WPP points the finger at ZBB as the most important factor driving cuts in WPP's agency revenues -- cuts that have taken 35% off WPP's share price from its 2017 high. Leading industry analyst Brian Wieser identifies ZBB as a major factor suppressing holding company organic growth, along with other factors like increased contract scrutiny. ZBB is the flavor of the month. Mention ZBB to an ad agency and watch the panic. "Here it comes! Another excuse to cut fees!"