Share of Model is a metric that measures how often your business is cited by AI systems — ChatGPT, Google AI Overviews, Perplexity — when users ask questions in your market.
It is the AI equivalent of market share. The higher your Share of Model, the more often an AI recommends your business when a potential customer asks for help finding exactly what you offer.
For most local businesses right now, the honest answer is: zero.
Why it matters more than page rank
Page rank tells you where you appear in a list. Share of Model determines whether you appear in the answer at all — before there is ever a list.
When a prospective client opens ChatGPT and asks "who is the best marketing consultant in Milton Keynes?" they do not see a list of ten blue links. They see a recommendation. One or two businesses, explained in a sentence. If your business is not in that sentence, you do not exist for that interaction — regardless of where you rank on Google.
AI referral traffic has grown 778% year-over-year. It converts at significantly higher rates than traditional organic search because AI-referred visitors arrive pre-qualified. They were told to contact you specifically. That's a categorically different kind of lead.
How to measure your Share of Model yourself
You don't need software. You need twenty minutes and the following process:
Build your query list
Write down 10–20 questions a potential customer might ask an AI when looking for your type of business. Include location-specific versions ("best [service] in [town]"), generic versions ("how do I find a [service]"), and problem-led versions ("I need help with [problem] in [area]").
Run each query across three AI systems
Query ChatGPT, Perplexity, and Google (to trigger AI Overviews) with each question. Use a fresh session for each — do not let conversation history affect responses. Screenshot or note the results.
Score each result
For each query × AI system combination, record: Was your business mentioned? (Yes/No), Was it mentioned first? (Yes/No), Was the description accurate? (Yes/Partially/No). Calculate your citation rate across all queries. This is your baseline Share of Model.
Do the same for your main competitors
Run the same query set and note which competitors are cited in responses where you are not. This shows you exactly who is currently winning your AI market share — and gives you specific examples to reverse-engineer.
What actually determines your Share of Model
AI systems cite businesses they can understand and trust. The factors that drive citation are different from traditional SEO ranking signals:
- Entity clarity — Does your website unambiguously define what you are, what you do, who you serve, and where? Businesses with vague or generic copy are rarely cited because AI systems can't confidently recommend what they can't clearly describe.
- Google Business Profile completeness — ChatGPT sources local data from Foursquare and Google's knowledge graph. An incomplete or inconsistent GBP hurts your Share of Model directly.
- Third-party citations — Being mentioned by name in local news, directories, review sites, and authoritative external sources tells AI models that you are a real, recognised entity in your market.
- Answer-first content — Pages that directly answer questions — with the answer in the first paragraph, not buried after an introduction — are far more frequently cited.
- Structured data depth — JSON-LD schema that precisely describes your service types, service areas, business hours, and reviews gives AI systems clean data to work from.
- llms.txt — A structured briefing file for AI crawlers that tells them exactly how to represent your business. Businesses that have one are giving AI systems a direct, reliable source of truth about what they do.
The compounding advantage of moving first
Share of Model compounds. Once an AI model has learnt to associate your business with a type of service in a location, that association persists and strengthens as your content, citations, and signals accumulate. Competitors who start optimising later will find it progressively harder to displace you.
Most local businesses in Buckinghamshire and Milton Keynes have a current Share of Model of zero for their target queries. That's not a problem — it's a window. The window closes as GEO becomes mainstream.
If you want a baseline measurement of where your business currently stands — exactly which queries you're being cited for, which competitors are being cited instead, and what the priority fixes are — that's the starting point of an AI Search Domination audit.
For background on the broader shift, see What is GEO? Generative Engine Optimisation explained.