Post-ATT Media Spend Index: Week 8

Post-ATT Media Spend Index: Week 8
June 24, 2021 Simon Whittick

Last week iOS 14.5+ adoption reached 70% according to data from Branch. We are now into mass adoption for iOS 14.5+ and firmly in the post-ATT world. So, have advertisers started reacting to diminishing IDFAs with their media spend yet? That’s what we’ll be looking at in this week’s Post-ATT Media Spend Index, which adds data from the week starting 14th June 2021. For a reminder on the data:

  • We’re looking at over $500m of annualised ad spend across over 100 apps.
  • We only look at apps who have been spending consistently over the period analysed.
  • It’s a longitudinal study using the Pre-ATT averages from the beginning of 2021 as a baseline. With “Post-ATT Week 1” being the week starting 26th April 2021.
  • The dataset isn’t representative of the whole market, it skews towards bigger spending apps based in North America and Europe.

So, let’s jump into the latest data. 

Spend split by OS remained steady week-over-week

The split of spend across OS’s hasn’t changed week over-week after a few weeks where advertisers were moving spend to Android as iOS 14.5+ adoption accelerated. 

However, looking ahead we still think that iOS budget share will reduce further in the coming weeks. Advertisers are only just starting to feel the impact of IDFA’s disappearing on media performance, so it’s unlikely to stay too stable over the coming weeks.

However, major Self Attributing Networks (SANs) saw further iOS dips

Despite the overall steady split of spend across iOS and Android week-over-week, the major SANs continued to see budget moving to Android.

All major Self Attributing Networks (SANs) aside from Google saw more iOS spend move to Android from iOS. Snap has seen the biggest switch to Android, whilst TikTok and Facebook have also both now seen a double digit percentage point decrease in the iOS share of spend vs their pre-ATT average. The most significant shift this week was on Facebook.

Percentage point change in iOS share of spend TikTok Snap Google Facebook
Percentage point change vs pre-ATT average -10% -16% -7% -10%
Percentage point change vs prior week -1% -2% 0% -3%

As iOS 14.5+ adoption went to 70% last week it’s no surprise that advertisers continued to shift budget towards Android on these channels, as the IDFA will increasingly have disappeared. Popular audience targeting options on these channels relied on the IDFA to power the machine. However, the IDFA is disintegrating, causing advertisers to switch budget where they can towards Android to find performance. However, when Android performance saturates for them they will likely move more budget between channels to find performance.

Overall share of wallet is still pretty steady

With iOS 14.5+ adoption reaching a critical tipping point last week, budgets did move a bit around channels, however, it’s still largely within the parameters we’ve seen previously.

Looking at last week in isolation, Facebook seems to be most impacted as their share of wallet dropped 3 percentage points vs the previous week and is back down to 4 percentage points below their pre-ATT average. Their share of wallet has been more volatile in recent weeks, with advertisers reporting CPMs went up significantly in week 7, which may explain the sudden jump in share of wallet that week. However, the resulting performance losses may have caused the drop in share of wallet we saw last week.

The winners appear to be Apple Search Ads who are up 1 percentage point week-over week and up 2 percentage points vs its pre-ATT average. Similarly, “Other” channels, which mostly consist of longer-tail ad networks, are up 2 percentage points week-over-week and 4 percentage points on their pre-ATT average.

These channels are less reliant on the IDFA to feed the machine, which may suggest why they are seeing some gains in share of wallet since iOS 14.5+ adoption reached a tipping point. 

However, it’s important to note that these share of wallet movements are still marginal right now as advertisers are only just starting to feel the impact of the loss of IDFA. We may see more volatility in the coming weeks.


Advertisers are clearly reacting to iOS 14.5+ adoption as they switch spend away from iOS on SANs to Android and start to reduce overall SAN investment slightly. However, the full impact of disappearing IDFAs on individual channel performance hasn’t been fully revealed yet. Expect more volatility in the next few weeks of data. Sign-up to our newsletter to get notified whenever we share new data.

Also, if you’re still trying to work out how to optimise campaigns using limited signals from SKAdNetwork (SKAN), you should join our webinar on July 7th “Under the hood of SKAdNetwork (SKAN): Getting maximum value from limited signals”. We’ll be joined by some of the brightest minds on SKAN to share early lessons and tips from working with Apple’s attribution tool. Fill out the form below to reserve your place for the live session and get your questions answered.