British bank Standard Chartered said today chief executive Mr Rana Talwar has resigned and will be replaced by the head of its Hong Kong operations.
Sources close to the bank blamed a corporate culture clash. Mr Talwar had been chief executive since 1998.
Banking sources say Talwar did not fit with the management style at the London-listed emerging markets bank and that there were disputes.
"It's nothing to do with his abilities, it's fitting in to a certain style," a company insider said, playing down reports Mr Talwar was in open conflict with bank chairman Mr Patrick Gillam.
Standard said it had appointed Mr Mervyn Davies (49) as chief executive. He joined Standard Chartered in 1993 after a 10-year spell at Citibank.
BNP Paribas analyst Mr Hugh Pye said: "It's a shock. Rana was very, very good and therefore him going is very, very bad".
His resignation comes amid press speculation the bank, which has most of its operations in Asia, is to become the target of a takeover bid. But the departure is not expected to soften Standard's determination to remain an independent company.
Standard Chartered said on Sunday it was not for sale following repeated press speculation it could be the target of a takeover approach and larger shareholders wanted bids to be sought.