Publicis Omnicom Groupe isn’t going to happen after all. Just days before the networks pitch their fall schedules to advertisers, the planned $30B mega-merger of ad giants Publicis Groupe and Omnicom Groupe is off. Citing “difficulties in completing the transaction within a reasonable time frame,” the companies — which together account for about 40% of U.S. sales — Omnicom-Publicis__130727165038-e1374943969989-200x108today announced the death of the “merger of equals” they had hammered out in late July. Pivotal Research Group analyst Brian Wieser said at the time that plan has “significant industrial logic to it, and thus shouldn’t be ruled out as plausible.” The thinking went that the combined company could have raised its fees because it would have faced less competition. “The challenges that still remained to be overcome, in addition to the slow pace of progress, created a level of uncertainty detrimental to the interests of both groups and their employees, clients and shareholders,” Publicis Chairman/CEO Maurice Levy and Omnicom President/CEO John Wren said in a statement. “We have thus jointly decided to proceed along our independent paths. We, of course, remain competitors, but maintain a great deal of respect for one another.”

The decision was unanimously approved by both companies’ boards. Omnicom’s properties include BBDO Worldwide, TBWA Worldwide and DDB Worldwide Communications Group, and its client base includes such household names as Apple, McDonalds, Johnson & Johnson, Volkswagen, and ExxonMobil. Paris-based Publicis has Publicis Worldwide, Leo Burnett Worldwide and DigitasLBi with clients including Fox, Comcast, AT&T, Coca-Cola, Allstate, Citigroup, Kellogg’s and Samsung.