John Wren and Maurice Levy, the chief executives of Omnicom and Publicis, which are in the process of merging. (Scott Eells, Bloomberg)
John Wren and Maurice Levy, chief executives of Omnicom and Publicis, which are in the process of merging. (Scott Eells/Bloomberg)

The blizzard of ads is over, the best and worst have been ranked, and the amount of money spent on each 30-second spot in this year's Super Bowl has been averaged and totaled up (it's $4 million, if you were wondering, more than ever before). Despite the number of concepts on display, though, the bonanza hides an important truth about how the industry works.

Advertising, of course, is no longer purely the province of Madison Avenue. There are clusters of creative agencies in Los Angeles and San Francisco, and even dotted through the South (like Chattanooga's Humanaut, which did Sodastream's ad) and Midwest (like Schaumberg, Ill.-based Pinnacle Advertising and Marketing Group, which did WeatherTech's).

But here's the thing: Even if the ad business is more geographically diverse, the ownership structure is not. Many firms are actually owned by what used to be known as the "big four" branding houses: WPP, Omnicom, Publicis and Interpublic. Now, with the $23 billion pending merger of Publicis and Omnicom, they're just the big three.

So how did the industry giants fare? By my count, using a couple of different lists, 43 companies advertised with one or more spots. Omnicom companies had 5 clients, Publicis companies had 6 clients, Interpublic companies handled 5, and WPP handled 3. That means the new giant, Omnicom Publicis, accounted for about a quarter of all the Super Bowl business this year — and making television commercials is only a small part of what they do, which also includes public relations, market research and media planning.

That's a big chunk of the biggest advertising event of the year. At the same time, there are still a lot of independent agencies, as well as companies who design their own ads in-house — it's not quite a monopoly yet.