Impression Share

What is Impression Share?

Impression Share is the percentage of auctions a keyword or ad group was eligible for in which it actually received an impression.

The formula:

Impression Share = Won Impressions / Eligible Auctions × 100%

If your “fitness tracker” keyword was in 1,000 auctions and won 320 impressions, Impression Share = 32%.

What “eligible” means

An auction is eligible for your keyword if:

• The user’s query matches your keyword (via Exact, Broad, or Search Match)
• Your campaign is active and within budget
• Your audience refinements (gender, age, device, customer type) match the user
• Your bid is at or above the floor

If any of these fail, the auction is not in your eligible set.

What lowers Impression Share

Several distinct causes:

Cause	What’s happening	How to detect
Bid below floor	Your max CPT is too low to enter the auction	Apple “Bid too low” warning, suggested bid > current bid
Lost auction by bid	You entered but lost on bid price	Avg CPT close to your max bid; competitors are outbidding
Lost auction by relevance	Your ad is less relevant than competitors	Auction position weak even with high bid
Daily Cap exhausted	Campaign paused for the day	Campaign status shows “Limited by budget”
Day-parting active	Ad group is outside its scheduled hours	Lookup ad group schedule
Audience refinements	Refinement filters cut the eligible set	Compare refined vs unrefined ad groups

Where to find Impression Share

Apple Search Ads dashboard:

• Keywords view → check Impression Share column
• Ad Groups view → aggregated impression share
• Apple Search Ads API → impressions and eligibleImpressions fields

The metric is more meaningful at the keyword level than at the ad group or campaign level. Aggregate impression share hides the distribution of which specific keywords are winning.

Healthy Impression Share by keyword type

Keyword type	Target Impression Share
Brand (own app name)	85-100%
Brand defense (competitor name)	30-60%
Category Exact (proven winners)	50-80%
Discovery (Broad + Search Match)	N/A — controlled by Apple
Long-tail Exact	40-80%

Brand should always be near 100% — losing brand auctions to competitors means you are losing the most valuable traffic in your account.

How to raise Impression Share

Diagnose first, then act:

1. If “Bid too low”: Raise the max CPT to the suggested floor + 20%.
2. If lost-by-bid: Raise the max CPT incrementally (10-30%) and observe.
3. If lost-by-relevance: Improve the keyword-to-ad-group match (move keyword to a more focused ad group), update Custom Product Pages, or accept that the keyword is weakly relevant.
4. If Daily Cap exhausted: Either raise Daily Cap or accept the impression ceiling.
5. If audience refinements too tight: Loosen filters or remove them for keywords where the refinement is not justified by performance.

Common interpretation mistakes

• Treating Discovery impression share as actionable. Search Match impression share is not directly controllable. Focus on Exact-match keyword impression share.
• Lumping all keywords into one number. Aggregate impression share is the wrong lens. A 70% account-wide impression share could be 100% on Brand and 40% on Category, or 30% Brand and 80% Category — radically different stories.
• Chasing 100% on every keyword. Some keywords are intentionally under-bid because the CPI math does not work. Don’t optimize impression share at the cost of CPA.

How ASAPilot helps

ASAPilot’s account audit reviews impression share per keyword and surfaces:

• Brand keywords with <80% impression share (lost brand traffic)
• High-CR keywords with <50% impression share (volume opportunity)
• Keywords flagged “Bid too low” by Apple (cleanup candidates)
• Impression share drops >30% week-over-week (auction shift signal)

See audit guide and pricing.

Related terms

• CPT — the bid that determines impression share dynamics
• Bid Floor — the minimum to enter the auction
• Daily Cap — the budget bound that can limit impression share