ZURICH, April 6 (Reuters) – UBS (UBSG.S) Chief Executive Sergio Ermotti has told Credit Suisse (CSGN.S) staff it is “critical” to remain focused on clients and keeping the business running as the merger of the two banks proceeds, according to an internal memo seen by Reuters.

“We cannot let ourselves get overly distracted by the integration efforts,” Ermotti said in the memo. “It’s critical for us to remain focused on supporting our clients and maintaining operational excellence.”

Last month, Swiss authorities announced that UBS would buy Credit Suisse in a shotgun merger to stem further banking turmoil after the smaller lender had come to the brink of collapse.

UBS announced last week it was rehiring Ermotti as CEO, its former boss from 2011 to 2020, to steer the takeover which will create one bank with $1.6 trillion in assets and more than 120,000 staff.

In his first communication to Credit Suisse staff after taking over as UBS CEO, Ermotti said there would be “change and hard decisions” ahead.

Still, he tried to calm the nerves of anxious employees worried about massive lay-offs and upheaval ahead.

The bank created by the merger is poised to reduce its workforce by 20%-30%, Swiss daily Tages-Anzeiger reported at the weekend, citing an unnamed senior UBS manager.

UBS Vice Chairman Lukas Gaehwiler told the bank’s shareholders on Wednesday that it was too early to speculate about job cuts.

Ermotti asked staff to be patient while the company worked out its next moves.

“While it’s too soon to speculate about the end state of the combined organization, you have my commitment that we will treat all employees of both Credit Suisse and UBS fairly,” he wrote.

Reporting by John Revill and Oliver Hirt; Editing by Kirsten Donovan

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