LONDON (Reuters) - HSBC's HSBA.L shock ousting of John Flint as chief executive was seen by some investors and bank insiders on Monday as a risky gambit by Chairman Mark Tucker given the political and economic uncertainties in the bank's core markets.

FILE PHOTO: Mark Tucker Chairman of HSBC arrives at 10 Downing Street in London, Britain January 11, 2018. REUTERS/Peter Nicholls

Only 18 months after presiding over the appointment of HSBC career veteran Flint as CEO, Tucker has now overseen his exit, while insisting the bank’s broad strategy will not change.

HSBC shareholders mixed apprehension with optimism when 61-year-old Tucker took over at the top of Europe’s biggest bank in October 2017 as its first ever external chairman.

Tucker was known before joining HSBC in 2017 as one of Asia’s most successful and hands-on executives for listing insurer AIA and then more than doubling its market value. Flint, 51, was widely seen as a safe pair of hands offering a ‘more of the same’ strategy at HSBC.

Tucker will now be under pressure to show he was right to remove Flint while HSBC grapples with political turmoil in Hong Kong and Britain, lower interest rates and escalating U.S-China trade tensions, rather than wait for a more benign environment.

“Although the tensions with HSBC’s chairman Mr Tucker were not unknown, it is always abrupt when the CEO of such a big and important institution must step down, especially in the context of a complicated Brexit and very complicated situation in China for HSBC,” Pierre Mouton, fund manager at Swiss-based Notz, Stucki & Cie, which has a small stake in the bank, said.

Tucker said there was no personality clash with Flint or disagreement over strategy, adding it was time for a change.

Three senior HSBC executives told Reuters the decision had come as a surprise, but that Flint was paying the price for an overly cautious approach that prioritized cost controls, and investment in China, over a more ambitious push into the U.S.

“It’s been a shock to everyone,” one said.

Flint won praise internally for his efforts to make HSBC a happier place to work, the executives said, citing his focus on his ‘healthiest human system’ initiative designed to improve work-life balance, workforce diversity and pay disparity.

But those initiatives and in particular the removal of sales targets as part of this people-first culture meant HSBC lacked hard-nosed focus on profitability just as the geopolitical environment for banks worsened, one said.

HSBC declined to comment on this.

TEARING UP TRADITION?

Tucker, who a former colleague previously told Reuters honed his competitive instincts during an early career as a professional soccer player and celebrated his 50th birthday with a broken nose and two black eyes from a clash on the pitch, appears to have ripped up HSBC’s internal succession manual.

The change bears the imprint of the decisive, hard-charging Tucker and the next question for investors is whether he abandons tradition at HSBC, which has long relied on carefully-managed succession plans, and picks an outsider as CEO.

“We are surprised to learn about the change given Flint’s short tenure as CEO, and did not think he was doing a bad job,” said Jonathan Rawicz, Lead Portfolio Manager of the New Capital Dynamic UK Equity Fund at EFG Asset Management.

Rather than being risky, the change could show how seriously Tucker is taking mounting political and economic headwinds.

“It is already a break from the past with what’s happened today, so if there was ever going to be an external person perhaps this is it,” said Eric Moore, fund manager at Miton Asset Management, another small shareholder in HSBC.