The Association of National Advertisers (ANA) is assisting the FBI with its investigation into media buying practices, the organization has confirmed.
Members have been notified and are urged to review their media buying history and contracts.
In a letter to advertisers, ANA chief executive officer Bob Liodice suggested members should "perform audits for indications of fraud and get advice on their options."
Part of the letter reads: "The FBI contacted our outside counsel requesting the cooperation of the ANA and its membership in a criminal investigation into media buying practices underway by the FBI and the United States Attorney’s Office for the Southern District of New York.
"While we view the FBI’s investigation as important, the ANA itself cannot provide help to the FBI other than to share communication and information with our members."
It goes on to add: "The opening of a federal criminal investigation is a significant event to the industry and to the ANA members."
The ANA’s general counsel, Reed Smith’s Douglas Wood, and his partner, Steven A. Miller, have so far had limited discussions with the FBI.
In June, Campaign US reported it learned from multiple sources that representatives from the FBI had been contacting people with knowledge of the ad industry and asking for their help in recent months.
One source suggested the FBI is taking an interest in certain companies and the role of senior leaders in those companies.
The launch of an investigation comes in the wake of the ANA’S report by private investigators K2 Intelligence about "non-transparent" practices at U.S. media agencies in June 2016.
The report did not identify any companies by name but suggested some agency groups were receiving secret rebates from media owners and marking up the cost of ads at a profit.
Agency groups maintained that they had done nothing wrong in the wake of the ANA report.
Separately, advertisers, agencies and publishers have raised concerns about the digital media supply chain because of the rise of online ad fraud in recent years.