The client did the forensics: Sony's alleged WPP rebate audit is now everyone's template

A new court filing says Sony investigated WPP's media operation and concluded it had improperly withheld rebates from clients, presenting that conclusion to WPP in 2025 in an analysis that, per the filing, called the arrangement a "global crime scheme" across several markets including China ^[14][15]. What matters for anyone holding a media contract is who did the work: not a regulator and not a reporter, but a paying client, using material a client can ask for ^[2].

The filing is an amended complaint in a suit brought in November by Richard Foster, a former longtime GroupM executive who says he was fired after raising concerns that the media investment division ran an improper global kickback operation ^[21]. GroupM was rebranded WPP Media last year ^[10]. WPP has moved to dismiss, arguing Foster failed to state a legally sufficient claim and objecting on jurisdictional grounds ^[4]. It declined to comment on the alleged Sony review, said both complaints are "baseless and without merit," said it will re-file an updated motion, and characterised the amended complaint as an attempt to avoid dismissal days before a hearing ^[5]. A Sony spokesperson said the company does not comment on pending litigation ^[3]. What follows is allegation.

The described mechanism has three steps: the media arm negotiated rebates from media owners on the strength of clients' pooled spending ^[16]; a network of intermediary brokers held some of that money rather than passing it to clients ^[17]; and rebate funds were used to subsidize inventory costs, with the resulting margin kept as profit that was shielded from audits ^[18]. One purported slide, titled "impact for WPP Advertisers - China 2024," says roughly $110 million was passed back to clients that year while $350 million stayed in a rebate pool "for later utilization" ^[19]. That is about 76 percent of the $460 million retained, roughly 3.2 times what was returned ^[13]. Foster estimates $1.5 billion to $2 billion retained globally over five years and seeks at least $100 million in damages ^[22][6]. A separate purported slide called the practice a "fraud scheme" and attributed its design to senior global executives ^[20].

The evidence inventory is the transferable part. According to the complaint, Sony built its case on contractual language covering rebate policy, transaction-level financial reporting, internal emails about rebate amounts and documentation of WPP's own tracking systems, supplemented by interviews with former WPP and GroupM executives and by independent investigators who attended a criminal trial in China involving WPP executives ^[2][1]. Three of those four document categories are things a large advertiser can already demand, provided its audit clause reaches brokers and affiliated entities rather than stopping at the agency's own ledger. The allegation that margin was shielded from audits is a claim about contract drafting as much as about conduct ^[18].

None of this makes rebates unlawful. They are structural in some markets, China among them, and become a legal problem mainly when undisclosed ^[7][9]. A US ad industry trade group has warned they can amount to breach of contract or fraud where the client was not told or was deceived ^[8]. Principal media has been divisive for years without being resolved ^[12].

Three things to watch: WPP's re-filed motion to dismiss and the hearing behind it ^[5]; whether any other advertiser in the tens of billions WPP handles commissions the same review ^[11]; and the detail that Foster says he refused a seven-figure exit package carrying an obligation of silence on rebate practices ^[23].