A side effect of last week’s Publicis Groupe-Bcom3 agreement to merge – little remarked upon until today – will be the unification of two of the globe’s most buoyant and hungry media planning and buying networks.

In the current world media rankings, Publicis-controlled Zenith Optimedia (Publicis 75%; Cordiant 25%) holds fourth place; Bcom3's Starcom MediaVest, fifth. Their marriage will propel them into second place, controlling some twelve percent of world adspend.

Crowed Rich Hamilton, ceo of Zenith Optimedia Group Americas: “This catapults our holding company into the same league as [Interpublic], Omnicom and WPP media offerings in terms of global breadth.”

Zenith Optimedia's exisiting modus operandi could act as a template for the merged media mammoth. ZO pursues a ‘separate but equal’ strategy in which the Zenith and Optimedia brands remain discrete. Explains Simon Lloyd, ceo-deputy chairman of Zenith Optimedia Group Europe: “We still compete for the same business, but we share things that are non-proprietary. We make sure the back office is efficient so that the front office can compete.”

But the new entity will find it difficult, if not impossible, to reconcile Starcom MediaVest’s General Motors business with Zenith Media’s Toyota Motor Corporation and Optimedia’s BMW. There is intense competition stateside between GM and Toyota; and Michael Browner, GM executive director, media and marketing operations, has spelled out in uppercase his allergy to agencies with competing auto accounts.

Now that Publicis/Bcom3 is about to join the big boys, how does the fast diminishing band of smaller rivals feel about the merger?

“No, I'm not worried about it,” avers Carat ceo David Verklin. “This deal is yet another indication that the media agency business is a big influence in this industry. The league-leading performance of Starcom was clearly something that was factored into the deal by Maurice Levy. He understands media. He's got Zenith, after all. The real question is: ‘Will Publicis be buying Bcom3 or is it buying Starcom?’ ”

Data sourced from: AdAge.com; additional content by WARC staff