WPP asks New York court to sanction whistleblower Richard Foster and remove his lawyers

WPP has gone on the offensive in the whistleblower lawsuit brought by Richard Foster, filing a motion in New York State Supreme Court that asks the judge to throw out his amended complaint with prejudice, impose monetary sanctions on him and disqualify his law firm, Brewer, Attorneys and Counselors. The filing, lodged on August 26, also seeks an order forcing Foster to explain how he obtained details of an internal Sony investigation and with whom he shared them.

Foster spent 17 years at GroupM, the media arm now branded WPP Media, latterly as chief executive of Motion Content Group. He sued in November 2025, claiming he was pushed out after reporting to senior executives that the group had kept between $1.5 billion and $2 billion in undisclosed media rebates over five years instead of passing them to clients. He is seeking $100 million.

The case took a sharp turn on August 13, when Foster amended his complaint to incorporate findings he attributes to a Sony investigation of GroupM’s media buying in China. According to that filing, Sony concluded that in one year the operation returned about $110 million in rebates to clients while roughly $350 million stayed in an undisclosed pool. WPP responded at the time that both versions of the complaint were baseless and that it would refile its motion to dismiss.

Why it matters

WPP’s new motion argues that Foster and his lawyers obtained the Sony material improperly and disclosed it unlawfully, and that they also revealed the substance of conversations with WPP in-house lawyer Nicola McCormick. Notably, the company is not disputing the accuracy of what Foster published; its objection is to how he got it. WPP told the court that sealing or redacting the Sony references would not undo the harm. Beyond its filings, the company has declined to comment.

William A. Brewer III, Foster’s lead counsel, said in a statement that “Mr. Foster believes that WPP’s motion lacks merit” and expects to prevail. The dispute sits alongside two other proceedings that Adweek this week grouped together as a single narrative: the Sony probe itself and a Chinese criminal case in which Di Fei, WPP’s former China chief investment officer, received a life sentence on bribery and kickback charges.

What’s next

The timing is awkward for chief executive Cindy Rose, who marks her first anniversary at WPP this week with a partial recovery in new business but a company whose market value has fallen from about £17 billion to around £3 billion over the past decade. Rebates are legal in many markets when disclosed; the allegation that they were withheld from clients strikes at the trust on which media agencies sell their services. A ruling on the sanctions motion will decide whether the case is narrowed sharply or heads toward discovery on the rebate claims themselves.