Who fills the space you leave vacant in AI search
When your brand does not appear in an AI answer, the response does not say nothing. It recommends someone else. We looked at who that someone else is across four categories and found the same pattern every time: 2-4 brands capture nearly all of the vacant space.
AI answers do not leave gaps
A buyer asks an AI assistant which project management tool to use. If your brand does not appear in the response, the response still names a tool. The question is not whether the space gets filled. It is who fills it.
To quantify this, we looked at a regional ISP's full audit: 184 buyer-intent AI queries run across four engines. The brand appeared in 52 of those 184 responses (28% mention rate). In the 132 responses where it did not appear, we tracked which competitors were named instead.
The ISP case: 5 brands split 72-84% of absent responses
| Competitor | Appeared in absent responses | Share |
|---|---|---|
| Xfinity | 111 of 132 | 84% |
| Frontier | 108 of 132 | 82% |
| EarthLink | 96 of 132 | 73% |
| MetroNet | 95 of 132 | 72% |
| Spectrum | 81 of 132 | 61% |
This is a regional ISP competing against national providers. The AI engines consistently recommend the national brands when the regional one does not appear. The regional brand is not losing to random competitors; it is losing to a specific and predictable set of five.
B2B SaaS: the pattern is the same, the brands are different
We ran the same analysis across 270 live AI panels in three B2B SaaS categories. Each panel tested a different brand against buyer-intent queries. We tracked which competitors appeared in the loss scenarios, the responses where the tested brand was absent and a competitor was named instead.
The pattern holds. In every category, 2-3 brands dominate the responses that exclude the tested brand.
Project management software (173 brands tested):
| Competitor | Appeared in brand's loss responses | Share |
|---|---|---|
| Asana | 173 of 173 brands tested | 100% |
| ClickUp | 173 of 173 | 100% |
| Jira | 167 of 173 | 97% |
Customer support software (58 brands tested):
| Competitor | Appeared in brand's loss responses | Share |
|---|---|---|
| Zendesk | 58 of 58 brands tested | 100% |
| Freshdesk | 57 of 58 | 98% |
| Intercom | 34 of 58 | 59% |
HR software (39 brands tested):
| Competitor | Appeared in brand's loss responses | Share |
|---|---|---|
| BambooHR | 39 of 39 brands tested | 100% |
| Rippling | 39 of 39 | 100% |
| Gusto | 38 of 39 | 97% |
Why the concentration is this high
AI engines pull from a shared pool of sources for each category: the same review sites, the same editorial roundups, the same G2 and Capterra pages. Those sources mention the same dominant brands repeatedly. When an engine assembles a response about project management software, Asana and ClickUp appear in nearly every source it retrieves. A brand that is not on those sources has no presence in the response regardless of its market share.
The concentration is also self-reinforcing. The brands that appear most often get cited most often, which trains the engine to surface them more reliably. Challengers trying to gain AI visibility are not competing against the full category. They are competing against 2-3 brands that have already locked up the source coverage.
What this means for improving your visibility
Gaining AI mentions is not a diffuse effort against 50 competitors. In any given category, there are 2-4 specific brands you need to displace from the sources the engines read. Knowing who they are, and where they appear, focuses the work considerably.
The practical steps follow from the data. If Asana and ClickUp appear in 100% of PM software AI responses and you do not, the question is: what sources is the engine pulling when it mentions them? Those are the pages you need to be on, cited in, or covered by. Trying to outrank them on your own site is not the point. Being present in the sources they already own is.
An AI visibility audit shows your current mention rate alongside the competitor who fills your space. Once you know which 2-3 brands are taking the responses that should name you, the source gap becomes specific enough to act on.
Find out who is filling your space in AI search.
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ISP data: 184 buyer-intent prompts run across four search-grounded AI engines (ChatGPT with web search, Gemini with grounding, Perplexity Sonar, Claude with web search). Brand mention extracted by word-boundary matching. Competitor frequency measured in the 132 non-mention responses only.
B2B SaaS data: 270 live teaser panels (173 project management, 58 customer support, 39 HR software), each consisting of 10 buyer-intent prompts run on the same four-engine stack. Competitor frequency measured as the share of tested brands whose loss responses included each competitor at least once. Data from CitedWell's audit engine, collected May-June 2026.