Share of Model (SoM)

What Is Share of Model?

Share of Model reveals a blind spot that the classic visibility index doesn’t capture: how visible is your brand in AI-generated answers? Different models have different training data and preferences — your brand may be well represented in ChatGPT but missing from Perplexity. Monitor your SoM across all relevant models to derive targeted measures for improving your AI visibility.

Share of Model (SoM) is one of the most important metrics in Generative Engine Optimization (GEO). It measures the percentage share with which a brand appears in the responses of a specific AI model — compared to all mentioned competitors. If you’re mentioned in 30 out of 100 relevant AI responses, your SoM is 30 percent.

The difference from classic Share of Voice lies in the frame of reference: while Share of Voice looks at the entire market, SoM refers to a single model. That’s crucial because ChatGPT, Perplexity, and Gemini can favor completely different brands. A brand with high SoM in ChatGPT may barely appear in Perplexity — and vice versa.

For measuring SoM, there are specialized monitoring tools that regularly send defined prompts to various AI models and analyze responses for brand mentions. This data shows you not only where you stand, but also which competitors dominate which models. This allows you to target your GEO strategy specifically at the models where you have the greatest room for improvement.