Which AI chatbot does each industry depend on? Referral shares for 2,429 top websites (September 2026)

A recent analysis by Similarweb has examined the share of AI chatbot referrals that top websites receive from various chatbots, with the findings revealing distinct dependencies among different industries. The study focused on the top 5,000 domains on the Tranco list, discarding AI companies' own sites and sorting the remaining 2,429 websites into 23 industries based on Similarweb's categories. Only websites receiving at least 5,000 AI chatbot visits in September 2026 were included in the study.

Key findings include Universities having the strongest dependence on ChatGPT, with the chatbot accounting for 83.5% of AI referrals to the average university or college website, and it being the top chatbot at all 109 of them. ChatGPT's share at other industries ranged from 39.6% to 97.5%, with the second most prominent chatbot being Gemini, which held an average of 8.6% of AI referrals across all industries.

Claude emerged as the "software chatbot," sending 4.5% of AI referrals at software and developer tool sites, with 21 of the 28 sites where it ranked first being in software, tech, or business services. Perplexity was most prominent in the news and Russian-language web, with 52 sites featuring it as the top chatbot, including 13 news sites.

Claude and Perplexity, however, showed more uneven distribution across industries, with Claude having strong influence in business service and marketing (3.7%) and finance (2.8%), while Perplexity showed strong presence in business services and marketing (4.3%) and science and research (4.3%).

The most Claude-dependent sites were all software and developer tool websites, with 97.4% of its AI chatbot referrals coming from Claude. Meanwhile, news and media sites had the lowest ChatGPT share (39.6%) and the highest Gemini share (13.2%), showcasing the varying dependence on AI chatbots across different sectors.