Shares in major advertising firms experienced movement today after a report claimed US federal prosecutors had started investigating media-buying practices in the US ad industry.
An article in the Wall Street Journal claimed investigators had begun reviewing the ad industry and started to hand out subpoenas as part of the probe.
Publicis shares fell 2.7 per cent in early trading, but have now clawed back to a 1.2 per cent loss.
FTSE 100 giant WPP shares also took a hit, and are now trading 2.35 per cent lower.
Media buying is a lucrative part of the advertising industry, although there have been calls for the industry to be made more transparent for customers.
Publicis and WPP are two of the biggest players in the sector alongside Omnicom, Interpublic and Dentsu.