Share of Model is the percentage of AI-generated answers in your category that mention or recommend your brand. It is to AI search what rankings were to Google: the one number that tells you whether you exist in the channel where your buyers now start.
For twenty years, marketing measurement rested on one assumption: buyers see a list. Ten links, ranked. Your job was to climb it, and your dashboard told you where you stood.
AI answers broke the list. Ask ChatGPT or Perplexity for “the best expense management software for a 200-person company” and you get a synthesized answer naming two or three brands. There is no position four. There is no page two. You are either in the answer or you are invisible — and your rank tracker has no idea which.
Measuring it is simple in principle: run a representative set of buying-intent prompts across the major models, count the answers that include your brand, divide by the total. The useful version also weights where you appear, how you are framed, and whose sources taught the model to name you.
Three things make this genuinely different from rankings. It is probabilistic — the same question can return different brands, so you sample, you don’t screenshot. It is winner-take-most — losing a slot means a competitor takes nearly all of your visibility. And it moves on the model’s schedule, not yours — answers can reorganize overnight.
One warning: a mention rate alone is the new vanity metric. “We showed up in ChatGPT” wins the all-hands slide. Connecting Share of Model to pipeline wins the budget. That connection is what we measure — and what this blog exists to teach.
Want your number? Run your domain through the free AI Visibility Score and see how the models describe — and rank — your brand today.
Want to know how AI models talk about your brand today?