The AI Search Real Estate Nobody's Claiming Yet
Kevin Indig just settled an argument that's been running in half-finished form since AI Overviews launched. Does topical authority—the thing that rewards brands for going deep on a subject instead of wide—actually carry over into AI search? Or is ChatGPT enough of a blank slate that a generalist brand can walk in and grab a category cold?
Indig's answer, backed by six months of ChatGPT answer data from Semrush spanning 1,094 U.S. categories, is that topical authority does matter in AI search. The reason is durability. Once a brand earns an outsized share of mentions in a category, it tends to hold onto it.
That's the tidy version. The messier and more useful version, buried a few paragraphs into his post, is that almost none of the market has settled yet.
The 89% Nobody Owns
Indig built three buckets. A category has a clear owner when one brand shows up in at least four of five test prompts and beats the runner-up by five percentage points or more. It's an emerging leader when a brand leads at least three prompts without hitting that gap. Everything else—meaning no brand leads even three of five prompts—counts as unsettled.
Run those definitions across the full dataset, and June 2026 looks wide open. Only 15.2% of categories had a clear owner. Just over half, 53.7%, were open fields with multiple credible contenders and no brand close to locking the door.
Indig ranked all 1,094 categories by estimated AI search volume and split them into two even groups. The higher-volume half accounts for 98% of all AI search demand in the sample, and it has the lower owner rate of the two: 11.3%, versus 19% for the lower-volume half. Stack that up and 89.3% of estimated AI search demand sits inside categories with no clear owner yet.
The categories worth the most money to occupy are, right now, the least decided.
Topical Authority Is Real. Here's The Proof.
I've spent the past three years watching SEOs debate whether topical authority is a real algorithmic force or a convenient story agencies tell clients to justify a content calendar. Indig's data is the first thing I've seen that actually resolves the question with a real number.
Topical authority is real in AI search, and the brands still treating category focus as optional are giving away nine-figure categories to whoever bothers to show up consistently across all five prompt types.
The second half of Indig's analysis is where the strategy gets sharper. He tracked month-over-month leadership changes across the same categories and found that a clear owner held first place in 90.4% of comparisons.
The switches that did happen were concentrated almost entirely in categories where the lead was already thin. Categories where the leader changed had a median lead of just 1.3 percentage points going into the switch. Categories where the leader held on had a median lead more than double that: 2.9 points.
Growth trajectory told Indig almost nothing on its own. He shows three examples where a leading brand trended upward month over month and still got overtaken, because a competitor simply grew faster or closed a narrow gap. The lesson isn't that momentum is meaningless. It's that a one- or two-point lead is not a lead worth defending yet, and a brand sitting in that range should assume it's still in a fight.
Citations Aren't The Room. They're The Door.
Indig also found something that undercuts a common assumption about how ownership gets built. Citations and brand mentions turned out to be only weakly related, with a slightly negative correlation of -0.229. The most frequently cited domain in a category was rarely the same as the most frequently mentioned brand, matching up only 20.8% of the time.
But the most mentioned brand was cited at least once 69.9% of the time. Getting cited a lot doesn't automatically make you the brand ChatGPT reaches for by default. That's a meaningful distinction for anyone whose GEO strategy currently starts and ends with "get more citations."
Owners did share some traits versus their runner-up: higher branded search volume in 55.7% of pairs, higher organic traffic in 48.4%, and a higher Semrush Authority Score in 52.5%. Indig is careful to call these correlations rather than a formula. A brand doesn't earn ChatGPT's default answer by buying branded search volume. It earns it by being the source ChatGPT's training and retrieval keep landing on when the model tries to answer all five variations of a question—the definition, the comparison, the alternatives list, the use case, and the buying decision.
What To Do With This Before The Window Closes
Here's where I'd point a practitioner's next quarter of work, adapted from Indig's framework and my own Citation Share of Voice approach to tracking AI mentions.
Pick your battlefield first, then measure it properly. List the 10 to 20 categories where your brand actually needs to be the default answer. For each one, track the same five prompt types Semrush used—a definition question, a comparison, an alternatives list, a use case, and a buying question—not just your brand name in isolation.
Sort by lead size, not by whether you're currently "winning." A category where you lead by 1.5 points is not a category you've won. Treat anything under roughly 3 points as contested and put real resourcing behind closing the remaining prompt gaps, since Indig's data shows that's the exact range where turnover happens.
Stop chasing citations as the whole strategy. Use citations to earn your way into the answer set, then shift budget toward the specific content types, comparison pages, proof points, third-party coverage, and clear positioning that determine whether you're the brand actually named once you're in the room.
The GEO conversation over the past year has fixated almost entirely on citation counts because citations are the easiest thing to drop into a dashboard. Indig's data says citations are a door, not the room. Practitioners who keep optimizing for the door while a competitor optimizes for being the name ChatGPT actually says out loud are going to lose categories they thought they were winning.
The window Indig describes won't stay open. Eighty-nine percent of demand sitting in unsettled categories is an unusually generous head start, and the brands that move on it in the next few quarters, rather than treating this as one more report to bookmark, are the ones that will still be the default answer when somebody runs this same study in 2027.
Source: Kevin Indig's analysis via Semrush data, published in his Growth Memo and on LinkedIn (July 20, 2026). Data covers 1,094 U.S. categories, five prompts per category, more than 50,000 brands, and over 600,000 citations from January to June 2026.
Quick Reference: Ownership Definitions
| Category Type | Definition | Share of Categories |
|---|---|---|
| Clear owner | One brand in 4+ of 5 prompts, beats runner-up by 5+ percentage points | 15.2% |
| Emerging leader | Brand leads 3+ prompts without hitting the gap | Part of 53.7% |
| Open field | No brand leads 3+ of 5 prompts | 53.7% |
| Unsettled (no clear owner) | Everything above 15.2% | 84.8% |
89.3% of estimated AI search demand sits inside categories with no clear owner yet.
Key Numbers From The Study
- 1,094 U.S. categories analyzed
- 5 prompts per category (definition, comparison, alternatives, use case, buying)
- 50,000+ brands tracked
- 600,000+ citations recorded
- 15.2% of categories with a clear owner
- 90.4% of month-over-month comparisons where a clear owner held first place
- 1.3 pts median lead in categories where leadership changed
- 2.9 pts median lead in categories where the leader held on
- -0.229 correlation between citations and brand mentions
- 20.8% of the time the most cited domain matched the most mentioned brand
- 69.9% of the time the most mentioned brand was cited at least once
Data: Semrush, January–June 2026. Analysis: Kevin Indig, Growth Memo.
