Why C7 Won't Be an Upfront Standard This Year Despite GroupM Agreements

Other media agencies aren't likely to follow in GroupM's footsteps by striking broad agreements to use C7 in upfront deals, according to people familiar with the upfront market.

GroupM has entered into agreements with broadcasters including CBS, Fox and NBC to pay for ad time based on commercial ratings across seven days, a measure called C7 in the industry.

The current standard, C3, only considers commercials seen within a three-day window. While most agencies did C7 deals for select clients during the 2013 upfront, GroupM's agreements will apply to a breadth of clients across its portfolio of agencies, according to people familiar with the pacts, making it the biggest move yet into paying for seven-day viewing.

GroupM, WPP's powerful media-agency group, controls about 30% of the total dollars spent on network TV, with clients like Procter & Gamble, AT&T and Paramount Pictures. And RBC Capital Markets analyst David Bank wrote that most other agencies will "likely have to move in lock-step at some point soon."

But its move isn't likely to generate a domino effect, at least not in 2014, some media buyers and others insist. Other agencies are still hesitant to strike broad-based agreements for C7 that would apply to a majority of their clients.