M&A report surfaced on financial blog.
Combined business will work for brands who spend more than $60 billion on marketing and media investment.
Bosses could get extra $8 million in cash bonuses for working on separation from Vivendi, prospectus reveals.
The agency group cut revenue forecast in August but won Amazon and retained Unilever in key markets.
South Asian countries including India, Bangladesh, Sri Lanka, and Pakistan remain with incumbents Mindshare.
Holding group CEO spoke to Campaign at Q2 results.
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