ChatGPT is the largest AI answer engine by user base. Citations.io tracks every brand mention, citation and competitor co-mention daily.
ChatGPT (GPT-5 and newer) uses a mix of its parametric training data and live web retrieval for queries that benefit from fresh information. For "best of" and comparison queries, it almost always retrieves - meaning the brands it names today can change tomorrow.
For a category leader, a ChatGPT mention rate above 60% on relevant prompts is realistic. Below 30% means ChatGPT rarely names you for the queries your customers ask - usually because you're not present on its preferred source pool.