Omnicom Media Group rebrands as Omnicom Media.
Former Dentsu staff say they were never contacted after the breach and are unsure what personal information was leaked or why it was still stored.
IPG Mediabrands is the incumbent on the account.
Asia-Pacific recorded a growth decline of 7.4%.
Email to staff says information, including bank and payroll number, salary, National Insurance number, and personal contact details have been taken.
All six networks were invited to pitch earlier this year.
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