Data, diversity, in-housing and 'outcomes-based' remuneration were all on the client's agenda.
As many as 6,000 roles expected to be cut.
Staff below board level will be eligible for bonuses.
Organic revenue fell in every region, including by 9% in Asia Pacific, although performance was ahead of ad spend forecasts.
WPP said "inappropriate and offensive behaviour is not tolerated."
Stock price underwent a temporary bounce as investors considered the move a vote of confidence.
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