Hang Seng Bank has announced that Vincent Cheng Hoi-chuen has been officially appointed chief executive of the bank, having performed as acting chief executive since March. Yesterday's development followed the announcement that Hang Seng Bank's former chief executive, Alexander Au Siu-kee, had resigned as executive director of Standard Chartered Bank after working there for less than two months. Mr Cheng, an executive director of Hongkong Bank, was appointed Hang Seng's vice-chairman and acting chief executive after Mr Au submitted his resignation in controversial circumstances to join arch-rival Standard Chartered. The 'acting' in front of his title invited speculation as to whether his appointment had been a temporary and emergency solution to the sudden departure of Mr Au. Mr Cheng has steadfastly declined to respond directly to inquiries relating to this speculation, repeating that the move to make him acting chief executive was the best arrangement the group could reach at the time. Mr Cheng's immediate challenge will be to report on Monday what is forecast to be the bank's worst interim result in 10 years. Analysts have forecast Hang Seng will probably see profit for the six months to June 30 plunge by as much as 13.65 per cent to about $4.3 billion, from $4.98 billion in the first half of last year. Analysts have said the bank should be relatively protected from the squeeze on interest margins in Hong Kong over the last six months due to its large deposit base, while the need for higher provisions will yet to have fed through. On average, analysts expect Hang Seng's provisions will reach $250 million, with $50 million in general provisions and $200 million in specific provisions.