
Digiday reported the latest news involving a
$100 million whistleblower lawsuit filed against WPP last year.
The
accusations target WPP and GroupM, the latter which was rebranded under the WPP Media banner in 2025.
If the
lawsuit ultimately impacts WPP Media, will the former GroupM shoulder the bulk
of financial burdens or will all media firms in the network equally share the
troubles?
Expect a crumby reduction of performative promises made to Black-owned media too.
In fighting
a whistleblower suit, WPP put its own account of media agency trading on the
public record
By Seb
Joseph
The $100
million whistleblower lawsuit Richard Foster filed against WPP last November is
back in focus. New court filings — including WPP’s motion to dismiss and
exhibits that place Foster’s own internal documents into the public record for
the first time — have added significant texture to both sides of a case that
initial headlines only scratched the surface of.
Most notably
among the exhibits is Foster’s own internal report to GroupM CEO Brian Lesser,
which contains internal data on client opt-in rates, platform spend, and income
targets that haven’t been public until now. The materials were first reported
by The Times.
Before
unpacking those materials, here’s a recap of how the case reached this
point.
Who’s suing
whom
Foster spent 17
years at GroupM, ending as global CEO of Motion Content Group — the division
that co-produced Love Island, managed roughly $500 million in annual
entertainment investment, and by his own filed data was posting 140% US revenue
growth in his final year. He was fired on July 10, 2025, the day after WPP’s
stock dropped 18% on a trading update disclosing serious deterioration at WPP
Media. He filed suit in November 2025 against WPP and GroupM (since rebranded
WPP Media), seeking at least $100 million, Business
Insider reported.
What Foster
alleges
Foster claims
GroupM, which according to the complaint controlled roughly $60 billion in
annual client ad spend at its peak, ran a hidden profit center by
systematically retaining rebates that should have gone back to advertisers.
Allegedly, GroupM’s media trading arm would aggregate client budgets to hit
volume thresholds with vendors, triggering rebates in the form of free or
discounted inventory. Rather than returning those benefits to clients, GroupM
allegedly reclassified the inventory as “proprietary media,” sold it back
through opt-in agreements, and booked the spread as “non-product related
income.” Foster estimates GroupM generated $3 to $4 billion in rebate-driven
deals over five years and improperly retained $1.5 to $2 billion of it.
The executives
Foster implicates include Mark Patterson, now global president of WPP Media,
whom he identifies as the primary architect of the rebate strategy and who
publicly called rebates “not a dirty word” in 2016; Andrew Meaden,
global chief investment officer, who allegedly institutionalized the practice
and in one meeting proposed diverting client spend away from Meta because Meta
refused a proprietary deal; and WPP general counsel Nicola McCormick, who
Foster alleges privately described the rebate situation as “existential” while
declining to formally investigate.
The document
at the center of everything
In December
2024, at incoming GroupM CEO Brian Lesser’s request, Foster submitted a 36-page
internal report, dubbed “Project Claridges”, laying out both a critique of
GroupM’s trading’s practices and a proposal for a new consolidated
entertainment division with projected net sales of over $2 billion by 2029. The
report contains internal data that is now in the public court record, including
a breakdown showing that among GroupM’s top 30 U.S. billing clients,
representing $13.5 billion in total billings, only 5% of eligible spend was
actually used through the proprietary inventory deals.
Breaking it
down further: among the top 10 clients alone, representing $8.5 billion in
billings, 62% of their spend went through non-proprietary channels entirely,
and 91.9% of the proprietary inventory generated went unused. Google, GroupM’s
single largest US client at $2.3 billion in annual billings, utilized just
0.51% of the proprietary inventory its budget was helping to
generate, meaning 99.5% went unused. These were the clients whose
collective spending was being used to hit the volume thresholds that triggered
the rebates in the first place.
Lesser
acknowledged the report’s concerns and said he’d investigate further. He then
asked Foster to send Patterson a “sanitized” version excluding criticism of
GroupM’s trading arm. Before Foster could do so, Lesser forwarded the unedited
original to Patterson. Patterson, having read a detailed critique of his own
practices, told Foster he had “all he needed.” Within hours, Foster’s division
was placed under Patterson’s oversight. Six months later he was fired.
Where the
money was being spent
The internal
documents also show the scale of GroupM’s platform relationships in 2023,
establishing the leverage at the center of the alleged scheme. Globally: Google
accounted for $9.4 billion in spend, Meta $3.7 billion, TikTok $1.1 billion,
Amazon $1.1 billion, and The Trade Desk $1.1 billion. In the US: Google
represented $4.9 billion, Meta $1.4 billion, Disney $835 million, NBCU $700
million, Paramount $540 million, and Warner Bros. Discovery $417 million. Total
tracked global platform spend: $18.5 billion. U.S. network and platform spend:
$9.8 billion.
With that
volume to direct, GroupM had considerable power to pressure vendors into
proprietary arrangements — and, the complaint alleges, to penalize those who
refused.
WPP’s
defense
WPP’s motion to
dismiss makes three arguments worth taking seriously.
First and most
damaging to Foster: according to a sworn affirmation from Lesser, Foster’s
counsel sent WPP a draft complaint on October 10, 2025 — more than two months
before filing — and threatened to go public unless GroupM agreed to a large
severance payment within 30 days. WPP refused, and the lawsuit followed. WPP
argues that offering to stay silent for a payout is fundamentally incompatible
with being a whistleblower.
Second, WPP
contends that the Project Claridges report — Foster’s supposed evidence of
protected disclosure — contains no mention of illegal activity. Its position is
that it’s a business proposal for Foster’s own promotion, not a whistleblower
document, and that Foster is retroactively reframing an ambitious pitch.
Third, Foster
was among hundreds of U.S. GroupM employees and thousands globally let go in a
documented restructuring. His entire division was eliminated. Six months
elapsed between his last alleged report and his termination.
Why it
matters beyond the lawsuit
The China
backdrop lends the allegations weight. In October 2023, Chinese authorities
raided GroupM’s offices and detained more than 30 employees for systematically
retaining client rebates — precisely what Foster claims was happening
globally. WPP hit a 27-year stock low in October 2025 when new CEO Cindy Rose
publicly conceded WPP Media had “lost its way”.
Where it
likely ends up
A settlement
would not be surprising. WPP cannot afford the discovery process, with internal
communications about rebate practices potentially feeding both the shareholder
litigation and client contract reviews. But the extortion allegation gives WPP
real leverage to limit the payout.
The bigger
question the case raises has nothing to do with Foster specifically: if
GroupM’s own internal data shows its largest clients were almost entirely not
benefiting from the proprietary inventory deals that generated nearly $1
billion in annual agency income, what exactly was the business model? That’s a
question advertisers, regulators, and shareholders are now all asking — with or
without this lawsuit.
WPP declined to comment.