MCM partners and ad management companies — the list

How to read this

Two independent sources, neither of them anybody's sales copy:

Where a company's sellers.json returned an error or wasn't at the standard path, every measured column is —. No estimates, no filling in gaps.

Measured — 131 companies

Sorted by publisher count.

Certified, but not measurable — 68 companies

All GCPP-listed. Their sellers.json returned 403, 404 or no usable response to an automated fetch on 26 August 2026. That is not a criticism — plenty of legitimate sites block bots. It only means these numbers aren't in the table above.

Six Premier partners

Google marks a small number of these as Premier: Mediavine, Publift, Affinity Global Advertising, Traffective by ShowHeroes, Ezoic and Raptive. If a company tells you it is Google-certified, this directory is where you check — it takes about ten seconds.

What the ads.txt scan could not do

I also ran a worldwide ads.txt scan — 2,200 publisher domains seeded across Europe, LATAM, Asia, North America and Australia, of which 1,165 returned a real ads.txt. Pulling every domain that appeared on a DIRECT line across 5 or more sites, and removing the saturated exchanges, left 708 candidates.

635 of those are not in Google's partner directory — and almost none of them are MCM partners. They are SSPs and platforms: Amazon APS, Sonobi, Teads, Ogury, MGID, Kargo, RTB House, Zeta. A DIRECT line means the publisher has an account with them, not that anyone manages that publisher's inventory.

That is worth stating plainly because it's the mistake most publishers make when reading their own ads.txt: frequency in ads.txt is not market share, and a DIRECT line is not a management relationship.

One number worth knowing before you pick

Across the 38,948 publisher domains listed in these companies' sellers.json files, most publishers work with exactly one. Just over 7,000 work with two or more.

Adding a second partner is normal in this market, not a betrayal of the first — and it's the cheapest way to find out whether your current one is competitive. What to ask before you do: seven questions for an MCM partner. If your traffic is Indian, the shortlist is different: which partners actually take Indian publishers.

Methodology

Limitations, stated plainly

• Worldwide seeds are biased. They were sampled from publisher domains already listed in some parent's sellers.json, so they over-represent publishers who already have a partner. A random web sample would look different.
• 68 certified companies have no measured numbers. A blocked file is not a small company — several of the largest names are in that table.
• Confidential sellers are excluded. The spec permits a company to mark part of its list private, so some publisher counts are floors, not totals.
• Geography is a TLD proxy, not a company headquarters and not where their revenue comes from.
• Absence means not found in this sample, not that they never work with anyone in India. 123 sites is a sample, not a census.
• I compete with these companies. That's the reason every number here is tied to a file you can open yourself rather than to my opinion.

Full method: methodology.

Before you talk to anyone

Run your site through the eligibility check first. If it won't pass Google's policy review, no partner on this page can help you — and the honest ones will tell you the same thing.