For most of the made-for-advertising (MFA) era, buyers handled the problem themselves. They licensed a verification vendor’s avoidance segment, uploaded a blocklist to the DSP, and hoped both were current. That approach had a structural weakness: the bid request still went out, the DSP still spent compute evaluating it, and the MFA site still got the chance to sell to anyone who had not blocked it. Over the past three years, a growing share of that filtering has moved upstream to the exchange, where MFA supply can be dropped before a bid request is ever built. That shift is real, but it is narrower than some of the vendor language suggests. Here is what has actually shipped.

Why the Filter Moved Upstream

The ANA’s programmatic transparency study made the economics hard to ignore. Working from log-level data, it found that made-for-advertising sites took 21% of impressions and 15% of ad spend in its sample. At that scale, a buyer-side blocklist is a tax paid on every auction: the buyer’s DSP receives and discards the request, and the exchange still carries the cost of processing and forwarding it.

Filtering at the exchange changes who does the work. If an SSP drops a known MFA domain before building the bid request, no DSP sees it, no one pays to evaluate it, and the site loses access to demand that never had the option of buying. That is also why the move is framed as supply path optimization rather than verification. It is a curation decision about what the exchange is willing to sell.

What Exchanges Have Shipped

The public record of exchange-side MFA controls is specific enough to separate it from marketing.

Sharethrough (2023). Sharethrough was the first exchange to remove MFA sites automatically, starting with all off-the-shelf deals and custom private marketplaces created after July 1, 2023. It used Jounce Media’s MFA classification and built the filter into its curation platform. The scope was deals, not the open exchange.

Teads (2024). In March 2024, Teads said its inventory was fully MFA-free, also using Jounce detection.

OpenX and Magnite. OpenX worked with MiQ to remove MFA domains from direct-sold deals, merging MiQ’s list with Jounce’s. Magnite committed to disabling MFA inventory at an advertiser’s request, both in private marketplaces and in its curated versions of the open marketplace. Both are real controls, but they are scoped to deals or triggered by the buyer, not applied across all open auctions by default.

Equativ (2025). The broadest commitment came on May 16, 2025, when Equativ said at the Jounce SPO Summit that it had blocked all MFA inventory across its global exchange, covering both Equativ and Sharethrough and including open exchange as well as deal spend. Equativ had already blocked MFA from its PMPs in 2023. This was the step from deal-level curation to exchange-wide exclusion.

On the buy side, verification vendors kept building. DoubleVerify launched MFA avoidance in September 2023 and later added tiered high, medium, and low classifications based on ad density, traffic sources, and content practices. Several DSPs now expose MFA controls natively as well.

The Detail the Announcements Skip: Whose Definition?

Nearly every exchange-side control listed above runs on an external classification, most often Jounce Media’s daily-updated MFA list. That is useful for consistency, since two exchanges filtering against the same list will agree on most domains. It also means “exchange-native MFA detection” usually means native enforcement of someone else’s classification, not a classifier the exchange built itself. We found no dated announcement in 2026 of a major SSP shipping its own proprietary MFA classification model. The trend is exchanges enforcing lists in the auction path, not exchanges replacing the list-makers.

That matters for buyers, because MFA definitions vary. A domain flagged by one vendor can be clean under another vendor’s method. Tiered systems like DoubleVerify’s exist precisely because ad density, paid traffic arbitrage, and thin content do not always appear together. When an exchange says its supply is MFA-free, the next question is always: MFA-free according to which list, updated how often, and with what appeals process for publishers who think they were misclassified?

Chrome Just Added a Public Signal

A new input arrived on September 15, 2026. Chrome added four experimental ad metrics to the Chrome User Experience Report: Ad Count, Ad Density (the average share of the viewport covered by ads), and two Ad Weight measures covering network bytes and CPU time. According to Chrome’s announcement, the metrics are reported at the same dimensions as existing Web Vitals data, carry no suggested thresholds, and are not part of Core Web Vitals or a ranking signal.

That last point is easy to overlook and important. Chrome has not defined MFA and has not said what density is too high. What it has done is make one of the core MFA traits observable from real-user data, at the origin level, through a public API. Until now, ad density was something a verification vendor or list-maker measured with its own crawlers. From here on, any exchange, DSP, or buyer can pull a browser-sourced figure and compare it with what a classification vendor says.

Expect this to show up in SPO conversations quickly. It gives exchanges a way to back up their MFA filtering with a third-party signal, and it gives buyers a way to check a list’s decisions against real-user data. It does not settle the other two MFA traits, paid traffic arbitrage and thin or recycled content, which CrUX does not measure.

How Buyers Should Use Exchange-Side Filtering

Exchange-level MFA exclusion is worth having, but it does not replace buyer-side controls. A few working rules:

  • Ask each SSP for scope in writing. Deals only, curated marketplaces, or all open-exchange auctions? On by default or on request? The answers differ across the exchanges named above.
  • Ask which classification is enforced and how often it refreshes. A daily-updated list and a quarterly one are different products.
  • Keep your own avoidance layer. Exchange filtering lowers the volume reaching your DSP. Your verification vendor’s segment catches what a given exchange’s list misses and gives you a consistent definition across every supply path.
  • Pull CrUX ad metrics for your top domains. Compare the origins you are buying against their Ad Density and Ad Count figures. Where a domain your vendor calls clean shows unusually high density, that is worth a closer look.

Moving MFA filtering into the exchange is progress because it cuts waste before any money moves. The weak spot is definition: most of the industry is enforcing a small number of shared lists, and real-user data on ad load has only just become public. Buyers who ask exchanges exactly what they filter, keep their own avoidance layer, and treat Chrome’s new metrics as a cross-check will get the benefit of upstream filtering without assuming “MFA-free” means the same thing everywhere.