HSBC has announced the shock exit of chief executive, John Flint.
The group denied talk of a management split as it also axed 4,000 jobs and warned of dark clouds on the horizon.
The London-headquartered lender gave no reason for Flint's sudden departure after just 18 months in the job, but said there was "no personal clash", adding it needed a change at the top.
Asia-focused HSBC also revealed it would axe 2% of its global workforce, or roughly 4,000 mostly management jobs, in a new restructuring aimed at weathering global turmoil.
"HSBC Holdings plc announces that John Flint has today stepped down as Group Chief Executive and as a director by mutual agreement with the board," read a statement.
The exact amount Flint will get as a payoff remains unknown until he leaves.
Monday's surprise news came shortly before HSBC reported first-half net profit up 18.6% at $8.5 billion from a year earlier.
"In the increasingly complex and challenging global environment in which the bank operates, the board believes a change is needed to meet the challenges that we face and to capture the very significant opportunities before us," said chairman Mark Tucker.
Addressing rumours that Flint was pushed out after a management bust-up, Tucker later told reporters that there had been "no personal clash" and "no disagreement over strategy".
Flint, 51, who has spent three decades at HSBC, was keen to lower costs with HSBC facing the double uncertainties caused by the US-China trade war and Brexit.
HSBC said its commercial banking division chief Noel Quinn would serve as interim CEO.
The lender added that it planned a buyback of HSBC shares worth up to $1 billion.
In late morning London deals, HSBC shares slid 1.3% to 637.70 pence on the FTSE 100 index, which was down 1.9% overall.
S&P Global Ratings said the decision came as a surprise against the backdrop of what it called a 'solid' set of results.
"The rationale for replacing the CEO is not obvious at first glance."
"We don't believe this ruthlessness suggests a broader strategic shift away from its approach to its balance sheet, which is generally more prudent and disciplined than most global banks," the ratings agency added.
It said the bank's first-half results were in line with expectations.
