Shares of the major agency holding companies took a hit after news broke Thursday that federal prosecutors are investigating their media-buying practices.

Data for Havas parent Vivendi and Dentsu Aegis Network parent Dentsu was not available due to delays in reporting, but MDC Partners and Publicis took the biggest percentage decrease, though Interpublic and Omnicom had the highest volume in terms of share trades.

Read the full MediaPost Agency Daily article here.