DUBAI- Qatar has appointed Mansour Ibrahim al-Mahmoud as chief executive of the Qatar Investment Authority, one of the world's largest sovereign wealth funds, the state news agency said on Wednesday.

The fund's previous CEO, royal family member Sheikh Abdullah bin Mohamed bin Saud al-Thani, was appointed minister of state, the Qatar News Agency quoted a royal decree as saying. It did not elaborate on the reasons for the switch.

The QIA has assets of $320 billion, according to an estimate by the Sovereign Wealth Fund Institute, and holds stakes in top Western companies such as Credit Suisse, Barclays and the London Stock Exchange as well as major real estate assets abroad.

Mahmoud was previously head of risk management at the QIA and sits on the boards of Qatar National Bank, real estate firm Qatari Diar and Hassad Food Co, according to his biography on the Qatar Museums website, where he is listed as chief executive.

QNB is the Gulf's biggest listed bank, while Qatari Diar and Hassad are controlled by the QIA.

Sheikh Abdullah, who served as CEO for nearly four years, oversaw a global acquisition spree by the QIA. Earlier this month, he said the fund would focus its future investments in Germany on the financial sector and developments in information technology, artificial intelligence and healthcare. 

The QIA said last year that it would continue expanding its holdings despite a dispute with Saudi Arabia, the United Arab Emirates, Bahrain and Egypt, which severed diplomatic and transport links with Qatar in June 2017.

During the early stages of the diplomatic crisis, the QIA pumped billions of dollars into local banks to prevent them from suffering funding squeezes as the other Arab states withdrew funds. The outflows of deposits have now almost entirely halted and banks' balance sheets are stable.

(Additional reporting by Asma Alsharif; Editing by Andrew Torchia) ((Tom.Arnold@thomsonreuters.com; +97144536265; Reuters Messaging: tom.arnold.thomsonreuters.com@reuters.net))