LONDON/HONG KONG (Reuters) - Dramatic change swept through HSBC on Friday as Europe's biggest bank named a new chairman, chief executive and finance director to repair its reputation after a shock boardroom bust-up.

Chief executive Michael Geoghegan will be replaced by Stuart Gulliver, the head of investment banking, at the end of the year, and finance director Douglas Flint will take over as chairman on Dec. 3.

Sweeping change at the 145-year-old bank came after a boardroom dispute blew up during the search for a successor to chairman Stephen Green, who announced two weeks ago he would leave.

"It's quite remarkable for a company that's renowned for its stewardship," said Chris Wheeler, analyst at Mediobanca in London.

"It's got to be bad news in the short term. It's not affecting the underlying performance, but it looks ugly, and it's unstable for a bank that's come through this (crisis) looking very healthy," he said.

HSBC executives denied there was a rift, but said leaks of details had been damaging. "It has been diabolical the way leaks have undermined certain individuals and what we're trying to do," Simon Robertson, the senior non-executive director who led the search process, said on a conference call.

Flint had been picked out as the best choice as chairman about 10 days ago, he said. Geoghegan said that was when he chose to step down.

"I was happy to stand aside and let the next team get on with it," Geoghegan said. He has been CEO for four-and-a-half years and said CEOs shouldn't stay longer than five or six years.

He added: "I never really went out of my way to be chairman. You have to be asked to be chairman, and the reality was that I wasn't asked."

Shares of HSBC, the world's third-biggest bank and the largest outside China, closed up 0.4 percent at 666.3 pence in London, while its Hong Kong-listed shares dipped 0.6 percent.

The changes were widely reported late on Thursday, and HSBC confirmed details after the market close once the board and regulators had approved them.

Gulliver will relocate to Hong Kong, Flint will keep a full-time role, while Geoghegan, age 56, will retire from the company at the end of March.

Iain Mackay will become finance director on December 3. He is currently finance officer for Asia-Pacific.

The Financial Times reported last week that Geoghegan had threatened to quit if he was not made chairman, but the bank dismissed it as "nonsense".

Analysts broadly welcomed the Flint and Gulliver double-act. Both are HSBC veterans familiar with the complexities of the bank, which spans 86 countries.

"The overall broad strategy is going to remain constant," said Dominic Chan, an analyst at BNP Paribas. "The (possible) Nedbank purchase and everything they've said recently all says they're not going to suddenly change direction and decide they want to be an investment bank."

Gulliver had been groomed for the CEO role and was given wider responsibility for running Europe and the Middle East when Geoghegan moved to Hong Kong earlier this year.

That symbolised HSBC's greater emerging markets push — it aims to be listed on Shanghai's international board and is in talks to buy a majority of South Africa's Nedbank.

Gulliver will become the second investment banking chief to be named CEO of a top British bank this month, following Bob Diamond's appointment at Barclays Plc.

That comes despite a backlash among politicians against riskier investment banking. UK banks will be subjected to a wide-ranging probe that will examine the possible break-up of retail and investment banks and ways to boost competition, a commission said on Friday.

Critics said the appointment of Flint would also go against best corporate governance practice, as it is hard for former executives to be objective about strategic decisions they might have helped make and could be reluctant to reverse.