By Anne Steele and Suzanne Vranica

The U.S. Justice Department's investigation into potential price-fixing in video-advertising production has reached at least three of the world's biggest ad agency holding companies.

French ad giant Publicis Groupe and the U.S.'s Omnicom Group Inc. on Friday each acknowledged that subsidiaries of their companies received subpoenas from the Justice Department on Wednesday. Interpublic Group last week acknowledged receiving a subpoena.

Last week, TheWall Street Journal reported the Justice Department is investigating whether advertising agencies inappropriately steered business producing commercials to their in-house production units over independent companies.

All three companies have said they are cooperating with the investigation.

Rebecca Meiklejohn, a government antitrust attorney based in New York, has been interviewing ad-industry executives on the subject over the past few months, according to people familiar with the matter.

The government is investigating whether agencies essentially rigged the bidding process, telling independent firms that compete for business to inflate their prices so that contracts would be awarded to agencies' production units.

Price-fixing and bid-rigging are prohibited under federal antitrust law.

Write to Anne Steele at Anne.Steele@wsj.com and Suzanne Vranica at suzanne.vranica@wsj.com

(END) Dow Jones Newswires

December16, 2016 14:14 ET (19:14 GMT)

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