Ad giants Omnicom, Publicis in $35.1 billion deal By: MarketWatch July 28, 2013 at 14:20 PM EDT Advertising giants Omnicom Group Inc. and Publicis Groupe SA said Sunday that they will merge in a $35.1 billion deal, in the industry’s biggest deal ever. Read More >> Related Stocks: Coca-Cola Company McDonald's Corp Omnicom Group PepsiCo Procter & Gamble