Google today announced it will experiment with an updated set of commonly used ad technology partners (ATPs) for AdSense, setting in motion a two-phase process that could alter which vendors automatically receive user consent signals across publisher sites in the European Economic Area, the UK, and Switzerland. The announcement, published April 6, 2026 in the AdSense Help Center, establishes April 20, 2026 as the earliest date the experiment will begin, with a potential permanent list update following on or after June 5, 2026 if the experiment is deemed beneficial for publishers.
The announcement matters because the commonly used set functions as a default. Publishers who do not actively manage their ad technology partner selections rely on this list to determine which companies are permitted to serve and measure ads under GDPR-governed consent flows. When the list changes, the consent collected from users effectively changes too - a vendor dropped from the default set will no longer automatically receive user consent unless a publisher explicitly adds that company to a custom configuration.
Google provides AdSense, Ad Manager, and AdMob publishers with controls to select which ad technology partners are allowed to serve and measure ads in regions governed by European privacy law. According to the AdSense help documentation, all partners listed have shared certain information required by European regulations policy, provided a link explaining their data usage that publishers can share with users as part of a consent flow, and agreed to comply with Google's data usage policy.
The commonly used set is specifically designed for publishers who do not engage with the partner selection controls directly. According to the documentation, "If you don't engage with the controls, the commonly used set of ad technology partners indicated will serve." The list is composed of partners "representing the most revenue to publishers from all programmatic demand sources."
The current JSON file - published at https://storage.googleapis.com/tcfac/commonly-used-providers.json and last updated today, April 6, 2026 - contains 199 providers. That file carries a version number of 1775495296 and lists companies with identifiers tied to two separate consent frameworks: the IAB Global Vendor List (GVL) and Google's own Additional Consent (AC) specification. Of the 199 entries, 127 carry IDs from both frameworks simultaneously, while 64 carry only a Google AC identifier. Providers appearing solely under the Google AC specification are handled outside the standard IAB Transparency and Consent Framework, a technical distinction that affects how certified consent management platforms process and transmit consent signals.
The structure of the announcement is notable. Google is not simply issuing a list update; it is running an experiment first. Starting on or after April 20, 2026, a subset of publishers will encounter a modified partner list. Google will then evaluate whether the experiment produces results deemed beneficial for publishers before deciding whether to apply the changes broadly. If that threshold is met, the full update takes effect on or after June 5, 2026.
According to the announcement, the updated list "will reflect the partners that work most closely with publishers globally, determined by data collected from all programmatic demand sources, as well as meeting our privacy standards." That framing mirrors closely the language used in a previous update cycle. Google announced a similar overhaul in April 2025, with changes taking effect on or after June 2, 2025 - a nearly identical timeline to the current round.
The repetition suggests Google has established a recurring process for refreshing the partner list, rather than treating it as a one-time event. Publishers who assumed the list was relatively static may need to revise that assumption.
Once the experiment begins, publishers will be able to see which partners are part of the experiment inside their AdSense account. According to Google's documentation, the controls, the list of current ad technology partners, and those participating in the experiment can all be viewed in Privacy & messaging, under the European regulations settings page, in the "Your ad partners" menu.
The up-to-date version of the list will also be published in the Manage your ad technology partners (ATPs) help page. That page is the authoritative reference point for the current state of the commonly used set and is updated each time the list changes.
Publishers who prefer not to participate in the experiment - or who want to prevent automatic updates from affecting their configurations - can select "Do not automatically include commonly used ad partners." Choosing this option creates a custom list pre-filled with the publisher's current partner selections, which can then be modified as needed. Once a custom list is in place, the publisher's configuration is no longer affected by changes to the commonly used set.
There is a further distinction for publishers using third-party consent management platforms. According to the documentation, if a publisher is using a third-party CMP to collect GDPR consent, the list of ad tech partners is managed through the CMP provider rather than through AdSense directly. Those publishers would need to consult their CMP to understand how changes to Google's commonly used set flow through to their consent configurations.
The commonly used ad partners list JSON file serves a specific technical function beyond serving as a reference document. According to Google's documentation, the file "can be used by certified CMPs to help inform ad vendor selections for publishers who are using their consent management solutions." The file will be updated each time the commonly used list changes, meaning certified CMPs can query it programmatically to keep their own vendor configurations current.
The current list includes some of the most prominent names in programmatic advertising. Amazon, The Trade Desk, Microsoft, Meta, Google itself, Criteo, Index Exchange, Magnite, PubMatic, DoubleVerify, Integral Ad Science, LiveRamp, and The Trade Desk all appear as commonly used partners. Measurement companies including Nielsen, comScore, Kantar, and Dynata are present. Brand safety vendors including HUMAN SECURITY and DoubleVerify feature alongside data companies such as Bombora, Neustar, and Epsilon. Retail-adjacent platforms including Coupang, Mercado Livre, OTTO, and eBay also appear, reflecting the breadth of demand sources feeding into publisher revenue.
Among the 199 current providers, the Google AC specification appears frequently. Companies that require consent via Google's Additional Consent specification - meaning they are not registered on the IAB GVL but operate under a separate Google mechanism - include AppLovin Corp., Meta, Roku Advertising Services, Unity Ads, ironSource Mobile, and Cloudflare, among others. The distinction carries operational weight: CMPs implementing only the standard IAB TCF string may not automatically pass consent to Google AC-only vendors. Publishers relying on the commonly used set should ensure their CMP handles both frameworks if they want consent signals to reach all 199 companies on the current list.
The intersection of partner list management and GDPR compliance is not an abstract compliance matter. It has direct revenue implications. A vendor removed from the commonly used set that is not explicitly added to a publisher's custom list will - in EEA, UK, and Swiss contexts - be treated as lacking the necessary consent to serve or measure ads. That means ad requests to that vendor will either be blocked or will run without personalization, typically at a lower effective CPM.
Google's TCF v2.3 migration mandate, announced in November 2025 with a February 28, 2026 deadline, established a hard requirement for updated consent string handling. The partner list experiment layered on top of that transition creates a compressed window in which publishers are simultaneously managing framework version upgrades and potential vendor set changes.
The broader context is one of sustained pressure on publisher-side ad revenue. Google's network advertising revenues - spanning AdSense, AdMob, and Ad Manager - declined 1% to $7.4 billion in the second quarter of 2025. Publishers already navigating that revenue environment now face a partner list reset that could, depending on which companies are added or removed, affect fill rates and demand competition on their inventory.
Google's replacement of the ad networks blocking control with an authorized buyers system in November 2025 followed a similar logic - standardizing and streamlining the set of entities publishers interact with, while reducing the operational surface area of legacy configurations. The ATP list update fits the same pattern: tighter curation, cleaner defaults, less manual management required - but also less visibility into what changes and when.
For publishers using the commonly used set without modification, the experiment starting April 20 will play out in the background unless they act. Google has created an opt-out mechanism; the question is whether publishers are aware of it and how many will engage with it before the experiment begins.
One aspect of the documentation is worth particular attention. According to Google, "It is your responsibility to build a vendor list that meets IAB TCF and GDPR transparency requirements." That language has not changed across multiple versions of the Manage your ad technology partners documentation. Even though Google curates the commonly used set and makes it available as a default, the legal obligation to maintain a compliant vendor list - one that accurately reflects all parties with whom user data will be shared - rests with the publisher.
The EU User Consent Policy requires publishers to clearly identify each party with whom data will be shared. Whether a publisher uses the commonly used set or a custom list, that transparency requirement applies equally. When Google changes the commonly used set, the disclosure obligation does not automatically update in users' browsers or in CMP consent logs; it is the publisher's responsibility to ensure that the consent infrastructure reflects the actual state of the partner list.
IAB Europe's supply chain transparency research from August 2025 found that 72.64% of European web publishers had implemented ads.txt files, but compliance with TCF vendor list requirements is a separate and more complex undertaking. A publisher technically compliant with ads.txt may still be operating with a vendor list that does not accurately reflect the consent actually required for personalized advertising.
Who: Google AdSense, affecting publishers globally who rely on the default commonly used set of ad technology partners for GDPR consent management in the EEA, UK, and Switzerland. Third-party CMP providers are also affected, as the JSON file used by certified CMPs will be updated when the list changes.
What: Google today announced a two-phase experiment to update the commonly used set of ad technology partners (ATPs) for AdSense. The current list contains 199 providers, identified across the IAB Global Vendor List and Google's Additional Consent framework. The experiment will test an updated partner set before any permanent changes are applied. Publishers who do not want automatic updates can opt out by selecting "Do not automatically include commonly used ad partners," which creates a locked custom list.
When: The announcement was made April 6, 2026. The experiment begins on or after April 20, 2026. A permanent list update, if the experiment is judged successful, follows on or after June 5, 2026.
Where: The changes affect AdSense globally, with particular operational impact in the European Economic Area, the UK, and Switzerland - the jurisdictions where GDPR and the EU User Consent Policy govern which ad technology partners can serve and measure personalized advertising. Publishers can view partner controls and experiment participants in the Privacy & messaging section of their AdSense account, under European regulations settings.
Why: Google states the update will reflect partners "that work most closely with publishers globally, determined by data collected from all programmatic demand sources, as well as meeting our privacy standards." The change follows a previous list refresh in June 2025, suggesting a recurring curation process tied to actual programmatic revenue data. For publishers, the practical consequence is that vendors added to or removed from the list gain or lose automatic consent collection through the default configuration - a change with direct implications for ad fill, competition among demand sources, and compliance with GDPR transparency requirements.
