By Selena Li and Lawrence White

HONG KONG/LONDON (Reuters) - HSBC Holdings beat third quarter profit expectations on Tuesday thanks to rising wealth and wholesale banking revenue, but kept investors waiting for more detail on how a sweeping overhaul of its structure will deliver cost savings.

HSBC announced last week that it will merge some operations, slash senior roles and split its geographic footprint into East and West, although its CEO Georges Elhedery said on Tuesday that the latter did not imply it will eventually split up its business.

The bank's shares rose 2.5% in London to a six-year high, echoing earlier gains in its Hong Kong shares after the lender also announced a fresh $3 billion share buyback.

HSBC's third-quarter profit rose 10% to $8.5 billion, ahead of estimates of $7.6 billion, as it benefited from slower-than-expected rate cuts, which had been anticipated to put more pressure on lending margins.

The London headquartered bank joined European peers in making robust progress on sustaining profits even as rates fall, but left bigger questions about the benefits of Elhedery's revamp.

HSBC's reorganisation of its geographic management along East-West lines was interpreted by some analysts and investors as reviving the debate about whether it should split up, following ultimately unsuccessful calls in 2022-23 by its then-biggest investor Ping An Insurance Group of China to do so.

"[The reorganisation] does not in any way signal our intention to split the group," Elhedery told reporters on a conference call on Tuesday.

Grouping its Middle East and China businesses together under the Eastern Markets umbrella will help the bank target one of its biggest opportunities, he said.

"We see the corridor between the Middle East and Asia as one of the fast growing business corridors, be it trade corridors or investment corridors, on the planet," he said.

MORE DETAIL NEEDED ON COST SAVINGS

Elhedery also declined to comment on how much the revamp will save the bank in costs, or how many senior roles may be cut, saying that more will be disclosed in February when HSBC reports full year results.

"The primary reason for the reorganisation is to simplify the bank and remove duplication of roles... the cost savings are an ancillary benefit," he said.

Analysts hailed a "solid" set of earnings from the bank, but said HSBC needs to explain more about the financial implications of its overhaul.

"Rather than the generally good results, I think the focus in today's conference call will be on the structural overhaul and details on cost cuts from the new CEO and CFO," said Michael Makdad, senior equity analyst at Morningstar.