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Safari’s iOS 27 Block Cuts eCPMs 10.5% For Updated Readers. The Sitewide Hit Is About 1%

Hamit Tümer ·3 min read·How we report Share Print
In this piece
    Most of the line holds; one strand has gone slack.
    Most of the line holds; one strand has gone slack.

    The story. The first publisher data on Apple’s Safari block shows eCPMs down 10.5% among readers who have updated. Only about 8% of Aditude’s Safari users had updated, so the sitewide loss is small today and grows with adoption. (Digiday, 12 October 2026)

    The numbers in this piece

    8%of Aditude's Safari users
    11.7%of ads on Safari
    11.4%of ad revenue
    10.5%eCPMs decline

    01What happened

    • Safari is a minor share of ad delivery. Aditude’s customers see 11.7% of their ads on Safari on iPhone and iPad, and 11.4% of ad revenue.
    • Updated readers are paid less. Among readers on the latest update, eCPMs fell 10.5%.
    • Few readers have updated. About 8% of users had upgraded, and Aditude puts the overall revenue hit at about 1%.
    • Subscription publishers see no change. Two senior commercial executives at news publishers reported no impact, and one CRO put that down to a mostly subscription-based business.
    • The timing is bad. Digiday notes the fourth quarter is when ad tech vendors and publishers earn most of their money, and the block landed at its start.
    • A fix is not near. Apple’s fix for the current iOS version is not expected until the end of the month at the earliest.

    02What it means inside a GAM network

    Read the 10.5% as a floor. It measures readers who updated early, and the adoption curve is still ahead. Scott Messer, who advises publishers through Messer Media, expects the impact to grow as more people install the update.

    The 1% figure is easy to check. Safari’s 11.4% revenue share multiplied by a 10.5% eCPM drop gives about 1.2%, so Aditude’s estimate looks like the loss if every Safari reader had updated. That arithmetic is APH desk analysis, not Aditude’s stated method.

    The exposure depends on your mix. A publisher with a heavy Safari-on-iPhone audience and open-auction demand sits above that average. A subscription-led site sits below it.

    The mechanism matters for how you respond. Apple blocked small pieces of code that let ad tech companies recognise the same reader across sites. Demand that bids on a recognised user loses its signal on those readers, which is consistent with a lower clearing price.

    Andrew Casale, CEO of Index Exchange, said his company is largely unaffected because it is not in the identity business. Supply-path partners that do not depend on cross-site IDs are less exposed.

    One limit on the evidence: this is one vendor’s customer base, and Digiday’s account does not say how Aditude’s publishers are weighted by vertical or geography.

    The loss is small today and tied to how fast readers update.
    Figure 2 Only about 8% of Aditude's Safari users had updated, so the sitewide loss is small today and grows with adoption
    8%of Aditude's Safari users
    Regulation Desk

    03What publishers should do about it

    04The bottom line

    The loss is small today and tied to how fast readers update. Measure Safari by iOS version now, so you know your exposure before the adoption curve decides it.

    Sources & caveats

    Sources: Digiday, “Ad industry tallies early losses from Apple’s Safari tracking block” (12 October 2026), for the Aditude data, the subscription-publisher accounts, the fourth-quarter timing, the fix timeline and the Messer and Casale statements. The 1.2% calculation and the Google Ad Manager framing and recommendations are APH desk analysis. This piece advances our 10 October coverage of the iOS 27.2 beta and the Trade Desk fix.

    Tags
    AppleSafariiOS 27AditudeeCPMMeasurement
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    More from this issue

    Ran alongside this piece in the Weekly of 12 October 2026 —