LONDON (Reuters) - Chancellor George Osborne has appointed a former Bank of America Merrill Lynch (>> Bank of America Corp) executive to oversee the sale of the government's stakes in Britain's banks.

Osborne named Oliver Holbourn as the new chief executive officer of UK Financial Investments (UKFI), the group, which manages the stakes, said on Thursday. Holbourn was previously UKFI's head of capital markets.

James Leigh-Pemberton, who was executive chairman, has been appointed UKFI chairman.

UKFI is charged with balancing the timing of selling off the government holdings in the banks to raise money to help to reduce Britain's budget deficit, while ensuring the best return for taxpayers. The government pumped a combined 66 billion pounds into Royal Bank of Scotland (>> Royal Bank of Scotland Group plc) and Lloyds Banking Group (>> Lloyds Banking Group PLC) to keep them afloat during the 2008-2009 financial crisis. "We have an outstanding team here and I look forward to working with them and our investee companies in my new position to continue to deliver good results for the taxpayer," Holbourn said in a statement.The government could lose some 17.5 billion pounds, or a quarter of the money spent rescuing the banks, according to an analysis by the Treasury's independent forecasters this month.The Treasury estimated it might take another five years for the government to sell off its remaining 73 percent stake in Royal Bank of Scotland as the shares are trading at about half their break-even price. The government is closer to returning Lloyds to the private sector, but had to defer plans to sell its remaining holding of less than 10 percent earlier this year due to financial market turmoil.

(Reporting By Andrew MacAskill. Editing by Lawrence White and Jane Merriman)