Mr Chai, who will be based in Hong Kong, became Merrill's CFO in December 2007, shortly after John Thain became chief executive of the bank. For Mr Chai, the new post is a significant step up from his duties at Merrill. He takes on operational duties across Asia and will continue to report to John Thain.

Mr Chai had worked with Mr Thain before joining Merrill. He was an executive at Archipelago when the electronic platform merged with the New York Stock Exchange in 2005. Mr Thain subsequently named him chief financial officer of the NYSE. When Mr Thain took over at Merrill Lynch last year, Mr Chai soon followed, taking the reins as CFO.

Bank of America agreed to buy Merrill Lynch in September, and last month Thain was named head of investment banking, securities and wealth management for the combined company.