Why is my impression share low, and should I raise my budget?

Two columns answer this, and they point at opposite fixes

Google defines them precisely, and the precision is the whole diagnosis.

Search lost IS (budget) is the percentage of time your ads were not shown on the Search Network due to insufficient budget. Search lost IS (rank) is the percentage of time your ads were not shown due to poor Ad Rank in the auction.

Read those side by side. The first is a money problem. The second is a quality and competitiveness problem, and no amount of money fixes it directly, because Ad Rank is not bought outright. Pouring budget into an account losing share to rank buys you more of the same losing auctions.

So what does move rank? Google names six things that determine Ad Rank: your bid, the quality of your ads and landing page, the Ad Rank thresholds, the competitiveness of the auction, the context of the person's search, and the expected impact of your assets and other ad formats. Your bid is one of six, which is why bidding harder helps a little and settles nothing. Two of the six, the competitiveness of the auction and the context of the search, are conditions rather than levers. What is left, and what genuinely moves between now and next month, is the quality of the ad, the relevance of the page the click lands on, and whether you are bidding on searches that match what you actually sell.

Microsoft documents the identical pair and goes further, stating the remedy in its own documentation: for impression share lost to insufficient budget, "If this number is high, you may want to increase your budget." That is the platform itself confirming that budget is the right lever for exactly one of the two columns.

One practical constraint before you go looking. Google notes that Search lost IS (budget) is available at the campaign level only. If somebody tells you an ad group is losing share to budget, ask where they are reading that.

Running out of budget hides your rank problem

This is the trap, and it decides the order you work in.

Google states it plainly: lost IS (rank) will not be shown on your ad groups tab if you ran out of budget at any point during the date range being examined.

So an account that hit its budget ceiling even once in the period you are looking at will show you a budget story and stay quiet about rank. You can conclude, entirely reasonably and entirely wrongly, that money is the only problem. Then you raise the budget, the rank problem surfaces for the first time, and it looks like the increase caused it.

The practical move is to narrow the date range to days the campaign did not run out, or to look at campaign level rather than ad group level, before deciding anything. Fix visibility before fixing spend.

One more timing detail worth knowing so you do not diagnose from a half-written number. Microsoft notes its impression share data is typically updated 14 to 18 hours after the UTC day ends. Today's figure is not a figure yet.

Raising the budget spends more than the number suggests

If the answer genuinely is budget, know what you are agreeing to before you nod.

Google sets two limits. The daily spending limit is your average daily budget multiplied by 2 for most campaigns, and on a given day a campaign might spend up to twice the average daily budget to take advantage of traffic fluctuations. The monthly spending limit is 30.4 times your average daily budget.

Google's own worked example: set an average daily budget of 10 dollars and the daily spending limit becomes 20 dollars, while the most you would be charged in a month is 304 dollars.

So a daily budget is not a daily cap. It is an average with a ceiling of double on any one day, and a monthly ceiling of about thirty times. Anybody raising a daily budget from 50 to 80 dollars is proposing a monthly commitment moving from roughly 1,520 to roughly 2,432, not an extra 30 dollars a day. That is a fine decision to make, as long as it is the decision you think you are making.

Full impression share is almost never worth buying

The last few points are always the most expensive, and this is where the number stops being a goal.

Impression share is a share of auctions you were eligible for, not a share of your market, so 100 percent does not mean you have saturated demand. It means you appeared every time you could. The auctions you are missing are, by definition, the ones where somebody else was willing to pay more or ranked better, which makes them the most competitive and therefore the most expensive impressions available to you.

Chasing the last stretch of share means paying rising prices for traffic you were previously outbid on. That can be worth it. It is worth it when the work those clicks produce is worth more than the higher cost, which is a question about your margins rather than a question about the column.

The honest framing is that impression share is a diagnostic, not a target. A 40 percent share on searches that convert beats a 90 percent share on searches that do not, every time.

How to decide this week

Six checks, in this order, because the order is what stops you buying the wrong fix.

• Look at lost IS (budget) and lost IS (rank) together, at campaign level. One number without the other tells you nothing.
• Check whether the campaign ran out of budget in the period. If it did, the rank column may be hidden, so narrow the range before trusting it.
• If the loss is mostly rank, do not raise the budget yet. The lever is ad relevance, the landing page, and what you are bidding on, not the ceiling.
• If the loss is mostly budget, work out the real monthly figure before agreeing: the new daily number multiplied by about 30.4, not by 30, and know a single day can hit double.
• Ask what the extra impressions are expected to be worth. More share is a cost with a benefit attached, and somebody should be able to state the benefit.
• Wait a day before reading today's number, since the data is still settling.

If the answer comes back as rank rather than budget, that is good news financially and uncomfortable operationally. It means the account has room to improve without spending more, which is a better position than needing a bigger budget to stand still.

Running and reading ad accounts is one of the things we do, so if the two columns are telling you different stories, that is work we take on.

Terms used on this page

• Impression share
• Daily budget
• Quality Score
• Cost per click

Sources

• Impression share: Definition and metrics
• About Ad Rank
• About spending limits
• Report Attributes and Performance Statistics (Microsoft Advertising)

Last reviewed 2026-09-11.