Search Impression Share

Your branded campaign spent its full budget and still showed on only 60% of the searches for your own name. The other 40% went somewhere. Search impression share is the number that tells you where: the impressions you won, divided by the impressions you were eligible to win.

Google splits the impressions you missed into two buckets. Lost to budget means the money ran out. Lost to rank means the auction was won by someone with a stronger bid or better Ad Rank.

The 78% that became 41%

An ecommerce brand’s branded Search impression share fell from 78% to 41% after a Performance Max campaign launched and began absorbing its brand queries, per a 1Digital Agency case study. Net branded conversions stayed flat.

The share the Search campaign lost, Performance Max picked up. Same searches, counted in a different campaign.

The number moved and the business did not. I think that is the trap built into impression share: it measures your slice of a fixed pie, and your own account can be the thing eating the slice. Neither “lost to budget” nor “lost to rank” names that cause, because from the Search campaign’s view nothing was overspent and no competitor outbid it.

Why “lost to budget” stops at the campaign

Google reports Search lost IS (budget) at the campaign level only, in its own documentation. It does not appear in the ad group report, and in June 2022 it was stripped from saved reports that broke results out by ad group, keyword, or ad-group label.

So a campaign can report a large share of its impressions lost to budget without telling you which ad group inside it is starved. The diagnosis stops one level above where the fix lives. A brand that wants to know whether it is the branded ad group or the prospecting one draining the shared budget has to split them into separate campaigns first, then read the metric again.

What a branded number should look like

A campaign bidding on a brand’s own name is supposed to sit near the top. DermWarehouse ran its brand campaign at 88.55% search impression share, by one account — 88 impressions won for every 100 it was eligible for.

For a term you own, anything much below the low 90s is usually one of two things: a daily budget that empties before the day does, or a competitor bidding on your name. The metric does not distinguish those on its own; the budget-versus-rank split is what points you at which one.

This matters most for accounts where the brand and product terms carry the account. Little Sleepies runs 524 Google ads built on 89 unique search headlines and lets the keyword do the targeting, with only 11 of 524 ads (2.1%) using any declared audience. In an account structured that way, the branded search term is the cheapest conversion it owns — and, as the 78%-to-41% case shows, the easiest to lose to a campaign sitting in the same account.