Publicis CEO Levy

Publicis Groupe is expected to conduct internal discussions next week about whether to attempt an acquisition of Interpublic Group of Cos. A merger of two of the ad industry's largest players would create a $12 billion behemoth.

The combined client list would include GM and Toyota as well as Procter & Gamble and Unilever, reports AdAge. One scenario would have Chairman-CEO Maurice Levy of Publicis, the fourth-largest holding company, teaming up with Dentsu, the fifth-largest player and a 15 percent shareholder in Publicis, to finance a purchase. Execs familiar with the Dentsu-Publicis talks say they are embryonic and could amount to nothing.

A run at Interpublic could set off a chain reaction, letting loose all manner of potential buyers and essentially putting the holding company in play. Over the last year or so, rumored potential buyers have included Google and private-equity firm Hellman & Friedman.

An Interpublic takeover would be the biggest Madison Avenue deal ever, surpassing the $4.7 billion that WPP Group paid for Young & Rubicam in 2000. Interpublic has a market cap of $5.3 billion.