About The Investigation. Every Wednesday, ADOTAT publishes one long piece built from primary sources rather than press releases: written on-record answers, contracts, filings, transcripts, and the questions the trades tend not to ask. The format is deliberately narrow.

One subject, named companies, named executives, and every claim put to the people it concerns before publication, with their answer printed as they gave it or their silence noted. Nothing here is sponsored, nobody reviews it in advance, and the reporting runs whether or not the subject is a friend of the publication.

Omnicom paid $13 billion for Interpublic. It now runs six media agency brands. PHD. OMD. Hearts & Science. UM. Initiative. Mediahub. Acxiom sits underneath all of them.

The man in charge is Florian Adamski, global CEO of Omnicom Media.

At CES, Digiday asked him the question everyone in media procurement is asking. Principal media. Where does he stand?

He didn't answer about principal media. He answered about the people asking.

"I feel that the premise of that debate starts in a wrong place. You also have to realize where some of that commentary comes from, and the sometimes vested interests that people have to come out with these types of statements. So there is a lot of noise. But I'm not seeing that noise coming from clients."

Hold that.

Four months later, Bill Duggan, twenty-six years at the Association of National Advertisers, the trade body for the clients, went on a livestream a week before the ANA's big procurement conference and said this:

"Marketers need to be aware of it. It's been out there for 10 years. Are you on Mars if you're not aware of it? Many of our members are on Mars."

So Omnicom hears no noise.

And the clients' own trade body says many of the clients are on another planet.

Both statements can be true. That's the story.

A client who doesn't know what principal media is doesn't complain. A client who doesn't know whether its agency uses it has nothing to complain about. A client who never sees the price the agency paid can't know it's being overcharged.

Silence isn't approval. Silence is the product working.

Here is the part the holding companies would like you to forget. Nothing about this is secret. It has been said into microphones, printed in reports and filed in court for more than a decade. Watch.

2014. The ANA and Forrester survey marketers. 46 percent say they have concerns about transparency with their media agencies. 42 percent say the concerns are getting worse.

March 5, 2015. Hollywood, Florida. Between 2 and 2:45 in the afternoon. Jon Mandel, former CEO of MediaCom, stands up at the ANA Media Leadership Conference. Rebates are real, he says. They're happening in the US.

GroupM puts out a statement the next day. Hidden US rebates, it says, are not part of its vendor relationships.

The ANA apologizes. To the agencies.

Mandel, meanwhile, tells AdExchanger that more than a hundred people have emailed him in confidence, many afraid of what their employers would do to them.

Fall 2015. An ANA and 4A's task force drafts principles. One of them reads, in full: "Rebates and other non-transparent incentives are not accepted industry practice in the US."

2016. K2 Intelligence reports for the ANA. Of 41 sources, 34 describe rebates that were undisclosed, not passed through, or demanded by agencies. Levels run from 1.67 percent to about 20 percent of spend.

Also 2016. Michael Roth, then running Interpublic, says transparency is paramount to trust between client and agency. Remember IPG. It comes back.

2019. The 4A's chief executive tells Ad Age nearly a hundred audits have been done, and agencies haven't returned money.

2024. The ANA publishes a report on principal media. The agency's purchase price isn't disclosed. The markup isn't visible. Audit rights can be restricted.

2026. The ANA updates it. 58 percent of marketers used principal media last year, up from 47 percent. Only 57 percent have formal governance.

Also 2026. A former WPP executive's lawsuit puts a number on one holding company's non-product income. About $1 billion a year. With 15 percent growth targets.

Every one of those was public. The practice grew every year anyway.

Nick Manning ran OMD UK. That's an Omnicom agency. Later he was chief strategy officer at Ebiquity, an auditor. He's now a paid expert witness for Richard Foster's lawyers in Foster v. WPP. That conflict appears every time his name does.

In March he told Digiday why he left agency life.

"We were being asked to increase what is known as the extraction rate from our clients by doing this kind of deal. I drew the line at that."

Extraction rate. Not margin. Not yield. How much comes out of the client.

Why holding companies love it: "You don't have to win new clients, you don't have to pitch, you don't have to employ any more people. You just have to set up the financial machinery to do it."

What the client signs: "A piece of paper that waives your right to know how much the media cost to the agency."

What happens when the big clients say no: "Smaller advertisers have to pick up the slack, and it takes a lot more smaller advertisers at lower volumes to compensate for the big volumes of the big guys who say 'no.'"

And the part nobody in a holding company will say on stage: "You need to be an engineer to understand the engine."

WPP says the Foster documents describe a rejected business proposal.

On September 2, ADOTAT sent the same four questions to Omnicom, Publicis, WPP, Havas, Stagwell and dentsu. Do you take rebates? Can a client's auditor see the media-owner contracts? Did you adopt the ANA's model contract?

The deadline was September 8.

Not one answered.

On September 7, ADOTAT asked ICON International and Omnicom about ICON's history and Omnet.

Neither answered.

Adamski says he hears no noise. We made some. We heard nothing back.