By Selena Li, Lawrence White and Sinead Cruise

HONG KONG/LONDON (Reuters) -HSBC Holdings said on Tuesday it would combine its commercial and investment banking operations in a major overhaul under new CEO Georges Elhedery that has also seen key senior staff depart.

Seeking to simplify the Asia-focused bank’s business and reduce costs, HSBC said it would be restructuring into four business units and slashing senior management positions.

The new leadership structure, which includes the appointment of Pam Kaur as the lender’s first female chief financial officer, would “unleash our full potential and drive success into the future,” Elhedery said in a memo to staff.

Elhedery, like many bank executives, is under pressure to address climbing costs and better manage expenses.

The group is carving up its operations into four business lines, namely UK, Hong Kong, corporate and institutional banking and wealth banking. The new corporate and institutional banking unit will house a newly combined commercial banking and global banking and markets business, and western wholesale banking businesses, including Europe and the Americas.

Kaur, 60, who currently serves as HSBC’s chief risk and compliance officer, joined the bank in April 2013 as group head of internal audit.

Jon Bingham, interim Group CFO, will resume his role of Global Financial Controller, HSBC said.

In other key management changes, Greg Guyett, CEO Global Banking and Markets, will assume a newly created role of Chair, Strategic Clients Group. Colin Bell, CEO of HSBC Bank and Europe, has decided to step down to pursue other opportunities.

The bank, which employs about 214,000 people globally, has been removing duplicate roles for years and reducing its businesses in Western markets such as the United States, France and Canada as it focuses on Asia and markets where it has scale.