A branch of HSBC Bank is pictured in Cairo, Egypt July 30, 2017. REUTERS/Mohamed Abd El Ghany

LONDON (Reuters) - Mark Tucker, the incoming chairman of HSBC HSBA.L, will likely face questions over who will take over as CEO when he meets investors in Europe's biggest bank ahead of taking up his post at the lender in October.

Tucker takes over from Douglas Flint on Oct. 1 and one of his first priorities when he meets shareholders from next week will be deciding on whether to appoint an outsider to succeed Stuart Gulliver or look within the bank instead.

Gulliver, who has been HSBC’s boss since 2011 and joined the bank 37 years ago, is due to step down next year.

Tucker, who previously led Asian insurance giant AIA Group and British insurer Prudential, is the first outsider to become HSBC’s chairman in the lender’s 152-year history.

Like the chairmanship, HSBC has only ever promoted internal candidates to become its chief executive.

Some investors are bout the idea of an external replacement for Gulliver amid worries that having outsiders in both chairman and chief executive roles would be a big departure for the lender and possibly too disruptive.

Tucker became a non-executive director of HSBC and chairman of the board’s nomination committee at the start of September.

That committee handles executive succession planning and board appointments.

(This version of the story was refiled to add dropped word in 6th paragraph)