Impression Share

Impression Share is the proportion of total impressions your ads captured for a keyword or search term, measured against all advertisers competing in the same App Store countries and regions. In Apple Ads, it answers a direct question: out of every time an ad was shown for this term, how often was it yours?

Apple renamed this metric from Share of Voice in 2026, alongside the release of the Apple Ads Platform API. The name change reflects what the metric always measured, and it arrived with two additions worth knowing about.

Why does Impression Share matter?

Impression Share tells you how much of a keyword’s ad inventory an app holds, which rank and spend alone cannot show. Two advertisers can pay the same cost per tap on a keyword while one appears on most searches and the other appears on a handful.

Key reasons it matters:

• Competitive visibility: A low impression share on a keyword you consider yours means competitors are appearing where you expect to.
• Brand protection: On your own branded terms, impression share is the clearest signal of whether a competitor is buying against your name.
• Budget decisions: A high-converting keyword with low impression share is usually a keyword worth more budget.
• Growth headroom: Impression share shows how much of a term remains available before more spend stops buying more visibility.

First ad position and all ad positions

Since March 2026, more than one ad can appear for a single App Store search. Because of that, Apple reports Impression Share in two forms:

• Impression Share (First Ad Position) is the share of impressions your ads captured in the top ad slot. This is the figure previously reported as Apple Share of Voice.
• Impression Share (All Ad Positions) is the share of impressions your ads captured in any ad slot for that term.

The gap between the two is the useful part. An app with high all-positions share and low first-position share is appearing often but rarely winning the top slot, which is a bidding problem rather than a visibility problem. An app with similar figures for both is competing in a term where few other advertisers are active.

How Impression Share is reported in Apple Ads

• Values are percentages: Apple returns an exact percentage between 0 and 90%. Once a value passes 90%, it is reported as a 91 to 100% range rather than a single figure.
• Data reflects the previous week: Impression Share is not a same-day metric, so it will not move in response to a bid change you made this morning.
• Not every term has data: Keywords and search terms with no impression share return N/A. At the search term level, Apple does not provide Impression Share for low volume terms.
• Rank is reported separately: Impression Share Rank places you against other advertisers on the same metric. See the Impression Share Rank entry for how that works.

Example in practice

A language learning app bids on “Spanish lessons.” Its Impression Share (All Ad Positions) for the term is 45%, while its Impression Share (First Ad Position) is 12%.

The app is appearing on nearly half of the searches for that term, so its relevance and budget are working. What it is not doing is winning the top slot, where competitors are bidding higher. The read is straightforward: this is a bid problem on a keyword the app has already qualified for, not a case for broader keyword expansion.

Improving your impression share

Raising impression share on a keyword is a mix of ASO and paid work, because Apple decides which ad appears based on the app’s relevance to the query combined with the bid.

1. Optimize your metadata: Title, subtitle, and description signal relevance, which affects whether your ad is eligible to appear at all.
2. Raise bids on priority keywords: On terms where you already appear but rarely in the first position, this is usually the constraint.
3. Test ad variations: Stronger creative improves tap-through rate, which supports performance on the terms you are competing for.
4. Defend your branded terms: Competitors bidding on your app name is the case where low impression share costs you traffic you would otherwise have won.
5. Expand keyword coverage: Mid and long-tail terms often have available inventory that high-competition keywords do not.
6. Use automation: Automation rules can adjust bids against Impression Share and Impression Share Rank conditions, which is more practical than watching a large keyword set manually.

Impression Share in other advertising platforms

The term is not exclusive to Apple Ads. Most auction-based advertising platforms report a version of it, calculated as the impressions an advertiser received divided by the impressions that were available to them. Platforms differ in what they count as available, and several also report lost impression share, which splits the gap into the portion lost to budget and the portion lost to ad rank or relevance.

Two notes for MobileAction users specifically. Apple’s Impression Share covers the campaigns in your own Apple Ads account. MobileAction’s Search Ads Intelligence separately estimates impression share for any app on the App Store, including competitors whose accounts you do not manage, so the two carry the same name from different sources.

Key takeaway

Impression Share shows how much of a keyword’s ad inventory you actually hold. Reported by ad position, it separates two different problems that a single number used to hide: whether you are showing up at all, and whether you are showing up first.