![John Wren Omnicom](https://static-ssl.businessinsider.com/image/5bec2890da27f808bd5d6bc7-2400/gettyimages-174890415.jpg)
Spencer Platt/Getty Images
John Wren is chairman, president and CEO of Omnicom Group
Federal prosecutors were specifically looking into "non-transparent" practices like receiving rebates from media outlets. Five holding companies had received subpoenas as part of the investigation: WPP, Omnicom, Publicis, Interpublic Group, and MDC Partners.
Click here>$4 to read more about the investigation.
In other news:
Snap reportedly subpoenaed by Justice Department and SEC for information on IPO disclosures.>$4 The federal inquiries follow an ongoing shareholder lawsuit in which investors allege that Snap misled the public about how competition from Facebook's Instagram service had affected the company's growth.
A LinkedIn exec explains how the company will hit $2 billion in ad revenue this year, and why it's betting big on video.>$4 The platform has redesigned brand pages with more tools and analytics to help brands build a following on the platform.
$4. The company will receive $1.5 billion in tax breaks from New York City, and $4.
$4. Facebook said it has now taken down 99 Instagram accounts, 36 Facebook accounts, and 6 Facebook Pages.
Facebook is shutting down its connected-TV ad network, Digiday reports.>$4 Facebook's connected-TV advertising ambitions appear to have been thwarted by a few factors, including the formation of new walled gardens within the connected-TV environment.