong growth in gross margins and an improved operating performance across the portfolio. Revenues rose 15 percent in 2010, thanks to commodity price-fuelled gains at Aluminium Bahrain.

Mumtalakat suffered a ratings downgrade last year as a result of sovereign downgrade, amid the political unrest that hit the Gulf state. Mumtalakat is rated triple-B.

Al Zain did not give details on his new venture.

"The new firm will be based here and will cover the whole Mena region," he said. -Reuters